Do these older motors need freshened?

[hd1937]

I’ve been told today that unless freshened up old Kawasaki motors are prone to failure. I would rather listen to folks here with experience than the naysayers. Chancing failure or reliable if not freshened up? Thanks.

[mswyka]

There is some truth to what you are hearing.  We have come to learn that there are a couple of things that are pretty important to the successful operation of these sleds.  Every sled that we bring in is torn down, checked, and reassembled at a minimum with new pistons & rings, new gaskets, new crank seals, new carb jets, and new carb needle & seat.  And usually new carb boots, new fuel line, rebuild on the fuel pump and new fuel and oil filters.

[gixxer6]

These sleds can be VERY dependable if the proper maintenance is done.  I agree with everything mswyka listed with the exception of the piston/rings.  Unless worn and out of spec I reuse them with great results.  Don’t do the maintenance and your asking for trouble! 

[Lloyd (ljm)]

 I agree with the others. I only install new pistons and rings if they are needed.

 Before I got my ultrasonic cleaner I always replaced the jets and needle and seat.  Now I ususlly clean them and reuse them.
I always replace the carb coot with a new genuine mikuni one. I have had engine failures due to the cheaper aftermarket ones. Always do a pressure test on the engine before you use it.


Lloyd

[kawhead]

seals for sure, rings and piston as needed,[rings if out of bore], fuel lines as needed [if in doubt change], I clean carbs every year before use

[hd1937]

Thanks for all the input. Only 305 miles on it so pistons and rings unless something shows up should be ok. Best to find nos parts or aftermarket? Thanks

[gixxer6]

IMO winderosa or cometic are fine for gaskets except for the head gaskets, I’ve only ever gotten NOS 4/6 head gaskets to seal permanently.  I only use OEM arctic cat carb boots, the last mikuni boots I bought were the same cheap crap as the other aftermarket stuff. 

[sprocket]

I put all new except the carburetor & parts. I put everything together 1st dry double check all measurements if everything measures out correctly I put a thin layer of yamabond on one side of the gaskets so example base gasket gets yamabond on the case side, head gaskets gets yamabond on the cylinder. Most people don't like using this stuff but what I found out in racing the base gasket likes to blow out. I let everything dry for a day or at 70 degrees for 5hrs before running