Author Topic: little advice needed here  (Read 1422 times)

Offline coater87

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little advice needed here
« on: 14.05. 2009 15:04 »

 As I have collected pieces of my basket case, I have had time to think things through but am stuck on one big thing.

 Rebuilding the engine and gearbox myself, or having it done for me.

  Here are my thoughts on having it done. First, its expensive- I have had estimates up to $3000.00 U.S. for a complete engine and GB rebuild, and that does not include a timing side conversion. But even though this is pricey, the work would (most likely) be done by people with MC experience and the right tools for the job at hand. I would imagine I would get a good many miles of riding on the bike. But there is always the thought of getting a hack job done, even if its only a minor thing. Kind of a "its good enough" deal, really, what do these guys care-its not like its their bike. But then again, it could turn out perfect.

 If I do this myself, I go into it completely blind. I have never done a MC engine, nor have I ever had to ream a bushing or inspect/repair a gear box. I "think" I could probably handle the job, it would save me quite a bit of money too. Yes, the tools will be expensive- but then I own them. I would also gain a super amount of knowledge of my own bike, having handled ever piece of the rebuild. But if I was to mess this up, it wont run and I am out the money. Or worse case it runs just long enough to throw a rod through the cases and take my barrels out with it. Or it could turn out O.K.

 What is the general concenses, can the average guy rebuild his own A10 motor with limited knowledge going in? Can you really line ream bushings to 1 and 1/2 thou by hand? Is it worth the trouble to try and gain this knowledge at the possible cost of an original motor trying to save a large chunk of money (for a nice chrome tank and some good paint or other stuff)?

 Someone give me the pros and cons of all this. I am really stuck on the fence with this one.

Central Wisconsin in the U.S.

Offline RichardL

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Re: little advice needed here
« Reply #1 on: 14.05. 2009 15:37 »

I'm a bit under the gun right now, so can't go into much depth, but let me offer a few comments.  If you've done some in-depth automotive (or marine) engine work before, you should be able to handle the motorcyle rebuild. While pooh-poohed by some (and not always wrongly), the Haynes manual does a fair job of taking one through the engine and gearbox rebuilds. Folks here can expand on the manual when the issue is tricky. There are few techniques, many of which have been mentioned in the forum, that can be added to Haynes to simplifiy the task. I think you need a good assortment of standard tools, including a set of Whitworth sockets and open-ends ("spanners" to the Brits). There are not many specialized tools required/suggested and some of those you can do without or make yourself. As for line reaming the bushes, you could send that task out and still end up with the sense of do-it-yourself accomplishement. (I recently heard from someone that Morrie's is still doing business. They could definately do the line reaming, as it was one of the tasks I've discussed with them. I need to try to look them up, just not now.) Considering your location, if you need to borrow any special tool I have, the invitation is open.

Maybe the big question is time.  If I tried to justify time at the bench against salary, the cost of doing it myself would have been be ridiculous. However, my satisfaction from riding the motorcycle I have mostly built myself from a basket case is my reward.

Richard L.
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Online flashblack

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Re: little advice needed here
« Reply #2 on: 14.05. 2009 20:54 »
    When i split my A10 cases many years ago, i found play in all bushes, and the big end journals and timing side main journal needed a regrind. I then found a company who could regrind the crank and line ream the bushes for a reasonable price, i can`t remember exactly how much, but then they also told me that, naturally the price would include cleaning out the sludge trap, and shimming the crank! Now i do like to do as much as possible myself for the satisfaction (like Richard said above), but i made the decision to let them do the sludge trap and the shimming as well as the grinding and reaming, so a bit of a compromise really.The result was that i ended up with a beautiful silky smooth bottom end (i did split the cases to inspect it, coz i`m like that, and it`s still going strong to this day.
     What i`m trying to say is that if you get the bottom end sorted out, be it fully or partly farmed out, then the rest of the engine will be easy to rebuild yourself (unless you need a rebore).
 So my advice is go for it, strip the engine down, then decide what to do yourself, and what to farm out, then the satisfaction you get will be huge.Compromise is ok, it`s whatever suits you!
   Anyway that`s just my humble opinion
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Offline rocket man

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Re: little advice needed here
« Reply #3 on: 14.05. 2009 21:59 »
i have to agree do the bits you can handle yourself
and the rest leave to an expert no use trying to do it all yourself
if something goes wrong and youve done it all then you will have to repair it 
and that would be very costly in the long run get it done right first time
and enjoy riding it


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Re: little advice needed here
« Reply #4 on: 14.05. 2009 22:27 »

Sound advice from all and I must agree even though I am no stranger to the BSA twin engines I always ask for advice if I am not sure and find it freely available. There will be a need to farm out jobs like regrinding journals and making under or oversize bushes (unless you own or have a friend with a lathe and the knowledge to make bushes to the correct tolerances.)There is a lot you can do with little knowledge of the A10 engine with just the manual to guide you. When my crank was reground for the timing side bush I got the engineering workshop to fit the bush they made to suit and ream it to the correct tolerance.
Fitting the conrods to the crank is straight forward as are the small end bushes and pistons. Fitting the crank in the cases and shimming up the end float is also straight forward. Things like reboring are best left to a machine shop but fitting valve guides and recutting seats is something you should be able to do yourself even if you can not recut the seats after fitting valve guides a machine shop will not charge much to do that and the final lapping in you will be able to complete.
So following on from all that I agree with the others save your dosh and do as much of it as you can. The feeling of satisfaction that you rebuilt it will be even greater.
All the best for the rebuild

Offline coater87

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Re: little advice needed here
« Reply #5 on: 15.05. 2009 03:07 »

 Thanks for the advice, you guys have turned the tide. I will do 95% myself, except grind the crank as my little lathe could never handle that. But it could handle the bushes once I figure out where to get the proper bronze.

 On the up note, I did just score the proper size expansion reamer on ebay for 30 bucks for the timing side bush, and I will turn a guide bearing for line reaming.

 But first I have to split the cases and see what needs to be done. Soon I will start in and take some pics as I go along.

Central Wisconsin in the U.S.


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Re: little advice needed here
« Reply #6 on: 15.05. 2009 20:51 »
Great look forward to following your progress

Offline fido

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Re: little advice needed here
« Reply #7 on: 15.05. 2009 21:27 »
I suppose things might be different in the States but I would guess the majority of our engines in UK have been rebuilt by DIY mechanics at some point during their long lives but they have survived the experience. Indeed, BSA will have designed them knowing this would be the case. At one time, most people who ran a motor vehicle knew about things like decokes and only the more affluent could afford to pay someone to have such jobs done.
I would agree with the others, do your own assembly work but farm out the tasks you are less confident or equipped to tackle. That way you still get to see everything and feel if any parts are stiff to move etc. One moving part that may surprise you with it's stiffness to turn is the oil pump. It's supposed to be like that though, if it spins freely by hand it's probably worn out!

Offline LJ.

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Re: little advice needed here
« Reply #8 on: 15.05. 2009 22:13 »
One moving part that may surprise you with it's stiffness to turn is the oil pump. It's supposed to be like that though, if it spins freely by hand it's probably worn out!

Phew! Nice to hear that Fido, Had my pump out of the M20 a day or two ago and it felt rather stiff, was a bit easier after a good clean out but still a bit tough to turn.
Ride Safely Lads! LJ.
1940 BSA M20 500cc Girder/Rigid- (SOLD)
1947 BSA M21 600cc Girder/Rigid-Green
1949 BSA A7   500cc Girder/Plunger Star Twin-(SOLD)
1953 BSA B33  500cc Teles/Plunger-Maroon
1961 BSA A10  650cc Golden Flash-Blue
1961 BSA A10  650cc Golden Flash-Red