Clatter

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pedro
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Clatter

Post by pedro »

I was giving my 350/501 the usual treatment at Cadwell when it suddenly developed a worrying clatter from the engine department. My first thought was that an exhaust was coming adrift,I know what that sound like and it was a similar clatter, however, when I got back to the pits it was not the case, several people had a listen and thought that it sounded top endy, Ollie suggested that it might be the primary gear nut coming adrift, but it's not. I have dropped the oil out and nothing nasty in that, removed the rocker boxes and clearances are fine, and nothing loose. Not sure where to go next. Any suggestions appreciated.
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72degrees
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Re: Clatter

Post by 72degrees »

Noisier with the clutch cover plate off, in/out of gear, clutch pulled or not?
pedro
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Re: Clatter

Post by pedro »

Doesn't seem to make any difference, I have to investigate the clutch side of things further because I misunderstood what Ollie was talking about, I thought he meant the nut behind the clutch plate with the tab washer, whereas he is talking further in, on the end of the crankshaft.
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Re: Clatter

Post by EVguru »

Have you checked the alternator?
Paul Compton
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pedro
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Re: Clatter

Post by pedro »

Yes Paul, all in one piece, seems fine.
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72degrees
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Re: Clatter

Post by 72degrees »

pedro wrote:Doesn't seem to make any difference, I have to investigate the clutch side of things further because I misunderstood what Ollie was talking about, I thought he meant the nut behind the clutch plate with the tab washer, whereas he is talking further in, on the end of the crankshaft.
Ah, the nut that also holds the oil pump drive gear. I had nightmares about that one when rebuilding the project 350. I used one of the new type that needs a special peg socket but I think I got it tight enough. It's a bit of a major job to get to it, including remembering the kickstart spring winding gotcha on reassembly but it's hard to think of a better check (including the primary gear bush) to do before that given the symptoms.

Any better or worse cold than hot? Just thinking out loud about pistons but if one was starting to break up you would expect the crankcase breather to be working overtime.
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Re: Clatter

Post by EVguru »

Having seen Pete Farrel's cylinder head, what about a loose valve seat.
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Re: Clatter

Post by 72degrees »

EVguru wrote:Having seen Pete Farrel's cylinder head, what about a loose valve seat.
I suppose so. Mind you, the only time I ever had that was on an AJS 350 single and it got beyond loose, dropped out and was bashed back 'crooked' thus losing compression - though I managed to coax it another few miles by keeping the revs up.
pedro
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Re: Clatter

Post by pedro »

Not being a mechanic, although I've been playing with bikes an awful long time, my spannering ability is not brilliant, I can take a bike apart and screw it back together OK, but when it comes to more technical stuff, engines/gearboxes, electrics etc. I'm not really up to it and I know it. George at the trackday thought the clatter sounded top endy, this tied in with Paul's thoughts about valve seats, and as that appealed to my limited ability much more than going with Ollie's suggestion, I pulled the heads off this evening, nothing to report in there though, all looks good, if a little rich on the main jet which I knew about. It's looking increasingly like Ollie is on the right lines. I have the clutch plates out and am trying to move the clutch centre nut, I've used a few old plates and a bit of bar to make a holding tool, but I can't shift the nut, I presume it is a conventional thread?
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Re: Clatter

Post by EVguru »

Yes, it's a normal right hand thread. An impact driver is your friend here, either air or electric.
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Re: Clatter

Post by 72degrees »

EVguru wrote:Yes, it's a normal right hand thread. An impact driver is your friend here, either air or electric.
Or a 'breaker bar' and well fitting socket.
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Re: Clatter

Post by norbert »

Be careful Pedro!

We had a friend of mine, well a couple, from Spain at our meeting last week (you can find some fotos here http://www.lamaneta.org/forolamaneta/vi ... 71&t=12402 and here http://mantaray.zenfolio.com/p128986472 ). They brought along a Bultaco Alpina to change it for a MM 500. When we had a look at the clutch of the 500 a part of the treadend end of the primary broke off :roll: . I also had a primary axle with a broken thread in my "spareparts" (now doing it´s job like a candleholder). There are manuals that say that you should tight it up with 9 while 6,5 will do :wink: Some of them must have had a hard live :roll:
Perhaps you should use a litte heat on the nut or cool down the axle if you can, before using too much force.

suerte!
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pedro
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Re: Clatter

Post by pedro »

Thanks for the warning Norbert, got the nut off OK by borrowing a friends compressor and rattle gun, got inside and--- nothing, all seems tight, no movement on the crank or anywhere, this has me baffled, going to screw it all back together and put a stethoscope on it.
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Re: Clatter

Post by MickeyMoto »

Tank rattling on the frame?
Loose engine mounts?
pedro
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Re: Clatter

Post by pedro »

Nope, my first thoughts after loose exhaust, definitely engine and quite harsh but can't find where, I'm secretly hoping it will have gone away when I get it all back together but I don't think it will have. Then it will have to be off to someone with more knowledge than myself, NLM maybe unless I can find someone in the South East willing to take a look. Does anybody know of a South Eastern competent mechanic familiar with these beasties?
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