Stroking a Dolmar 7900

[usmcbuckwild]

Too many cervasas. [emoji16]

Not enough. I was HURTIN

 

[RI Chevy]

LMAO

 

[redline4]

@Fruecrue you going to try the pipe again with the new carb?

 

[Fruecrue]

@Fruecrue you going to try the pipe again with the new carb?

Probably not.
She’s a muffler saw through and through.

 

[Fruecrue]

BTW, these cuts have been with the STFU cover on the angry mufkin. Perhaps the added airflow from a larger carb Venturi would justify taking the muzzle off.

 

[redline4]

View attachment 183025
Probably not.
She’s a muffler saw through and through.

I laugh every time I see that!

 

[RI Chevy]

Too funny!

 

[Redfin]

Nice work Dave.

 

[Time's Standing Stihl]

Swapped to an HD-12, found some gains.

2.4
2.44
2.53
2.37
2.22

No upcuts? Wtf


Looks pretty strong man, definitely a top contender. Still using factory boot?

 

[Fruecrue]

Nice work Dave.

Thanks John.

 

[Fruecrue]

No upcuts? Wtf


Looks pretty strong man, definitely a top contender. Still using factory boot?

Thanks Clint.
Nah man, if I’ve got any chance at all there can’t be an upcut a involved.
Factory boot.

 

[Fruecrue]

RWJ gained over the HD12.
Didn’t run the air filter, would have taken some modification to make it fit.
Perhaps I should run the HD-12 again without a filter for comparison.
Wood is also getting slightly larger.
I wrote down the cut times but left them in the garage.
Average was 2.36, didn’t time the *s-wordty upcut, that was just for Clint.

 

[mettee]

Up cut!

 

[huskyboy]

RWJ gained over the HD12.
Didn’t run the air filter, would have taken some modification to make it fit.
Perhaps I should run the HD-12 again without a filter for comparison.
Wood is also getting slightly larger.
I wrote down the cut times but left them in the garage.
Average was 2.36, didn’t time the *s-wordty upcut, that was just for Clint.

How far out on the screws are ya? Just curious.

 

[Fruecrue]

How far out on the screws are ya? Just curious.

No idea.
I did have to take them way out.
I thought for a minute there was an air leak as I couldn’t get it to idle under 4K.
I need to check the throttle plate.
This was a brand new RWJ-4.
It was idling near 5K and piss revving to 16k out of the box with both limited screws at max.
I grabbed the spline adjustment driver and just kept spinning until the chain stopped at idle and max piss rev was 13,800.

 

[RI Chevy]

Time to jet up. Lol

 

[huskyboy]

Check to make sure that the throttle arm is touching the idle screw. I had to take some material out of the plastic cable holder to allow mine to idle properly with the zama. Wasn’t quite touching the screw when I let off the throttle. Sounds like your gonna have to mod that carb either way.

 

[mettee]

When this is done, I'm curious, but drop right back to the modded zama and see how it compares. I'm curious what the difference would be as you described it, or a guess at % gain.

 

[huskihl]

No idea.
I did have to take them way out.
I thought for a minute there was an air leak as I couldn’t get it to idle under 4K.
I need to check the throttle plate.
This was a brand new RWJ-4.
It was idling near 5K and piss revving to 16k out of the box with both limited screws at max.
I grabbed the spline adjustment driver and just kept spinning until the chain stopped at idle and max piss rev was 13,800.

I believe the throttle arm hits the plastic bulkhead between the carb box and cylinder at wfo. On some 372's I've needed to trim some sheath to get enough cable so it would idle

 

[Fruecrue]

Throttle arm hits the idle screw which is backed out to the point that it’s useless.
No trouble going wide open as long as the filter isn’t on.
I just figured it has something to do with the divider. Runs good where it is for what it is, I’ll look into it a bit more when I find the time.

I do feel it necessary to try the HD12 again without the air filter.