We determined there was a slight secondary air leak. The customer also requested carburettor maintenance.
We removed the carburettor. It has a shape that could be called the final form of a negative-pressure carburettor.
That’s Honda engineering for you.
Before we get into disassembly, I should mention that the angled fuel hose—a part commonly used on Honda bikes—is fine while you can still get it, but becomes a hassle when it’s discontinued.
This one is just the angled type with an inner diameter of 10 mm—pretty thick! But like the RC30 we worked on recently, there are also angled hoses with different diameters. The one at the fuel cock side is as thick as a breather hose, then tapers down at the carburettor side. And it’s discontinued too. Nowadays you can search by part number online and find these things—modern convenience.
The condition wasn’t bad, but it was definitely sucking hard from the engine side.
I’m impressed by Honda’s attention to detail—even the fit and band position are engineered into the OEM part.
Back to the carburettor. The float level is the kind you don’t mess with. It’s reassuring to see such confidence in the design.
The float valve seat looks press-fit too. That means no side leaks.
Square-plus-plate slide valve. Single hole. Doesn’t look like it’ll wear down.
The slide valve shows virtually no wear—reassuring.
The tank looks rust-free—good news.
The angled design looks like an FCR. Even with the same carburettor type, just a different maker makes this much difference—that’s what struck me.
We quickly cleaned it and checked the passages. We couldn’t adjust it, but we did verify the fuel level.
That’s how we balanced the carburetors.
The customer asked us to do something about the fluid hose that looked ready to break.
We shortened it and tucked it inside.
The customer wanted the pedal lower.
We removed the master cylinder and pressed off about 10 mm.
This should make it easier to ride.
Going back to when we removed the carburettor: one piece broke—honestly, aluminum at the clutch wire bracket isn’t ideal.
Aluminum was nice for easy removal, though.
I think steel would be better.
After a test ride, we’ll be done.
