Yamaha TRX850 Enthusiasts Forum

Hey Gang,
Did a basic oil and filter change yesterday and cleaned the air filter (removed fuel tank ect). Alas, when I tried to start it today it sounded horrible and only one cylinder seems to be firing (one pipe hot while one remains stone cold).

I checked everything was back in place properly (vacumme hoses ect.) all good. I didnt touch the spark plugs so am kind of surprised they would just die but it seems like thats the next step. So I'll have to wait until tomorrow to go hunting for spark plugs and a spark plug socket (brother pinched the old one) but I just thought I would check if there was anything else I could be missing/knocked that would cause only one side to die.

Cheers!

Ended up being the spark plug! Still dont know why it fowled so suddenly. Just glad it wasnt something more horrible.

The earth electrode has been positioned or knocked to close the gap right up



Mark.

I had an iridium plug that died on me and only lasted a 500 km's or so.. Started one day and ran fine. then the following day started and only ran on one cylinder. just like that... Put the clean plug in each coil lead,earth it off somewhere on the motor and turn it over and see if you have spark from each coil hopefully it's just a plug, if not just follow the chain,check the power to the coils or change the coils around and see if they both are sparking

Hello!

Have you checked your emulsion tubes in your carbs? That may be your issue to why your plugs have fowled.

Calamity !!
KFC in the.tubes

looking at the fouled plug on the right I can see some sign of water getting onto the plug, but just the one on the right. I would make sure the cap is sealing against the cam cover and that the drain hole on the left side of the engine is clear

The plugs should be cleaner somewhat than those, suggest fitting the carburettor kit so your motor isn't running so rich and causing carbon build-up and fouling the plugs...
Short term, fit a new set of plugs..
Long term, fit a carb kit....she's running too rich.

Good thought as well Paul

alextrx850 wrote:The plugs should be cleaner somewhat than those, suggest fitting the carburettor kit so your motor isn't running so rich and causing carbon build-up and fouling the plugs...
Short term, fit a new set of plugs..
Long term, fit a carb kit....she's running too rich.

Good thought as well Paul

Something like this?

http://www.trx850.com/phpBB_forum/viewt ... 18f#p91643