Hello,
I recently traded for an 82 CM450. It had been sitting for about 3 years with a broken accelerator cable. The guy had a new cable so that was a quick fix. This is my first bike. I've worked on cars since I was 12 (dad owns a mechanic shop), but this is the first bike I've worked on too. It was obvious the carbs needed a good cleaning because it wouldn't idle without the choke pulled out halfway and didn't have enough power to ride in overdrive. I took it to a small shop around here, where it sat for three weeks and he never touched it. I finally got frustrated and went and got it and decided to try to clean them myself. This went fairly well, as the bike had good power above 3/8 throttle (it was like it picked up another half of an engine!), but at idle it backfired through the carbs and would spit and sputter up to 3/8 throttle (lean problem?) I assumed it had something to do with the air needle, but on one carb it had seized in the body and the adjustment head broke off flush with the carb body. At any rate I rode it around like this for a couple of days and the stalling aside it ran well.
I ended up ordering a full kit off ebay that came with all the jets, needles, air cutoff valves, etc. I did note that the one pair of jets were the 115 size, the ones that the Clymer manual called for were 112. At any rate I tried to install everything that came in the kit (including float valve seats). This was obviously a huge mistake as when I was pressing the new float seats in it cracked the carb. So I figured I was up Schitt's creek. I ended up finding a motorcycle guy close by that had a pair of carb bodies (VB22's, same as what I had except a different letter after the 22) so I bought them and moved all the new parts over and put everything together. Everything was identical except the jet underneath the rubber plug. The bike will idle, but when you give it throttle it shuts off. If you twist the throttle really quick, it will lope, spit and sputter but never pick up. Air and gas blow back out through the carbs. I though maybe the jets were too large, so I replaced all the original parts, same problem.
I cleaned all the parts in an ultrasonic cleaner, checked all the vacuum ports and jets for blockage, but I notice when you open the throttle the vacuum pistons don't move. I reached in with a plastic bar and pushed up on one of the pistons while opening the throttle, and the thing never missed a beat. Also, if you shut off the fuel, as the carbs run it out, it will pick up like it should.
I don't know what should be my next step here? Can anyone please shed some light on my ignorance of motorcycles and CV carbs and help me figure out what I should be looking into? Thanks so much in advance!
-Lloyd G
OOO And Pron!
