I have worked on the quad off and on through out the day. Not much success. Starts fine, idles fine, low to mid throttle fine, but too fast a rev or too much throttle it bogs down and puts smoke out the pipe. It sounds like others with electric choke problems, but mine is a manual choke. Carb cleaned (numerous times) all jets clear, diaphram in good shape, intake manifold in good shape (new), clean gas, exhaust clear, filter clean. CDI? Not sure what else to try. If I stay off the throttle it will run fine, it will even climb hills pretty good. But if I get on he throttle or go past 3/4 it is like putting on the choke. Suggestions/help? I bought this used and it did not appeared to be well cared for, so fuel is new, oil is new, filter new. Also one front tire keeps loosing seal on wheel if it sits for more than 4 days without moving. Any help is appreciated.

 

Still using the stock spark plug? If so Id try a NGK C7HSA and see if that helps. For the tire try inflating it to 30 PSI overnite to seat the bead.

 

Thanks for the reply . I changed the plug to the NGK after cleaning the carb, no luck. I also inflated to 36 psi and let sat for two days, but I am still losing seal. Is there a rev limiter that could be causing the problem? A symptom of a bad CDI? I hate the thought o just replacing things as a means of eliminating the problem. I have read a lot of posts, but I haven't seen this problem. I can't imagine it is a first.

 

Next time the tire goes flat and unseats try cleaning the bead and the rim with some solvent. Then go for the 36 psi over nite again.

Has the engine done this since you got the Yamoto? Or did it start suddenly? Did you buy this new or used?

 

I bought it used. The gas tank was off, the front fender missing (still is), and the tire flat, air box missing and air filter replaced with a K&N type filter. The guy's son had poured transmission fluid in the tank, which actually kept the carb clean. I knew I was taking a chance, but over all the quad didn't look too bad. The tank cleaned up, I changed the fuel lines, put in an inline filter, cleaned the carb (now several times), new plug, new oil. The key was missing, but a quick twist of the wires and a few kicks it started. It doesn't matter whether I am on the quad or the quad is on a lift it does the same thing. I am stumped.

 

I discovered something by accident yesterday. The weather dropped to much cooler than it had been. I started the quad and was taken by surprise, it took full throttle. Thank goodness the rear wheels were lifted, it really screamed. This only lasted for about 10 seconds or until it was "warmed up". This makes it seem like it is a choke issue. Is there a way to bypass/disable the choke?

 

If it ran well with the choke on...Its more than likely jetted real lean from the factory..The choke simply richens the mixture while its on..