The Mosquito!

Two-strokes with oil injection will have a variable rate oil pump that is driven off the crank. The oil is usually, but not always, injected just down stream of the carburetor. Sometimes it's also injected directly into the bearings. Those ports are all normal. I can't remember which is which but I know there is one for the pilot jet, one for the main jet, and one for the enrichener circuit.

Disassembly has begun. Got the engine out of the frame and lots of unnecessary stuff unbolted. Slapped on some Super Bike bars I had laying around....looks better already, huh?


I took the engine over to my Dads house. He has LOTS more experience with engines than I do when it comes to getting inside of them. This thing hardly weighs anything!

Tied up the cam chain and had the head off in no time. The tach drive pinion gave us the most trouble. It didn't slip out like it was supposed to. Stupid me damaged the seal on the end, but I think I can repair it with an o-ring. We had to remove the cam and then remove the tach drive once we had the head off.

This was the source of all our woes. Someone left the bike sitting outside and the piston was stuck. A few raps with a block of wood and a hammer and she freed right up.


It's a shame, too, because this engine is like new. The piston barely shows any wear, measures out fine and we can reuse it. Unfortunately, the cylinder wall has a ring from the rust that a hone won't remove. No worries, I have a new (used) cylinder on the way.

Inside the engine shows like new, as it should with only ~4,000 miles on it. We also peaked inside the oil fill hole and the clutch basket looks the same....like new.
The oil was fine when we drained it; no water, so I feel like the bottom end is fine. It turns over easily.


I'm going to try removing the carbon from the head and cleaning up the combustion chamber with a brass brush. Think I can get away without lapping the valves? The rockers, springs and adjusters are all in great shape.

The head has been bead blasted, cleaned, valves lapped and new valve stem guides installed.

The "before" pictures came out blurry, but here are some "during" and "after" pics of the carb. It was pretty nasty.
I talked to Sudco and, best they can tell, it's an OEM carb. What model and for what bike...who knows? It's based on/closely related to a VM28. I also found a proper air filter that fits it and a manifold that will only take a little bolt-hole modification to make it work (NOT wrapping with duct tape! : )

While I was working on that, my Dad was cleaning the piston, the rings, ring grooves and checking everything to make sure it was within spec. This engine still measures out brand new. It sucks that someone let it sit outside for so long.

My girl and I went to a nearby motorcycle junkyard yesterday to scout for parts. We didn't have much luck but ,just as we were getting in the car to leave, she spotted this tank covered in some leaves.
It's a Garelli moped tank. The inside is pretty clean, it's solid and amazingly straight. It will take some minor frame mods to make it fit, but it's just the look I was wanting. Plus, it was only $15! They had a cool Monza style flip cap for it for another ten bucks!
I'm not sure of the capacity, but if the KZ250 gets 70MPG, it ougt be good for at least 100 miles. Stay tuned for this one....it's gonna look neat.

cool tank man!

leon

Thanks! The stubs on the frame for the gas tank rubber are holding it up right now. I'll get rid of those and make a few other frame mods and get it to sit more horizontal.

more horizontal would be real nice.

leon