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  #1  
Old 09-02-2016, 08:47 PM
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Default Ktm 85sx 2008 rattle from flyhweel

     

On Rick over there's a rate type noise coming from flywheel cover but you can't hear it when you Rev the bike! But once your riding at high speed say 4th or 5th and come off the revs the flywheel is really loud, I actually thought there was a little two seater plane flying above me that's exactly how it sounds and that's through a helmet too so it's quite loud any ideas what it is is it something to worry about? Just bought the bike off someone who says he just done a full rebuild on it

---------- Post added at 03:47 AM ---------- Previous post was at 03:28 AM ----------

On tick over there's a rattle noise
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Old 09-02-2016, 10:57 PM
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1st check the obvious it could be loose or something on that side. my belief something needs tightening try that.
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Old 09-03-2016, 04:46 AM
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Is it just a simple remove the cover job? Maybe it is that when he's rebuilt it not tightened it enough easily done if you rush
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Old 09-03-2016, 05:33 AM
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There are a few of possibilities.
1. The flywheel nut is not tight or the flywheel key is worn. If either of these are the issue the flywheel will come off while running and cause damage.
2. The crank shaft bearing is bad. If this is the case, the bearing will fail and cause major damage if not replace quickly.
3. It could be a bad or worn rod bearing.
You need to find the cause and not ride the unit until it is fixed.

Paw Paw
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Old 09-03-2016, 11:40 AM
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The flyhweel is tight! But there's a bit of movement forwards and backwards pulling away and towards to bike is that normal? Or should there be no movement in it apart from it spinning of course
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Old 09-03-2016, 12:17 PM
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No movement should be there. You have a bad crank shaft bearing. They need to be changed in sets. It will get worst and then it will destroy the crank seal and you could have a blown engine in very short order. The engine needs to be removed and torn down.
Do not ride it until you fix it!

Paw Paw
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Old 09-09-2016, 07:18 PM
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Sorry for slow response been so busy! But paw paw you was spot on!! Crank bearings needed doing so doing everything else while engines apart, now real question how long would you say run it in for cos doing top end too! People are telling me ten minutes get engine hot let it cool then go some are saying two I'll tanks of fuel 😂 You seem to k kW your stuff what would you give it
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Old 09-09-2016, 08:37 PM
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I would run it through a couple of heat cycles with no load. Then give it a ride using no more than half throttle with minimum load. Then it should be ready to ride hard.
You need these heat cycles to allow the new parts to settle in before running it hard.

Paw Paw
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Old 09-10-2016, 06:01 AM
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Great stuff I'll do exactly that, would you say use a little extra oil ? I usually run on 125ml to 5 litres of fuel
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Old 09-10-2016, 06:23 AM
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That mix should be ok. If you add extra oil you will be leaning the fuel mix and that could cause extra heat.

Paw Paw
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