Yanclone- head off

[arnaud]

Partly because i'm curious, and because the yanmar manual says it's time to inspect the injector nozzle, i just removed the head of the 418cc yanmar clone.
The cupper gasket ring seems te be consisting of (looks partial because its compressed to tightly) 2 thin layers.. Does anyone recognise this?

2nd; In the cilinder head, at the place of the head gasket, 2 grooves are present all around, I guess the cupper ring needs to wedge in here to seal off?
Anyway, these grooves are partly filled with carbon. Any tips how to clean this without damage? (does oven cleaner really work?) The same also for the injector tip.. Although it ran fine, it has some carbon on it and i think it's best to remove it now it's possible.

Also, Outside the gasket ring, a spot of carbon was present. I will check later if it corresponds with a spot on the cylinder, but i have never noticed it leaking through the head gasket. This should be noticed in the running of the engine, because of the high C.R, right?

And, the cupper seal for the injector nozzle, replace it also?

And, the carbon at the top end of the cylinder, remove or leave it there?

Merry X-mas and don't eat too much!
Or else we get these questions; Last year my bike was running 110km/h, now hardly 90, how come?'

Arnaud

[andrewaust]

Hi Arnaud


I'd replace the head gasket and copper ring/seal for the injector. If the cylinder runs at the right temperature and your not using straight veggie oil that gums up the engine I'd leave the carbon alone.

Usually once you compress copper it looses its sealing properties. If you go by the book they would say to replace all gaskets and sealing rings. If you were stuck on the side of the road you would re-use the gasket/s to get you home only.

Just my opinion, others no doubt may have a different opinion.

Instead of pulling the head off I look down the exhaust port, it's very crude, but does give me a rough indication of carbon build-up.

Diesels will let you know when they are not running right, hard starting, smoking etc are signs something is not right. If an injector really screws up it may produce a very loud knock also, very distinctive from the usual Diesel Knock.



A

[arnaud]

Yes, but i want to check the valves anyway.
3 summer holidays might have created some pitting..
The yanmar-book also says i should replace the valve seals (never had a bike which had those) when they are dismounted. These parts must be cheap but to pay 17,50 for posting is rediculous.. If i knew before i would have ordered them with the head gasket set.
Do yanmar parts or other (must be a sdt size) fit? Yanmar is current in holland, while diesel engine dealers want to run away when you mention it is a chinese one..

Also the manual states under 'checking and servicing' the measurement of the space between het piston and head, but does not say why..
Might this be a reason why a double head gasket was in place?
Is it neccesary to check this before running?

[arnaud]

Hey guys!
Recieved my valve-removal tool today (the springs are slightly too stron to do it the dnepr-way)
The yanmar manual mentions (rubber?) valve stem seals wich have to be replaced after dissasembly, but they are not present..
Also with your china engines or have they forgotten to insert them?

[arnaud]

So, the valve seals are not present in any diesel yanmar clone.. So don't look for em,
sind emy engine is still not in use (enjoying a jawa at the moment) and i am told that the big-end bearings van collapse at a moment, i was thinking about overhauling the little engine with new piston rings (according to the book replecment is scheduled after 1000 hours, so 70.000km) new non-chinese ball bearings and seals, and new big-end caps, to be sure of a long life again..
Tips/comments?
Is there someone here who has done far more mileage with a china engine? expereinces??