Britbike forum

Classic British SparesKlempf British PartsBaxter CycleBritBike Sponsor SteadfastCyclesThe Bonneville ShopLowbrow CustomsSRM EngineeringGirling Classic MotorcycleLucas Classic MotorcycleHepolite PistonsIndustrial tec supply

Upgrade your membership: Premium Membership Gold Membership


New Sponsor post
Cyber Monday Sale - 10% off at The Bonneville Shop
by The Bonneville Shop - 11/29/21 5:34 pm
New FAQ post
How to find my own threads?
by reverb - 11/20/21 3:55 pm
Manuals on DVD - Buy 4 for 3
All 4 DVD Manual
Member Spotlight
The Bonneville Shop
The Bonneville Shop
Broomfield, Colorado, USA
Posts: 102
Joined: November 2018
ShoutChat
Comment Guidelines: Do post respectful and insightful comments. Don't flame, hate, spam.
Top Posters(30 Days)
NickL 79
Rohan 73
Top Likes Received (30 Days)
Newest Members
old ion limey, muzz750, Motorcycles and Art, SteveDee, Gus_Carrero
11,924 Registered Users
Who's Online Now
3 members (Chris the camper., Morgan aka admin, 76degree-triumph), 21 guests, and 21 robots.
Key: Admin, Global Mod, Mod
Previous Thread
Next Thread
Print Thread
Page 3 of 4 1 2 3 4
Joined: Jan 2012
Posts: 520
Likes: 3
P
Britbike forum member
Offline
Britbike forum member
P
Joined: Jan 2012
Posts: 520
Likes: 3
Looks great Tony! Thanks for coming over and helping on my Triumph and Norton for the last several years! The bike is looking good.

Check out some eBay stuff
Joined: Oct 2012
Posts: 6,033
Likes: 181
knuckle head
OP Offline
knuckle head
Joined: Oct 2012
Posts: 6,033
Likes: 181
A pleasure to work on your old buckets....I can almost hear the BSA on our rides through the countryside, exhaust sound reveberating through the hills, scattering wild life and mothers clutch their children as we thunder past like demons from hell...


79 T140D, 89 Honda 650NT ,61 A10 .On a bike you can out run the demons
"I don't know what the world may need
But a V8 engine is a good start for me
Think I'll drive to find a place, to be surly"
β€œ
Joined: Oct 2009
Posts: 642
Likes: 21
P
Britbike forum member
Offline
Britbike forum member
P
Joined: Oct 2009
Posts: 642
Likes: 21
Tony, Lookin' good! I think that anyone who rides these things can appreciate that image. Sure better than some other descriptions! PRT

Joined: Oct 2012
Posts: 6,033
Likes: 181
knuckle head
OP Offline
knuckle head
Joined: Oct 2012
Posts: 6,033
Likes: 181
and the valve issues continue......The machine shop owner calls and says his man took just a .002 cut using the Newen machine and the exhaust seat is into the aluminum..The cast in insert has a flattened side, stack up of clearances went against it. They do a lot of speciality valve seat replacements, so no big deal for them. ...The only issue will be what's left of the original insert after it's machined for the new seat. It might require more aluminum removal, welding, and more machining..It's just money.....


79 T140D, 89 Honda 650NT ,61 A10 .On a bike you can out run the demons
"I don't know what the world may need
But a V8 engine is a good start for me
Think I'll drive to find a place, to be surly"
β€œ
1 member likes this: GrandPaul
Joined: Oct 2012
Posts: 6,033
Likes: 181
knuckle head
OP Offline
knuckle head
Joined: Oct 2012
Posts: 6,033
Likes: 181
Ok, staring to make some progress. Mocked up the crank for end clearance check, it was .007" , I shimmed it to .003.
The head got new exhaust seats , I did the guides. The shop has a Newen single axis valve machine that holds very tight clearances, .001 on intake guides, .0018 on exhaust. Valve stem and installed spring heights all came out right on target...

79B60976-D29C-4828-AFA3-B27ECF8A6262.jpeg CB4FC743-70DD-4D24-B0A6-300B975527AF.jpeg 91534CF0-BBF8-40DD-9706-FC58EDB83AD3.jpeg

79 T140D, 89 Honda 650NT ,61 A10 .On a bike you can out run the demons
"I don't know what the world may need
But a V8 engine is a good start for me
Think I'll drive to find a place, to be surly"
β€œ
1 member likes this: GrandPaul
Joined: Feb 2008
Posts: 5,789
Likes: 316
Britbike forum member
Offline
Britbike forum member
Joined: Feb 2008
Posts: 5,789
Likes: 316
Nice job, Tony, very impressive.
BTW--if you dont have one already --I recommend getting the extended nut for the bottom magneto fixing.
Using a standard nut in that position is a real PITA!
Regards,
R

Joined: Oct 2012
Posts: 6,033
Likes: 181
knuckle head
OP Offline
knuckle head
Joined: Oct 2012
Posts: 6,033
Likes: 181
Thanks .Yes, I do have that nut rolling around here somewhere.. .


79 T140D, 89 Honda 650NT ,61 A10 .On a bike you can out run the demons
"I don't know what the world may need
But a V8 engine is a good start for me
Think I'll drive to find a place, to be surly"
β€œ
Joined: Oct 2012
Posts: 6,033
Likes: 181
knuckle head
OP Offline
knuckle head
Joined: Oct 2012
Posts: 6,033
Likes: 181
More .......The rotating parts were balanced, the shop said it was the one of the best original Britbike factory balance jobs....R&R. rods, made in UK IDP pisons with thin metric rings.....the bottom end is ready for the cylinders..
.

CFD5FC00-10D8-4BF1-9C5E-3CE496FBAED1.jpeg 96B75125-4A58-4D60-9433-0F486CBD70BD.jpeg

79 T140D, 89 Honda 650NT ,61 A10 .On a bike you can out run the demons
"I don't know what the world may need
But a V8 engine is a good start for me
Think I'll drive to find a place, to be surly"
β€œ
1 member likes this: GrandPaul
Joined: Oct 2012
Posts: 6,033
Likes: 181
knuckle head
OP Offline
knuckle head
Joined: Oct 2012
Posts: 6,033
Likes: 181
Checking the cam timing, It's a 0357......Intake centerline is 96.5 degrees...100 degrees would be nicer, I can fabricate an offset key...I notice the cam has lazy initial lift to be more gentle on the valvetrain...

93DA542A-FFB8-4CCC-89BB-E979E164625B.jpeg

79 T140D, 89 Honda 650NT ,61 A10 .On a bike you can out run the demons
"I don't know what the world may need
But a V8 engine is a good start for me
Think I'll drive to find a place, to be surly"
β€œ
1 member likes this: Stuart Kirk
Joined: Feb 2019
Posts: 715
Likes: 248
S
Britbike forum member
Offline
Britbike forum member
S
Joined: Feb 2019
Posts: 715
Likes: 248
Originally Posted by Hillbilly bike
Checking the cam timing, It's a 0357......Intake centerline is 96.5 degrees...100 degrees would be nicer,..
How far down (in the rev range) do you think that will move the power? I am using the same cam in my A10 and am also planning to advance the cam timing a few degrees to somewhat reduce the peakiness.

Looks good btw, and hopefully motivates me to get back on it with my own project.

Joined: Oct 2012
Posts: 6,033
Likes: 181
knuckle head
OP Offline
knuckle head
Joined: Oct 2012
Posts: 6,033
Likes: 181
I asked the question in the BSA forum. Generally , advancing the intake will lower the power band maybe 500 rpm....Exhaust has a big influence on peakiness...


79 T140D, 89 Honda 650NT ,61 A10 .On a bike you can out run the demons
"I don't know what the world may need
But a V8 engine is a good start for me
Think I'll drive to find a place, to be surly"
β€œ
Joined: Feb 2019
Posts: 715
Likes: 248
S
Britbike forum member
Offline
Britbike forum member
S
Joined: Feb 2019
Posts: 715
Likes: 248
Yeah, I noticed that after I left this thread. That got me looking at the srm 357 cam specs and they were quoting 105 deg LCA. Quick math on the numbers gave 104.5 deg. That's lots different than your actual measured spec. Good thing you're checking it.

I just did a quick calculation. It looks like .006" of offset key = 1 deg on the crank. One tooth on your crankshaft pinion equals 16.36 deg.

So if you were advancing the cam from the published spec, you would need 12.5 deg to get from where you are right now, it looks like you could go a whole tooth and then offset key it back 3 or 4 degrees.

Joined: Jan 2014
Posts: 1,758
Likes: 206
N
Britbike forum member
Offline
Britbike forum member
N
Joined: Jan 2014
Posts: 1,758
Likes: 206
'I notice the cam has lazy initial lift to be more gentle on the valvetrain...'

A well built a10 engine is a very quiet motor, compared to your triumphs you will
not know it's running...............................

Advancing the 'splatfire cam' a few degrees is not hard with a file and some key steel.
A normal mod on the a65 is to retard it around 3-4 degs. But unfortunately, you are stuck
with the in/ex centres so it restricts the advantages gained. The 'get around' as i'm sure
you know, is slightly larger inlet valves and/or work on the inlet tracks.
I remember on my old SR A10 carving spiral type channels in the left hand inlet track
and angling the carb to get more flow that side too. That was a great old 'Hoon' machine.

Joined: Oct 2009
Posts: 642
Likes: 21
P
Britbike forum member
Offline
Britbike forum member
P
Joined: Oct 2009
Posts: 642
Likes: 21
PS to Stuart, The factory setting on their 357 and 473 is not straight up but advanced like the readings that Tony has. Obviously that is a good setting but 'tuners' might squeeze a bit more top end by retarding a bit. Maybe as much as 4 degrees.
PPS I like the siamese. Really picks up the mid range! PRT

Joined: May 2013
Posts: 8,267
Likes: 191
A
Britbike forum member
Offline
Britbike forum member
A
Joined: May 2013
Posts: 8,267
Likes: 191
Originally Posted by Stuart Kirk
Yeah, I noticed that after I left this thread. That got me looking at the srm 357 cam specs and they were quoting 105 deg LCA. Quick math on the numbers gave 104.5 deg. That's lots different than your actual measured spec. Good thing you're checking it.


If thats the figures SRM are giving, it isn't the same cam as the factory specs. using the book values the LCA of the spitfire cam should be around 98.5 crankshaft degrees ATDC. A couple of degrees either way is more than acceptable.

The SRM race cam is around 105 degrees LCA for inlet and exhaust, they did annother version of the cam that has similar timing to the standard spitfire cam but with about 0.400" lift and more duration. This is quite a nice cam to use (least it is in the A65)

I've never heard or seen of IDP pistons in the UK, but... theres a lot of "made in the UK" parts being sold on american Ebay that I have never seen sold in the UK.


Now let’s all have a beer beerchug

68’ A65 Lightning β€œclubman”
71’ A65 823 Thunderbolt (now rebuilt)
67’ D10 sportsman (undergoing restoration)
68’ D14 trials (undergoing transformation)

Joined: Nov 2011
Posts: 558
Likes: 62
K
Britbike forum member
Offline
Britbike forum member
K
Joined: Nov 2011
Posts: 558
Likes: 62
The best way to get adjustment of your lobe centers is to get a crankshaft pinion made with 5 differently spaced keyways. If each crankshaft tooth equals 16.36 degrees, then with five different keyways, each different key position can give you about 3.3 degrees of change. If you want finer adjustment, then making offset keys can be used. However, I really can't imagine that any changes of less than 3.3 degrees can be noticed by "seat-of-the-pants" testing. Dyno tuning can reveal changes in the torque curve, which will generally move the torque curve higher with later timings. Unfortunately, changing the keyway position, and re-testing on the Dyno is very time consuming (expensive) and changes of even 3.3 degrees may not show obvious changes in the torque curve because so many things affect it.

I run my land speed race bikes with my Megacycle cams (108 degree LSA as measured in camshaft degrees) retarded 2 degrees from straight up, (110 degree intake LC, 106 degrees exhaust LC) but I'm only interested in obtaining the highest HP possible, which occurs at redline. I admit, though, that even I have not played around with changes in keyway settings on the dyno.

BSA single cylinder cams are interesting in that they use flat tappet cams which are tapered. The crankshaft pinion has something like 30 teeth which means each tooth is 12 degrees. But by flipping the tapered tappet, you can change the timings by 6 degrees (BSA attempt at allowing easy changes?). I have one B50 with a Sifton HT cam that I retarded the cam by one tooth, then flipped the tappet(s) (I can't remember offhand the exact set-up). I also added dual spark, and some light porting, Boyer ignition as well as a JE piston and Carillo rod. In any case, I gained about 5 hp over stock and moved the torque and hence horsepower curves upward by as much as 1000 rpm. It will out pull about any British bike in group!

But best advice for a road bike may be to build it close to standard and ride it. With new pistons and rings and a nice valve job, changes to ignition timing and carburetor settings will usually be sufficient to make the bike a pleasant rider.

Tom


Life's uncertain - go fast now!
Joined: Oct 2012
Posts: 6,033
Likes: 181
knuckle head
OP Offline
knuckle head
Joined: Oct 2012
Posts: 6,033
Likes: 181
Allan, I meant ADM pistons. They primarily make Japanese pistons but now offer A10 pistons only in a 7.25 compression. They offer parts for other Brit bikes now..


79 T140D, 89 Honda 650NT ,61 A10 .On a bike you can out run the demons
"I don't know what the world may need
But a V8 engine is a good start for me
Think I'll drive to find a place, to be surly"
β€œ
Joined: Oct 2012
Posts: 6,033
Likes: 181
knuckle head
OP Offline
knuckle head
Joined: Oct 2012
Posts: 6,033
Likes: 181
Tom, changes in lobe centers 3 degrees had a slight but noticeable improvement on top speed for our Triumphs...most aftermarket cam recommend 103-105.Mine is 105
intake and 107 ex, Kevin runs a bit later timing.
On the dyno with the 390 Sifton cams , a mild racing grind, cams at 105 degrees, maximum torque was at 5100 rpm and still had 90% percent of that torque at the HP of 7100 rpm...

Last edited by Hillbilly bike; 04/17/21 12:56 pm.

79 T140D, 89 Honda 650NT ,61 A10 .On a bike you can out run the demons
"I don't know what the world may need
But a V8 engine is a good start for me
Think I'll drive to find a place, to be surly"
β€œ
Joined: Nov 2011
Posts: 558
Likes: 62
K
Britbike forum member
Offline
Britbike forum member
K
Joined: Nov 2011
Posts: 558
Likes: 62
Originally Posted by Hillbilly bike
Tom, changes in lobe centers 3 degrees had a slight but noticeable improvement on top speed for our Triumphs...most aftermarket cam recommend 103-105.Mine is 105
intake and 107 ex, Kevin runs a bit later timing.
On the dyno with the 390 Sifton cams , a mild racing grind, cams at 105 degrees, maximum torque was at 5100 rpm and still had 90% percent of that torque at the HP of 7100 rpm...

You have effectively "dynoed" your bike at Loring, which showed that retarding the cam by 3 degrees had the effect you wanted. Also, you have a different bore and stroke ratio than I do, which can a different effect.

You of course are dealing with a twin cam motor, so changes to your intake LC do not affect your exhaust LC. The Megacycle that I'm using on my BSAs, which Stan Millard once said he had designed, has the LSA (lobe separation angle, camshaft degrees) at 108 degrees. If I ever get back to Colorado where my race bikes are, I could try advancing the intake lobe center to 105 degrees, but that would also have the effect of advancing all functions including lobe center of the exhaust cam. So 105 degree LC on the intake cam will result in 111 degree LC on the exhaust. So what would that do? Can't change one without changing the other.

I am not smart enough to design my own cam so I have to leave that to others and just make small changes as may be recommended by others. If anyone wants to become more confused about cam timing, try the Hot Rod Magazine article here: https://www.hotrod.com/articles/cam-lobe-centerline-angle-tech/ If that doesn't make me feel stupid, nothing does!

Tom


Life's uncertain - go fast now!
Joined: Oct 2012
Posts: 6,033
Likes: 181
knuckle head
OP Offline
knuckle head
Joined: Oct 2012
Posts: 6,033
Likes: 181
I had the bike on a dyno two times when I raced at the one mile in Ohio. Then with no changes when it ran at Maine with the same speed in the mile, 125 and 128 in the one and a half mile. Over the winder I made a new fuel tank for better ride position, regeared the bike for for 135 mph at 7000 rpm, shortened the exhaust 4 inches,and changed exhaust cam timing to 107 degrees. The bike was not on the dyno again...
I ran 130 in the mile and 133.1 in the mile and a half...Because of the several changes I have no idea how much improvement in power there was , perhaps 3 or so hp..This engines likes lower rpm compared to the competitors.... Of course the ever changing wind conditions are. factor at Maine....
Tom does your BSA single run in a naked frame class if so, what was the best speed?


79 T140D, 89 Honda 650NT ,61 A10 .On a bike you can out run the demons
"I don't know what the world may need
But a V8 engine is a good start for me
Think I'll drive to find a place, to be surly"
β€œ
Joined: Nov 2011
Posts: 558
Likes: 62
K
Britbike forum member
Offline
Britbike forum member
K
Joined: Nov 2011
Posts: 558
Likes: 62
HB,
Yes, I can take all the bodywork off and run it naked in A class. It has the APG 500 record at 118 mph back in 2011, but 125 mph at Bonneville a few years later with more changes. I had the APG 650 record at 133 or so until Kyle Malinky broke it in 2019.

Tom


Life's uncertain - go fast now!
Joined: Oct 2012
Posts: 6,033
Likes: 181
knuckle head
OP Offline
knuckle head
Joined: Oct 2012
Posts: 6,033
Likes: 181
133 is a good run from a 650,especially a single, altered at BV....My run at Maine is supposedly the first naked frame modified production 650 pushrod over 130 mph in modern LSR history...


79 T140D, 89 Honda 650NT ,61 A10 .On a bike you can out run the demons
"I don't know what the world may need
But a V8 engine is a good start for me
Think I'll drive to find a place, to be surly"
β€œ
Joined: Oct 2012
Posts: 6,033
Likes: 181
knuckle head
OP Offline
knuckle head
Joined: Oct 2012
Posts: 6,033
Likes: 181
Back on topic......I was installing the head today and was on the second torque go around when a bolt got loose. The thread of the bolt was ruined taking some of the cylinder thread with it... They are new Uk made bolts.They are marked 8.8 so it's likely they are reworked and plated metric bolts. Scrap. Ordered 3/8 -24 UNF Heli coils and Grade 8 bolts...I have changed the crankcase ,side covers, mag mount hole to US bolts and studs along with the rocker box almost all the thread original threads are 1/4-20, 5/18-18 and so on....Easy to do...


79 T140D, 89 Honda 650NT ,61 A10 .On a bike you can out run the demons
"I don't know what the world may need
But a V8 engine is a good start for me
Think I'll drive to find a place, to be surly"
β€œ
Joined: Feb 2014
Posts: 941
Likes: 140
Britbike forum member
Offline
Britbike forum member
Joined: Feb 2014
Posts: 941
Likes: 140
Hi All,
HBB,
Is this the piston suppliers ? https://imdpistons.com/

John

Joined: Oct 2012
Posts: 6,033
Likes: 181
knuckle head
OP Offline
knuckle head
Joined: Oct 2012
Posts: 6,033
Likes: 181
Yes, nicely finished....


79 T140D, 89 Honda 650NT ,61 A10 .On a bike you can out run the demons
"I don't know what the world may need
But a V8 engine is a good start for me
Think I'll drive to find a place, to be surly"
β€œ
Page 3 of 4 1 2 3 4

Moderated by  GrandPaul 

Link Copied to Clipboard
Job CycleBritish Cycle SupplyMorries PlaceKlempf British PartsPodtronicVintage MagazineBSA Unit SinglesBritBike SponsorBritish Tools & FastenersBritBike SponsorBritBike Sponsor






Β© 1996-2021 britbike.com
Powered by UBB.threads™ PHP Forum Software 7.7.5