Suzuki dr 250 revving high

Check compression and timing. Shouldn't ever smoke.

blockage in fuel tap or carberretta

have it checked either at a local shop or dealer my scan tool reads in minutes and depending on problem how long to repair. i scan a lot of cars for free at our dealership.

Try this:
Clean and gap the spark plugs. Clean the air filter,and then run some carb cleaner through the carb.
Hope this helps.

I would stay with the same heat range(BR8) to stay on the safe side. You didn't say if when you are at the camp sight the bike is cold and just off the truck or warm and right off the trail. But usually alot of 2strokes need to be cleaned out when their being warmed up or they can foul a plug. Get it started, blip the throttle a few times to get some heat in the cylinder and then hold it open until you hear it rev faster and run smooth. Thats usually enough.

I would have it checked out. I know that it has limitors on it but it shouldn't be half throttle. It should rev as soon as you start twisting the trottle.

The engine is water cooled. The exhaust pipe is air cooled. Sitting idle and revving the engine is likely to exceed the cooling capacity of the motionless air. Air needs to flow over the pipe to cool it. If the pipe is glowing red while riding then consider re-jetting the carb. Too lean a fuel/air mixture burns hotter.
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Its okay. For as long as you're not revving the bike on its redline for too long. CBR, XJR and other inline engines love high RPMS. They're built for it.

your carb got stuck and it sounds like your rings are burnt out like u were running to high of an octane or something in your gas

usually when surging like that happens there is a vacuum leak where the carbs are attached to the heads check the rubber rings that hold the carbs on to see if they are cracked if so then replace them and that should solve your problem