Hey guys, I just joined the forum and it seems like a pretty cool place. Recently I bought a 1980 kz550 ltd. It’s my first project bike and I’ve had it for about a month now. I’ve gotten it close to roadworthy but I’ve run into an issue.

The bike is rough to start and once I’ve finally coaxed it into running, it doesn’t want to run without choke or me giving it throttle. I suspected it was a carburetor issue at first but I’ve taken the carb apart several times and checked pilot jets/main jets for blockages each time. I’ve tinkered with just about everything on the carbs I can think of but I’m at a loss.

Any suggestions as to possible problems/solutions would be greatly appreciated, thank you.

 

Carbs need washed out with a carb cleaner machine. We ran into that stuff frequently when I was working in a bike shop. There are passages that just cannot be unclogged without getting fluid in them to work for a while to dissolve the crud. Find a bike shop or auto shop that can put the disassembled carb block in a washer and clean them.

 

Thank you for the advice. I’ll definitely look into my options for having that done.

 

I found the issue and it didn’t end up being a nasty carburetor.

It turns out that my float height on two of the carburetors was so off that those two weren’t getting any gas at all. Once I realized that I adjusted the float heights properly and it fired right up. Definitely a goofy think to overlook for sure but I’m glad it’s running now.

 

Now that I have it running there’s another problem I have discovered. Two of my cylinders on one side aren’t putting out any heat through the exhaust and it has an odd ticking sound coming from one of the two cylinders.

I have spark to both and I think they are firing because if I pull either plug the bike dies, it just seems to be a very weak reaction. My theory is that the head gasket has gone bad but maybe I’m overthinking it. Any advice/suggestions are greatly appreciated, thank you.

 

If you suspect a head gasket or even a valve or a ring issue, have you done a leak down test yet?