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Replacing timer shaft bushings in WL/Servicar

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slimlavud
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Bikes: Harley 45 (1945) engine in BSA A7 (1954) frame. A chopper of course.
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Replacing timer shaft bushings in WL/Servicar

#1

Post by slimlavud » Tue Aug 07, 2018 6:37 pm

Dear All, I have just got a Servicar timer with auto advance for my 1945 WL-engined BSA-framed chopper. The shaft is a bit slack and has 0.010"-plus side play in it.
I have taken the shaft out and that seems almost unworn, a few thou below 0.500". The old wartime manual says that the shaft wears but it does not look like that...
As it is an auto advance timer, there don't seem to be any new old stock shaft and body items available and so I was going to renew the bushes.

My questions are:
1. Is it usually the bushings that wear out or the shafts?
2. Once I have pressed new bushings in, will I need to ream them to fit the shaft nicely?
3. I can buy an adjustable reamer but if anyone in Europe wants to ream the bushings for me or knows of somewhere trustworthy...?
4. Does anyone have a hold-down clamp for the auto timer plus the two screws for it and two locking or nyloc nuts for the studs in the timer please?

Thank you
Simon



RUBONE
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Re: Replacing timer shaft bushings in WL/Servicar

#2

Post by RUBONE » Tue Aug 07, 2018 10:29 pm

1) Both, due to poor oiling, when dry the bushings will prematurely wear the shaft. the bushings tend to wear egg shaped due to thrust.
2) Yes, ideally the bushing are undersized bore and must be fitted to the shaft. Be sure whatever bushings you use are grooved for oiling. All the
lubrication is by mist/vapor, so it needs a pathway to get in.
3) Hopefully someone local to you has an idea.
4) Easy to fabricate if an original is not found.

slimlavud
Posts: 44
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Bikes: Harley 45 (1945) engine in BSA A7 (1954) frame. A chopper of course.
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Re: Replacing timer shaft bushings in WL/Servicar

#3

Post by slimlavud » Wed Aug 08, 2018 9:38 am

Thanks RUBONE
The shaft shows no wear by measurement, I shall have to see if there is wear that I cannot seem to measure with a micrometer, once I get the bushes. I will buy a reamer if I need to, I have found some quite good adjustable ones on ebay for about $15, or I might drive a 1/2" bearing ball through the bushes if there is not much to take out. As there is a scroll/quick thread at the top of the shaft, which I presume is to keep oil down and stop it from flooding the timer base, I think that quite a bit of oil gets up there by capillary action - between the shaft and the bushings...
I am going to buy new old stock genuine Harley bushings - I guess these are the best and probably made to fit without reaming - I can't imagine any precision reaming going on in the theatre of war...

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