I just bought a 2002 Polaris scrambler off e-bay. The guy said it ran good and I went to MD last weekend to pick it up. Of course it snow like crazy and I didn't get much of a chance to test ride it. When I got it home and rode it was missing badly from mid range to top end. I pulled the plug and it was black. I put a new one in and ran it for 20 minutes or so and that one is black now too. It has a White brothers e- series pipe on it and the owner said the carb was not jetted to this pipe. What jet should I use? What other adjustments should I do to the carb?
Any suggestions would help?

 

You bought a 500 Scrambler right?

Before you mess with the jet, Get rid of the fuel in tank and start fresh, get a new air filter or clean the reuseable one in it. Change fuel filter and change oil and filter while your at it. Drain carb bowl. Take carburator bowl off and inspect for dirt, oxidation and unwanted materials. Clean the mail jet and pilot jet. Check the choke cable and make sure choke isn't staying on all the time. Make a note of jet sizes while apart. Put it back together and see how it runs.
You could call manufacture of pipe and get their recomendations on jet sizing.

If you don't do all these things to begin with than it is just a shot in the dark what is wrong.


good luck.......................handycap

 

Bubba thanks for your response. It is a 500. I changed the oil and had frsh fuel in there the only thing left is to pull the carb and go thru it. I tried white brothers and they still have not gotten back to me yet. I only have the silencer not the pipe. I was hoping to have a jet standing buy just in case the jet that is in there is way off. The best answer I got so far was to go up 2 jet sizes. I believe stock is 155. Does this sound right to you? Also do you have any idea what the compression ratio on this bike should be? Thanks again for all your help!

 

A black plug would indicate a rich condition (too much gas), you need to go leaner (smaller main jet). Before you do that you could raise the needle clip (lowers the needle), it would have a similar effect as a smaller jet. There is some good info on carb tuning and plug reading on the net, just google search those words.

 

I'd try to drop it down a jet size or two. That will probably help a lot. Then, you can mess with your needle. Make sure you keep on top of the jetting though, seems odd it was never jetted differently than factory.....and then a pipe is put on, and it is still real rich. Usually not the way it works. Your oil pump could also be out of whack too.....