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#541665 - 05/07/14 5:52 am alloy barrels + 5 speeds A65 750 OIF 1971  
Joined: Aug 2001
Posts: 3,399
gavin eisler Online content
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gavin eisler  Online Content
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argyll. scotland, uk
Hi there,
My 1971 Devimead lightning is due some TLC, the bike currently has not run for a few years and needs excavated from the back of a friends shed. It was running when it was put away but will need a new battery and carb cleaning at the very least.
This thread will be about small time resurrection , with a bonus feature of replacing the old worn Devimead 750 barrels with brand spanking new Alloy barrels supplied by John Hill.
The following pics are shots of the barrels in my secret underground layer.
The barrels were cleaned with a citrus based cleaner then blow dried.


Here they are posing in the turbine pit of Unit three, thats the reg ring and machine shaft in the cage
All clean now

Riding on a barra in the machine hall

Last edited by gavin eisler; 03/08/16 9:48 am.

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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#541666 - 05/07/14 6:07 am Re: alloy barrels for 750 OIF 1971 [Re: gavin eisler]  
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gavin eisler Online content
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argyll. scotland, uk
Next part,
The gasket needed the mounting holes enlarged , part 2 in the underground lair.
An amusing cupboard note the BSA mod

Not a BSA cupboard

Barrels pistons rings and gasket posing on the lifting beam beside U4
The name plate details for U4 also made around the same time as the BSA but around 60 thousand times more powerful
On the minus 26 level at the drill press with the Colchester student in the background

Need drills, yes, but even with such choice the ones I needed were4 blunt, typical of shared tooling

De burring the holes , spot the deliberate error.
Gee it a wee bit file

Job done, ready to go
.
Part 3 in a week or so.
Bye for now


71 Devimead A65 750
56 Norbsa 68 Longstroke A65
Cagiva Raptor 650
MZ TS 250
The poster formerly known as Pod
#541685 - 05/07/14 8:09 am Re: alloy barrels for 750 OIF 1971 [Re: gavin eisler]  
Joined: Jan 2006
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GrandPaul Online content
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GrandPaul  Online Content
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Laredo (South) Texas, USA
That's too much. Very nifty.


GrandPaul (does not use emoticons)
Author of the book "Old Bikes"
Too many bikes to list, mostly Triumph & Norton, some BSA & European
"The Iron in your blood should be Vintage"
#542691 - 05/12/14 9:25 am Re: alloy barrels for 750 OIF 1971 [Re: gavin eisler]  
Joined: Aug 2001
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gavin eisler  Online Content
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argyll. scotland, uk
Part 3, checking ring end gaps ,
a quote from an interesting discussion on ring end gaps
"Now the ring gap deal. I don't have access to the kind of support data that I could throw at you six months ago. Its too bad - - but thats just the way it is.

Big second gaps work. We run them in most if not all OE applications no matter what the RPM. We ran them in Greg Andersen's Pro Stocker. We ran them in Moran's turbo stuff. And everything in between.

The original concept work was in math from a computer simulation series run on a Cray in Ann Arbor. This was followed up by OE dyno testing and development aimed at emissions and fuel mileage enhancement. You cannot sell an OE on a change of this magnitude without solid support. After the OE modeling showed an advantage we input the data from a then current Cup motor to see if it also applied to higher power, higher RPM applications. It did.

The reason for the testing was to gain an enhanced understanding of the ring and piston package as a dynamic sliding seal system - rather than as a bunch of parts. Old thinking was that the smaller the gap - the better. Since 2nd rings ran cooler we set the gaps smaller and thought that we were doing good things. For top rings we were right - as tight as you can without butting is the answer. But for second rings it was not true - - they function as a squeegee for oil moreso that anything else. By allowing blowby gasses to flow through the ring gap we were able to improve top ring sealing and add directional impetus to any scraped oil helping to send it back down to the sump."

I go this from a link posted somewhere on this site.

At home, on the kitchen table inserting a new ring and pushing it square with the piston,

using a banana to back light the end gap.


Gaps on all three check out at a tight ish 0.010",

the manual ask for 8 - 13 thou, .A general rule for end gaps is 4 though per inch of bore, so about 12 thou by the general rule. So using the info above I am going to size the rings at 10 thou top and oil ring and 13 thou for the 2nd compression,.

Here you see the "top " mark on the compression ring against my claim form for Scottish ethnicity, this is not normally needed for end gap fitting but I want to add an element of mystery.


The eagle eyed will note that this is post prandial ring measurement , salt , pepper, digestive biscuits and posh crisps accompany the barrels piston rings and a hovering magnetic pen I got at the Glasgow science centre.
Part 4 will follow with the bonus of a castrol R incense burner to set the correct mood.

Last edited by gavin eisler; 05/12/14 9:29 am.

71 Devimead A65 750
56 Norbsa 68 Longstroke A65
Cagiva Raptor 650
MZ TS 250
The poster formerly known as Pod
#542695 - 05/12/14 10:07 am Re: alloy barrels for 750 OIF 1971 [Re: gavin eisler]  
Joined: Apr 2005
Posts: 1,582
Adam M. Online content
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Adam M.  Online Content
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Mississauga, Ontario.
Hi Gavin, what pistons and rings do you use ?

#542702 - 05/12/14 10:45 am Re: alloy barrels for 750 OIF 1971 [Re: gavin eisler]  
Joined: Aug 2001
Posts: 3,399
gavin eisler Online content
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gavin eisler  Online Content
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Posts: 3,399
argyll. scotland, uk
Hi Adam, John kindly supplied the pistons , I think they are originally for a B44 , stamped 79 ( bore in mm ) on top with a casting mark 824 on the underside of the crown , they are 2nd hand and have very light scuffs on the thrust faces.
The rings are Italian "Gandini", supplied by MCA Birmingham, England,
The label says
Serie segmenti GPM, ( maybe for GPM pistons, they fit the pistons in the pic anyway))
794 ADATT B.S.A
Diam 79.00

5743/2010

They are cast iron with a one piece oil ring. Weighing 363 grammes each without the rings.

Compared to my old 750 "Omega" pistons they are slightly higher comp with a crown about 3 mm taller, but the gudgeon pin to ring lands are the same as the Omegas.
New piston, pin, plus rings on scale, 385 grammes

Old worn Omega piston, pin and rings on scale 393 grammes

Gandini ring box details

Crown height differences a bit exagerrated note pins and rings are not co planar

Rings married in slots , note extra meat above new piston top ring slot, sorry about the blurry shoy

HTH



Last edited by gavin eisler; 05/12/14 10:47 am.

71 Devimead A65 750
56 Norbsa 68 Longstroke A65
Cagiva Raptor 650
MZ TS 250
The poster formerly known as Pod
#549944 - 06/24/14 7:34 pm Re: alloy barrels for 750 OIF 1971, [Re: gavin eisler]  
Joined: Aug 2001
Posts: 3,399
gavin eisler Online content
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gavin eisler  Online Content
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Posts: 3,399
argyll. scotland, uk
A bit of background, I got this bike in 1981, it already had the end feed , big bore and close ratio box. It is my friend , weve had some good, great, bad and shitey times together, its gone up dirt tracks with TT100s and silly gears, and shown a lot of newer stuff the way home. Seen me through three SWMBO and never had the full strip restore.
Its gone through two sets of mudguards /fenders, stanchions seats and fuel tanks . ( Crashtastic , to a point).
I like its simple serviceability and the way the 1/2 x 7/16 ringer plus 2 Allen keys does all the top end work. Not BSAs best moment but a good rework like Hendrixs take on Hoochie Coochie man.



the old bike up for surgery, this bike has never been restored, just worked on as required, it hasnt run for 11 years and has developed some patina


got the tank off



Balance pipe and rocker cover showing late 5/16 UNF rocker fasteners



Carb rubber has split



Tools for exhaust removal, slackened off the pinch clamps on the balance pipe and removed the rear footrests, the block of wood is bumped against the headers at the front mounts, the long brass drift is used to chivvy off the balance pipe, slowly slowly catchee monkee, I was dreading this, but it all came free with limited hassle. Woohoo.



My old tools, left to right a 12" brass drift, Copper rawhide small mallet,Open ended BSF whit spanners for removing the fuel pipe connections Ring spanners , 9/16 x 1/2 AF and 1/2 x 7/16 AF ( the wee britool ringer is an all time favourite , had it for nearly 40 years now, this bike has a mix of BSF UNC and UNF , so more than one set of stuff is needed, two allen keys, the 3/16 AF fits the 1/4 UNC casing screws
My Kamasa 1/2 " drive socket set, Imperial , AF and metric in one set, very useful. Used to remove head fastener but too clumsy to reach the centre head stud I use a 3/8 drive 9/16 socket for that.

Rocker cover lifted, some fancy rockers in there , the inlets are non std, and have stellite pads where they touch the valve stems with adjusters at the push rods

Last edited by gavin eisler; 10/24/16 8:49 pm.

71 Devimead A65 750
56 Norbsa 68 Longstroke A65
Cagiva Raptor 650
MZ TS 250
The poster formerly known as Pod
#549949 - 06/24/14 7:55 pm Re: alloy barrels for 750 OIF 1971 [Re: gavin eisler]  
Joined: Aug 2001
Posts: 3,399
gavin eisler Online content
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gavin eisler  Online Content
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Joined: Aug 2001
Posts: 3,399
argyll. scotland, uk
Getting the head off. First take out the exhaust rocker spindle a 15 mm ringer fits the nut and a long thin brass drift knocks out the spindle and is handy for keeping the spacers rockers and washers in order..

Remove all head fasteners and the rocker line then aff with its heed.
This head gasket was well sealed , no sign of blow byWell maybe a little at the RHS rear stud , inner section onlyModifing the ring spanner for the base nuts, I already have one of these but it was twenty miles away, time to get filingSpanner in actionLook at these babies, this was where I realised I had broken the first law of maintenance, if it ant broke dont fix it.These pistons are fresh , no blow by , why am I doing this, oh yes to save weight and keep the old girl running for longer, Showing the knife edged skirt, cool running crown and unblued gudgeon pin, everything good.Not scuffed at allWarming up the piston prior to pushing out the gudgeaon pin, yes I did set the rags on fire, but only briefly
BOOM stamped onto the crankcase centre piece, someone had a sense of humourleaning up the base gasket
Testing the new barrels for size

Last edited by gavin eisler; 06/24/14 8:05 pm.

71 Devimead A65 750
56 Norbsa 68 Longstroke A65
Cagiva Raptor 650
MZ TS 250
The poster formerly known as Pod
#552399 - 07/11/14 5:55 pm Re: Big Bore alloy barrels for 750 OIF 1971 A65L [Re: gavin eisler]  
Joined: Aug 2001
Posts: 3,399
gavin eisler Online content
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gavin eisler  Online Content
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Posts: 3,399
argyll. scotland, uk
Managed to put some quality time into the build , the barrels were fitted, this was not quite plug and play, fair does to John, he did explain that the cylinder spigots which hang down at the barrel base were deliberately oversize ( to suit longer stroke motors with short skirted pistons), I had to relieve the outer edges of the barrel spigots by about 3 mm.

I used a 3/8" round file and cut a clearance zone at a chamfer going approx 10 mm up the barrel , this took a few trial fits as I wanted to remove the least possible amount. I enlarged the base flange stud holes for a bit more clearance, to 27/64". Also replaced the two base flange dowelled studs.

Here is terrible picture of the main brg cheek that was saying hello to the barrel spigots, my camera technique is somewhat lacking here , I will use less exposure in future. Ive tried to joey the image up , the con rod end cap bolt can be a frame of reference.

Cleaned off the remaining joint compound with some petrol/ gas and dug out an old but fresh base gasket,
test fit showed that it needed trimming aroud two of the front studs



The nuts were clatty, cleaning materials, aluminium foil, aluminum may also work, Belgom alloy and scotch brite, a job in the sun , nice, it took an hour ,

Before



After



Fitted the piston rings after opening up the second ring clearance a tad , why not, it may give better sealing, so a few strokes with a diamond file only took seconds..

Took the cam followers out of the old barrels and matched them to there original cams, , with a dod of anti scuffing paste to help them settle in. The pic is awful so Im not putting it in the thread,
cleaned up the cases a tad.
scotchbrite for the centre cases and a rag with polish for the outer



Cut 3 pieces of foam pipe lagging at 3 .5 inches long. with 2 nuts fitted to the front centre stud pair it trapped one piece, 2 to the rear by the follower tunnels, gave great accessibility.



The pistons were fitted to the barrels with circlips to the inside , this is so much easier to do one at a time. The pistons were set so the gudgeon pin/ wrist pin hole was just visible.



The cam follower duct tape was a pain, I ended up jamming a rag down the follower tunnel to trap the followers. The pins slipped in a treat, Important , the squishability of the foam allows very fine adjustment of the barrel height relative to the con rod small end, this makes "fitting the pin " a piece of pish) and the with the barrels now resting with cloths against the rods the foam props were pulled and some well seal joint compound was smeared on the gasket.
. Nuts on , swish the pistons round a bit , to settle the barrels .Nip up .job done, will check the torque later.
This pic shows the releived area at the base of the spigot







The head is next.

These pistons come up the bore a bit more than the old set, the 2mm gasket will offset thisa bit, I will measure the chamber volume with a burette once its built to get the comp ratio.
The pistons have had the valve pocket edges lightly radius, and they are lighter than the originals so I am leaving well alone.



I spent a bit of time cleaning the stud holes and annealed the head gasket , scrounged up some 3 mm thick O rings to fit in the 2 mm head gasket for the oil drains,
Jon has supplied a correct bore gasket , with the holes tapped to give max gasket area, this is badly needed, the rear cylinder stud is awfy close to the bore.

IMPORTANT, the two rear centre head fasteners must be fitted to the head before lifting the head over the studs, its a squeeze, I may trim a thread or two off the rear studs just to give a bit more room, these big bore devimead pattern barrels are about 3 mm shorter than stock, stock would be really difficult, probably have to fit the studs to the barrel then double nut the studs to the barrels.

A test fit of the head


The bike is now radiating newness, fading to oldness around the edges..
It was running well before the lay up, so I am doing minimum head work , the RHS exhaust valve is looking a bit hotter than the left and the coking is minimal.




The trial fit with no gasket showed a light free join, and the fly cutter marks I put on the head with a light skim seem to be helping with the sealing.
Tragically , I dont have the good copper sticky gasket stuff any more, cant find it.
Its not available here in the UK.
Will use a light coat of the blue compound instead.
Need to find a suitable socket allen key to fit the inner head allen bolts ., and 3/8 torque wrench, will be reusing the old thick head washer.

If I can get some rhubarb I may make cylinder head surprise, or I may let the bike do its own ultra sonic clean.

I used to torque the old head to 28 lbf, this kit has larger threads , John reckons 30 lbf is safe.




Last edited by gavin eisler; 07/11/14 8:55 pm.

71 Devimead A65 750
56 Norbsa 68 Longstroke A65
Cagiva Raptor 650
MZ TS 250
The poster formerly known as Pod
#552403 - 07/11/14 6:14 pm Re: alloy barrels for 750 OIF 1971 [Re: gavin eisler]  
Joined: Dec 2004
Posts: 8,885
kommando Online content
kommando  Online Content


Joined: Dec 2004
Posts: 8,885
Scotland
Quote:
Tragically , I dont have the good copper sticky gasket stuff any more, cant find it.


I got an aerosol can from Eriks couple of years ago, pricey though.

#552405 - 07/11/14 6:19 pm Re: alloy barrels for 750 OIF 1971 [Re: gavin eisler]  
Joined: Aug 2001
Posts: 3,399
gavin eisler Online content
BritBike Forum member
gavin eisler  Online Content
BritBike Forum member

Joined: Aug 2001
Posts: 3,399
argyll. scotland, uk
Eriks? let me google that. Ta

Looked, they only seem to have loctite products.

Last edited by gavin eisler; 07/11/14 6:34 pm.

71 Devimead A65 750
56 Norbsa 68 Longstroke A65
Cagiva Raptor 650
MZ TS 250
The poster formerly known as Pod
#552521 - 07/12/14 1:26 pm Re: alloy barrels for 750 OIF 1971 [Re: gavin eisler]  
Joined: Apr 2005
Posts: 1,582
Adam M. Online content
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Adam M.  Online Content
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Posts: 1,582
Mississauga, Ontario.
Gavin awesome thread, continue please smile.

#552538 - 07/12/14 3:56 pm Re: alloy barrels for 750 OIF 1971 [Re: gavin eisler]  
Joined: Aug 2001
Posts: 3,399
gavin eisler Online content
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gavin eisler  Online Content
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Joined: Aug 2001
Posts: 3,399
argyll. scotland, uk
Thanks Adam.
Back to the shop today to finesse the fit of the head studs,




the two rear were trimmed by three threads and the two front by 1 thread. Spot the spider, rear stud pre trimming



After trimming



This tool helps with the torque up, I need to find the small torque wrench that fits into it.



A man cant have too many tools, my all time favourite is the wee britool, second from the right.
Its a gem to use, the others are variously the curvy Snap on , Elora and Britool
2nd from the right.

If theres one new thing Ive learned today its how to use the Camera , its a Canon G10 , Ive found the manual focus function and the flash colour balance is now set to fluoro, hopefully the pics will improve.
Photo bucket is being weird.

It seems to be working again, heres some new parts laid out, new spokes top , Carb rubbers, gear pedal rubber, theres a new battery and a fresh rear arromax hoop out of shot.




More of the same tools arranged a different way but also showing the 8 mm hex bit with 3/8 th drive ratchet and extensions. .




Not too much goo squeezed out, excellent.
I took a flat file to the barrel pattern joins at the fin outers , dressed them all smooth to bonny them up.



Hmm , the barrels make the rest of the bike look scruffy, these down tubes are more than a little battle -scarred.
A touch up may be in order. This frame still wears most of the original paint . A few years ago I was in Oban getting fish and chips for the family using the BEEsa for fast food and the original dealer from Edinburgh stopped me as I was heading off, he remembered the plate number as they were awarded certain numerical series, he was a treat to blether with, the chips got back a lot colder than normal that night.
He told me that they used to sell a load of Lightnings to US guys over here on the bases.





That silicone rubber that I last used to stick in the headers still has a serious hold in the exhaust ports, its much more effective than the exhaust paste I tried before.



I met this guy on the way back tonight , Jamie from Ballachullish, There had been a shinty match , he was very cheery, thats vodka and diluting orange, I think, he made me drink some. He works on shift with me.






Last edited by gavin eisler; 07/12/14 4:56 pm.

71 Devimead A65 750
56 Norbsa 68 Longstroke A65
Cagiva Raptor 650
MZ TS 250
The poster formerly known as Pod
#552565 - 07/12/14 7:50 pm Re: alloy barrels for 750 OIF 1971 [Re: gavin eisler]  
Joined: Dec 2004
Posts: 8,885
kommando Online content
kommando  Online Content


Joined: Dec 2004
Posts: 8,885
Scotland
Quote:
Eriks? let me google that. Ta

Looked, they only seem to have loctite products.


I went in for some bearings and it was on a display next to the counter and not a Loctite product, this was the Kilmarnock branch, it was dusty. I took the display can, it sprays out a coppercoat type substance.

#552628 - 07/13/14 5:39 am Re: alloy barrels for 750 OIF 1971 [Re: gavin eisler]  
Joined: Aug 2001
Posts: 3,399
gavin eisler Online content
BritBike Forum member
gavin eisler  Online Content
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Posts: 3,399
argyll. scotland, uk
Ive found some rhubarb, the jelly pan and the spring compressor, Cylinder head surprise is on.
possibly the only advantage of a midsummer rebuild, Rhubarb is plentiful, weve already made cordial and Im using up the scabby leftovers.

Torquing thoughts, this web site will be handy
http://www.freeinfostuff.com/TorqueExtension/TorqueExtension.htm.
John suggests using a 1/2" combination spanner plus formula from the site above, Its another option, most folk can find the combi spanner fairly easily.

Last edited by gavin eisler; 07/13/14 5:53 am.

71 Devimead A65 750
56 Norbsa 68 Longstroke A65
Cagiva Raptor 650
MZ TS 250
The poster formerly known as Pod
#552684 - 07/13/14 12:34 pm Re: alloy barrels for 750 OIF 1971 [Re: gavin eisler]  
Joined: Aug 2001
Posts: 3,399
gavin eisler Online content
BritBike Forum member
gavin eisler  Online Content
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Joined: Aug 2001
Posts: 3,399
argyll. scotland, uk
Ive had an interesting day.
I visited the polly tunnels to get some rhubarb leaves.



Next door had a haul of chanterelles.



I had some for lunch while the leaves were simmering then got the muslin bag, bucket and pan out.




Its important to eat well when working on your head, so they tell me.

Cylinder head surprise, recipe, preparations

Cut a half dozen large rhubarb leaves , they have more Oxalic acid in them.




Chop leaves and add to large pan of water .







Boil for about an hour.






Strain through a mesh bag.





I tested out the cleaning powers on an old MZ brake plate, left it it for a few minutes.





Some bits came out patchy, I think where there were oily fingerprints.





Rubbed it a bit with a tooth brush from the tooth brush tree.





Nothing quite like a motivational toothbrush from the Seas rich Harvest for getting right in about it.



It definitely does something, confirming the old rural myth.

Degreasing the head first looks like a must do, better get some gunk.

These dips were only a few minutes each, with a bit of rubbing with the brush and cloth.



The effect is quite satisfying, most of the surface bloom has vanished leaving pit marks, the denser areas around the cable entries look like they need hours rather than minutes.


I will put the Organic gluten free rhubarb toxic tea back into the big pan for cleaning the head.

Will try a one side dip for a half hour as a starting point.

Spent the rest of the afternoon looking for a substitute for the lost head stud washer and cleaned up some head working tools.
Dug out the spring compressor, found the bike key ( yay) didnt even know I d lost it.

Also found a burette, torque wrench , the wrench is nothing special, its only had light use by me its probably not dead on but its mid range is where I want it to be around 30 ftlbs,

[img]http://i101.photobucket.com/albums/m79/argpod/2014-07-13174500_zpsebb0413c.jpg[/img]


TDC finder, some handy tapery thing , pointy things, allen keys and a good old screwdriver, the tape round the handle means its out of the old toolkit which is still in a safe place, so safe that it remains un found.


<a href="http://s101.photobucket.com/user/argpod/media/2014-07-13174443_zpsb47b5e9b.jpg.html" target="_blank"><img src="http://i101.photobucket.com/albums/m79/argpod/2014-07-13174443_zpsb47b5e9b.jpg" border="0" alt=" photo 2014-07-13174443_zpsb47b5e9b.jpg"/></a>

The tapery pointy thing are handy for the rocker shim mess around that comes soon.



For some reason the link is coming up rather than the image, but Im doing the same stuff.?
Found out why , too many pics in one post. Will do multiple posts in the future/





Last edited by gavin eisler; 07/23/14 7:49 am.

71 Devimead A65 750
56 Norbsa 68 Longstroke A65
Cagiva Raptor 650
MZ TS 250
The poster formerly known as Pod
#552772 - 07/13/14 9:12 pm Re: alloy barrels for 750 OIF 1971 [Re: gavin eisler]  
Joined: Aug 2001
Posts: 3,399
gavin eisler Online content
BritBike Forum member
gavin eisler  Online Content
BritBike Forum member

Joined: Aug 2001
Posts: 3,399
argyll. scotland, uk
Valve spring compressor, its a Syckes Pickavant, I made a bridge piece for the end from some heavy walled hydraulic pip, slotted on the milling machine then burst the corners off with a file.
Its made for the job.




Showing cut out to access collets



The inlet rocker with superflous washer and deead gasket left in place for protection



Inlet rocker details, shimmed endfloat , stellite pads at valve end, polished. Originally the pads were much larger, I have ground quite a bit off, this was done ages ago.



Warming the pillars to help the shaft out



A terribly posed picture, the end caps get a clout with a socket to help free the collets, otherwise they stick.



Casting marks and filed off flash.



Trying to capture how lettle meat there is around the rear stud on the head, showing carbon in the chamber.



This needs cleaning, a before shot




side


3/4



Rear, pretty clean!


other side



The spider is leaving soon



trying to use a packing case as a light box


71 Devimead A65 750
56 Norbsa 68 Longstroke A65
Cagiva Raptor 650
MZ TS 250
The poster formerly known as Pod
#552773 - 07/13/14 9:15 pm Re: alloy barrels for 750 OIF 1971 [Re: gavin eisler]  
Joined: Aug 2001
Posts: 3,399
gavin eisler Online content
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gavin eisler  Online Content
BritBike Forum member

Joined: Aug 2001
Posts: 3,399
argyll. scotland, uk
Head part two
Top end of valve spring compressor in place.



Bottom end, the socket spacer is not needed, later valves came out without it, got the settings out of whack when I cleaned it up.


A poor pic of the exhaust seat,




The head held in a parrot vice with a thick towell to prevent damage, the tool in action.



The parrot vice stripped bare


It swivels round this centre pillar then locks when nipped up, a great idea for fiddly work.



I may give this a D shape, the ports have been worked around the guides.






A clearer shot of both exhaust seats, a bit of pitting but still nice broad seats, these will get a light rub before going back in.



I am glad I pulled these valves now , that flake of carbon on the seat isnt going to help much.


This is the only dodgy thread I have found, for some BSA reason, although the rest of a 71 motor has 1/4 UNC female threads, the rocker box is different, the two centre tappings ( the 4 outer holes are tapped 5/16 UNF) on this one are 26 tpi, 1/4 BSF. This one had a couple of broken threads at the top, here I am using a pair of sprung caliper legs with fine end to clear the bad threads out, theres still good purchase futher down, maybe a jog for a 1.4 UNC helicoil the next time.




God the studs to an aesthetically pleasing length . Cabochon filing, what fun.




Ive half a mind to alloy up the footrests as part of the weight loss thing, some measurements for an e mail to Barley corn.


[IMG]http:
//i101.photobucket.com/albums/m79/argpod/2014-07-13233448_zps2a9a04c8.jpg[/IMG]



Showing the challenging , footrest , kickstart , gear lever interplay, thats bad road rash on the kick lever.




Ive sussed the camera focus, set on manual at around 20 cm, its easiest to have strap pulled tight then sway back and forth till the image sharpens up.

The head is back home now getting degreased before the Oxalic dip.


71 Devimead A65 750
56 Norbsa 68 Longstroke A65
Cagiva Raptor 650
MZ TS 250
The poster formerly known as Pod
#552780 - 07/13/14 9:33 pm Re: alloy barrels for 750 OIF 1971 [Re: gavin eisler]  
Joined: Aug 2001
Posts: 3,399
gavin eisler Online content
BritBike Forum member
gavin eisler  Online Content
BritBike Forum member

Joined: Aug 2001
Posts: 3,399
argyll. scotland, uk
Back home cleaning the old mung off the head.

In the kitchen sink




Its not that powerfull



BSA service tool 71- 667, ornate japanese engraved brass cylinder head bowl. For holding an A65 head any way you want. An essential piece of equipment, note the serenity candle.





Other way up, no bother.



Last edited by gavin eisler; 07/13/14 9:35 pm.

71 Devimead A65 750
56 Norbsa 68 Longstroke A65
Cagiva Raptor 650
MZ TS 250
The poster formerly known as Pod
#552996 - 07/15/14 7:31 am Re: alloy barrels for 750 OIF 1971 [Re: gavin eisler]  
Joined: Aug 2001
Posts: 3,399
gavin eisler Online content
BritBike Forum member
gavin eisler  Online Content
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Joined: Aug 2001
Posts: 3,399
argyll. scotland, uk
After a a crude session at degreasing in the service bowl ( this donnggs in a very sonorous manner when handling the head, which amused me no end). I opted for some more aggressive chemical for the head chamber and bought some Gunk degreaser.



Scrubbed away at the carbon with 1500 grit paper ( slow but shiny) , looked out some tapering hardwood sticks to help reach the tricky bits.









Chamber exhaust seat




Showing exhaust seat pitting



Inlet seat much cleaner





Before Oxalic dip pics








Immersed the head in the Oxalic solution and set a cooks timer to ten minutes, every time it went off I turned the head over to see what was going on.






After ten minutes



Used this to help




Last edited by gavin eisler; 07/16/14 2:01 am.

71 Devimead A65 750
56 Norbsa 68 Longstroke A65
Cagiva Raptor 650
MZ TS 250
The poster formerly known as Pod
#552997 - 07/15/14 7:38 am Re: alloy barrels for 750 OIF 1971 [Re: gavin eisler]  
Joined: Aug 2001
Posts: 3,399
gavin eisler Online content
BritBike Forum member
gavin eisler  Online Content
BritBike Forum member

Joined: Aug 2001
Posts: 3,399
argyll. scotland, uk
part 2



After about 100 minutes, 50 per side.

Rubbing with AL kitchen foil really helped shift some of the more stubborn carbon, goo marks.







The last shot is kind of telling, yup the head is cleaner, the rhubarb is working but it needs a bit more pizzaz. Took the dremel out and polished various areas with the small brass brushes. OOOh now its a bit tarts handbag, also took the rocker lid fasteners to the wire wheel.


Outside next day in the fierce midday sun. This is as far as the head clean up goes.
















Trying to show the central air passage, this had some sloppy casting flash masking clean air flow, I have dressed it up with the dremel dental burr.



A better shot, the bright line is where the casting flash was.


The head clean was a days work, this is some gods way of saying I should have tried harder at school, if I had " made it " I would have some lacky to do this for me. Head work is humbling.

Some thoughts on the Organic gluten free Toxic acid rhubarb Tea clean.

It smells OK, rhubarby , natch.

It starts pink and turns black.
I still have all my skin, rinsed fingers in cold water a few times to be sure.

The Al boiling pan prevents head damage.

I was probably hasty, I thingk and overnight soak may have had more effect.

It needed mechanical help.

The oxides seem to bloom into a yellow/ greenish layer which brushes off easily.

Would I do it again, yes.

Benefits.
Cheap, no grit, controllable. Backyard chemistry is fun.

Disadvantages.
Slow. Maybe too weird for some folk

Today, valve clean up and grinding.


Last edited by gavin eisler; 07/15/14 7:52 am.

71 Devimead A65 750
56 Norbsa 68 Longstroke A65
Cagiva Raptor 650
MZ TS 250
The poster formerly known as Pod
#553008 - 07/15/14 9:16 am Re: alloy barrels for 750 OIF 1971 [Re: gavin eisler]  
Joined: Aug 2001
Posts: 3,399
gavin eisler Online content
BritBike Forum member
gavin eisler  Online Content
BritBike Forum member

Joined: Aug 2001
Posts: 3,399
argyll. scotland, uk

Playing around in the sun before cleaning the valves.
To seal the inlets I wrap the stubs with a turn of self amalgamating tape. Some vaseline will help the rubbers slip over the grippy tape, the tape is stretched to twice its original length then wrapped, as it touches the long chain polymers which have stretched to breaking point reunite with the layer below to make a contiguous join, its amazing stuff and has worked well for me in the past for sealing this junction.





Dig out an old inlet valve and tried some crude flow bench tests, result wet and inconclusive, needs more water.
Valve held at small opening.


A spilt dowel with coarse grit is prepped for cleaning up the ports.





Thats all for now. Valves to follow.


71 Devimead A65 750
56 Norbsa 68 Longstroke A65
Cagiva Raptor 650
MZ TS 250
The poster formerly known as Pod
#553114 - 07/15/14 8:49 pm Re: alloy barrels for 750 OIF 1971 [Re: gavin eisler]  
Joined: Nov 2011
Posts: 257
Pre Unit Offline
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Pre Unit  Offline
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Joined: Nov 2011
Posts: 257
terra Australis
If you put your finger over the end of the hose , and aim it down the center of the intake ,
youll get a fair approximation of the buisness .

Try various lifts , & valve & no valve .

This is best on hot days , or wear your raincoat .

Be carefull not to repeat this information , as its classified .

#553143 - 07/16/14 1:28 am Re: alloy barrels for 750 OIF 1971 [Re: gavin eisler]  
Joined: Aug 2001
Posts: 3,399
gavin eisler Online content
BritBike Forum member
gavin eisler  Online Content
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Joined: Aug 2001
Posts: 3,399
argyll. scotland, uk
@ Pre unit, cheers, will give that a go at work where we have a better water supply.

While the epoxy cures in the head I took off the old rear hoop




pulled the broken spoke, these are high flange Borranis, been on the bike since I got it in 1980



New tyre 1/2 mounted



This old ape came round and forced the tyre on with his bare hands ( not true, more like knees and feet), start to finish this took over an hour and amused the kids no end, I used a record no 5 G clamp to break the bead on the old tyre. While the rim was bare I put a drop of light oil on each exposed nipple with a view to tweaking the rim later, must find a spoke key first, the new spoke is so shiny.







I reused the old tube, and completed the task without nipping it, woo hoo.

Also cleaned up the pipes, gunk , Al foil and belgom Alu , pics to follow, off to work.








Last edited by gavin eisler; 07/16/14 1:31 am.

71 Devimead A65 750
56 Norbsa 68 Longstroke A65
Cagiva Raptor 650
MZ TS 250
The poster formerly known as Pod
#553181 - 07/16/14 11:11 am Re: alloy barrels for 750 OIF 1971 [Re: gavin eisler]  
Joined: Apr 2005
Posts: 1,582
Adam M. Online content
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Adam M.  Online Content
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Joined: Apr 2005
Posts: 1,582
Mississauga, Ontario.
Hi Gavin, with cleaning a head soda blasting would be faster and still safe for the head.
Doesn't look as good as yours after cleaning though, still you can see the blasting effect.
About these valve seats - do they look like 3 angle job ?
They are quite wide and look like make with one seat cutter from factory.
Were your guides worn ?

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