Fuel Pump or the Carb...help guys!!!?????????

[Darius1502]

Ok...I was riding my Tri Z and everything was going fine. Trike started when cold with the choke on since it was pretty cold outside. Then as it warmed up I turned off the choke. Ran great but I never went full throttle for very long or generally over 1/2 throttle.

When I start going over well over 1/2 throttle or really just nail it full throttle for about 15 seconds it acts like its running out of gas. Almost as if the fuel value has been turned to off and the gas is emptying out of the carb.

My thought is that the fuel pump is working but its just not working good enough. (i.e., not enough flow to replace the increased gas being used)

The strange thing is that after this happened about 5 times or so the bike would only run with the choke ON....and at this point it was fully warmed up. If I turned the choke off then it ran really rough and acts like it wants to stall.

Keep in mind this is not all the time. Only after it dies after really hard acceleration for an extended period of time. I have not done any carb modifications and dont have any new parts requiring jetting.

So is this the fuel pump or the carb? When I start it after it has been sitting it runs fine with no choke when warmed up. It can run all day (normally with no choke) no problem at up to 1/2 throttle or even at full throttle but not for more than a couple seconds. If I go over for very long its acts like its running out of gas.

Thanks in advance everyone!!

Darius

[J.D.]

Are you sure it's jetted right? Sounds like the main jet may be too small. Have you looked at your plug, and is your air filter in good condition?

[Darius1502]

Main jet is stock.

[Darius1502]

air filter needs to be cleaned but its not bad. When I take the gas line off the second peacock and kick it over....gas trickles out...but not too much.

While its running there is good stream. My thought was that its just not enough to keep things running a full throttle for an exended period.

The bike runs fine and will idle, and rev to full throttle. It runs clean and crisp. Like I said its only after a lot of WIDE OPEN or semi WIDE open riding (read: over 1/2 throttle) that this happens.

Could it still be jetting then or would bad jetting make it run rough all the time. most of the time the Z runs very clean and revs perfectly.

[polabareus]

maybe its getting too much gas? maybe the weather being colder is effecting the jetting some how?

[TimSr]

I doubt its your fuel pump, but start the bike, and open the gas tank, and you should see it swirling around in there. That hose that runs from the T to the top of the gas tank, acts like an overflow recirulator, as your pump squirts out way more fuel than your carb can accept, and without the oveflow running back to your tank, it would build pressure and blow the line off the carb. If you still have any doubts, just start it, and pull the gas line off the carb, and see what it does.


Most likely cause is that youve got some crap in the carb, but these symptoms are also classic of a restricted exhaust or intake.

[bbechtel16]

Tri-Zs have fuel pumps? :shock:

[Tri-Z Pilot]

Yeah, tri-z's have fuel pumps. It sounds like your mainjet is a little lean or maybe rich. Has the temperature dropped eradically since your last ok ride? If it has, you could be running lean, or if you are going at a pretty good pace, it could be that the cold air on your radiators are making your bike run colder, thus making it run rich. If you think it is running rich, put a small piece of cardboard in front of one of your radiators.

[J.D.]

Have you taken a look to see what your plug looks like Darius?

[Darius1502]

no have not looked at the lug yet. Got tired of messing with yet.

[Darius1502]

What about the carb vent hoses? I just realized that mine are pointing upward and go all the way up the frame with some very long pipe. I know they should be pointing downward right?

Tim Sr: Which 'T' at the top of the tank are you talking about? Does the carb feed back into this somehow?

Thanks a million guys

Darius

[twgranger]

my bike ran the same way and the main jet was too high. put a smaller one in and it runs great. :-D

[Darius1502]

Just looked at the plug. Its black with a slight tan color on one side. The Z also will not start.

It seems strange that it would be acting up all of a sudden. Before the temperature drop everything was fine.

Any advice is appreciated.

Darius

(i got a bunch of main jets with the bike so I think the previous owner may have messed with the jetting somehow.)

[Red Rider]

Tri-Z Pilot, don't Tri-Z's have thermostats which restrict the coolant flow as necessary until it reaches the proper temperture?

Darius, I'd definitely clean that airfilter though. You'd be surprised how much less airflow there is through a semi-dirty filter, even though it doesn't look all that dirty.

[200Xtreme]

If it looks like you've got plenty of fuel to the carb, when the engine is running, I would pull the float bowl and look for dirt in the needle and seat assy. If this is partially plugged, when the float drops, the carb may not refill as fast as the engine is using the fuel at high throttle settings. good luck!!