Yamaha TRX850 Enthusiasts Forum

Guys,

Cold night here and the bike started only running on one cylinder (right hand side). I assumed it was just a fouled left plug but I cant get at the plugs to remove them - the spark plug spanner is too long to fit from the side.

After putting the plug lead back on it wont even fire at all



So - my questions:

How do I get the tank off?
Any other ideas than fouled plug?

Tank has 2 bolts, one each side, at the front, and one at the back under the front seat. You also need to remove the tank drain pipe from its stub, the fuel tap pipe from the pump end and the vacuum hose from the fuel tap.

If you want better access to the plugs remove the mounting bolts from the radiator and ease it away from the motor. you can then get your hands in behind it and onto the plugs.

Could be a bad LV connection onto a coil?

You might also check that you have enough fuel, if it is near reserve it is nearly impossible to get it to fire.
Thats right eh Pete

Oh yeah...that too...happened to me last week

Pretty sure it had heaps since I just topped it up saturday afternoon after a ride. As such I've probably done no more than 3kms out of the tank.....

Could potentially have got a bad batch of fuel though..... although I use that place regularly and it was premium fuel. I wouldnt have thought what was in my carbies would have been enough to get me home without sucking in any of the bad fuel. I wasnt even thinking of fuel as a suspect.


I thought the back bolt you can leave in place and swing the tank up out of the way? So it's the bolts from either side?


Think I'll shorten one of the Spark plug spanners to make things easier in future. It seems to be hitting the frame rail more than the radiator.

Yes tank does flip up

Remove rear seat pad, remove riders seat.

Undo bolt at seat end of tank and lift slightly. Remove pipes connected to tank (fuel and breathers - MAKE A NOTE OF HOW THEY ATTACH) and them swing tank up.

Job done

Well, just fouled plugs. Once I got the left out and cleaned it it runs on the left and not the right......


Another half our and it should be done.


Jeez... radiator off and tank off to check the plugs... wouldnt have happened on my old suzi

I find the "flip up" method to be a bit cumbersome. And I've had the damned thing fall back down on my hand before. Once you've removed the front bolts and the hoses, the only remaining thing is that one bolt in the back. I just take it out and remove the tank completely...

Now if it could be done without removing the hoses it would be trick. I've always wondered if they added the feature to make it even more like a Duc...

On the RZ500 I had I extended the fuel hoses so I could flip the tank without removing them and then hooked a cable through the front tank mount to the back of the bike. Hey presto take one bolt out and you could flip the tank up & hold it up while you worked.
From memory cable to hold tank up was a genuine yamaha part.

Not sure if this is applicable to the TRX as I haven't needed to do it. Yet.....

I've extended the tubes on mine so it can be done without disconnecting.

Got very pissed off whilst jetting the carbs (which made sorting the FCRs out a whole load easier)

phuk72 wrote:I've extended the tubes on mine so it can be done without disconnecting.

You must've extended them quite a bit if you remove the back bolt to lift your tank!

I cracked one of the old fuel lines tilting the tank back so took it off. In the end I didnt even need to,

Had to remove the radiator and fan to get at the right plug. Tank gained me nothing.

Suprise suprise... it's got a K&N fitted too. Dunno if thats a win or a lose.

So, first one plug, then the other. Hoping it's all good now.

Max wrote:

phuk72 wrote:I've extended the tubes on mine so it can be done without disconnecting.

You must've extended them quite a bit if you remove the back bolt to lift your tank!

Well spotted Max - I was talking complete bollox

You need to undo the bolts at the headstock end and swing it back that way

OK guys, give you a rundown of where it is right now and see if anyone has any ideas.




1) Initial Fault. Was clearly running on right cylinder only.

Took out left plug. Cleaned it, checked for spark, all was good.

2) Left Plug in and it started on the left cylinder but not the right....

Took out right plug. Cleaned it, checked for spark, all was good.

3) Put in and restart. Running on Right, carrying the left cylinder.




Tonight: Try again.

4) Earlier. Running on Right, carrying the left cylinder.

Cool down and re-try.

5) Running on left, carrying right.



Any ideas people?


It's a brand new tank of premium juice, still havent changed that - may be next step.....

Just to clarify, do you check this by putting your hand over the end of the can or by carefully (so as not to fry your finger) touching the header pipe?

The latter is the correct method.