Motorcycle Repair: 1981 CB900C hesitates when hot, honda cb900c, freeway ride

Question
Hello,
I just recently purchase a great '81 honda cb900c that is in excellent condition.  It has had no problems until this summer the bike  hesitates after it is fully warmed up.  It seems to run very well for thew first 20 minutes or so, but once its good and hot, driving at low speeds becomes difficult.  It will begin to hesitate and sometimes stall out when I'm starting out in first gear.  If I rev the engine up to at least 2500 RPMs and get up to speed, it doesn't hesitate. This is very annoying and makes it difficult to cruise at low speeds.  My wife and I took a 300 mile freeway ride on it this weekend and had no other problems except for this.

Any ideas?  Thanks a heap for your consideration.

Sincerely,

Stephen K Hicks
Olympia, WA.

Answer
Hi Stephen.

You lucky bastard.  I lived up there for a while and you have some of the nicest riding roads.

Anyway; Since I know the area and the weather, I'll bet that you had the bike in storage over the winter. There are certain things that need to be done when you do that, to minimize problems after the winter thaw.  I'll get to that shortly.  Basically, it sounds like you have to clean the fuel system.  Carb clean and fuel tank reseal both may need doing.  This may be able to be resolved without doing the carb clen; just use some carb cleaning fuel treatment like the STP made with jet fuel.

For next year, drain the tank and floats and make sure that there is no fuel in the system when you store the bike and when you prep the bike for the new riding season, after storage, make sure that you change the oil and oil filter.

You may want to do that now as well, if you haven't already changed the oil and filter.

Let me know what happens.
Good luck and ride safe.
FALCON