Engine overheating and smoking a lot ?

[poelinca]

You guys are right, just ordered a dial bore gauge and a micrometer just to be sure.

[barossi73]

Mine was A spec,replaced with an A wossner at 70hrs (200)from new.no problem.you say you have 100hrs on it.is that from new?or has it had a topend previously?if from new the same spec will be fine.

[poelinca]

Originally Posted by barossi73

Mine was A spec,replaced with an A wossner at 70hrs (200)from new.no problem.you say you have 100hrs on it.is that from new?or has it had a topend previously?if from new the same spec will be fine.

Mine came with B spec from the factory, 100 hours from new (this is the first top-end job for me and for the bike). I'll check before ordering the piston, just to be sure.

[poelinca]

Measured the cylinder bore last night:
- 0.008-0.009mm is the tightest spot i could find (the needle on the bore gauge changes direction right under the 0.01mm mark, very hard to approximate how much) in diagonal
- 0.02mm exhaust to intake (largest spot i could find)
- 0.01mm side to side

So in the end, same piston will go in. I will also rinse the coolant system with vinegar, new gaskets, clean the PV mechanism and remove any play. Hopefully it will all be good, will keep you informed with the process as I go along and the outcome (ride report) probably Sunday if all goes well and parts arrive soon enough.

[barossi73]

Get engine extra clean.Leave the 't' coolant fitting on the head if possible.the gasket wont be in the set.remove exhaust spigot.be careful not to bend pv actuator rod.dont let the actuator plate turn clockwise when refitting the nut.you will find you cant remove/refit cylinder 'square'.tip cyl backwards slightly as it comes off the studs and on reassembly lead slightly with rear studs.any writing on rings goes up.ring gaps/locator pins in piston to the rear.check small end bearing is exact match to old.take extra care fitting retaining clips on gudgeon pin,its easy to slip and scratch piston.carefully start rings into bore as you lower cylinder.a little 2stroke oil on the piston skirts.be patient,dont force the issue and it will be all good
Pv gaskets can often be reused if they came off clean.then you have new spares

[adriano.ro]

I use a little oil for new gaskets,in future will be more easily to take off.

[poelinca]

Found:
- oily white slime on the carb slide (witch would indicate water i presume)
- carb mouth where the air boot fits had a "leak", you could see where the dirt came in with water
- small pieces of dirt on the air screw
- no water in the bowl tough
- small pieces of dirt on the boot mouth

All of the above coupled with worn out piston and rings could have caused it right ?