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  #1  
Old 22-07-2012
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Loud rattle at cold start

Hi guys,
My 'TM 450 exc that has developed a loud rattle when starting from cold. For a start the kick start has a lot of resistance at a certain point which I assume is the compression stroke, more so than I have noticed before. When the bike finally starts (after a few pops from the exhaust on few kicks) there is a loud metallic rattling coming from the engine that changes in tone but stops when throttle is blipped and comes back when revs settle back to idle. After a period of warming up the noise disappears.

I thought the cam chain may have some slack and perhaps slipped a tooth on the cam, on inspection the cam chain appears tight, the auto decompression arm moves freely and by locating the grove in the crank I have tested that the cam in correctly indicating TDC.

Not sure what else to check? Any help is appreciated.

Thanks,

Buster
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Old 22-07-2012
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Valve clearance ??? Compression ???
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Old 22-07-2012
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oil pressure/volume/freshness????
loose primary gear nut/clutch basket?
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Old 22-07-2012
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Piston slap.
Once it warms up it expands in the bore and the rattle goes away.
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Old 22-07-2012
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It's stuffed, a time bomb waiting to go off.
I'll give ya $500 to take it off your hands, i will want it delivered though, and washed too thanks.
Fresh tyres would be nice but not a deal breaker.
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Old 22-07-2012
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Timing chain tensioner, surely?
It is a KTM...
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Old 22-07-2012
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Quote:
Originally Posted by spac View Post
timing chain tensioner, surely?
It is a ktm...
+462,000
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Old 23-07-2012
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cam chain seems pretty tight although I know what you're saying with ktm chain tensioner. Valves are borderline at the moment and will need new shims pretty soon but would that explain the noise?

Piston slap? what would cause that, rings, little end bearing? It doesn't seem to be burning any oil. Oil has recently been changed in both engine and trans.
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Old 23-07-2012
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Hey Buster, is it a KTM or TM? not that it makes too much difference, all 4Ts are pretty similar, if is is not excessive clearnaces in the valve gear (recent service?) then sounds like an oil pressure issue to me, weather it is the oil pump or losing line pressure somewhere sounds like what it most likely should be
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Old 23-07-2012
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Quote:
Originally Posted by Hivisibility View Post
Hey Buster, is it a KTM or TM? not that it makes too much difference, all 4Ts are pretty similar, if is is not excessive clearnaces in the valve gear (recent service?) then sounds like an oil pressure issue to me, weather it is the oil pump or losing line pressure somewhere sounds like what it most likely should be
It's a KTM mate, interesting you say about excessive clearences, when I said they were borderline they are on the excessive side. I've only recently go the bike so I'm not sure if there has been this issues previously or the last time it was serviced apart from the servicing I am doing on it now. Regarding the oil pressure, I will check the oil pressure spring and make sure it's also in spec.

Cheers

Last edited by BusterG; 23-07-2012 at 01:01 AM. Reason: typo
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