Yamaha TRX850 Enthusiasts Forum

Well, bike won´t start...bastard...

Story goes...dude who done my TRX:s head was looking into porting the 41´s so i´ve sent them back/forth...well packed me thinks. Dude (the mechanical guy with tuning knowhow) had never seen such long intakes so he figured he take some off....and 41´s was stuck on the oilpipe....bugger....send them back....tig them....wait for post...

Installed tonight, fuel comes to them....bike started but needed help keeping revs up....like it was flooded with fuel.
Second try and i got 2 backFIRE´s (had tank up so they almost took out the brows) but nothing more, now it won´t fire up at all.

So, what could have fekked up in the carbs....OR (here comes the CI part) could it be valves at last....was out of spec on 4 of them when checked a while ago and it HAS done 39K KM now.

It would be GREAT have it running as it did before posting carbs....but if valves i´m about to change head anyway....

WHAT SAY YOU?????

Whaley...

Sounds a bit like you might have a tooth out on the valve timing... worth a double check I think..

Sounds exactly like my XR250R after I f*cked it up first time.,..

Greg.

Everything can happen i guess, would be surprised if it is as i changed the chain not 100 metric miles ago.
Stripped/cleaned everything in the carbs after their 200 mile (metric) trip so i´ll do a try today...
Otherwise i just going to strip it as the other head waiting to do it´s magic!

Greg wrote:Whaley...

Sounds a bit like you might have a tooth out on the valve timing... worth a double check I think..

Sounds exactly like my XR250R after I f*cked it up first time.,..

Greg.

Daft question, but You had the carbs ported as well? Did he port them D-shaped? That might be the problem then. Flow is very different compared to round carbs, Your jetting is most likely way off especially in the low range.

HansJ wrote:Daft question, but You had the carbs ported as well? Did he port them D-shaped? That might be the problem then. Flow is very different compared to round carbs, Your jetting is most likely way off especially in the low range.

No, carbs never touched as it already where maxed out by keihin (could have done a mm or so but not worth the effort)