Yamaha TRX850 Enthusiasts Forum

Bike was running fine yesterday morning........20km commute to work , early morning, 10 deg C.
Yesterday afternoon, started fine, revved freely but didn't seem to have much power on acceleration, like when it's due for a service.
Started bike up this morning, on slight choke. Even after 5 minutes,it wouldn't seem to clear itself when revved. The motor sound seem a bit subdued and there was this phhtt, phhtt sound coming from the motor. It sounded like it wouldn't clear itself or was running on 1 cylinder even though it clearly wasn't (checked the exhausts)
Stopped the motor, and tried to restart it.
Heaps of current, BUT the motor wouldn't fire up. Tried a few times, but no go.
Honestly, this is the first time this bike has let me down in 10 years!
Valves were checked at last service - 84,000kms and were fine. Bike has been running excellent up til now. Doubt if it was the fuel tap, new one not that long ago.

What I'm thinking is COILS - they are the originals (14 yrs old) or the CDI - original too!
Am I on the right track? Bike isn't flogged and most things on it are still original. Help?

Had to take day off and am gonna ring the mechanic later on to see if they can pick it up.

Bob

Could it be fuel related?! Prob worth checking the fuel line and vaccum/breather hoses.

It sounds like a problem that I had once, symptoms are similar. When my bike began to run rough I checked the exhausts and both had similar heat with fumes etc. Due to this I presumed that both cylinders were fireing fine, so I disregarded the plugs coils etc, after weeks of pulling my hair out I dicided to bung a set of plugs in and hey presto, fault cured!!!!! Plug was faulty and not producing a strong spark under load. It may be worth your while sticking a set of plugs in just to see?

My old bike did similar things when the regulator was on its way out. Lights were not glowing consistently and under load the reg could't get the sparks sorted.

Sounds like either not enough fuel or not enough spark. Hopefully something minor and cheap to fix.

When my battery died, and i rolled the bike to get it started it was just firing on one cylinder

Vacuum tube had come off the tap - reconnected and viola it started. Pity I didn't find it later, I was only 2.5 hrs late for work

Bob

Going by the symptoms you describe, I'd suggest its almost definitely the vacuum hose thats come off the tap.

That's what the dude said