One is on the greyish side and the other is darker charcole maybe.

 

Just a thought here big guy, if you rebuilt the top end, did you bore the cylinder? If so, did you get the piston and rings to match the bore? Holding your finger over the plug hole and not blowing it off when turning it over means compression is getting past the rings. The Namura piston and rings are a solid replacement, I use them in all my rebuilds, price dictates that vs. Wiseco or Pro-X. If you put a compression tester on that cylinder and you are below 100 PSI, it is going past the rings, and you either got a bad cylinder bore, or if you didn't have the cylinder checked, you are out of round on original bore.

 

Cylinder and piston w/ rings were taken to the guy who bored and honed it so the job would match the fit. Do you know which ring goes on top and which goes on the bottom?

Thank YOU

 

Anyone know for sure on the rings?

 

Well, I'll tell ya what I think........

When I looked at mine, I had the lettering up like it was supposed to be but it looked as is I had the darker ring on top and the lighter ring on the bottom. I think it is supposed to be the other way around, lighter colored ring on top and the darker ring on bottom.

 

Well-
I'll answer my own question about the rings. I finally got some time to call Namura today and the silver one goes on top and the darker one goes on the bottom.

We'll see if this solves all my problems

 

Rings were in correctly.

I brought my cylinder and piston to a guy who was recommended to me by a local motor cycle racing shop who has this guy bore and hone all of their motors. So, he had the cylinder and piston. I too, have thought maybe this may also had something to do with my problem. First I brought him the cylinder so he could tell me what size piston to get.
He did a really nice job on the cylinder.

It was weird- like I said before, the last two times I put the top end back together I had awsome compression when testing, but then when I went to actually fire the motor up, I lost it drastically. Deffinately way under a 100psi.
I agree, it seems as if air is going past the piston.
I have the top end dissasembled now and am gonna try and get some measurements when I have time.

Can I ask you what specs you usually bore your cylinder out to for the Namura piston and rings.

When moveing the piston and shaft up and down in the cylinder with the top of the top end off it looks like a really good fit, although I know that to the naked eye I could not tell if it really is and I have no way of seeing how it reacts under preassure.

What do you recommend doing?

Thanks
Kelly

 

Called Namura up today and the tech told me it was probably cause I didn't deglaze the cylinder with soap and water before putting it all back together.

Any thoughts???

 

Kelly: Put both new rings (one at a time) down in the cylinder by themselves - use the top of the piston to push them down about 1/2" and get them square and then check to see how much distance you have between the ends of them (called end gap) measure with a feeler gauge and tell us what you measure. Ask the guy that did the re-bore how much clearance he used between the piston and the cylinder (s/b like 0.0025-0.0035). There is no way you s/b able to keep your thumb in the spark plug hole when you spin the engine. You need right around 100 psi to have a decent running 2-stroke engine. Something is very wrong.

 

two threads from the same person on the same topic.
I feel You have no respect for those that tried to help You in the original thread and thaat to Me is a waste of time and mighty disgusting.
http://forums.atvconnection.com/pola...oap-water.html