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

[Matt_E]

Tell you what. Since I sold my hull I need to take everything out tonight. I'll take the head off and take some pictures. To make things interesting, I also have another engine here right now with the head off that was broken in with Dino oil. I'll post them later

 

[the WaTeRhAwK]

Travis trust me I don't have to be told, but seriously the compression will only come up if the rings seat in, the only other thing that can possibly bring the compression up is carbon buildup on the piston crown and combustion chamber, I guess if you substituted 30 weight non detergent motor oil for two stroke oil you could accomplish this feat.You could also increase compression by plugging up the exhaust, neither will run well for long.

Nope, The compression will come up, just not where it should be, because the surface of the cylinder is being "polished" and closed off, or "sealing" against the rings. Where if the rings were cutting into the bore like they're supposed to the, crosshatch will be cut into by the rings, rather than polished, and the compression allowed to come up evenly, and evenly in both cylinders.

The compression will also begin to drop a lot sooner than it would normally, had the cylinders been cut into by the rings, and seated properly before normal use.

 

[the WaTeRhAwK]

Tell you what. Since I sold my hull I need to take everything out tonight. I'll take the head off and take some pictures. To make things interesting, I also have another engine here right now with the head off that was broken in with Dino oil. I'll post them later

Matt, before you do that, lets get a compression reading on the cylinders first if that's ok. Also, how many hours do you have logged with them?

 

[WFO Speedracer]

Nope, The compression will come up, just not where it should be, because the surface of the cylinder is being "polished" and closed off, or "sealing" against the rings. Where if the rings were cutting into the bore like they're supposed to the, crosshatch will be cut into by the rings, rather than polished, and the compression allowed to come up evenly, and evenly in both cylinders.

The compression will also begin to drop a lot sooner than it would normally, had the cylinders been cut into by the rings, and seated properly before normal use.

Ummm no Travis I am afraid not, the oil in the crosshatch is what seals the rings and creates compression, I have on more than one occasion seen engines with extremely low compression because of lack of oil on the cylinder crosshatch, I had one come back to life yesterday

Pink 1993 Seadoo GTX, customer brought it in because it was cutting off, I cranked it over and knew immediately that one cylinder had no compression, verified this with a compression gauge. Customer did not want to repair the ski at this point, reluctantly I bought it $400.00 for a clean a$$ ski on a galvanized trailer. At any rate the thing sat here all Summer , I didn't have time to mess with it, I looked at it and both oil lines from the pump were broken.

I pulled it out yesterday and cleaned it up. Apparently the crank seals are weeping a bit because when I fired it up it smoked up the whole yard. Somewhere in that short time span it began running on both cylinders, I verified this by alternately pulling the plug wires off each cylinder, sure enough when I pulled the plugs and checked the compression it was back to normal, I pulled the carbs , cleaned them, fixed the oil lines , bled the pump and took it to the lake, it runs flawlessly.

 

[the WaTeRhAwK]

Terry, you can have compression with a mirror finish on the bore, it just won't be as good and even as if you had cut the rings in properly and evenly. You're missing the point....lol The high strength filming of full synthetics will not allow the rings to cut into the bore and seat....lol Heat and friction is what makes the oil film break down and allow it to occur. Full synth properties are so resilient to heat and friction, the rings merely pass over the surface and polish it.....lol

omfg...lol

 

[Matt_E]

Matt, before you do that, lets get a compression reading on the cylinders first if that's ok. Also, how many hours do you have logged with them?

Way ahead of you. :biggrin: new it was 175. Now it's 185. About 200-250 gallons of gas through it.

 

[the WaTeRhAwK]

nice. :biggrin: you tree hugger....lol

 

[jetpilot08]

I broke my engine in with synthetic oil and two years later I fried my total loss....I should have listened.

 

[WFO Speedracer]

Terry, you can have compression with a mirror finish on the bore, it just won't be as good and even as if you had cut the rings in properly and evenly. You're missing the point....lol The high strength filming of full synthetics will not allow the rings to cut into the bore and seat....lol Heat and friction is what makes the oil film break down and allow it to occur. Full synth properties are so resilient to heat and friction, the rings merely pass over the surface and polish it.....lol

omfg...lol

No Travis you cannot have a mirror finish on a bore and have compression, no crosshatch = no oil retention = no compression, what is so hard to understand about this concept ?

I HAVE JUST PROVEN MY THEORY CORRECT, YOUR TURN !

 

[the WaTeRhAwK]

Yes you can sir, and it will even run, it will just run like crap and be difficult to start with a load on it. When breaking in an engine, there is only a small period of time where the rings can seat properly before the high parts of the crosshatched surface is cut or polished down. If you run it without cutting the rings in for a long period of time, you end up with a smooth finish, rings not seated, and have to start all over again.

 

[WFO Speedracer]

Yes you can sir, and it will even run, it will just run like crap and be difficult to start with a load on it. When breaking in an engine, there is only a small period of time where the rings can seat properly before the high parts of the crosshatched surface is cut or polished down. If you run it without cutting the rings in for a long period of time, you end up with a smooth finish, rings not seated, and have to start all over again.

So its Ten paces at dawn then, choose your weapon sir !

 

[the WaTeRhAwK]

I'm going to opt out for now, and wait...lol When you guys finally figure it out, I'll be here. :biggrin: enjoy........

 

[WFO Speedracer]

Dammit Travis I had already chosen my weapon too

 

[the WaTeRhAwK]

I like it.

Although, my "weapon" will speak for itself...lol

 

[the WaTeRhAwK]

...

 

[Matt_E]

Alright Travis.
Here's two different ADA cylinders. One was broken in on synthetic, one was not. Which one was which?

 

[the WaTeRhAwK]

Which one performed better?

 

[Matt_E]

Come on now. With all your glazing talk, you should be able to visually identify which one is which. Both increased in compression equally.

 

[the WaTeRhAwK]

Well, I really need more information regarding both cylinders to be absolutely sure as to what I'm looking at. Hours of use, per each one respectively, etc..

Are you kidding? I hope so.


It's not just an issue of "glazing", although, I can totally understand how you would come to that conclusion. It has to do with wear and seat patterns, as well.

 

[Matt_E]

So you're saying you cannot visually identify the cylinder that was broken in with synthetic oil and you can't tell by the compression increase numbers, either.
Amirite?

Surely you should be able to see glazing?