Hi I have a 00 sportsman 500 recently i noticed that it wouldn't rev like it was supposed to so I decided to clean my carb, change the plug and set the valves. After I got it running again the problem was worse than before so I took off my air-box to see what was going on and I noticed that the throttle valve/ diaphragm is not opening all the way. I inspected the diaphragm real good and it seemed to be in good shape. I was wondering is there possibly another reason this thing isnt opening? If I use a screwdriver to lift it while throttling, it revs great. Also if I replace the diaphragm should I replace the Jet block assembly too? Thanks for your replies.

 

Well didnt get any reply's so bought the throttle valve/ diaphragm and jet block and i noticed that the new diaphragm didnt spin around on my throttle valve like it did on my old one. So if anyone is having problems with your bike not reving up like its supposed to, pull the air box and check your throttle valve and see if its opening. If not you may have a bad diaphragm.

 

It will not open with the air box off.