Author Topic: Engine Rebuild  (Read 1651 times)

Offline bikerboy

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Engine Rebuild
« on: 05.01. 2012 14:05 »
Hello all new member just a few questions.

After many years of my bikes being in the garage (none of them together and running) I have recovered from the cost of divorce and intend to rebuild all the bikes. I have completed one, purists please close your eyes, its a Tribsa. 1956 A10 frame, 1975 T140 engine, Trident swinging arm, T140 front end, Mag Alloy wheels and various other changes.

I now have two A10's on the go, one plunger and one swinging arm. I saw a post on here recently where somebody had attacked his cam followers with a grinder and if I remember rightly was blocking up an oil way to the camshaft area ?

I am capable as a mechanic but its been a fair while and would appreciate any tips anybody can give, particularly if I should start grinding slots in my cam followers which I assume was to improve the oil supply in some way.

Sorry purists but none of my bikes are standard :( I always build them to suit me :)

Offline Goldy

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Re: Engine Rebuild
« Reply #1 on: 05.01. 2012 17:12 »
Hi bikerboy and welcome to the forum. Fact is some people like everything original and some don,t. It,s just personel choice, don,t worry about it. The main thing is to get another  A7/ A10 on the road so enjoy this forum and the restoration. As far as the cam followers are concerned, as long as the engine is correctly restored they will get lubricated quite well. All the best Goldy
56 A10 Golden Flash - Restore, ride, relive.                                          
56 C12 BSA project ongoing

Offline bikerboy

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Re: Engine Rebuild
« Reply #2 on: 05.01. 2012 17:20 »
Thanks Goldy, I have to say I have done 1000's of miles on my old A10's and have never had a big problem with cam or cam follower wear but if there is an adaption I cant seem to resist having a go at it ;) I am just looking at this offset crank idea and am even considering the thru bolting mentioned on here as I have had a couple of barrel flanges crack over the years.

Offline muskrat

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Re: Engine Rebuild
« Reply #3 on: 05.01. 2012 19:36 »
 G'day bikerboy, welcome to the forum.
                                                     Don't worry too much about the cam & followers, they get plenty of oil.
Never seen a A10/7 with an offset crank. I've been using pistons with offset gudgeon pins in the cafe. Great on the track but don't last long on the road.
Through bolting really only needed if your going up around the 10.5:1 compression with thin flange barrels.
Cheers
'51 A7 plunger, '57 A7SS now A10CR, '76 XT500, '77 AG175 '83 CB1100F, '81 CB900F project.
Australia
Muskys Plunger A7

Offline mike667

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Re: Engine Rebuild
« Reply #4 on: 05.01. 2012 23:48 »
G'day bikerboy, welcome to the forum.
                                                     Don't worry too much about the cam & followers, they get plenty of oil.
Never seen a A10/7 with an offset crank. I've been using pistons with offset gudgeon pins in the cafe. Great on the track but don't last long on the road.
Through bolting really only needed if your going up around the 10.5:1 compression with thin flange barrels.
Cheers

fest yee eyes

http://www.offsetcrank.com/bsa.htm

while i havn't heard a BSA run with an offset crank i have heard a commando w/ one and it was a dangerous sounding beast - bit a like a V twin howl  but not a dumpy harley type - would of loved to try it out for a ride but sadly wasn't able too


Offline bikerboy

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Re: Engine Rebuild
« Reply #5 on: 05.01. 2012 23:59 »
muskrat

Cheers I think it was you article and your drawings I was looking at for the thru bolting

Offline muskrat

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Re: Engine Rebuild
« Reply #6 on: 06.01. 2012 06:37 »
 Thanks Mike, that will be about $2K+ for a bottom end. Will have to find a busier corner for the missus to work. *whistle* *loveit*
Cheers
'51 A7 plunger, '57 A7SS now A10CR, '76 XT500, '77 AG175 '83 CB1100F, '81 CB900F project.
Australia
Muskys Plunger A7

Offline mike667

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Re: Engine Rebuild
« Reply #7 on: 06.01. 2012 14:41 »
Thanks Mike, that will be about $2K+ for a bottom end. Will have to find a busier corner for the missus to work. *whistle* *loveit*
Cheers

haha - nice!

Offline bikerboy

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Re: Engine Rebuild
« Reply #8 on: 08.01. 2012 01:24 »
I live just outside Bracknell in Berkshire can anybody advise a good engineering shop for reboring / regrinding etc ?

Offline Rocket Racer

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Re: Engine Rebuild
« Reply #9 on: 12.01. 2012 01:20 »
There was a magazine article by the owner of cake street classics that made reference to modifying cam followers to improve oil flow to the cam lobes.
My opinion is that the bigger cause of cam wear would be excessive valve spring pressure.
There is also often limited clearance in the cam bath between the cam lobe if using a 357 which can mean the cams effectively empty the cam channel , but I would expect splash to still be adequate and the channel adequate for start up. I've certainly not had issues with my cams/followers but given the followers are quite narrow have seen plenty of worn ones.
A good rider periodically checks all nuts and bolts with a spanner to see that they are tight - Instruction Manual for BSA B series, p46, para 2.
New Zealand

Offline bikerboy

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Re: Engine Rebuild
« Reply #10 on: 19.01. 2012 14:01 »
Thanks for the comment I have two A10's I am rebuilding, one of which has a 357 cam, but I have had no wear problems in the past and have owned both bikes for over 30 years

Offline A10Boy

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Re: Engine Rebuild
« Reply #11 on: 19.01. 2012 14:56 »
Quote
I live just outside Bracknell in Berkshire can anybody advise a good engineering shop for reboring / regrinding etc ?

It would be well worth the drive to Bedford to T&L Engineering, they are the best. Ask for Derek. They have a website.

HTH
Regards

Andy

1960 A10 - Black Golden Flash
Plus
1974 Kawasaki Z1a
Yam XJR 1300