Yamaha TRX850 Enthusiasts Forum

Hi all

Been having a bit of frustration with the Rex on what seems to be a random/adhoc fuel starvation and it has happened again today.

In short, yesterday, it was running just fine but this morn when starting up, no way she would idle (cold or warm) and so have to keep the throttle slightly open to keep her running (running rough by the way). Accelaration is fine although I can feel a little less pull than usual, there lots of farting about about from the exhaust on decelaration (already runs a little lean) and lots of farting about from the cylinder head breather when at low revs/light throttle. Fuel tap is on "on" mode, nothing changes if I put reserve or PRI, the fuel in the tank is fresh and the engine oil level is good. When I open the tank lock, there is pshhhh of air making me think the fuel doesn't go down properly but where to look?! Didn't touch anything over night, it was parked in the usual spot in the back garden, under the cover so I am little confused.

Had this problem randomly appear before and lifted the tank up, played with the hoses etc and the problem went away but it's obv a little annoying when it comes and not knowing what causes the issue.

By the way, my old tankhad two breathers and hoses to connect on the lower right side (when you sit on the bike) and the tank I have now only has one... this is the only difference I have noticed.

Any prompt help welcome as I am taking her to France Thursday eve

Thanks
Adrien

There is a mesh filter attached to the fuel tap, that might want cleaning,tank off and drain job, then remove the tap from the tank.
there is another filter as the fuel pipe goes into the carbs, just at the point where the one pipe "T"'s off to the two seperate carb feeds again might need a clean.

Phew, problem solved.

She was running on one pot as one header was getting warm whilst the other one wasn't on idle/low revs. This was due to a split carb inlet rubber... bought and cut some to fit the wider FCR inside diameter a few weeks ago but it obviously didn't like the work I did to it and its short life on a TRX engine .

Good idea about the mesh filter clean

Anyone got any ideas on the one tank breather hose instead of two and the pshh from the tank cap?

Cheers
Adrien

Really, did you get a tad carried away with the Dremmel or die grinder matching those internal diameters?

Mincehead wrote:Really, did you get a tad carried away with the Dremmel or die grinder matching those internal diameters?

Possibly

Thought what I'd done was ok and didn't think the rubber would split open horizontally I guess you learn from you rmistakes. One thing for sure is that I am becoming a pro at taking off and putting back on those FCRs!

Run a piece of fine wire down the breather hose while attached to the tank (from the cap down)and make sure it's not blocked just to make sure

+1.

Use some 1mm stainless mig wire, it`ll bend around anything but remain rigid enough to find it`s way through, alternatively a blast from a high pressure air gun often clears anything.

I'll sure give that a go!