Tearing Down the Carbs
Finished tearing down the carbs to prepare them for a cleaning. Found a missing washer (carb 4) on one pilot/air mixture screw and a missing O-ring (carb 1) on another. The missing O-ring likely explains the amount of fuel build up on the number one carb. In addition, the primary main jet emulsion tube has noticeable stripping on the head; someone was trying to play with the jets at some point. Lastly, the bellows for the accelerator shaft was missing. All of these should be included in my Randakk’s DOHC rebuild kit, so shouldn’t be a problem getting things back together when it shows up.
The first round of cleaning was done using a 96oz can of Berryman Chem-Dip followed by a dunk in a 1-to-2 part mixture of Simple Green and Water in an ultrasonic cleaner. The carb bodies I placed in the Chem-Dip for 30 minutes and into the ultrasonic cleaner for 20 minutes followed by a rinse of water. The combination of the carb cleaner and a run through the ultrasonic cleaner did a decent job of cleaning things up. Hitting it with an air compressor I was able to blow out the passage ways and make sure everything was dry.
Doing some research about the problems the CB900 is having, it seems that with aftermarket exhausts the carbs start running extremely rich. This was very apparent by the amount of fuel build up and the color of the spark plugs. I had previously purchased a stage 1 & 3 jetting kit from Dynojet and realize now is the time to go ahead and put it into place. I haven’t decided on what to ultimately do with the airbox, but either way I should have jets that are ready. One step is to drill out the vent holes in the slides, so I went ahead and did that now.
The overhaul clean is pretty much done, the next step is to get into the smaller passage ways and make sure everything is really nice and clean. That’ll be another day, hopefully when I get the rebuild kit in the mail.