my friends 250R revs up real loud when u start it and it wont shut off. whats wrong with it?

 

stuck slide in your carb would be my guess, check the needle in the carb, that could be your problem

 

This might not be much of a help but mine does that alot, I just adjust the throttle almost all the way shut then start it then readjust it but, more that likely its the throttle slid,take off the carb and blip the throttle a few times to see if its sticking

 

Your pilot circut is too lean, or no gas is getting to your carb when you start it up. Try putting in a different pilot then if it isnt fixed add a primer bulb and prime before you start it.

 

Adam,
This is a carb problem but a few more details might help us pin down the problem, like temp and or mods, did he just buy it or this just start happening out of the blue. One thing for sure is that you do have carb trouble, If this bike has sat all winter then it is probably all gacked up and needs cleaned. The pilot circut could very well be the problem but I would remove the carb and work the throttle as you look into the carb make sure it is opening and closing all the way as you work the throttle. The 2 main reasons that slides hang up are usually a bad throttle cable that is rusted or frayed, or routed in a binding way, and over oiling of the air filter, when you over oil your carb will suck the excess off the filter and make the carb tacky. Being that we are coming out of the winter months I find it hard to believe you are running lean if the bike has ran ok all winter, but like I said I don't have all these details.

 

no it just started doin it one time when he started it up. i remember ridin it whn he first got it runnin and the throttle would tick every now and then. it has a pipe and the head i milled. other than that i think it is stock.