I have a twister 2004, which until the other day has been running tiptop. Performed the regular maintenance (oil, air filter) and took it out the next day; ran great as expected. Took it out yesterday and was running well when I just lost all power. Engine will idle just fine, but if you give it any throttle, it dies. Weather conditions in the high desert are rather chilly this time of year, but the engine was warm. I towed it back home and proceeded to take the gas filter out of the equation w/ no change.

Suggestions?

-Byron

 

Either your main jet is clogged or you are having trouble with the auto choke mechanism. Check the choke first.


-Steve

 

hey. i kno this sounds stupid but there is a round mechanism on the carby for the accelerator cable and sometimes that can jump off, does ur accelarator feel unnusually soft?
RETZ

 

I agree with hopsterguy.

 

I agree, if the engine was warm when it wasn't running correctly its probably a clogged mainjet. Clean out your mainjet, sometimes "stuff" gets left behind in the manufacturing process. A clogged mainjet is the problem 90% of the time and is very simple to check on your twister. You may have to do this more than once if it stops running again (sometimes hard to see the tiny stuff). As far as I know, when the choke malfunctions, it does so in the off position, meaning it will be harder to start but will run fine when warm. It has to receive voltage to lift the needle. I think most atv's with this style of choke malfunction this way. I think eventually everyone will be going away from the auto choke system.

Let us know,
Kell

 

I've cleaned the main jet (three times - found nothing) and checked and rechecked the connections. Vaccum is fine, gas and air flows are good. Only thing remaining is the choke. Can anyone take a voltage reading on their's so I can compare? Bottom line is that it starts fine and idles great; give it throttle and she dies...[img]i/expressions/face-icon-small-frown.gif[/img]

 

Wow, I feel like I led you in the wrong direction now. As far as the choke, I am not sure mine even works. When I start mine, it will not accept throttle for quite a while until it warms up some. It will only die until I coax it into taking little jabs at the accelerator, I usually just let it sit there for a minute or so. This is even on warm days, on cold days it gets much worse.

I guess you have checked to make sure gas is flowing when engine is running? It's vacuum operated. Is the vacuum operated slide going up? should be able to push it up with your finger. Yours is too new to have a tear or something but you could easily pull the top off to check the diaphragm. I am sure you did this but did you use compressed air to blow the jet out? Sounds like you cleaned it good and visually inspected it. Maybe one of the screws on top has come loose allowing it to lose vacuum?

I am sure this is something simple, let us know what you find out. I will try to remember to get a reading off the choke this weekend for you.

forgot to mention, I have heard of SEVERAL people saying they have had loose electrical connections causing it to not run properly at higher rpm (due to vibration). You could easily check these also.

Kelly

 

Kelly,

"Vaccum operated slide"? Are you referring to the vaccum check valve on the gas tank? I removed the gas filter and replaced it with a clear hose to verify that I was getting gas flow. I did not drain the tank and visually inspect the vaccum check valve on the tank though. Something to check off I guess.

I really do believe the carb is fine. I failed to mention that I did remove the spark plug, cleaned it (wire brush) and verified good spark while cranking (no change to the final outcome though). Question; I've disconnected the choke (unplugged it electrically) and the engine starts and idles fine. That's why I assume the choke is engaged during startup and requires a voltage from the system to disengage. Curious if I can simulate a voltage to the choke or find a way to by pass it all together (short of buying a new carb) to verify my assumptions.

-Byron

 

This carb has a slide that is operated by vacuum as opposed to the older motorcycle style which had a cable running directly to the top of the slide. If something causes the diaphragm to be ruptured it will cause problems by not lifting correctly or at all. YOu may have noticed your throttle cable is connected to a butterfly on the front.

I think but am not positive that the choke is operated the oppostite of what you are saying. I think it requires voltage to activate it, it has a spring in it to keep the choke off (enrichening circuit they call it now I think). The spring keeps the choke needle down. Like I said before, mine will start but just barely when its cold. It takes it awhile to get it to idle and then a longer while to get it to accept throttle.

Definetly remember those electrical connections, take the top off the black box and make sure the connections are tight on the cdi etc. My only problem has been the battery cable vibrated loose causing it to not charge well, this has happened to a few people also.

Yes, as you have said, the engine has to be running in order for the gas to flow because of the vacuum valve.

The slide diaphragm is easy to check, 2 screws on top. I think you said you had checked for air leaks already. Did that involve the intake screws and air boots?

Good luck,
Kelly

 

Ahh.. good point Kell. Could be a blown diaphram on the slide.


-Steve