coolant leak

[martinfan30]

Just noticed a small trickle at the base gasket, in the front of the head. Is this common? Obviously it needs replacement. Recommendations for gaskets?

Will this continually worsen? Is there danger of coolant entering the gear oil?

I'm also wondering if I should just do a top end while apart. I am the third owner, and I was told its never been apart. I am hoping the standard bore is good still, so I can just get a standard piston kit.

What is the best choice for pistons? OEM? Other? Is there any possibility of just getting away with rings only? I know that depends on alot of things... Just wondering.

[barryadam]

have you checked compression? That'd be my first move.

It's easy to get a quick visual on the piston through the exh port with the pipe off.
Doesn't tell you too much, but can tell you right away if it looks really bad.  Plus you can see the condition of the exh valve.

[DoldGuy]

Get the leak taken care of now, it could be leaking into the cylinder bore and will eat away at the top of the bore. Check in with Stewart on this forum, he can get you setup with a piston kit (with window) for a resonable price.

[muleman]

I have the same leak on my 95. But it looks like it mite be from the alum elbow on the side of my cylinder then dripping down to the base gasket.

[martinfan30]

What do you mean with window?

[muleman]

he machine a window in the intake side of the piston =)

[martinfan30]

For what purpose?

Stewart, are you listening? I'm interested in this...

[Hillclimb#42]

You'll have to search. Search function will keep you busy with that for a few hours. Wiseco puts a window in there. I think Stewart is making it bigger, with dyno-backed precision. Its all about increasing power. Putting a fresher fuel charge in the cylinder and getting the exhaust to exit completely, make it run more effeciently and increases power everywhere. Its just one of the many mods that add up to the fastest dirtbike in the world.
  Pull that cylinder. Then you will know, if you need a base gasket or a top-end kit. Wiseco has a great kit that comes with all gaskets, rings, wrist pin, needle bearring, piston with window. You really have to see cylinder to be sure the coating is OK. The coolant can cause alot of damage if it is leaking inside. Its better to have it apart for a short time, than to destroy the whole motor putting off the repair.

[KXcam22]

Martinfan,
 Also keep in mind that base gasket leaks can leak IN as well as out.  IN is really bad as it brings dirt into the engine.  The main issue I found with keeping the stock piston is that they like to crack and the cracks can be difficult to find.  Stewarts piston kit sounds like the way to go. The window mod helps the power delivery. cam.

[martinfan30]

OK, thanks boys. Not knowing previous owner work and maint. , sounds like I should do it. I did the KIPS bolt mod yesterday, and impressed with just that.

So I'm looking forward to this new piston with the window mod.

Is the wiseco much lighter than stock?