Yamaha TRX850 Enthusiasts Forum

hi people, need some help, when starting the bike the other day it began to turn over then clunked and stoped tried the starter again, it span[starter] but motor not. put it in gear rocked it, tried again motor then started now the problem realy starts its now missing on the right cylinder, runs poorly when reved and will tickover only on the left, also smokes out of the right, [this could just be unburnt fuel.] the right must be firing at point, as the exhaust gets hot. i have changed the plugs, right side was black and wet . so to sum up , do you think the 2 problems are related? i thought the starter clutch could be the first prob, but cant see it affecting the firing. i have checked the coils and a basic check of the carbs. please any thoughts

Get a good spark plug stick it in RH lead earth it out while turning motor over and check condition of spark and go from there. Battery fully charged of course.

yep got the same spark from both sides, it must be getting fuel as it stinks of it from that exhaust,! ?
think i may strip the carbs

An outside thought, fuel leaked into r/h cyl and hydraulic'd, damaging something ????
Compression test first then go from there Just a thought, maybe try the other simple things first.
Good luck.

Hmmm, the CLUNK sounds ominous.
Compression check for definate, then a process of elimination.The hydraulic lock scenario is not too likely but if the vacuum fuel pump has been allowing excess fuel to run into one cylinder through the vacuum hose to the inlet stub you may have had one huge detonation effect.
Starter clutch problems on TRX`s are not common so get that compression checked.

ok people, will have to do a compression test will keep you posted

soooo the bikes been in the shop and the compression came up good, but the fule pump is stuffed 260 nz dollers for a pump and a 2 week wait from japan but at least i know what it is now

Aww that`s a shame pom in nz, over here you can pick up serviceable TRX vacuum fuel pumps for 20 quid, actually I`ve already got a spare.
Did you not think of going down the electric fuel pump route, it might have been cheaper?
A quick search turned up brand new low pressure pumps at pretty low prices:

http://www.merlinmotorsport.co.uk/p1461 ... _info.html

Obviously a second hand electric fuel pump from any other bikes could be used too, low pressure pumps (for carburettor systems) are usually easily found for little money.

Mincehead wrote:Aww that`s a shame pom in nz, over here you can pick up serviceable TRX vacuum fuel pumps for 20 quid, actually I`ve already got a spare.
Did you not think of going down the electric fuel pump route, it might have been cheaper?
A quick search turned up brand new low pressure pumps at pretty low prices:

http://www.merlinmotorsport.co.uk/p1461 ... _info.html
Obviously a second hand electric fuel pump from any other bikes could be used too, low pressure pumps (for carburettor systems) are usually easily found for little money.

Sorry to hijack pom in nz but I've considered this.
Mincehead, How difficult would this be? Vacuum outlets on the carbs would need to be blanked off? Would a fuel regulator be needed? Thanks

You`ve got it, blank off the inlet stubs then it`s simply finding a low pessure pump.The float needles take care of demands so fuel pressure doesn`t need regulating.
Breakers yards are full of cheap fuel pumps from many types of bikes and you can find new quite cheaply too as in my link.Although, you would like to keep to something not too large or ugly eh?
The crank driven coolant pump can be junked too for more efficient and thermostatically controlled electric pumps, the crank driven pump does sap half a pony or so from the motor too remember.
I nearly went down that route on my Skorpion (XTZ660 motor) as Yamaha-hahahaha wanted over 160 quid for a water pump assembly!
I eventually managed to repair the original with the help of a local pump seal company and some ingenuity.

yeh got me bike back today, picked it up rode it round to the gas station, filled it up,....................................and took it strait back to the shop, as it promptly only ran on 1 again .
1hour later phone rings, bikes done,........................earth wire to the right side coil was only just touching all happy all done.
now about that R6 shock and dynojet kit

thanks for your feedback people, this is an excellent site. cheers