Topic: 76 CB550 Overheating?

[neurotoxin312]

Any ideas why my 76 CB550 could be overheating? The throttle response goes to crap and it has difficulty idling once I ride around for about 20 minutes. I checked oil levels and currently using Shell Rotella T 15W-40. I've spent the last two years building it up (nothing with the engine yet) and haven't really rode it to start to notice any major issues.

It's been used in the city mostly with some highway riding.

[Gene]

Running too lean?  I'm not commenting on the oil.  Won't do it.  You can't make me.

But, check your plugs and your pipes - if you're lean it'll heat up.  Also, make sure oil is going everywhere it should - pop your tappet covers, nice and oily?  If it's dry - there's a serious issue.

[neurotoxin312]

Haha. This was my first time trying Rotella T. I will probably change back to valvoline and add a little zddp. Will I need to rejet if it's lean or what?

[ekpent]

 Are you running pods or an unbaffled exhaust on stock jets ? Gas cap vent clean ? May be other issues than overheating,as mentioned look for blue pipes and ultra white spark plugs.

[neurotoxin312]

I'll do a sparkplug reading when I get home. I do have pods. My pipes are black actually but they do not appear to be bluing (MAC 4-1). I don't think there is a problem with fuel flow to the carbs from the gas tank. The gas tank was recently repainted and thoroughly cleaned.

In fact, I do get a little fuel leak occasionally from the overflow valve of carb #3. I presume my fuel float gets stuck in there.

[neurotoxin312]

Ahh I see. I haven't changed my jets yet. With K&N pods and a 4-1 exhaust are you guys thinking that I will have to jet up most likely?

Also, I am not entirely sure if its stock. There should be jet sizes visible on the actual jets correct?

[Gene]

Should be stamped.  You'll need to up the jets.  I don't know enough about it to recommend sizes - mine's a stocker - except USE ONLY GENUINE KEIHIN JETS.

[Bankerdanny]

Your symptoms do appear to indicate lean operation, but not necessarily overheating. I've never had an issue with my 550, but when my FJ1200 was overheating (a known issue with that bike) you could smell it as well as really feel the waves of heat coming off the engine beyond even the normal heat from a large air cooled engine.

[BomberMann650]

BTW, with a painted header, they won't blue, but they will oxidize (turn orange-brown) pretty quickly. Especially the Mac pipes as their coating is not very high quality.

What bit of the mac black didn't flake off turned white on my bike.

Hence the repaint.