Yamaha TRX850 Enthusiasts Forum

I have a 99 model[stamped on frame.Carbs have mikunu corp could not find a number.
intake near the plastic slide measured about 37mm with the roughlinometer[cut some cardboard then put it on a tape measure]so not the 40mm mentioned on some 99 models
suggestions for carb kit or needles/tubes please as plugs black,wet and L plug fouls engine misfires then stalls after low speed runs has even wet new iridium's after 20 mins needing a plug change..The pro-jet kit could not be made to run properly so the original's were putback [on the dynotune]
Live in oz so can get a carb kit here if it will fit any help much appreciated.[with the dyno cost,projet kit almost up to fcr cost]

Hi craybait, grab the carburettor kit there on e-bay..mine done myself and works well...all the o rings and tubes and needles are in there...just be sure to have the needle clip in the lowest of the three adjustment notches..[which will have the needle as high as possible for good fueling...assuming your carbs havent been molested before..float height should be ok.
You,ll be running.

Too bad about the Factorypro stuff.
It's in my carbs (TI needles, FactoryPro emulsion tubes with std sized jets) and runs great.
two into one pipes, long oval can with a DB killer, K&N filter and std airbox unmolested.
middle clip on the needle, three turns on the mixtures.
without the DB killer, i had a hole in the power you could drive a truck into between three and four and just on takeoff it would bog and then catch.

cheers
fung

You have checked the fuel tap isn't letting fuel thru by itself (not on demand via vacuum)
this may pool in the left cylinder inlet tract causing some of your symptoms.
if you disconnect the fuel line in the on position, there should be no fuel escaping.
perhaps a weak and/or intermittent spark on the left plug not letting it burn cleanly?
cheers
fung

Thanks Guys for the input
The fuel does not run when checked. and both plugs are black L>R and it goes well on new plugs for half to one hour running then starts to miss,chug then stall eventually at idle.
A filing coil on the left is a good thought for part of the problem as with high revs and freeway speeds it is ok so will get that checked bike seems allergic to 2500-3000 klm rev band.
If they are 99 model carbies but 38 mm throats[not 40 mm ]will the carb kits from ebay fit.
The factory pro site mentions there's will not work with 99 models.Hence trying to I.D the carbs prior to further purchase of kits

sounds silly but one thing always worth checking is that the battery connections are good. It is not unheard of for them to work loose with the vibrations......most probably not your issue but that said its an easy one to check.....as they say where I come from to be sure to be sure