Stroking a Dolmar 7900

[mettee]

So you cut squish, what did you end up doing with the base? How much squish did you cut out?

 

[Fruecrue]

So you cut squish, what did you end up doing with the base? How much squish did you cut out?

.060” out of the band with OEM base gasket, no base cut.

 

[mettee]

How did that leave your numbers?

I can't remember did you bump timing when you did the coil

 

[Dub11]

No pics of chain when sharp and it’s dull now.
Swapped out for a round filed RS which also cut real well. Dead ash is tough on chains and air filters.

leave the AF at home, it'll stay clean that way.

 

[Fruecrue]

95/123/78
Husky coil 30 degree flywheel advance from stock position.

 

[huskihl]

95/123/78
Husky coil 30 degree flywheel advance from stock position.

Did you go for a little more intake or leave it at 78? Guessing you left the others where they were?

 

[Fruecrue]

Did you go for a little more intake or leave it at 78? Guessing you left the others where they were?

Intake landed there. 83 was my original thought but that 78 sure was a convenient place to start.
After base cut, with stock gasket, 109/144/78

 

[mdavlee]

What’s compression like? I never took more than .035” and they would be 200 or a touch over

 

[Fruecrue]

What’s compression like? I never took more than .035” and they would be 200 or a touch over

Tuned it in the garage night before, this was first thing this morning. Felt like it went up throughout the day.

 

[huskihl]

Intake landed there. 83 was my original thought but that 78 sure was a convenient place to start.
After base cut, with stock gasket, 109/144/78

Oh. I was thinking you had good squish after only the band cut. I doubt you can raise the exhaust above 100 without grinding through the flange. Maybe with a bell mouth you can

 

[Fruecrue]

Oh. I was thinking you had good squish after only the band cut. I doubt you can raise the exhaust above 100 without grinding through the flange. Maybe with a bell mouth you can

I’m sorry, meant to write band cut.
I did not cut the base.

 

[Fruecrue]

Parttard thing again.

 

[huskihl]

I’m sorry, meant to write band cut.
I did not cut the base.

I see. That makes sense.
I originally ported a bb for mine and went through the flange roof trying to go straight out at 95. Guessing the oem has a thicker roof

 

[mettee]

95/123/78
Husky coil 30 degree flywheel advance from stock position.

Okay so a normal after porting set of number in a 7900/7910 would be 98-100/128/85....roughly.

I gotta draw this out and see how the two compare. It still confuses me a little bit.

 

[chipper1]

I see. That makes sense.
I originally ported a bb for mine and went through the flange roof trying to go straight out at 95. Guessing the oem has a thicker roof

Need a stock one to try .

 

[huskihl]

Need a stock one to try .

Just gotta send it

 

[Fruecrue]

Okay so a normal after porting set of number in a 7900/7910 would be 98-100/128/85....roughly.

I gotta draw this out and see how the two compare. It still confuses me a little bit.

Some guys wouldn’t do that much intake.
78-83 for a work saw.

 

[redlight066]

Fine looking work Dave. Great thread.

 

[Fruecrue]

Fine looking work Dave. Great thread.

Thank you Rich.

 

[mettee]

Some guys wouldn’t do that much intake.
78-83 for a work saw.

So you hit 78, and that is actually a better number I take it? Pardon my rookie questions.