So for about a year I have been having problems getting my cb900 to rev at all. After full cleaning, with guitar wire, laquer thinner and a ultrasonic cleaner, i still could not get it running, but i think i have the cleanest 1980 carbs i have ever seen. I have found this thread numerous times: https://honda-tech.com/forums/showth...2931960&page=2 and tried to figure it out from here with no luck. Finally i just started putting old pieces back in, one by one. One must note that I did get a kit from ebay that was suppose to be all new parts and a rebuild kit. I also notified the seller. Much of it worked except one piece was a killer. The needles attached to the cv pistons were slightly larger in the kit. This was extremely hard to tell but once i swapped back in the old ones, it rev'ed right up. It was stopping around 2/3 unless you REALLY choked and reved it hard. Even with the old needles, i had to make sure that they smoothly moved in and out of the seat to make sure the pistons moved up and down smoothly. Does anybody know if those needles are different sizes between 1980 and 81/82?

Trying to figure this out, we found 1 cracked coil, a few clogged holes even after lacquer thinner and the ultrasonic cleaner. Now i just need to get the idle jets set right.

I hope this helps anybody that may have had a similar problem.

 

hard to say whether or not the needles in 33 year old CV carbs are the same OD or even have the same tapper. I could have sworn that those CV needles were fixed and not groved for height adjustment?