Yamaha TRX850 Enthusiasts Forum

Hi all need help -

The TRX was running like a pig snatchy throttle and running rich - so went for factory pro emulsion tubes and needles. Stripped the carbs, fitted new tubes - all good. the needles however looked nothing like the dyno jet ones i took out ( badly worn with wear groves in the top of the needle ). the factory pro items were shorter that the dyno jets and I could not fit the factory pro needle through the spacer and washer. tried without spacer and washer, matching the needle hight form the circlip to the dyno jey needle. put it all back together and the bike ran like a dog. tried various positions with no joy. put the dyno jet needles back in the bike ran OKish - would not tick over properly. reasoned that pilot setting affect tickover so set the pilot screws at 2.5 turn out and balanced carbs, ran OKish tickover cold but degenerated when warm. Any ideas? Pilot jets seem likely as it is affected at tickover and lower rev range. the exhaust also smells petroly, like it is running rich. Which way do the pilot screws turn to lean off the mixture at tickover?

Any other suggestions gladly accepted

Did you set your float heights? Air filter ok?

Check out this for some tips if you haven't already http://www.factorypro.com/tech_tuning_p ... gines.html

Turning the screws out richens, turning in leans out.

Getting worse when hot is a rich condition (unless I've got it arse about...)

From memory, my needle is on the middle position, not sure about the rest of my settings though.

What is the float hight measurement.-? If it is too high would be semi flooding causing it to run rich, but wouldn't it affect the bike over the whole rev range? my idle screws have been set at 2 turns out - standard setting, the bike has stubby end cans and a K&N, which I would have thought would weaken the mixture and need more fuel hence more than 2 turns???

thoughts greatly appreciated

My bike has K&N ans Scorpion cans. I have fitted the factory pro needle jets ans set the carb as follows
Float height 15mm set on the lower of the 2 floats.
Fuel Screw 3 turns
Everything else std