KX 65 rebuild - bottom and top end

[Mike-Evans]

Hey guys,

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

Ive split the cases, fitted new Koyo mains, seals and gaskets, fitted a new Mitaka crank assembly and sent the cylinder away to 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?

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?

Cheers all 

[Bidule]

Hi Mike

Just curious, did you find something wrong to fix the front sprocket resistance ?
Did you buy the case splitter ? I am asking because I want to do the bottom end on my son's KX85 soon and I have never done this before.

[Mike-Evans]

With the sprocket resistance, I removed the clutch casing and removed the clutch again, the resistance had then disappeared, so it is clutch drag.

Weve used the bike now and the clutch is fine.

I didnt buy the Tusk splitter, I bought a harmonic balance puller off ebay, it was £8 and worked perfect, a few people have used these to split cases. It fitted perfect on the stator casing.



Let me know if you have any questions or need any tips as its still fresh in my head.

This was my first time doing a bottom end