Yamaha TRX850 Enthusiasts Forum

the question is to all those that have done it ,,, "is it worth it ",, TTS will do the the pistons and the bore and hone inc head gasket and base for £400, i may well need new pistons anyway when i do the rebuild so i was thinking kill too bird with one stone ???? what do those that have done it think ??? ,,, ps, will the crank take the strain my engine has done about 20,000 miles,,,update ,,did a search should have done it first loads of info

yes...be interested to find out myself???? from info gathered,larger pipes and carbs can bolt on upto 15 h/p

just priced up yamaha bits ,,pistons ,rings ,gudgeon pins, gaskets and bore comes to about £300

steve speed wrote:..... will the crank take the strain my engine has done about 20,000 miles

My TRX had upwards of 50,000 kms before I fitted my 878 kit!

Yes it's worth it. IMO, Pound for pound it's the bestist mod you can do (apart from FCR's)

wot he said ^^^^

thanks chaps i thinks this is a good plan,,paul at tts said he didn't think the crank will need re balancing but iam not to sure ?? are the je pistons lighter or heavier ???

Hey steve, does yamaha supply its own genuine factory 878 kit or was that just a/market pistons and resleeve bore with genuine gudgeons/gaskets??? are they a higher comp or std 10.5 to 1????

cobbadiggabuddyblooo wrote:Hey steve, does yamaha supply its own genuine factory 878 kit or was that just a/market pistons and resleeve bore with genuine gudgeons/gaskets??? are they a higher comp or std 10.5 to 1????

the yamaha ones are .5 bigger so you can bore it,,, no difference in compression or cc much,,the 878 are JE pistons with there rings and pins not sure if there is any compression increase but honk or puck will be along to put us straight

yes, the 878 JE pistons are higher compression than the stock Yamaha items

btw, neither involve resleeving the barrels

will i need to rebalance the crank??

steve speed wrote:will i need to rebalance the crank??

the JE pistons work perfectly well (and indeed were designed for use with) the standard crank.

phuk72 wrote:

steve speed wrote:will i need to rebalance the crank??

the JE pistons work perfectly well (and indeed were designed for use with) the standard crank.

thanks phuk

Who is TTS and does anybody know of a supplier of a similar or the same kit in Australia? I looked at the JE Pistons site and couldn't see any reference to the TRX at all.

http://www.tts-performance.co.uk/

If Paul at TTS is to be believed, they had a hand in the design of the pistons

Thank phuk for that!