Author Topic: Help - bike's gone bang!  (Read 2120 times)

Offline wortluck

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Re: Help - bike's gone bang!
« Reply #75 on: 22.04. 2018 08:37 »
Cheers bikerboy - I'll look into that. Currently, the ATD is with my mate who's making the rivets (plus a spare set) for me.  May never need them but it makes sense to me.  I've looked at Priory Magnetos and it seems Andrew is not taking new business until July (from the website - please correct me if I'm wrong).  The kit Andy offers is well priced, will probably cost me more than that to get them made but, hey, the guy's going to repair the ATD and show me how to time the beast up (fix and tutorial all in one).
UPDATE:  Have removed oil tank and cleaned out 3 times with brake cleaner, cleaned the feed and return pipes.  Removed sump plate and gauze and OH MY GOD, the crap that was in there. :o  Must have been pretty much all of the shredded teeth, some general crap, and the remains of a small antelope.  *eek* Cleaned all that off with brake cleaner and replaced.  All timing side is as clean as I can get it (tips for removing old gaskets and liquid gasket please).  I used brake cleaner (great stuff) and a very sharp razor blade (at right angles to the case!!) - seemed to work ok.
After the timing's sorted, plan to put a couple of litres of my cheapish oil in, give it a quick run, and repeat once more before filling it up as normal and going for a hell of a run.  What d'you reckon?

Online muskrat

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Re: Help - bike's gone bang!
« Reply #76 on: 22.04. 2018 11:01 »
G'day wortluck.
Go for it.
Listen and feel for anything unusual.
5/16" (0.3125", 7.9mm) btdc full advance will work fine.
Cheers
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Offline wortluck

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Re: Help - bike's gone bang!
« Reply #77 on: 22.04. 2018 13:14 »
Cheers musky, and thanks for the timing info - pretty much confirms what my mate said too.  He's a good guy, is 70 and has been running, racing, repairing and rebuilding British iron since he was 17 - knows his stuff.

Will go steady until I'm sure.  I reckon after the second oil change, if there's nothing in the gauze, I should be good to go for it.


Offline wortluck

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Re: Help - bike's gone bang!
« Reply #78 on: 05.05. 2018 19:08 »
G'day guys.  First up Musky, manual says 11/32 for the timing not 5/16  *conf2*  My mate has now fixed the ATD and the bike's up and running on 11/32 timing.  It's running well except........ it sounds different under load.  Don't want to say detonation, more like a tappety sort of noise - and not all the time??  I've just started using Castrol lead additive and octane booster as I suffered a bit from detonation before.  Super unleaded improved it further and it was running really nicely prior to stripping the mag gear.  Don't know if it's anything really - ideas??
For stripped gear, changed oil twice and cleaned gauze SIX times before taking it for a long run (still bits of fibre teeth in there).  I put the timing cover on using semi-hardening gasket, so checked the gauze again to clean out any excess that may have got in - only a tiny bit there and cover is virtually oil tight.  On that score, my machine pisses oil out everywhere, but not in huge amounts (chaincase, gearbox, forks + seals).  The old tale I heard when I was a kid that British manufacturers made the engines out of old colanders seems to be correct. *eek*

Online muskrat

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Re: Help - bike's gone bang!
« Reply #79 on: 05.05. 2018 19:47 »
G'day wortluck.
With todays unleaded fuel (not what we used to know as petrol) ignition needs to be a tad retarded. Any noise, rattle under load is either pinging/detonation or mechanical (big/little end). As you said octane boost and super fuel helped, retarding the ignition will help further. Orabanda did some dyno testing and found best performance was 30.5 degrees btdc.
Cheers
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Offline wortluck

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Re: Help - bike's gone bang!
« Reply #80 on: 05.05. 2018 21:32 »
Cheers Musky, may well be worth doing what you said at retiming 30.5 degrees.  I'm pretty sure it's not big/little end as it doesn't make that noise all the time - even when it's under load.  It's way better than it used to be, and that's a combination of super unleaded and going easy on the throttle (sometimes give it too much of a handful!).  I'll keep you posted and thanks again.

Oh, and it looks like a thread has stripped in one of the timing cover screws.  I'm guessing this might be some sort of helicoil job.  Again, any advice.  At present, it tightens slightly so I've put some threadlocker on it for now.

Offline a10gf

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Re: Help - bike's gone bang!
« Reply #81 on: 05.05. 2018 22:09 »
Congrats with the engine coming back to life. Agree with Muskrat, try some slight retarding.

Before doing the real timing adjusting, you may try a 'cheat' for testing purpose by decreasing the points gap (if practical). Will retard timing, and one can test if the engine likes it. But mag performs best with correct gap, so go back to normal afterwards.

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Offline wortluck

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Re: Help - bike's gone bang!
« Reply #82 on: 05.05. 2018 22:31 »
Cheers guys, much appreciated!

Online morris

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Re: Help - bike's gone bang!
« Reply #83 on: 06.05. 2018 11:49 »
Oh, and it looks like a thread has stripped in one of the timing cover screws.  I'm guessing this might be some sort of helicoil job.  Again, any advice.  At present, it tightens slightly so I've put some threadlocker on it for now.
Easy job. Just make sure to drill and tap as square to the case as possible. The screws are fairly long and the timing case holes tight so any misalignment and the bolt won’t go in.
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Online bsa-bill

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Re: Help - bike's gone bang!
« Reply #84 on: 06.05. 2018 12:08 »
Quote
Again, any advice.

Helicoil inserts come in different lengths, mostly kits come with X1, this being the diameter of the insert but X2 and X3 can be had so measure how deep you want ( remember you wont be able to tap the full depth).
All the best - Bill
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