Yamaha TRX850 Enthusiasts Forum

Hey y´all with the JE kit...

I´ve left a cylinder for rebore and the guy at the shop asked what play he should bore for....
I´ve never seen a different number than 1,5mm over, 91mm bore.
Is it 91,0000 mm or should they bore for play?

Absolutely no idea

91mm at at guess

is there no spec from JE ?

I'd assumed that you fitted a liner.

steve speed wrote:is there no spec from JE ?

There where none in the boxes, passed the question on the German forum where they where bought....

youngy wrote:I'd assumed that you fitted a liner.

I did what???

in better English..................my assumption was that one fitted a liner for this size of overbore - 878cc? is this not the case? zylinderlaufbusche ?

youngy wrote:in better English..................my assumption was that one fitted a liner for this size of overbore - 878cc? is this not the case? zylinderlaufbusche ?

I hope not, in that case i´ve misunderstood completely....and as i wrote on the other forum that the cylincers where at rebore i guess they would say something.

I know kedo do have sleeves to press in there though....

No liner needed - the standard barrels are bored to 91mm

phuk72 wrote:No liner needed - the standard barrels are bored to 91mm

I´ve started contacting company´s with JE so it will become clear soon, luckiliy the mechanics did not have time today anyway....


...well, according to JE specialist in Sweden all Je pistons have a specific play wich are unique and should have been sent with the pistons....*hmmm*
Alway´s me!!

What Phuk says, but You need a small play between cylinder and pistons, I guess that's what the workshop's asking for. If I re-call correctly, the play should be 5/100 mm, but check it with JE. I would leave the pistons with the workshop and let them sort it out themselves, they should know!

And BTW, if You're contacting JE, ask them what ring gap clearance should be. I didn't bother, just set it to Yamaha Standard, but it might have been wrong...

HansJ wrote:If I re-call correctly, the play should be 5/100 mm, but check it with JE.

Großewächter answered, it should be 5/100 - 6/100 so you remember correctly.
The machining dudes where not that off either, he had measured the piston and wrote down 4-600....

Now for the biggie Hans....brutal run in or not!?

Brute, just make sure You have oil by checking the tell-hole in the head first, then go for it and

iam going to run mine in as motoman says ,, hard,, i feel its the only way to get the rings to seal ,,i went to the ducati factory last year and every new bike went on the dyno and was run though the gears hard up to the redline ,but not in top gear , but i still saw 120mph on there dyno