SXR What's the best way to run in a fresh 2 stroke motor

[WFO Speedracer]

wait say high film strength, high ash content, and glazed one more time and I'll feerr suuure be convinced.

extra credit for if you can get wear pattern or crosshatch in there.

I went to the doughnut shop to get some glazed doughnuts, I needed some spare change and looked in the ashtray, thats when I noticed my ashtray had a high ash content. I tried cleaning it with high film strength formula 409, that didn't get it so I resorted to steel wool, thats when I noticed it was leaving a crosshatch wear pattern in my ashtray, if only I had used synthetic steel wool this would not have happened !

 

[the WaTeRhAwK]

Well, I'm tired of making Matt chase me around the block, so I agree with him now. The necessity to break an engine in with conventional oil is complete BS. Now if we can just convince the rest of the industry, we won't look so much like we don't know wtf we're talking about.

hmm,... let's see.... where to start........

 

[ready to ride]

I just rebuilt my motor. 84.5 mm pistons with a the high compression ada head. I did a compression check before i put the motor back into the ski and only came up with 63 pounds psi. So I removed ada and put back on the stock head. Also came up with around 60 psi. I know there's a break in process but I was thinking the 60 psi is way too low. Does anyone know about where my psi should be after new pistons and rings?

 

[yamanube]

I just rebuilt my motor. 84.5 mm pistons with a the high compression ada head. I did a compression check before i put the motor back into the ski and only came up with 63 pounds psi. So I removed ada and put back on the stock head. Also came up with around 60 psi. I know there's a break in process but I was thinking the 60 psi is way too low. Does anyone know about where my psi should be after new pistons and rings?

It depends on what domes are in the head but I would expect to see no less than 150. Try with a different gauge, if that still shows low pull the topend and make sure you installed the piston rings, installed them correctly, they are not stuck in the piston grooves and that your cylinder bore is within spec of the pistons that are in it. Are you getting 63 PSI on both cylinders? If so, I would definitely check with a different gauge (try putting that gauge on a different motor if possible as well).

 

[ready to ride]

Yes, I checked my other ski and the gauge is working properLy. It's 63 in one cylinder and 66 in the other. I've pulled the top end back off and the rings look to be ok and not hung up on the walls.

 

[Quinc]

Yes, I checked my other ski and the gauge is working properLy. It's 63 in one cylinder and 66 in the other. I've pulled the top end back off and the rings look to be ok and not hung up on the walls.

Are they upside down?

 

[ready to ride]

just went back to the machine shop to talk to the guy who did the machine work. and he told me that everything was In intolerance. I told him that there's no way because the piston wouldn't fit into the top of the cylinders only through the bottom.so the hole can't be the same size if the piston won't fit through it Both ways.

 

[yamanube]

If the piston didn't fit in the top of the cylinder....how did you possibly get a chance to compression test it?

Yes, I checked my other ski and the gauge is working properLy. It's 63 in one cylinder and 66 in the other. I've pulled the top end back off and the rings look to be ok and not hung up on the walls.

You are not looking to see if the rings are hung up on the walls, you want to see if they are sticking in the grooves on the piston and not allowing them to seat against the cylinder wall.

 

[Quinc]

 

[ready to ride]

Lucky the piston didn't come up high enough to hit the sides of the cylinder walls. the piston wouldn't fit in through the top in either cylinder. I looked at the rigs and the looked to be free and not hung up on anything. I did notice at the bottom of the sleeves that one side has a noticeable amount of material on in then it then the other side of it. Looks like it was bored at a slight angle. Do you think there's any saving the sleeves?

 

[yamanube]

I would send your entire topend to a competent engine builder and get a professional opinion, a lot of what you are saying doesn't make sense.
If you want actual help on here, you will need to take pictures (good) and measurements (accurate). Starting a new thread with those two items will greatly help somebody diagnose your issue over the internet.

 

[bored&stroked]

When I was in automotive engine building class as a kid we didn't have a bore machine so we used the honer. Took a while but it was school so we didn't mind. Because of the stroke pattern of the hone machine the bottem of the bores would always be larger then the top, we would have to manual hold the machine up top to make up the difference. Kinda sounds like your problem.