HOLY SHIT! Glad I didn't push the button...

[george formby]

We have the same problem & more or less the same motor. After turning on the ignition my TDM has done the same thing, petrol coming out where the headers join the rest of the exhaust. I turned the fuel off, left it & had another crack at starting it. Off she went. I now keep the fuel turned off when I start it & have had no more problems. On the TDM forum, home of some real gurus, the concensus was a perforated diaphragm in the fuel pump. My problem only manifested with a full tank of juice. Their are photos of a stripped down pump on carpe-tdm.net, posted by a guy who had this problem.

[mud boy]

damnnnn!

[SPman]

FCRs - same as the SP.........has someone been out in the garage playing "vroom vroom" at night and pumping the cylinders full of gas......

[The Pastor]

I had the same problem with my mc22, took the carbs apart - including the float valve, didnt see anything wrong, seals ok, carbs clean etc etc. Put it back together and it never happend again.

My guess was a tiny bit of dirt was on the float needle valve and i disloged it when i took them apart.

[R6_kid:Me]

My problem only manifested with a full tank of juice. Their are photos of a stripped down pump on carpe-tdm.net, posted by a guy who had this problem.

Initially mine seemed to be the same - only after going from reserve to full after filling the tank. I might take a look at the carpe-tdm site, I'm on trx850.motomaniac.net which is the only TRX forum I can find that is in English (I don't speak French, German or Dutch, which seem to be where TRX's are most popular!)

FCRs - same as the SP.........has someone been out in the garage playing "vroom vroom" at night and pumping the cylinders full of gas......

A ghost maybe? No one goes in the garage except for me and my father - he knows he'd flood it if he "vroom vroomed" the throttle especially considering that it has dual throttle pumps!!!

I had the same problem with my mc22, took the carbs apart - including the float valve, didnt see anything wrong, seals ok, carbs clean etc etc. Put it back together and it never happend again.

My guess was a tiny bit of dirt was on the float needle valve and i disloged it when i took them apart.

Current setup has a fuel filter in the tank, and an in-line filter, both in good condition. I'm thinking it's got something to do with the either the tap/pump or the carbs (they are the only three things that could be wrong!). The carbs were clean when i opened them up, though one slide sits a fraction higher than the other.

[The Pastor]

Initially mine seemed to be the same - only after going from reserve to full after filling the tank. I might take a look at the carpe-tdm site, I'm on trx850.motomaniac.net which is the only TRX forum I can find that is in English (I don't speak French, German or Dutch, which seem to be where TRX's are most popular!)



A ghost maybe? No one goes in the garage except for me and my father - he knows he'd flood it if he "vroom vroomed" the throttle especially considering that it has dual throttle pumps!!!



Current setup has a fuel filter in the tank, and an in-line filter, both in good condition. I'm thinking it's got something to do with the either the tap/pump or the carbs (they are the only three things that could be wrong!). The carbs were clean when i opened them up, though one slide sits a fraction higher than the other.

did u spray some carb cleaner in there just to be sure?

[R6_kid:Me]

Will be doing a full strip/clean/reassembly in the next couple of days - exams have to take priority for the mean time.

[kwaka_crasher]

Prime setting is designed to flow fuel in to the carbs

Unless faulty, the float valve prevents the fuel flowing up into the intake.

Would a needle stuck open allow fuel to drain even if the floats are closed??

The floats control the float needle valve. When it shuts, the level in the float bowl cannot rise and fill the engine.

We have the same problem & more or less the same motor. After turning on the ignition my TDM has done the same thing, petrol coming out where the headers join the rest of the exhaust. I turned the fuel off, left it & had another crack at starting it. Off she went. I now keep the fuel turned off when I start it & have had no more problems. On the TDM forum, home of some real gurus, the concensus was a perforated diaphragm in the fuel pump. My problem only manifested with a full tank of juice. Their are photos of a stripped down pump on carpe-tdm.net, posted by a guy who had this problem.

But again a float valve would have to be faulty. In this case some portion of the fuel in the tank would also have to be below the float level to cause the problem to not occur when low on fuel. This is highly likely, as if all the fuel in the tank was above the float bowl level, you wouldn't actually need a fuel pump - it could be completely gravity fed.

[Kwaka14]

That was my thoughts...

Would a needle stuck open allow fuel to drain even if the floats are closed??

Yes, the needle is the valve that the float "closes"..... if it's stuck, then its not closed.

[jonbuoy]

Yeah the on/off fuel tap should only be a backup the seat should be enough to stop the gravity fed fuel from getting past it - if not they are stuffed. Maybe a little leakage is acceptable. Could it be the float isn´t floating? If it has a hole in it it will have fuel inside and not float properly.

[R6_kid:Me]

I wasn't meaning the float valve needle, I was meaning the Jet Needle.

[vifferman]

I wasn't meaning the float valve needle, I was meaning the Jet Needle.

That has no effect on fuel flow except when the engine's actually running.

Could it be the float isn´t floating? If it has a hole in it it will have fuel inside and not float properly.

Same thing will happen if the arm's bent or the pivot's sticking, or the needle valve seat is worn or grubby. Some models of bikes are also notorious for misbehaving when leaned over on the sidestand.

[R6_kid:Me]

Same thing will happen if the arm's bent or the pivot's sticking, or the needle valve seat is worn or grubby. Some models of bikes are also notorious for misbehaving when leaned over on the sidestand.

Thanks for clearing up about the jet needle.

I just took the bottom off the carbs to have a better look at the needle valves and the seats. The needle valves look fine to me - identical condition to a set of new needles I installed on the carbs on the CB650. The seats however look worn/dirty. I sprayed them with some cleaner and scrubbed them the best I could but it doesn't seem to have made difference to how they look. The right hand one looks a fair bit worse than the left hand one which is in line with only the right cylinder flooding with fuel.

Still doesn't account for the volume of fuel that is getting past though. I'll take the fuel pump apart and make sure that is all kosher, otherwise it will have to be the tap that is the problem - but then the tap hasn't been leaking while I've had it off the bike...

[Rodney007]

hope you get it sorted bro.... ring up those carb dudes in the city!

[R6_kid:Me]

hope you get it sorted bro.... ring up those carb dudes in the city!

I'm gonna hit up treads this arvo and price up some new valve seats... they are $13.95USD so hopefully shouldn't be too expensive to get locally. I've used Auckland Carburettor Specialists before - didn't help much at the time, though it wasn't really their fault.

Update: took the fuel pump apart - looks like it's pneumatic, wasn't expecting that. All seals and diaphragms are in good condition.