Ive had my 250 jetmoto for 2 years now and i know it needs a tuneup but im totally new to atv's and dont know where to start. I have changed the oil, brake fluid, and spark plug. It runs good but I know it can run alot better. Can anyone give me some advice on what to do next? I would really like to give it some more power and speed. How do I tighten my chain, it has alot of slack. I would appreicate any advice I could get. Like I said my 1st atv and I want to learn as much as I can!

 

It's been a while since I have seen the 250 sport, but I do believe your model adjusts by pivoting the rear housing. If that is the case, loosen any bolts that would prevent movement of the carrier (including the brake caliper) and rotate the housing to achieve the desired tension. They are often very stubborn. There should be a 12mm? hex head protruding from the center of the carrier, slip a box end over this to use as a fulcrum. Careful not to damage the bolt. While you are focusing on the rear, check your bearings and make sure the rear caliper is not grabbing. We have seen a fair number of failures with these items and although heavy, your machine should roll easy. Anything holding it back will destroy the performance.

This engine is probably a Yamaha platform. For maintenance, you might want to check your valve clearance and dial in the carb. For performance, the 250 Sport could always use some help with the gearing. If you are less concerned with top end, you might consider dropping a tooth on the front sprocket or going up some teeth on the rear. It will give you a more effective use of power in low and mid range.

Regards