i have an 09 klx250sf. with 351 big bore kit and pumper carb. the bike cranks hard cold and hot so i replaced the battery put lrger cables on as well replaced the one set of starter gear bushings. had starter tested checked to make sure bike was timed right. replaced exhaust cam. checked cam tenstioner. all seems good. the only thing i havent done was checked valve clearance. any info would be great.

 

What do you mean by cranks hard? Won't crank? or just hard to start

 

cranks over really hard and at times fires and it runs great.

 

When the cam was changed the valve clearence should have been done as it was put back together I'd think. What does cranks hard mean does it crank slow or is it just hard to start as these are different issues.

 

Does it sound like the starter is struggling to turn? Or is the bike just not firing

 

Check the ACR as it might be stuck and not releasing any compression at startup as it should.

 

The acr is working fine. The bike seems to crank hard when on compression stroke. I have had the starter tested by 3 companies and all say im wasting my money if I buy a new starter. The only thing left has to be the valve clearance but I wanna be sure is all.

 

how does it crank with out the spark plug ???

and when is the last time you checked you valve clearance ???

also what mods have you done to the bike ???

 

check your valve clearance...starting is hard when it is off, but run fine when running

 

According to others ACR or valve clearance should not effect the rotational speed of the starter. I'm going with an undercharged battery.