QuestionJan,
I hope you will find this a unique enough situation that you won't mind answering, even though you don't list 1982 Honda CB 900F as your area of expertise. I suspect it will be close enough to the other CBs you list that you'll know the answer.
I am the original owner of a 1982 CB900F which went in to storge for over fifteen years after being used for only 1,500 miles. When I stored it many years ago, I took all the recommedned precautions and after several hours of work on weekends, I started it for the first time today. Everything works great except for one major problem. This bike has an in-line vacuum fuel diaphragm between the manual petcock and the four in-line carbs. Accoring to my Haynes Shop Manual the diaphragm was added by Honda
mid-way through the 1982 model year.
In order to start the bike, I had to prime the carbs but there was no fuel getting through the diaphragm. As I'm sure you know, the diaphragm should open via vacuum when the engine is running. I tried by-passing it but the carbs immediatly flooded and overflowed onto the garage floor. I then tried taking it apart to check for blockage, varnish, etc. but found nothing. I reinstalled it and now too much fuel flows through it, once again flooding the carbs.
Any ideas on how to fix this? If repalcement of the diaphragm unit is the only solution, any idea where to find one? I've done a quick check on the internet but didn't see much. Also, I know from research there were very few of this particular model made and I believe they were only imported to the US for two years or less.
Any help would be appreciated!
Steve
AnswerHi Steve,
You have two problems. The vacuum actuator is not functioning properly, and also your carburetters are not closing the fuel supply off. So the floats are stuck or the float valves are dried out. The vacuum actuator is not too bad to work on, just make sure the unit is impeccably clean inside, and check the diaphragm itself for perforations. Try www.cmsnl.com for replacement parts. Good luck, Jan
