MS250-Too Much Compression?

[HarleyT]

As I said earlier, the stock ms250 ez-start system requires a decomp button to work there, not even trying to imagine running your little Frankenstein, so you will have to at least swap back into just a normal ms250 crankcase and starter.. Or go the other route and get a cylinder with a decomp button.

 

[drf255]

Do I have to give the Dirko 24 hrs to cure?




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[c5rulz]

EZ start and tooless tensioner, there is just so much to love.

 

[AKDoug]

Do I have to give the Dirko 24 hrs to cure?

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I'd give it a minimum of 4 hrs.

 

[blsnelling]

Do I have to give the Dirko 24 hrs to cure?

Fire it up. It's fuel proof. I've never had an issue.

 

[drf255]

Fire in the hole.

It didn't explode.

Will compression test it when it cools.

Is noticeably stronger than a stock 250.

Once I can tune it I'll post a video.

Thanks for all the help.

 

[drf255]

24 inch oak knot. All I had.

18" bar with yellow non picco RS chain. Needs sharpening actually.

Need to adjust it. Afraid to free rev yet.








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[blsnelling]

Congrats, it runs! Looks like it's making good power, but not making the RPMs I like in a good ported saw. Get a degree wheel on that bad boy I think you'll also find that 6°-8° of timing advance will make an improvement as well. That's quick and easy to try, and easily reversible.

 

[drf255]

Thank you Brad.

 

[AKDoug]

Congrats, it runs! Looks like it's making good power, but not making the RPMs I like in a good ported saw. Get a degree wheel on that bad boy I think you'll also find that 6°-8° of timing advance will make an improvement as well. That's quick and easy to try, and easily reversible.

Brad- Do you have numbers on a 250 that would work good? This is the best running one we have. It's just a tick behind our 241 in the same wood.

 

[drf255]

I'm at slightly over 180 psi with a dry cylinder now.

 

[blsnelling]

Brad- Do you have numbers on a 250 that would work good? This is the best running one we have. It's just a tick behind our 241 in the same wood.

I have not ported a 250. The numbers are probably close to other similar saws though.

 

[CR888]

You're missing a very critical part. Until you degree that cylinder, and put the port timing where it should be, you're leaving a huge piece of the pie out of the equation. The transfers likely need raise, and the intake probably needs lowered. You will see gains for your port widening, but not what it could be. You can print out a paper degree wheel, sized to the diameter of your flywheel, and then simply glue it onto the fins. Make sure it's centered and that will be plenty good enough. Let us know what your stock port timing is and we can go from there.

This is what's special about AS....people with plenty of experience helping others achieve their best.

 

[drf255]

A few more questions.

I tuned it quite rich for the first cuts. How many tanks should I put through it before I can free rev it with a tach and set the H screw? Can I do it briefly now?

I should be slightly 4 stroking out of wood and not at all in wood, correct?

If the piston wasn't gonna hold together, would it have destructed by now? I would assume infancy failure in some thing like that.

Should I expect a bump in compression after the cabers seat? Did I reduce the compression too much?

The timing is already advanced. 1/2-3/4 of the keyway.

I ordered the correct chain for my bar and sprocket combo. Will post a video with some clean wood and the saw running when it comes in. The small video I made didn't really do it justice. That was a hard knotty northern red oak stump. Had only that and locust. I'm gonna keep the RS chain for the 028 super I'm gonna build.

 

[old-cat]

EXCELLENT job!!!!!!!!!!!!!!!!

 

[AKDoug]

You can free rev it now. Saws from the factory are free revved within minutes of being built to set the carb.

 

[drf255]

You can free rev it now. Saws from the factory are free revved within minutes of being built to set the carb.

I thought it was bad for the rings?

 

[AKDoug]

Everyone has their opinions. At the factory they are free revved to check tune. When I sell a new saw, I free rev it to check for four-stroking and I check it with a tachometer at the same time. Otherwise, you honestly don't know if you are too lean or not with a new or fresh rebuilt saw.

 

[drf255]

makes sense

 

[1Alpha1]

Back in Nov. 2002, I bought a new BMW motorcycle. The dealer I bought it from was about 110 miles from where I live.

Anyways, when I went to pick it up and ride it home, I was told not to baby it on the way. I was told, don't be afraid to ride it hard. The dealer said, if you baby it on the way home, you might end up regretting it.

So, once on the highway, it was me, the machine, and a somewhat heavy throttle hand, all the while, bearing in mind, that I was risking over $16K.

It all turned out fine.