80cc Mystery

If I may throw another question out there while we're on the subject.I just removed the head on my 70cc boy go fast with about 1100 mi. on it.Rings and cylinder wall look new,but top of cylinder and head have about 1/64" or less burnt crud on them.Too rich or normal? How do you clean that off.Thanks,Ron

Normal buildup of burned oil Ron. Carb cleaner and a wire brush will clean it.

Ok, this is kinda crazy for me, since the most mechanical thing I've every done is change the oil in my car...but,

I took the piston apart. (rings, head, bearings, etc.) and i showed them to my friend, who has actually seen a bad piston before. He looked at the head, rings, and cylinder and said all were perfectly fine. The cylinder itself is flawless. the piston head has no scratches, just some light rubbing near the bottom. nothing that changed the shape. and the rings are still in tact, spring'y' and looking good he said.

__________________
http://www.youtube.com/watch?v=MOQuj2XukHc

Yes.. They look good in the pictures. What does your head gasket look like? Also.. Running a new motor at such high speeds will burn it up. Mix 20:1 and keep speed under 20mph for the first 200 miles or so. Vary speed up and down. Run engine under load for 15-20 min and shut down for 10. Do this for the first 50 miles. Once you get 500 miles or so, you should be broken in. All the while checking for air leaks. An Air lead is certain death for any 2 stroke. Once you get broken in, switch over to AMSoil synthetic oil 30:1. You should last a long time if you observe these few simple rules. Oh.. Also.. There is no such thing as an 80cc out of china. This is your chance to find out, measure your bore and stroke and then do the math. You will then know that who ever sold you an 80cc motor is either unknowing or lying. Both are not good . Let me know.. Enjoy the ride..

__________________
visit www.thatsdax.com for more !!

ok, so maybe there is no problem? I am on mile 120 right now. I can sometimes get up to 27mph, highest was 36. avg about 20 now. I ordered new gaskets all around. I will also mix a new back of fuel, 20:1 (real quick, how many gallons of gas is that to 8 oz or oil?)

what brand of synthetic should I be using? best?

__________________
http://www.youtube.com/watch?v=MOQuj2XukHc

You are definatly lean... Look at the pic of the spark plug, Might want to raise the needle in the carby (lower the clip) one slot......Parts all look ok though. Also when you put the piston back in the cylinder make sure you line the opening of the rings up with the little pins in the grooves...

8oz @ 20:1 = 160oz of gasoline 128oz = 1 Gallon So 8oz of oil to 1 Gal and 1qt of Gasoline

Any QUALITY oil..... I use Amsoil Sabre....

rgr, i'll look for Amsoil Sabre. and I'll remix my fuel. I've seen the pins, thanks for the heads-up on that.

now, what is this suggestion?
this is my carborator

__________________
http://www.youtube.com/watch?v=MOQuj2XukHc

You might not find Amsoil locally I order it from Pablo, a member here. Just get a good oil, not weedeater oil, lol, maybe Pennzoil, or a good name brand 2 stroke oil. But if you can find Sabre locally it seems to be very good IMO.

In this post Norman shows you the internals of the carb. You need to read it an familiarize yourself with it then you might want to try moving the clip one notch and riding your bike and see what you think. And then maybe try another slot and test ride etc. Looking at that spark plug I think you are running lean so you should start with moving the clip DOWN 1 slot to increase fuel to air mixture....

Carburetor pictures how to install and rebuild

hmm, well I thought I had found the solution...i replaced the gaskets on the intake, exhaust, head/cylinder, and lower block. my bike ran great for about 20 miles...then it started acting up again, same as before.

i am beginning to think that something is loose on the inside, that got tightened when I was putting it back together after the new gaskets, and now it has come loose again. any ideas?

i also moved the 'c' clamp to the lowest position in the carborator...isn't that suppose to give the most oxygen in the mix? i don't think i'm getting maximum combustion...lots of oily black on plug...and i mixed 4oz 2 cycle oil with 1 gallon gas, that's the right mixture, right?

__________________
http://www.youtube.com/watch?v=MOQuj2XukHc

Lowering the clip is raisng the needle giving you more fuel LESS air. I would move the clip to 2nd from top as a starting point...

If your engine is already broken in 4oz would be ok thats 32:1

__________________
"No such thing as a stupid question, just a stupid answer"

48cc Grubee Starfire Round Head......