My LT250r was just borred 25 over and it is poping almost every stroke. Thinking it is the jets or its my mixture. The carb is an after market carb. The guy that owned it before me blew the piston. Not quite sure what to do. Is it normal for it to pop? I would like any advice that anyone has to give. Thanks.

 

It sounds like it's really lean. Get it jetted or you will just burn up another piston.

 

If the exhaust is white dose that mean that the mix is wrong? Or dose that have to do with the jets.

 

If it is aftermarket and actually made for your quad call the distributor and ask them for the specs. I might suspect an air leak as an additional cause to your problem.

Joe

 

Would the air leak be in the carb? or the connections to and from the carb. Im not very great with carbs. Thanks. Quadomb

 

First, start simple and make sure your carb has the recommended jets from whoever made the carb. Second, check the engine side of the carb manifold and make sure its on snug, no cracks around the rubber, make sure the reed valve is properly sealed. If that is all OK, you might need to check around the Main Seals on the crank. With age they can leak causing a lean condition.

I would also suggest that you are way more specific in your signature so everyone knows exactly what you have. What aftermarket carb for example?

Joe

 

I have a lt250r 92 that i just rebuilt. I bored the top end over .025. I bought the LT250R with a blown piston. Now that it is a new engine it is running with a pop every 2-3 fires. it has a after market exhaust with fatty pipe and a modified MX muffler. It is really hard to start without starter fluid. The carb is a mikuni 33mm. The main jet is a 260 and i dont know the pilot jets size. The exaust is white. It pops during idling and threw revving up to half throttle. The gas mixture is about 26/32:1 The gaskets in the crank case are not leaking. Dose any one know about the sound of a lean engine or anything about an engine being too lean?

 

there is a rip in the connection from the carb to the engine but it is on the away side of the lip that the o ring tightens down on and the oring it really tight.

 

33mm carb seems a bit small.. Didnt they come stock with 34 or 36's?