When I ride the bike around 40 miles an hour, it starts to spitter and sputter and almost stall. This just started so I have no idea why this occurring. I put a new spark plug in it and it didn't help. This is NOT an EFI.

Thanks for the help.

 

how did the plug look? was it fouled or oily/wet? does it run fine the rest of the time and idle good.

 

The plug simply looked like crap...fully blackened. Not sure if that is normal or not.

 

Hello, I have an 07 Sportsman 450 and it is doing exactly the same thing, it acts like it has a rev limiter at around 40, and it does it when giving it gas uphills. The spark plug is jet black everytime that i remove it to clean it. I think that it is running rich. I took mine to the dealer and should have it back in a few days. I also cleaned the carb and didn't see any trash in it. Other than this problem it runs fine. I think that the fuel mixture needs to be adjusted, I don't think it is the jetting, because it would do it all of the time. I will let you know what the dealer said.

 

Let me know would you..whatever happens.

 

I will let you know what the dealer said and what they did. I will get it back Saturday and test it to see if they really fixed the problem.

 

Sounds like the float valve is to high in the carb or the air cleaner is dirty. Choke may be sticking. Just a couple of ideas.

 

Thanks, I'll check that but will have to probably bring it back to the shop.

 

I got it back from the dealer and here is what they found. I had trash in the jet and water in the tank.... they replaced the spark plug and installed an inline fuel filter, THERE IS NO FUEL FILTER INSTALL FROM THE FACTORY. I could not believe that. To save money, you might want to take the carb off and clean it and dump you gas,and change your plug. It runs like a top and putting a fuel filter on it will stop trash from getting back in the carb. The water in the gas was from crappy ARAB gas. Just wanted to let you know. chris.

 

Thanks. The boys at the dealer did the same thing here with the carb, (Cleaned it out) and I changed the plug. I took it out for a 50 mile run and it worked fine so I'm assuming that is what the problem was.

Thanks again.