Belt woes

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Prof
Founder, Choppers Australia
Posts: 5795
Joined: Sat Oct 22, 2005 3:54 pm
Location: Willunga, South Australia
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Belt woes

Post by Prof » Mon Nov 19, 2018 12:12 pm

Jason has been having problems with primary belt alignment on his S&S chopper. Came up Saturday to reduce the spacing between the inner primary and the crankcase to get a more perfect alignment as the belt under power would run into the inner primary.

Jason hopped onto the lathe and machined up some narrow aluminium spacing washers...
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Set it all up at home and although a bit better still not enough, so came back up Sunday to see what we could do.
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After some experimenting, we settled on reducing the spacing another couple of mm's...
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Rob in the meantime was here working on his shovel which has been experiencing some noise at the kicker end of the gearbox. A couple of weeks ago he was up and we'd established that his clutch pushrod was badly worn and his thrust bearing was noisy, so mindful of costs he played around with some parts out of another gearbox he had. The most obvious noise was a slight clatter that appeared to be the kicker ratchet. His changes improved things slightly, but time was up and the bike went back in the workshop.

This time around I had a closer look at things and we found that the ratchet cog (back one in this pic) had a almost completely stuffed bronze bearing which was allowing it to tip and rattle against the outer ratchet. So in went a ratchet set, a new push rod and a thrust bearing. Of interest, the four speed boxes have three different length pushrods due to beefing up the outer clutch bearings and offsetting with the later alternator models, but the ratchet set and thrust bearing are the same from 1936 (the first knucklehead) through to the late seventies/early eighties. Clutch plates are the same... and testimonial to the toughness of these HD bits, my shovel which gets a real workout on the clutch is still running the original plates after 160,000 miles... and I run two less plates less than stock!
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Screwing the rear pipe on for the umptheenth time and the 5/16 recoil thread stripped out. So we drilled it out to take a 3/8 recoil. Handy little tool shown here. I have welded a half inch drive socket to the end of a thread tap tool so I can use a ratchet in confined spaces...
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Rob finished his work and went for a short run with everything working fine at last. With everything back together, Jason took his for a blast as well and all seemed good... two happy chopper jocks...
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I then gave Jason's a good workout up Willunga Hill and back and despite some gear box noise on the over run, seemed that the belt was running true. I was going to suggest we pull the outer primary off again and do a final check, but it was getting late and he was a bit sick of the process having done it so many times.

So as a final check we decided to take a quick run down to Aldinga Beach...
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Travelled one mile and bang. Jason's drive train locked up. Didn't get a photo, but I towed him back behind the shovel and pulled off the primary cover. Busted belt!...
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...and the cause. An inner bolt jammed between teh pully and starter cog...and tore up the belt. On stock Harleys, the two inner primary bolts are wired to prevent this happening. Some how Jason had missed tightening this one... despite the many times he has done this... just one little slip can be expensive...
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Anyway, now late and after some refreshments Rob and Dylan headed off and Jason took my Diamond tanked CB home. Was a beautiful evening, so I cruised along with him as far as Beach Road. Little traffic and pretty cool, two choppers side by side on the expressway. I then ambled off home enjoying the steady beat of the big V Twin beneath me.

New belt ordered this morning, so he will be mobile again for the Muster...
Chopit'nrideit... Prof

EASTY
Posts: 3
Joined: Mon Jul 04, 2016 12:48 pm
Location: Plympton Park
Interests: Hotrods, choppers and kustom kulture

Re: Belt woes

Post by EASTY » Mon Nov 19, 2018 1:33 pm

Had a horrble feeling on the TOW back to the Chopper Shed that I had missed nipping that bolt up, thanks Rilda for pointing out that I had a screw loose..... Haha thought that was gold!! More like the nut behind the handle bars hehe. :D

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