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My copycat A65 head porting. #720379
12/29/17 2:15 pm
12/29/17 2:15 pm
Joined: Apr 2007
Posts: 835
Brisbane, Australia
BrizzoBrit Offline OP

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BrizzoBrit  Offline OP

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Joined: Apr 2007
Posts: 835
Brisbane, Australia
Hi Folks,

Thought I'd dump this in here as much of the A65 head porting material is in other forums on here. Mods if you think should be in the 'projects' forum please move.

Firstly, my thanks to Mark Parker, Allan Gill and Gavin Eisler for sharing their efforts on modification of A65 ports. Also, my apologies for blatantly ripping off their hard work. Additional thanks to others who have contributed and fleshed out the relevant threads on A65 porting over recent times. This has all inspired me to 'ave a go myself.

Having mostly refined my A65F to the point that it works well and fits my requirements I thought the next thing might be to have a crack at improving the 'rideability' by following the advances made by the posters mentioned above. I had a spare head that had been put on the shelf because the valves had been recessed by an unknowledgeable (car) head shop. This was part of the steep learning curve for me 10 years ago when getting this bike up and running.

Based on feedback here and from my (knowledgeable and motorcycle-focused head guy) I bought some Manley Magic Seal Epoxy (putty) and had the head cleaned by wet blasting.

Reawoke my 1st year chemistry skills in burette use to check the port volume. I mixed some putty (equal portions and it is quite like modelling clay), then using dimensions close to that quoted by Allan and Gavin, filled the port floor. Target port area at the start of the inlet port in the head was to be equivalent to a 28mm port and then with area tapering down . Target port height would be about 21mm just in front of the valve guide. When the goo set, I flattened the floor using a long shaft rotary file. Port sides were straightened a bit, mostly on the side nearest the centre of the head. Everything was matched up to the 3/4 phenolic spacers I run between carb and head and the port floor was tapered to no fill through the spacer.

I tried to be reasonably conservative with changes, but then the scary bits started - point of no return- where I started wholesale carving out aluminium. Didnt go any higher in front of valve guide, but cut up beside the guide holes (guides removed) maybe about 5mm, more on the centremost side. More cutting on the sides of the port (7-8mm wider, with greatest removal on centremost aspect). Just in front of the guide the port was about 21mm high 30mm wide and at the guide about 34-35mm wide. A deep-ish bowl was then formed behind the guide to try and get a 'straight' shot at the valve and the rear wall was quite steep relative to how it started.

My external hard drive is playing up so will post some more photos when I sort that out. (edit: done now)

Photos show the start of the process (with duct tape all over seat area) and close to final shapes for bowl and throat

Port volumes before starting were around 56.7ml and after finishing LH was 58.1 and RH 58.0. The goal was not to increase port volume (significantly). Increasing intake charge velocity was the overall key goal.

Did some of the calculations for areas and stuff based on published info for port to valve size and port taper etc. None of this really hits the 'magic' numbers, but the trend is definitely better than it was before starting.


I also decided to do a small fill on the floor of the exhaust ports. I was particularly sold on this after looking at photos of a Fullauto Commando head which gave me an idea of the scale of what might be aimed for. The primary goal here was to build in an 'anti-reversion dam'. For this I used Aremco Pyro Putty 1000 ceramic paste (good for 1400 degrees F). This was like sticky mud and difficult to use. Instructions said to mix powder and liquid together store overnight and use, but I used straight away as it was drying out. Apparently it does 'gas out' and certainly what I put in as a flat fill looked like a puffed up pillow the next morning. Not too much was done to the exhaust port other than fill the floor and put a larger radius curve from the valve to the port floor. Photos (last 2) show the floor fill and the minimal amount of anything else

Head then went off for valves, guides and seats.

Attached Files IMG_1704 resize.jpgIMG_1716 resize.jpgIMG_1717 resize.jpgIMG_1721 resize.jpgIMG_1723n resize.jpgIMG_2077 resize.jpgIMG_2078 resize.jpg
Last edited by BrizzoBrit; 12/29/17 10:31 pm. Reason: correct grammar & add photos

BSA 1969 A65F
BSA 1966 A65H
Triumph 1968 T120
Kawasaki A1R
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Re: My copycat A65 head porting. [Re: BrizzoBrit] #720399
12/29/17 7:08 pm
12/29/17 7:08 pm
Joined: May 2013
Posts: 5,151
Rotherham - S. Yorkshire
Allan Gill Offline

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Allan Gill  Offline

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Posts: 5,151
Rotherham - S. Yorkshire
Nice work. No worries about moving it, it’s bsa based wink

Don’t be worried about leaving steps in the port, it will increase flow. I recently made a phenolic spacer for a guy who had a D10 bottom end and a D7 barrel (unknowingly) and went to mount a 26mm carb to its 22mm throat. I supplied him with a couple of jets as it wasn’t pulling very well and told him to try them first. The phenolic spacer is stepped in about 3 or 4 places so it reduces from carb to head. I believe the bike runs quite well now. I then altered my 30mm spacers on my A65 to take from 32mm down to 30 in a step and not angled. There’s a further step down to the 28.5mm port orriface (the actual spacer wasn’t quite 30mm to start with either) this also works quite well with the bike.

Hope you don’t mind me saying but I don’t know if the widening of the port will have any good effect, it will reduce the level of vacuum applied to the carb... however the port shape may help. The first ones I modified were wider, later on I never altered the width of the port and seemed to get better results.

Do you have any photos of the bowl area you mention? A deeper bowl should turn the direction of flow towards the centre of the valve, if the bowl is shallow it will direct most of the flow towards the opposing (exhaust) valve and most of your mixture won’t get burned.

On the exhaust, I had made my own Siamese, based on the factory style but apart from it being shorter (and like the factory style the two pipes are twinned for a longer length than the repop ones) but I also welded up the power of the pipe where it goes into the head. This seems to work quite well also.

HTH


beerchug
Re: My copycat A65 head porting. [Re: BrizzoBrit] #720433
12/29/17 11:19 pm
12/29/17 11:19 pm
Joined: Apr 2007
Posts: 835
Brisbane, Australia
BrizzoBrit Offline OP

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BrizzoBrit  Offline OP

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Joined: Apr 2007
Posts: 835
Brisbane, Australia
Thanks Allan,

I've posted additional images which should help. On looking back through the images I took during this, I realised I should have collected more - oh well.

All insights are useful. I tried to maintain a fairly steady reduction in port area to achieve a reasonably constant taper on the port. As height was reduced, my area calcs suggested I needed to widen a little bit and the port does seem to 'constrict' at the sides in the guide area. Also took note of Gavin's dimensions in that area. I haven't achieved the 80% reduction that John Robinson suggests is optimal. You may well be closer to that mark. I think the 'effective' area / volume expands again in the 'bowl' , so one would hope that there is enough kinetic energy developed in the inlet tract upstream of the guide to 'push' the charge in the 'bowl' into the cylinder.

I will continue to run 930's on this bike. It's currently fitted with clubman pipes and a Brituro 'short goldie' muffler which is essentially straight through, but I've shoved some additional perforated pipe up its guts to quieten it a bit.

Head was sent off to head guy with SRM springs and he fitted new inlet valves and guides (KPMI) and reused the already fitted exhausts (KPMI). Spring height was to be 1.325 as per SRM specs.

Head came back with a nice valve seat job. He also cleaned up some of the area around the recessed valves. I checked spring installed heights and they all ended up pretty close to the 1.325 (~1.32-1.33) that was probably a bit tough as collects were all sitting at different heights in the spring cap. I might redo this with lighter spring caps and new collets. Anyone use the R&D titanium ones? Or are steel spring caps the go for long term road use?

Head was fitted to the bike over the holiday break. SRM springs are good. There was an additional 4-5mm of travel left at full lift (Megacycle X2 cam).

Carbs were left as they were but were probably due for new needle jets. Ignition timing set at my usual 28 BTDC.

Other than a quick ride around the block a couple of times, yesterday was the first real ride with the new setup. I took it into the hills behind our place in Brissy. I planned on doing some plug chops, but my favourite bit of road I use to use for this now seems to be located in a recently developed semi-urban area. Bugger! Did the best I could but it was clear it was running rich, but not terminally so.

As for overall performance. Well I must say this was the easiest ride through the hills ever. Much less need to change gears. Notable improvements in the unoptimised state without sorting carb settings were better idle noticed instantly, will pull away from the lights nicely now whereas before it always needed a good handful of throttle previously (CR 1st/2nd & 21/47 final dive).

Snatch-free pulling from 2500 rpm in 3rd, sluggish but will do it in 4th. Ran very smoothly and the motor just seemed to have an extended 'useage range' from low to high revs. Didnt create a rocketship but rideability is so much better. I havent really tested it on any fast road yet.

Engine seems very sensitive to small setup changes at low throttle openings and a slight imbalance between carb synchronisation was really obvious. Will need to fiddle with slide and jetting as I can get it partially 8-stroke if too much throttle given and its puffing black smoke when I crack the throttle from idle. This reassures me that I'm finding what Allan and Gavin found with jetting and that I havent gone backwards by doing this. I''m sure the port profile could be improved but I tried to do something fairly conservative that would improve, but without the tools to max this out like Mark has.

After my ride I advanced ignition (from 28BTDC) to 34 BTDC where the bike usually pings and vibrates and is a bit of a pig. I always feel that 28 loses some get up and go, but makes the bike more rideable. At 34 BTDC I could not elicit any pinging with a hot engine despite trying and the bike ran smoothly and felt quicker around the block. I'll give it another run out the road to see if thats the case. Then start fiddling with jetting.

Overall, a success I'd say. Hopefully this will get better with some carb sorting. smile

Cheers
Ray



BSA 1969 A65F
BSA 1966 A65H
Triumph 1968 T120
Kawasaki A1R
& too many projects!
Re: My copycat A65 head porting. [Re: BrizzoBrit] #720473
12/30/17 11:13 am
12/30/17 11:13 am
Joined: Aug 2001
Posts: 4,256
argyll. scotland, uk
gavin eisler Offline
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gavin eisler  Offline
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Posts: 4,256
argyll. scotland, uk
Great works and result, V similar to my initial findings. I think you will be very pleased with this set up.

My bike is 732 , big valves, spit cam, 9:1 , 2 into 2 pipes with balance pipe . STD 71 air filters, carbs rubber mounted.
30 mm Concs. Before porting, 200 MJs, 3.5 slides, needle in leanest setting. 106 NJ
After porting, 170 MJs, no.3 slides, weaker needle ( commando type) in middle setting, 105 NJ.
The first thing I noticed was the slide cutaway was too weak and the motor would spit badly at low throttle openings, no3s fixed that straight away, the next change was the NJs and needles, using choke to test if going too lean or not. did MJs last ( I know this is the wrong order, but since getting the MJs correct everything else seems fine) Only change after settling on the MJs was to lift the needles one notch.. The old step in power as it came on the cam was smoothed out and more pull from lower revs was pleasing ( this may be partly to fitting the OIF air boxes, previously ran with short bell mouths, I noticed a slight improvement at lower revs before doing the port work)). A little richer at the bottom and quite a bit leaner from there on. 4- 5 K is still the sweet spot for cruising, but pulls past 5 more willingly than before.
Running similar ignition timing, stock mark on rotor erring to the retarded side, I tried a few degrees either way , this seems to work best, advancing made it rougher, retarding made it gutless. Biggest improvement is fuel economy, best so far 67 mpg, mid 50s is the worst I have seen, usually around the 60 mpg mark, with the 4 gallon tank a very useful range.
i suspect the nozzle effect of restricting the port then expanding past the valve guide improves the fuel atomization hence the better mpgs and need for a less rich mix at larger throttle openings.


71 Devimead A65 750
56 Norbsa 68 Longstroke A65
Cagiva Raptor 650
MZ TS 250
The poster formerly known as Pod
Re: My copycat A65 head porting. [Re: BrizzoBrit] #720528
12/30/17 10:04 pm
12/30/17 10:04 pm
Joined: May 2013
Posts: 5,151
Rotherham - S. Yorkshire
Allan Gill Offline

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Allan Gill  Offline

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Joined: May 2013
Posts: 5,151
Rotherham - S. Yorkshire
My results have remained similar to what Gavin said, one richer on the jet and the 105 needle seemed to be the only option with any of my mods. The really small port I did with 38mm valves norton needles on the lowest slot were needed to stop the bike fouling plugs, even then it was too rich but revs went up to 8500, the same head unmodified it would top out at 8000 (in second) cam was the SRM race with 1.125 radii tappets.

Start at top end for jetting change first, as long as it runs I wouldn’t alter the lower end until you have the main jet sorted. The first head I did I needed to drop 5 jet sizes, before then it maxed out around 50mph - just too rich... after that it would pull 107mph in third... it really flew! It also had a leak at the plug threads on the left cylinder. Although it didn’t seem to effect it when tanking on.

See how far you can advance the motor, mine is over advanced but doesn’t ping, I need to refit the strobe timing pin to see exactly where it is. I believe it’s over 37 degrees.. a check on the dyno will tell me where’s I can adjust it to the best power. But advanced seemed to suit the smaller ports.

I believe the x2 is the same as stock but retarded 6 degrees


beerchug
Re: My copycat A65 head porting. [Re: BrizzoBrit] #720598
12/31/17 2:47 pm
12/31/17 2:47 pm
Joined: Oct 2009
Posts: 504
new jersey usa
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pushrod tom Offline
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This is an interesting thread. I always read about the experiments by posters. Good stuff! Allan, the X-2 is not the same as a 473. It is Mega's 'street performance' cam with numbers similar to the SRM and Johnson but a very different animal. I found that for best results it needs to be advanced a few degrees kind of like the 473 in it's stock position. My needs are different than most peoples but, I think the cam setting would be similar in a street or race application. My X-2 has seen service in several builds and is currently in the turbo motor. Mainly because I did not want to buy a new 'turbo' cam. Works well!
Cheers, PRT

Re: My copycat A65 head porting. [Re: BrizzoBrit] #720695
01/01/18 3:26 am
01/01/18 3:26 am
Joined: Apr 2007
Posts: 835
Brisbane, Australia
BrizzoBrit Offline OP

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BrizzoBrit  Offline OP

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Joined: Apr 2007
Posts: 835
Brisbane, Australia
Thanks folks. This has been a great experience. You know it goes so well I can hardly be bothered messing with it, but I'll be pulling the tank off today and having a fiddle. Just need a bit more free time. Gavin and Allan, I followed your post-porting jetting changes in your posts closely. Seems I'm maybe closer to std settings. I'm wagging work for a few days (working at home really) so will have a little time each morning for a quick run.

What impresses me is that when I go for a run through the hills behind home I 2.5k to about 5k with without feeling the need to change gears at all and change at 6k. This is bl**** awesome. Always felt I had to pump the gear lever previously. So enjoyable. Havent given a run on flat straight road yet, but pulls well up to 6k and still has urge.

Current settings are 2.5 slides, 106 NJ, needles usually bottom or middle notch and IIRC 190 mains, idle screw usually 1 1/4 to 1/12 turns out. New plugs with 10 miles on were black and wettish when running 3-4 uphill on 1/4-1/2 throttle (all on curvy road so no fixed throttle setting). I need to find a new suitable bit of straight road for testing.


Allan, I will test more advance. The lack of pinging could be because it is so rich. I always had to err on the rich side to help alleviate pinging previously.

PRT, thanks for the tip. I checked cam timing and got lobe centres at 106 BTDC for exh and 96 ATDC for inlet. As you'll know m/cycle quote 106 and 106. Not sure if I measured this correctly. This was based on .040 of travel. I dont have a 3 key cam pinion, but considering getting one cut. That would give a good degree of adjustability, but if my readings are correct seems like inlet is a bit advanced already, I'm OK with being shown I'm wrong on the cam timing. Both cylinders were the same.

You know, I was intimidated by doing this before I started, but it wasnt that hard once i committed to it. Could probably be done better, but for a DIY it's great.

Cheers
Ray


Last edited by BrizzoBrit; 01/01/18 4:28 am. Reason: correct a detail

BSA 1969 A65F
BSA 1966 A65H
Triumph 1968 T120
Kawasaki A1R
& too many projects!
Re: My copycat A65 head porting. [Re: BrizzoBrit] #720752
01/01/18 4:46 pm
01/01/18 4:46 pm
Joined: Oct 2009
Posts: 504
new jersey usa
P
pushrod tom Offline
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Brizz, This got me checking my numbers. I also use .040 and have I 36-62 = 103 and E 66 - 32 = 107 so it seems, other than measuring differences, you are in a good place! I think Mega lists all their stuff straight up and leaves the builder/tuner to figure out what is best for the application. Fair enough I suppose. Sounds like once you get your carbs and timing set up you will be in good shape. I think I would go to the stock ignition timing and work out the carbs and then play with the timing if need be. Outdoor work is a bit slow for us now. It was 0 degree F here last nt.! Have fun. Cheers, PRT

PS 21/47 is pretty tall gearing especially with c/r gears. Good for travelling. Not so good for backroad curves etc. That is just an opinion.

Re: My copycat A65 head porting. [Re: pushrod tom] #720763
01/01/18 5:36 pm
01/01/18 5:36 pm
Joined: May 2013
Posts: 5,151
Rotherham - S. Yorkshire
Allan Gill Offline

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Allan Gill  Offline

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Joined: May 2013
Posts: 5,151
Rotherham - S. Yorkshire
plus one on starting with the ignition timing from stock, and jet from there. You can then advance or retard a couple of degrees to see performance changes without having a huge effect on jetting (once its been set)

I used to run 36:70 primary and 19:42 Final drive, and a close box.... It was excellent for touring and it still pulled well through the twisties, Like Brizzo I found I didn't have to do much with gear changes either, it would pull cleanly from a low rpm to higher revs (unless you were in completely the wrong gear, but you could get away with 3rd in a 2nd gear corner... same with the standard box) Thats really tall gearing too! (stock primary is 28:58) and would be more like 22/47 to put it in prospective. I now run 36:70, 18:42 with a standard box, not as much fun as the CR but its kinder to clutch cables when doing ride outs with bigger groups.

Exhaust makes such a big difference though, if you didn't have enough back pressure then you would still be up and down the box. I sleeved my tailpipe (when I ran a clubmans exhaust) and it made the bike more tractable.


beerchug
Re: My copycat A65 head porting. [Re: BrizzoBrit] #720829
01/02/18 2:14 am
01/02/18 2:14 am
Joined: Apr 2007
Posts: 835
Brisbane, Australia
BrizzoBrit Offline OP

Life member
BrizzoBrit  Offline OP

Life member

Joined: Apr 2007
Posts: 835
Brisbane, Australia
Thanks guys,

Tom- In the high 30's oC here (high 90's oF IIRC), so stinking hot! Much hotter than this and its too hot for riding.

I'm happy with cam where it is for now. Was my first attempt at checking cam timing so I could have made a calculational error. Could have checked at .060 I suppose.

Allan - these mufflers (use that term very loosely, they are loud) do have a large diameter tail pipe.

Yes gearing is high and great for touring. From the lights it was crap, but now great with this mod. The hills behind us are fairly slow (for me at least) so 2nd and 3rd gear which works pretty well.. Even better now.

Did a run with new NJs and needle and dropped needle with clip in top groove. Also changed slides to #3 from #2.5. Surging on the slides 0-1/8 or 0-1/4 throttle. this was overcome with richening the idle mixture (to 3/4 turn out). OK 1/4 throttle on. Did a plug chop after a constant throttle run at 60-70mph (bit over 1/4 throttle). Mixture ring was about 2/3 way down the insulator. I'm happy with that (i'm always conservative with jetting). Did a flat out accelerating run in top gear wide open. Mixture ring was about 1/3 the way down the insulator. So still potentially slightly rich. I'll buy some 180 through to 160 (currently 190) and check that. I'll put the 2.5 slides back in I think. Might be right with the needle/NJ changes?

Getting pretty close.


BSA 1969 A65F
BSA 1966 A65H
Triumph 1968 T120
Kawasaki A1R
& too many projects!
Re: My copycat A65 head porting. [Re: BrizzoBrit] #720879
01/02/18 5:36 pm
01/02/18 5:36 pm
Joined: May 2013
Posts: 5,151
Rotherham - S. Yorkshire
Allan Gill Offline

BritBike Forum member
Allan Gill  Offline

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Joined: May 2013
Posts: 5,151
Rotherham - S. Yorkshire
As I say you need to start at the main jet, ( as per the AMAL tuning guide) the rest of the numbers will come right from there. If you have chokes fitted, that will help a lot if your finding a lean mixture at one point in the jetting range, until you get to full throttle then open the choke fully and give it a good blast on a straight road, flat out, if you can close the choke somewhat and the speed doesnt drop or it doesn't start 8 stroking then its pretty lean.

I normally use the choke to aid for the rest of the settings too. marking off the choke and the throttle at 1/4 stages. if you can apply the choke and it improves/ pulls more cleanly/ increases in speed then its too lean. Worth also noting that you can end up raising the needle to overcome a lean slide issue.. thinking youve cured the problem then find your plugs fouling up.

Regarding the tail pipe, if you reduce the outlet pipe so it has the same ID as the inlet pipe, or no less than an ID of about 35mm then you won't loose any performance but gain back pressure, at 35mm it will also quieten the motordown somewhat. most aftermarket pipes use the same pipe (which is same as the sleeve pipe, for the tail outlet pipe too). It is already too big. A spare piece of down pipe section in the end is enough to restore back pressure, without restricting the expansion part of the silencer.


beerchug
Re: My copycat A65 head porting. [Re: BrizzoBrit] #720938
01/03/18 12:16 pm
01/03/18 12:16 pm
Joined: Aug 2001
Posts: 4,256
argyll. scotland, uk
gavin eisler Offline
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gavin eisler  Offline
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Joined: Aug 2001
Posts: 4,256
argyll. scotland, uk
Re valve springs, and collars. I used the alloy top collars and keepers supplied by SRM. The keepers were fiddly to fit, no issues after assembly.


71 Devimead A65 750
56 Norbsa 68 Longstroke A65
Cagiva Raptor 650
MZ TS 250
The poster formerly known as Pod
Re: My copycat A65 head porting. [Re: BrizzoBrit] #721118
01/05/18 2:01 am
01/05/18 2:01 am
Joined: Apr 2007
Posts: 835
Brisbane, Australia
BrizzoBrit Offline OP

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BrizzoBrit  Offline OP

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Posts: 835
Brisbane, Australia
Thanks guys. Nice to know Gavin.

Been faffing around with oil pressure and OPRVs (see Dave Madigan's OPRV thread). Will get back to this soon. Finding hard to find a compromise with slide and idle settings. Havent really spent any committed time to this, but it's really just fine tuning from here as it's pretty close.

Think my Mk1 bodies are at the end of life, so might spring for some new premiers and go from there.

Cheers
Ray


BSA 1969 A65F
BSA 1966 A65H
Triumph 1968 T120
Kawasaki A1R
& too many projects!
Re: My copycat A65 head porting. [Re: BrizzoBrit] #754457
10/29/18 12:41 pm
10/29/18 12:41 pm
Joined: Apr 2007
Posts: 835
Brisbane, Australia
BrizzoBrit Offline OP

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BrizzoBrit  Offline OP

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Joined: Apr 2007
Posts: 835
Brisbane, Australia
OK, reinvigorating this thread with some updates. Just getting my bike ready for the run to the International rally and compression was a bit uneven so lifted the top end for a hone and re-ring. This gave me time to check the head.

The porting putty used in the inlet port (Manley MagicSeal epoxy) was all still in place but now turned very dark brown. The Pyro Putty I used in the exhaust port was all completely gone. This was probably consistent with gradual loss of performance I'd been feeling.

I'd thought I'd just give the valves the lightest lap and be good to go as I'd only done 6000 miles, but the inlet valves and seats had a lot of carbon build up and the exhaust valves and seats were very pitted (see photo). Never had this before. One side of the inlet valve head was quite clean, the other had some carbon build up so flow must be still 'across' the valve head somewhat.

So, I rebuilt the exhaust port floor fill with the Manley epoxy. It's not rated thermally as high as the Pyro Putty, so we'll see how it goes. I whizzed the head of to my head guy for new Black Diamond valves and seats cut. I put quite a bit of fill in the exhaust port in order to try and build an 'anti-reversion dam'. I felt that as I hadnt cut any metal out this was all readily reversed if I went too far.

I've got the bike back together and it's back to being fantastic again. My feeling is that the exhaust side floor filling really compliments that on the inlet side. Pulls OK from 2.5k, but comes on at 3k and goes especially grunty and hard in the 3-4k range then starts to rev out well to 6k, which I dont ever go much over.

I have a few observations if anyone else is interested in going this route.

The exhaust gases seem to be hotter. Much more colour in the exhaust pipes since making the port mods. The engine seems to emit more heat (might be my imagination) and there was scorched/burnt oil under the exhaust spring bottom cups.

I struggled a little with carb settings and eventually replaced my worn out 930s with new premier carbs, which in itself generated a whole new set of challenges. But I persisted and it runs well. Maybe a little rich still but runs clean. Gettin the off-idle through 1/4 throttle range working properly was tedious. A quick plug check yesterday at 1/4 throttle suggested it was rich, but I'll fit new NJ and needles before going further into that. I'm now running 930 preniers with #17 pilot, idle screw 1 1/2 turns out #2.5 slide, .105 NJ, needle in middle clip currently I think and a .190 main, but have really had a chance to fiddle with the main properly. There is nowhere close to home that I can hold WOT for very long, but it runs clean at that. It seemed to take a while for the premiers to 'bed in' and settle down and stabilise close to the old carbs. The other thing I found was getting the fuel height set to be problematic, couldnt get it high enough for the specified 0.17-0.25" down from the flange. It seems like the stay-up floats are way too buoyant and if you try to get fuel height up, the floats touch the body and dont close needle & seat. My solution is, as these are a closed cell foam to trim some of the bottom to reduce buoyancy.

I found the idle to be problematic. Had to set idle speed failrly high (1000-1100rpm) for a 'stable idle and then it was very 'lopey'. Sounds cool, but was not good for a stable idle. If idle was set lower the speed would surge badly up and down and go close to stalling. Bike is running a Megacycle X2 cam. I have a new neighbour who is not a motorcycle lover and got in my and my wife's face about my motorcycle noise. It is loud (105-106dB at the conditions specified for a 100dB limit), So I shoved some loosely rolled up chicken wire up the muffler. This actually improved the bottom end and did not restrict the top end. Idles very smoothly now, so this helped limit reversion a little bit also.

Lastly, I find the bike is now very sensitive to imbalances between the carbs and extra-special attention must be paid to keeping the carbs balance. Once this is sorted as it is now the bike is an absolute dream Looking forward to the run to the International rally.


Cheers
Ray



Attached Files IMG_2921.JPGIMG_2959.JPGIMG_2963.JPGIMG_2997.JPGIMG_2999.JPG
Last edited by BrizzoBrit; 10/29/18 12:49 pm. Reason: correction

BSA 1969 A65F
BSA 1966 A65H
Triumph 1968 T120
Kawasaki A1R
& too many projects!
Re: My copycat A65 head porting. [Re: BrizzoBrit] #754474
10/29/18 3:27 pm
10/29/18 3:27 pm
Joined: Aug 2001
Posts: 433
Iowa
konon Offline

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konon  Offline

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Iowa
That exhaust valve looks like it's been extremely hot, for only 6000 miles.


1968 BSA Firebird
1200 HD
XS 1100
1972 Rickman 125
Re: My copycat A65 head porting. [Re: BrizzoBrit] #754495
10/29/18 6:54 pm
10/29/18 6:54 pm
Joined: Aug 2001
Posts: 4,256
argyll. scotland, uk
gavin eisler Offline
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gavin eisler  Offline
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argyll. scotland, uk
My exhaust valves are usually that biscuity way on strip down, however the pitted seats are a bit worrying, i had about 10% little black dots on the ex valve seat last strip for re ring at 3 K miles. i wonder if its the valve material.
The carbon on the back of the inlet valve is suspicious , maybe the inlet guides are passing a bit.
Any hoo , glad you are enjoying it, good to hear the manley filler is holding in there.
I use the original plastic floats in the carbs, no issues, I think cutting material off the float will mean more fuel is required in the bowl to support it, making for a richer mixture, from what i recall AMAL had a bad batch of plastic floats some time ago, but originals seem to be OK, mine are anyway. No experience with the stay up type.


71 Devimead A65 750
56 Norbsa 68 Longstroke A65
Cagiva Raptor 650
MZ TS 250
The poster formerly known as Pod
Re: My copycat A65 head porting. [Re: BrizzoBrit] #754497
10/29/18 7:35 pm
10/29/18 7:35 pm
Joined: Apr 2005
Posts: 1,721
Mississauga, Ontario.
A
Adam M. Offline
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Adam M.  Offline
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A

Joined: Apr 2005
Posts: 1,721
Mississauga, Ontario.
+1 to the Gavin opinion about inlet guide passing some oil.
What valves did you use?

Last edited by Adam M.; 10/29/18 7:36 pm.
Re: My copycat A65 head porting. [Re: BrizzoBrit] #754503
10/29/18 9:52 pm
10/29/18 9:52 pm
Joined: Apr 2007
Posts: 835
Brisbane, Australia
BrizzoBrit Offline OP

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BrizzoBrit  Offline OP

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Brisbane, Australia
Thanks guys,

Agree about the possibility of the inlet guides passing some oil. There were new KPMI guides fitted and have been with Black Diamond valves. Clearances seemed fine when pulled apart, with no real 'play' in the inlet stems in the guides. Exhausts were a bit looser, but are set up with additional clearance (have to look in the book to check that). I had noted your efforts Gavin with inlet stem seals and had considered that prior to this. Might have to think a bit more about that.

It had definitely definitely been burning some oil from somewhere as there was a fair bit of carbon on the pistons, it had been using some oil and was just starting to get a hint of blow-by if used for continued fast running and accumulating a little emulsified oil on the oil tank cap. Not sure if was running hotter because of the oil burning.

I was / am very concerned by the state of the exhaust valve.

I'm confident its not running lean based on all the plug checks I have done. Of the 6k miles done about 4k were on long trips with sustained >65mph running. I'll be checking the exhaust valves regularly through the spark plug hole as I progress on the trip to and from the rally (1200 miles each way).

Gavin, I run the fuel height in the AMAL specified height range, checked using a tube from a drilled float bowl plug and measured at the idle speed screw as a central point across the float bowl. I think this is better than manually adjusting based solely on how far the float is below the top edge of the bowl. An issue might be that the carbs sit at an angle from the vertical. There are impressions on top of the float from where it rubs the carb body (not just the tickler shaft). I found setting the fuel height was critical to sorting out the settings around the small throttle openings. I think that it might play toward the need for more fuel doing the transition from idle to needle as indicated by the universal requirement for a 'richer' slide that you, Alan and myself all seemed to have seen. Because of the angle of the carb this might get fuel closer to the pilot jet and misxing chamber. There seems to be some consensus that the .017 pilot jets might be a little small for many applications. Of course I could be overthinking all of this.

Cheers
Ray

Attached Files IMG_2537.JPG

BSA 1969 A65F
BSA 1966 A65H
Triumph 1968 T120
Kawasaki A1R
& too many projects!
Re: My copycat A65 head porting. [Re: BrizzoBrit] #754510
10/29/18 10:36 pm
10/29/18 10:36 pm
Joined: Jan 2014
Posts: 4,192
Aus
N
NickL Offline
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NickL  Offline
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N

Joined: Jan 2014
Posts: 4,192
Aus
It took me a while to sort out the exhaust valve heat problem when racing.
It's a fact, when you produce more power, you produce more heat.
Looks like your inlet guides need replacing or seals fitting.

I thought you were using an SRM cam?

Last edited by NickL; 10/29/18 10:41 pm.

No-one expects the Spanish Inquisition................
Bring in the 'Comfy Chair'
Re: My copycat A65 head porting. [Re: BrizzoBrit] #754520
10/30/18 12:47 am
10/30/18 12:47 am
Joined: Apr 2007
Posts: 835
Brisbane, Australia
BrizzoBrit Offline OP

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BrizzoBrit  Offline OP

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Brisbane, Australia
Hi Nick,

I'm sure I'm not using the kind of power you would have been making when racing. But temps definitely seem up. Overall oil temp doesnt seem to be too much higher than previous, however.

I've wondered about over-oiling the top-end, but top-end oil feed is after the spin on filter. Oil in there when the rocker cover is taken off, but not excessive, but that doesnt mean too much is not flowing in while the bike is running. The metering split-pin is in place. I'll be keeping a close eye on oil consumption this trip.

I was running an SRM cam at once stage, but embarrassed to say that got buggered too. Lobe tips and closing ramp were worn. This was even despite having what seemed like adequate additional movement from max lift before coil-bind occurred. The SRM valve springs seem to have fixed this and there is oodles, by comparison, of additional travel at max lift (5mm minimum). I put it down to the springs in the absence of anything else that I can find. The X2 cam was a reface from Waggot engineering of my old Megacycle X2 cam. They did a very nice job and had the profile in-house. $340 AUD, bit under the SRM price with minimal postage and a lot cheaper than a megacycle. See notes above about exhaust timing which not entirely as expected, but I could have measured that incorrectly.

Cheers
Ray


BSA 1969 A65F
BSA 1966 A65H
Triumph 1968 T120
Kawasaki A1R
& too many projects!
Re: My copycat A65 head porting. [Re: BrizzoBrit] #754539
10/30/18 4:11 am
10/30/18 4:11 am
Joined: Jan 2014
Posts: 4,192
Aus
N
NickL Offline
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NickL  Offline
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Aus
G'day Ray
You won't be over oiling the top end so discount that. My race bike had much greater flow up to the head than standard
and did not suffer the oiling problem on the inlets. Inlet guide clearance can be quite tight around 1.5 thou with decent valves and guides,
seals are a nicety but not essential. I suspect that the guides are oval or leaking in the head fixture or you have broken through somewhere
and can't see it when you did the porting. (Possibly it's cracked, as the bloody things do when you get them a bit thin!)
Running the ignition retarded with a 'hairy' cam can burn the exhaust valves in some cases as you in effect open them sooner and with a
late ignition timing point temps will be higher.
The anti reversion dam is interesting, i remember Mr Vizard was a big advocate of those but the gloop you are using i feel, may be the
stuff causing the valve and seat pitting if it's atomising? Perhaps the dam should be added in the exhaust header pipe with weld rather than in the port?


No-one expects the Spanish Inquisition................
Bring in the 'Comfy Chair'
Re: My copycat A65 head porting. [Re: NickL] #754559
10/30/18 10:11 am
10/30/18 10:11 am
Joined: May 2013
Posts: 5,151
Rotherham - S. Yorkshire
Allan Gill Offline

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Allan Gill  Offline

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Posts: 5,151
Rotherham - S. Yorkshire
Originally Posted by NickL
Perhaps the dam should be added in the exhaust header pipe with weld rather than in the port?



That was exactly what I did on mine, and much happier that I did. unless you have really cut back the port with a sanding disc it isn't easy for the epoxy to stick, even if it looks clean, I've had JB weld lift in one lump out of an inlet port because I wasn't as OCD about these things as I normally am, and that was before I added fuel and just performed an adhesion test.

The exhaust port filling will much about with jetting, any port filling does (I prey for EFI on these things as sometimes trying to jet can be hard with a good flowing port)...

Also, if you do get that SRM cam back, have the followers radius'd to 1.125" (Z profile) instead of the wider 1.25" there might be something lost at the top end but it isn't much compared to the gain at the bottom end I think.

Looking forward to seeing you at the Rally!


beerchug
Re: My copycat A65 head porting. [Re: BrizzoBrit] #754562
10/30/18 11:14 am
10/30/18 11:14 am
Joined: Apr 2007
Posts: 835
Brisbane, Australia
BrizzoBrit Offline OP

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BrizzoBrit  Offline OP

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Joined: Apr 2007
Posts: 835
Brisbane, Australia
Thanks Guys,

Yes Nick. Good suggestions and food for thought there. Seems to take a bit more ignition advance now so its currently sitting at about 32o BTDC, I usually run 28-30 to keep vibes under control. Biut it defeinitely like more advance when the ports are working.

I looked in my book but no record of the clearance the guides and valves were set to, but that sounds about my recollection. Could definitely be leaking around the guides as that head has had a couple of new sets put in it over the years. I agree with the 'gloop' suggestion and thought that 'leaching' of the epoxy might be leading to the deposits on the inlets. I did look around for reversion cones for the pipes at one stage, but never really got around to sorting that out. Could have been losing carbon out of the combustion chamber too I guess as it was a bit flaky on the pistons. Hope the oil is under control now.

Yea, Allan, agree. The epoxy in the exhaust was really just an experiment to see if it is durable. I kind of suspect not. Anyway, I think it has emphasized that something in the exhaust helps.

I'm very happy with it at the moment. Freshen up the NJ and new needles today and that brought it back to how it should be as well.

Yes Allan, see you in Grampians.

Ray


BSA 1969 A65F
BSA 1966 A65H
Triumph 1968 T120
Kawasaki A1R
& too many projects!
Re: My copycat A65 head porting. [Re: BrizzoBrit] #754572
10/30/18 2:49 pm
10/30/18 2:49 pm
Joined: Aug 2001
Posts: 4,256
argyll. scotland, uk
gavin eisler Offline
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gavin eisler  Offline
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Posts: 4,256
argyll. scotland, uk
I used to have a Sportster tuning book that showed a neat exhaust anti reversion dam, a washer about an 1/8" between ID and OD, was welded to the inside of the header pipe and a small short tube/ sleeve fitted to the ID of the new washer. Never tried it. Seems more permanent than hoping for goop to stick in the ports.


71 Devimead A65 750
56 Norbsa 68 Longstroke A65
Cagiva Raptor 650
MZ TS 250
The poster formerly known as Pod

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