I just bought a 88 250r from this guy and it won't idle. It isn't the stock carb either i think it is a 38mm keihn. Also when i am accelerating from the midrange up it just sounds like it tries to go then it bogs.
Any help appreciated.

Maybe your reeds are shot, or your main jet isn't right. Have you done a plug check? Is your air filter clean?

Sounds like a carb problem. First dissassemble & clean the carb real good. Pay special attention to the air passages connected to the air screw. Also, while you're in there, write down the sizes of both jets. What position is the needle in (1 thru 5). Can you still contact the previous owner to find out all modifications and aftermarket parts? First thing you need to do is get it to idle, then tweak it from there. If it's a 38 Keihn, the idle stop screw is on the side of the carb as opposed to being incorporated with the choke, like the stock carb was. Also, chekc for intake air leaks - around carb boot, reeds, etc. Spray carb cleaner around the area while someone keeps the engine running. If there is an air leak, the engine will speed up when you spray something flammable in the leak. Good Luck!

reeds are new put them in my self. the guy who i bought it from live in Illinois and i live in FL
do u think the main is to rich?????

could be your fuel valve. take the fuel hose off and check for even flow, or better yet take the fuel bowl off and see if it is gummed out

FIRST priority is to get it to idle. Whatever is causing it not to idle, may be the whole problem, but try to work on one problem at a time. Dirty carb or air leaks is the most likely problem with the idle. When you can get it to idle, then look at main jetting.

i did a compression check today... Not good only 145 pounds not good.. should be alot higher. tore off top end. rings are shot and cylinder is scratched up so new top end rebuild and bore is on the way