More on the CB900
It’s been a little while since my last update. I had some time today to see if I might be able to get some bugs worked out on the CB900. A few days ago I decided to take the bike around the block to see what the current status is. While it sounds quite mean, there’s a problem with the power. About half way through the ride the engine died, and though it started right back up it couldn’t even make it up my drive way without stalling. Basically this leads to the following list in the hopes of getting the CB900 back on the road:
- Clean and check the carbs.
- Check carb synchronization.
- Check engine compression.
- Check valve clearance.
A few days back I took a look at the carb synchronization, and surprisingly everything looked good. So, today I decided to start the day with checking the compression across the 4 cylinders. Making my way down the line, everything seemed a little bit low, but not too bad. The next step was to start tearing down the carbs and see if there’s anything out of the ordinary there.
Digging into the four carbs and checking the jets took a better part of the day. Looking closely at every jet, everything actually looked fine. I noticed that carb three had a bit of rust color in the float bowl, but everything seemed pretty solid and a quick clean fixed that. No major problems were found so everything seems good in that realm.
I popped the carbs back onto the bike and started the engine to see if maybe I just got lucky. Alas, it was not so; still the same problem. In addition, I took some temperature readings at the headers. I’ve always suspected that cylinder 1 and 2 seems to be doing everything and the temperatures backed that up. Cylinder 1 and 2 were running above 200 degrees F, and cylinder 3 and 4 were down around 90 degrees. Somethings not quite right. In addition, I noticed while doing the compression test that the spark plugs on 1 and 2 looked pretty good, but 3 and 4 were wet.
It’s pretty clear, next step is to open the engine and start really figuring out what’s wrong.