262XP Day

[Mastermind]

All the machine work is finally done.

 

[skippysphins]

I see mine I think

 

[Mastermind]

I'm gonna eat supper.......when I get back I'll bolt on a stock jug to check all factory numbers. Then we'll see where we wanna go.

 

[skippysphins]

Have some pie you deserve it today buddy

 

[fastLeo151]

Is this where the cool kids hang out??

If no, point me in the right direction.

 

[skippysphins]

Not here lol

 

[Mastermind]

Is this where the cool kids hang out??

If no, point me in the right direction.

It was.......then you showed up.

Just kidding Andy. Come on in.

 

[fastLeo151]

[Don't E="Mastermind, post: 5307453, member: 43167"]It was.......then you showed up.

Just kidding Andy. Come on in. [/QUOTE]

Dont forget us Ohio guys are thin skinned and cant take a joke....

 

[Mastermind]

OK, I've checked the timing numbers. Stock Mahle jug, with a base gasket.

EX: 103.5
TR: 116
IN: 69

That means we have only 12.5 degrees of blowdown. Cool huh?

Case compression angle is 47 degrees.

No wonder these saws are factory hotrods.

 

[skippysphins]

OK, I've checked the timing numbers. Stock Mahle jug, with a base gasket.

EX: 103.5
TR: 116
IN: 69

That means we have only 12.5 degrees of blowdown. Cool huh?

Case compression angle is 47 degrees.

No wonder these saws are factory hotrods.

Can you explain a Lil deeper for me I am a newb

 

[Mastermind]

After cutting the base I end up with the intake at 71.5.

 

[M&Rtree]

 

[Mastermind]

Can you explain a Lil deeper for me I am a newb

I'll try Chris.

Remember, this are just my thoughts.....

In a two stroke engine the transfers are everything. The air/fuel mix has to get around the piston from the crankcase to get into the combustion chamber.

This saw has a very short intake duration, and a high transfer opening point. The intake being short is what allows the transfers to open as soon as they do.

People think about blowdown far too much IMHO. The transfers opening is what pushes the remains of the exhaust out........as long as the pressure is not greater than the transfer flow. If the intake is too low, then there isn't as great of a pressure when then transfers open, and the exhaust can travel down the transfer ports......

There's a hell of a lot more at play here, but that's the quick and dirty version....

 

[Mastermind]

After cutting the base I end up with the intake at 71.5.

I'll take the main transfers to 118, and the fingers to 116. The exhaust will open at 103.

As you can see, I will not vary from the factory timing numbers much at all here.

 

[Mastermind]

I'm gonna be finding all my port heights now.

If y'all have questions.......post up.

 

[fastLeo151]

Randy keep an eye out for a good user 262 out for me please.

 

[Mastermind]

Randy keep an eye out for a good user 262 out for me please.

I might have an extra one. It would be an ugly son of a gun though.

 

[skippysphins]

Are the numbers the same for the ks cylinder? Or is that a different ball of wax ?

 

[drf255]

How much did you take out of the squish band?

How do you "take the transfers to 118" if they're at 116? I'm assuming that they come out lower after the machine work.

Do you feel that your theory of lowering exhaust helps the exhaust pressure to be lower and thus helps the difference in transfer pressure differential?

Can you post the numbers, after the squish and base cut, before you monkey with them?

BTW, you look more like Ergo.

 

[drf255]

So the way I read it, you're adding 2.5* to all with your cut. So you're exhaust will be at 106.5 and the tranny's at 118.5?

So you'll have to raise the exhaust.

Am I reading you correctly here?

This thread is awesome Randy. Thanks again. I'm about to do a 262 up.

I'd love some pics of the jugs and the fingers. Bridges too?

The single ring with the centered groove is nice in these saws.