Coolent leaking?

[cougar99v6r]

I'm new to repairing my self and i just gotten my 94yz 125 back from top end re-build, new piston, rings, gasket and o ring. well iv only ridden it for about 4 hours and 2 weeks ago my kick starter fell off during riding so i didnt ride for 2 weeks, today i went to fix it and i got it put back on good, and when i went to kick it over it seemed a little stiff, but every time i would kick it coolent with dots of oil would gush from the breather on the head. I took my plug out and noticed coolent inside, i also opened up the coolent cap and it was about 1/4 way down or so, but when i put the bike away 2 weeks ago it was fine. Any sugestions? Im hopiing its just the head gasket. thanks again.

 

[mobrown]

When you got the top end done was it because something was wrong or just routine maintenance? First thing to do is to make sure all of your head nuts are torqued to specifications.

If you had a bad head gasket before the chances are that you either have a warped head or if the cylinder had a sleeve put in before the top of the cylinder (where the sleeve meets the jug ) may not be flat. Sleeves are installed into cylinder as a replacement to getting the cylinder replated if the walls had been damaged.

Check to see if a sleeve has been installed in the cylinder. If you don't know what it is then have someone who does take a look at it and determine if it is flush with the cylinder top surface... if it isn't then you must get it machined flush at a machine shop (about $50-$75) If you have a warped head you will need to get another one (about $150). If your bike had been leaking coolant before then you could have been running hot causing the head to warp.

 

[cougar99v6r]

No, i gotten it done because the piston was shot when i first got it. The guy told me someone beofore tried to re-sleeve it themselves and didnt do it right so he had to mill somthing down.

 

[cougar99v6r]

Another thing, can i even atempt to start it right now? or should i just leave it alone until i determine the problem?

 

[mobrown]

Get it looked at...

Running it now will only do further damage. You need to get it looked at to determine why fluid is entering your combustion chamber.

Both the cylinder and cylinder head need to be perfectly flat to creat a barrier between the cooling fluid and the combustion process. If the cylinder has been milled flat then it is most likely the head. I have heard of some folks who will use a copper based sealing compound to put on the gasket mating surfaces but I have not tried it myself. Sometimes you can also get thicker gaskets but the real fix is to get a new head or machine the old one flat. The problem with machining the head though is if you take away material you are in essence increasing the compression (conversly if you get a thicker gasket it will decrease compression) so a new head is really the way to go if that is indeed your problem.

 

[cougar99v6r]

i have 2 rubber o-rings under the head, the one goes all around the outside of the studs, and the other inside of the studs, the smaller one was shot, could that be the cause?

 

[mobrown]

Probably

Probably is the reason for the leak but again you want to ask yourself... why did it blow? Gaskets don't just blow they require a force to have them blow. If it was simply installed poorly then maybe that's why but my guess is that it overheated because leaking fluid can not cool your engine. High temperatures (overheating) distorts metal.

You could save yourself a lot of time and money by simply letting someone tell you if your head is warped or if your cylinder needs machined or both. This is not a big deal and could really make a difference in how well your bike holds up... any bike shop can check it out for you. At the very least they tell you'yea it's a little bad but should be okay". If you have it apart just take the cylinder and the head down to a shop... it's pretty easy to do and there are many here to advise you if need be.

Keep us informed and good luck :cool: