The BSA A7-A10 Forum
Technical (Descriptive Topic Titles - Stay on Topic) => A7 & A10 Engine => Topic started by: bikerbob on 29.05. 2014 12:32
-
Been to look at an A7 and am considering it, has a few issues couple of bad oil leaks not charging but the thing that concerns me the most is it had a major break down about a year ago and the present owner gave it to a professional repairer to fix. On stripdown the repairer found that a previous owner had fitted a sleeve over the crankshaft timing side and this sleeve had turned thus causing the problems. I asked the present owner what was done he said it had new bearings fitted and a new camshaft fitted but the bores and pistons were perfectly Ok. He has since done about 500 miles on the bike no problems. I asked what was done about the crankshaft but he did not know he said he has always used this engineer to do work on all of his bikes and his work has always been good he just lets him fix whatever needs doing. He said that at present he is doing a Norton engine for him it seems he just takes the bikes to him and lets him fix whatever needs doing. The bike itself is 100% original never been restored all chrome and paintwork original nice patina, I did say as regards the charging which he blames the Lucas voltage regulator for he could fit a new solid state one but he gave me a strange look and said well if I did that it would not be original. The bike is swinging arm model with 72000 miles on the clock and has had 6 previous owners So what about this sleeve on the crankshaft never heard of any one doing that before.
-
Well it should work if its done properly. Never heard of it being done before though.
Doesn't that sleeve make it non-original too? *smile*
Easy enough to find another A7 crank I would have thought.
I have to admit I never really got the 'originality' thing when it comes to things that wouldn't be noticed. You could hide an electronic regulator inside an original one if you wanted, although lack of airflow over it might be an issue.
-
For my tuppence worth I say you still need abit more info with at least a phone call to the guy who did this sleeve. I'll bow to Britz is superior knowledge of engineering over mine but only 500 miles on the clock so bearly run in, unusual work done by unknown engineer ? and you're probably paying top dollar . I'd ask for contact details of the work and the name of the company/guy who did it and post them here .Someone will know of them and you'll but your mind at ease also could be of help for us all. At least he told you about it ,which is a good start , lets know how you get on regards Bob.
-
I think the repairers name is Bob Wardle I have heard of him before and have only heard good things about him I think he has his own machine shop and he does end feed conversions etc. I have no doubt that if he done the work it would done correctly but it is just something I have never heard of and am wondering how it was resolved.
-
The only way to resolve it would be to make a bush to suit. The shaft might be getting a bit small if the groove was machined off for the sleeve to fit. If it was me I'd like to take the timing cover, oil pump and pinion off to see the size of the journal.
Cheers
-
I've heard of that guy and only good things! hsn't he posted on the forum before now or was it a friend who commenting on his work but this could get interesting ,BobH
-
Sounds like a very strange thing to do.... *conf*..but thanks for the reminder-
after I read most, was thinking drive side, as I had to do this to mine when I first started on it late '70s...
someone posted a while ago about building up the D/S journal, but I had forgotten about mine until after that when I needed to pull the bearing to redo the shims and the sleeve came along for the ride *eek*, and I've been meaning to mention it but keep to forget...
.... but he gave me a strange look and said....
......don't yea hate that...? *bash*(I'm not really a violent type-except !)
-
Back in 1985, SRM in Penarth, near Cardiff, Wales - Steve Macfarlane the boss (sorry Steve if I have missspell your surname) offered a hardened sleeved crank with larger timing bush which increased loading by 25% - I have the details somewhere. I had this done on my RGS back then and had no problem revving the guts out of it. Nothing came loose or exploded - yet!
-
Sorry, a bit nervous as a newby!
I meant to have said - SRM fitted a hardened sleeve to the customers crankshaft, a larger timing bush in the crankhalf, reamed true.
Nowadays it is the roller bearing /end feed job. I had this done to my SR by SRM in Aberystwyth - a good bunch of lads....
-
The reason for my scepticism is that a shaft that has been sleeved should not be any stronger than std as the weak point is still the original radius of shaft and web. If the shaft has been turned down and sleeved it would be weaker. I may be wrong as I was only a fitter & turner, not an engineer.
I saying all that I have broken a few cranks but always at the big end journal not the main shaft.
Cheers
-
Hi Muskrat - thanks for the welcome!
If my grey cells are not afflicted by forces in the cosmos today - no reduction in diameter to crank prior to sleeve fitted.
-
Yes. My Flash has this original Steve McFarlane SRM sleeve and solid bush mod. At the time he was not doing the little roller/ball bearing timing side job on pre units, if I remember correctly. Only of real benefit on very highly loaded engines, Spitfire type of effort. Cheaper too naturally enough.
The aim is to provide more ideal bearing combination to slow wear rate. Bronze bush on softer shaft can have wear problems. Mine was ok many thousands of miles and a good many years on, last time I looked. Oil filter helps a lot as well of course.
AFAIK the strength of the shaft timing end was never an issue.
-
Been trying to contact Rob Wardle but the phone is not answering maybe on holiday. But I have been looking at a small journal crank and the drive side shaft is a lot smaller than the timing side so maybe if the timing side has been machined no smaller than the drive side prior to sleeving it would be Ok as I would have thought most strain would be on the drive side, also maybe BSA made the timing side bigger to have a decent size bush. Your Thoughts. I am tempted to go for this bike because of it,s unrestored originality.
-
Hi this is wardley bob I rebuilt the engine on the a7. If you pm me I will fill you in on the details bob.
-
Thanks to all those who replied, I have spoken to Bob Wardle who informs me that the crankshaft was not sleeved what had happened was the previous owner had fitted a new timing side bush and the inner bronze sleeve had turned inside the outer steel casing causing major problems which he has rectified. Bob Wardle is a really nice helpful guy and I appreciate him contacting me to let me know the correct history. Thanks again for the responses.
-
That was much ado about nothing!
-
I don't think the present owner who has had to spend a considerable amount of money in order to rectify this problem would consider it to be much ado about nothing.
-
Hi, I have heard of American racers back in the '60s using hardened steel bushes on the TS main, with a bronze bush made to size to suit. I have seen photos of this on the Internet too. They did this so that a change of bush could be done without a crank regrind. I have contemplated using a needle roller inner bush in this way but have not so far got round to it (project no. 748 etc.). The oil groove could also be made narrower than BSA chose to. BTW is it allowed to mention here that I am having some parts for A10s and A7s made, choosing them to fill what I estimate are peoples' needs. The site is http://eborbikes.com/ if anyone is interested.
-
i m glad you mentioned the parts you are having made as i was looking for some copper gaskets for the rocker boxes.
i ve tried them on mt t160 and they really do help stop oil weeps.
-
I have now bought the A7,have attached a photo of the bike it came with quite a bit of history some photos of previous owners one taken back in 1962 with the owners wife bike all loaded up with camping gear and it had a windshield then another colour photo taken in the late eighties with a different owner. A letter from the second owner explaining why the first owner only had the bike for a few months it seems he had a heart problem. The tax disc attached to the rear mudguard stay is the original 1956 tax disc. Original buff log book and MOT,s going back to 1976 plus names and addresses of previous owners. Now in the process of curing the oil leaks then onto the not charging problem I rode it home and it goes quite well.
-
Congrats Bob, she looks a beauty, and reasonably unmolested. Enjoy.
Cheers
-
Great! Whatever you paid for it, it's a bargain... *wink2*
Always good to have some history with it to.