Ok I bought this old Blaster as a project quad and it needs some cosmetic work but the problem with the throttle is that it doesnt respond well at all when I try to rev the engine up it hesitates before gaining any rpm's and when I let off the throttle it hesitates before returning to a idle ive inspected the throttle valve and it works and returns fine and the carb is a Keihin. Thanks for any help.

 

sounds like a vacuum leak. does it idle rough? spray some WD40 around the connections while at idle if the revs drop off it's a vac leak. look for cracked boots or mis aligned boots. good luck. I was thinking since it is an "old" blaster check the reeds if they are cracked it could cause throttle problems too I think.

 

It could also be jetted wrong.

JaMeS