Kx65 Motor Died

Joined
Sep 16, 2009
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#1
Hey guys,

The big end failed recently on my lads 2002 KX65 causing it to kill the motor....

Images added

Ive split the cases, fitted new Koyo mains, seals and gaskets, fitted a new Mitaka crank assembly and sent the cylinder away to our local cylinder repair company - Langcourt for minor weld repair and replate. I have a new "A" Mitaka piston kit to fit when cylinder is back.....

This is the first time Ive ever split the cases and done bottom end work, only ever done top end work...

I froze the mains and warmed both cases and the bearings dropped right in. Warmed right case (with crank seal and main bearing in) and froze the crank, the crank dropped right in... cases when back together without and issues. Used Yamabond 4 sealant

Sprocket shaft turns nice and free at this point. Fitted all right side gears and clutch basket and clutch plates and fitted the clutch casing, again no issues.... now the front sprocket has some resistance when turning... i removed clutch casing and clutch plates and sprocket was free to turn again, so it must be resistance caused by the clutch plates - is this normal?

Also, has anyone got experience with Mitaka bottom and top end is kx65s? Any good? Any issues? Seems to be some negativity about this brand online, but Ive spoken with 3 UK Mitaka dealers who day if the maintenance is done right and engine looked after, it will be fine.......

Also, is there anything I should know about when doing bottom and top end work on the kx65? Any common probs?

What break in method do you guys recommend?

My theory of the failure is big end failed throwing part of a needle bearing up top causing the damage to the top of the piston and cylinder head?

Cheers all













 
Joined
Sep 16, 2009
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0
#3
Yes it turns freely. Once in the cases it needed a tap on the right side to centre it