no high end power

I have a 92 Suzuki DT 115. Storage for 3 years. Runs fine up tp 3500 rpm, then stuggles to get up to 4000 rpm max. Doesn't seem to be running smoothly after 3500 rpm. Fuel problem? New line, filter, bulb-noticed bulb stays soft, even after engine is started and has been running for awhile. Aftermarket bulb-should I change with new "major manufacturer" bulb?

Re: no high end power

This sounds like a fuel issue and probably its not enough fuel. Question then is why not enough. I would start at the fuel tank and work my way back to the crankcase. <br /><br />-Make sure the fuel pickup and anti-siphon valve are working and aren't restricted.<br /><br />-Make sure the fuel line connections aren't leaking air, and make sure the fuel bulb is installed in the correct direction. <br /><br />-Try pumping the fuel bulb at WOT and see if it helps. If it does you need to rebuild or replace the fuel pump.<br /><br />-Remove the airbox and try squirting some premix into the carb throats. Alternately, try maually choking (partway) the engine at WOT. If either of these cause it to pickup the problem is in the carbs and you will need to do a thorough cleaning and rebuild of the carbs. (If its been sitting 3 years you should probably do this anyway). Make sure the throttle linkages are opening up the carb butterflies all the way and that the ignition timing is up against the stop at WOT (later models such as 92 have electronic ignition timing and this won't apply)<br /><br />-When you reinstall the carbs make sure you synchronize the carbs with the ignition timing linkagae according to specs.