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'76 cb360 trouble. again.

2176 Views 14 Replies 6 Participants Last post by  tbpmusic
Ok. I had the bike running pretty well for a while, it wasn't perfect but I was getting closer. Then it started fouling the right cylinder plug and causing the right side to quit running. I would pull the plug, clean it up and put it back in and all was well for a few miles. I tried adjusting the air mixture screw (after syncing the carbs as best I could) and it didn't seem to make any difference (I know the bike has to be warmed up to make carb adjustments). All the while the left cylinder has been running great, plug looks good and all.

Now a more troublesome issue. I have been trying to figure this out, mostly by trial and error, which means I get the bike running and go for a ride, bring it back and make adjustments. I pulled the carbs and cleaned them, again. Well, it starts right up on both cylinders and I can rev it fine, I pull out and it spits and sputters in first, pulls well in second and then the right cylinder dies. Turn around and limp it back on the left cylinder and when I park it and shut it off, I get real black oil coming out of the header to muffler joint in the right side exhaust! What? I did seal the header to muffler joint as was suggested here when I got the new mufflers, but obviously its not sealed anymore. So I can get it running on both cylinders again without much problem, but then I get a lot of smoke out of the right side because there's all this oil in there.

Now, I'm just assuming its oil that's in the exhaust. I had to add a little oil today but I really haven't been running it that much. I checked the compression again today, 150 psi in the right, 152 in the left. The points are spot on, both sides, as are the valves. I know the compression is right on the line for a top end job, but I'm trying to avoid that if possible.

I honestly don't know where to start. Help.

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I'm there with you, check my build thread. The ring size depends on the piston size. Piston/ring size depends on how much meat you have to take off the cylinder walls(boring) to clean up scratches and/or return the whole thing to the same dimensions from the top to the bottom of the sleeve. If there's next to no scratches and the dimensions are uniform top, middle, and bottom, a good honing may be all that's required(for the cylinders-put in new rings regardless). If that's the case, AND there is no damage to the stock piston( measurements and tolerances can be found in the manual downloadable on this site) STANDARD ring sets are needed. If the piston is damaged, STANDARD pistons and ring sets. If the cylinder needs to be bored, it can be bored one quarter of a millimeter bigger in 4 increments, up to one mm larger TOTAL, then it's time for new ones. There are piston and ring sets for each of these overbored sizes(.25, .5, .75, and 1.) A very wise man from the website named Two-Tired taught me that Honda carb parts are available and worth the money so you don't have to guess whether they're good or not. Your call, though.
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Also, do you have the cam out? No way to tell if the journals are toast without looking under it...While you're in there you need to pull the tensioner and slipper to see if they're decaying also.
I'll see what I can find out. He's a 550-4 junkie, has like 4 of them, but if they're available, he probably has a source. which ones, the 3 tops, or the main and secondary group?
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