YZ80 transmission fluid color problem

[BuzZz]

I found that GM's wonder-juice isn't all it's made out to be in practice. I was responsible for a fleet of 35 or so pick-ups, all GM, untill a few months ago. It lasts somewhat longer than the green stuff before turning sludgey in pick-ups, but not dramitically so. I wouldn't go out of my way to change it if I had it or not, either way. In a cage.

Most automotive coolants have a high silicate content, mostly to lightly abraid the internal coolant passages and keep them clean and scale-free. But in a bike, these silicates tend to eat the waterpump seal quickly. In a car, the waterpump seal is a double-faced mechanical seal that is hardly affected by this. The flimsy rubber lip seal found in many bikes is nothing more than a beefy dustseal, and gets chewed up easily by these abrasives.

If you notice on most any bottle of decent motorcycle-specific coolant, it usual says 'Silicate Free' someplace.

And after all of that, I can't tell you if GM's Texron has high silicate or not.
I suspect it does, but it may have none for all I know. I've never seen real data saying yes or no, so your guess is as good as mine...

[Todd]

well i got good news and some bad news the good news is that the oil seal fixed the problem and i put the whole thing together and went to run it and while i had everything apart i put some performance reeds in and better airfilter so when i went to run it it started fine idled and when it went to take off it would rocket and then it would just stop and i had this problem before with my other engine if you remember and the problem was the piston and rings so i thought that had to be it but just in case i thought i would try some stuff with the reeds so i put the stock ones back in and it didnt make any dif well it actually ran worse so the only thing i can think of is the piston and rings so i took the cylinder off and there isnt very much that is really noticebly wrong but it does look like in one spot that it has a little bit of blow by so im gunna try n change the rings and see what happens bc i have my race this sunday so it needs to be working any ideas of what you might thing is wrong or something i missed that it could be? do you think its the rings?

[BuzZz]

Cripes, Man, buy a period.
Here's a free one to start you off.

.

.

Back to your engine...

Sounds alot like it's running lean. Either your new reeds and filter are flowing enough more air that your jetting is leaned out, or else you have an airleak in the intake tract someplace. The carb boot cracked? Carb seated in the boot properly? New gaskets used on both sides of the reed block? You didn't split the crankcases, did you (no need to split em if your just doing the waterpump)? Crankseals good and not leaking?

If the area of the piston that looks bad is the part that passes over the exhaust port, it's normal for that to look a little carboned up and slightly burnt....

A leakdown test would be the best way to track down the problem.

[Todd]

well i took my cylinder and piston to the local motorcycle shop and the guy is telling me that my cylinder is shot and with my luck that cylinder is made out of a certain metal that cannot be bored out so the only thing i can do is buy a new cylinder...any alteratives?

[BuzZz]

There are places that can re-plate your cylinder with the correct material. They can size the bore to your new parts, too. You might have to ship the parts off to the place if there is none in your town. Google 'cylinder re-plating or check your yellow pages under motorcycle repair.

[Todd]

ok ill try a little harder on the periods...

well i found a place in PA that does nikasil replating on cylinders. Their prices werent bad, but is that what i need, that kind of re-plating? should i be looking for something else?

[BuzZz]

Punctation is good. No need for perfection, just enough so that us non-texting fogies can understand it is all.

Nikasil is a trade name for the product used and belongs to the company who makes the material. The bike manufacture may or may not use it in thier own literature. Nikasil was first widely used by Kawasaki in the late 80's on thier KX line.

Yamaha did use Nikasil for a time, then I believe they switched to another, similar material. The best way to know for sure is to call your dealer and ask them what the cylinder is coated with, or call the plating place and ask them. You may be able to use Nikasil anyway, depends on compatibility with what the rings are made out of. I'm guessing it will work, but don't trust that, call and find out for sure.

[Todd]

Well, a month and 300 dollars later i have it back together and running. I have a few questions though. I went and looked up on how to break in a new top end and im following the steps of letting it idle n such for 15 min or so and then cool down and repeat again. Today was the first time i drove it tho and the motor is so much stronger but every now and then it would give a little lag like it did when there was blow by. Is that normal for a new top end to do until its broken in? It seemed to get better as tim progressed.

[BuzZz]

Good to hear the thing is running well again. I suspect your hesitation is probably just a slightly out of adjustment idle/air screw. Try fine tuneing it a quarter turn at a time.

I'd almost rather talk religion or politics than talk break-in.... and now 2-stroke break-in ......

Default, factory-safe, politicaly correct answer is... do exactly what it tells you do do in the manual, when it tells you to do it, for exactly as long as it tells you to do it..... to the second. Sleep the sleep of the contented masses tonite, safe in the knowlage that you did it exactly "BY THE BOOK!!!"

That particular book was written by a mid-level engineer in Japan who's prime concern is to not look bad to the bosses. Then it is edited by those Bosses (all 437 of them), accountants, lawyers and a wack of other poeple who have no business being involved in your break-in proccess.

What does the manual list as the sevice life of the top-end in that engine? 25-30 hours? It's something like that, I bet.

Idle 15 minutes, cool and repeat several times and you just used up 1/25th of your engine. And probably glazed your rings. Good for the parts department......

They want you to idle it to soak heat into the engine so everything grows to operational dimentions before you put the motor under heavy load. This is a holdover from the 70's when materials and processes were not what they are today, not to mention the quality of oils. Modern engine parts and oils are significantly improved.

What I do is.....

Warm it up for several minutes, gently blipping the throttle to avoid constant speed running. Then I go for a short, easy ride, never reving it to than about 2/3 of redline, and always pulling a load or engine braking. Stop and let it cool off a bit. Take another, longer ride, with a few more revs at the end of each pull.

Then resume normal operation.... ballstothewall.

[Sev]

I don't believe you've ever removed your balls FROM the wall.