Cho90

[EJ mcnamara]

Running better all the time

 

[EJ mcnamara]

View attachment 158683

I was going to ask you the booster port up the middle do you have a hole cut in your piston for it

 

[Chainsaw Jim]

Here's a boost I did for an 041 super.

 

[sawracr]

Hey Jim, got another 090 going together, by taking part of the cylinder spigot can roll more fuel up transfers, this cylinder is over ported on exhaust and going to take a pipe to bring it back, it worked before, just got to get it all together piece by piece along with my other chores!

 

[Chainsaw Jim]

Good Morning,

I know I am late to the game, but could the original starter cup be utilized. Instead of the extra spool and shortening the crankshaft. It would add a little weight, but might be a solution.

Take care, Larry. HOS

I think know a way it would work. It would take a very skilled machinist.
I'd cut the aluminum "cup" portion from the 090 flywheel and with the right machining tools I'd cut reverse direction threads on the end of both pieces to join them without welding.

 

[Billy Currie]

Any progress on this?

 

[Chainsaw Jim]

Yeah I took it up for a quick run last weekend. It ate the starter pawl and I had to shut it down.

 

[RI Chevy]

Sorry. I cant like that post.

 

[Dub11]

Sorry. I cant like that post.

Holy *s-word!

Thats a first lol.

 

[RI Chevy]

Yessir. Sir

 

[sawracr]

Been there done that, must have been early small pulley.

 

[Chainsaw Jim]

It feels like this thing is starting to get broken in a little bit. John Reilly sent me a race loop for it at the last minute and ended up joining the pnw gtg in spirit, lol.

 

[Billy Currie]

Awesome job Jim!

 

[Absolution]

And they say 070 and 090s are pigs.

 

[Shane10]

What’s the circled recessed area do and what do you call it? I’m curious. Sorry if this has been answered somewhere else or if this is the wrong place to ask but I don’t even know what to call it to do any research. Thanks in advance.




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[dall]

What’s the circled recessed area do and what do you call it? I’m curious. Sorry if this has been answered somewhere else or if this is the wrong place to ask but I don’t even know what to call it to do any research. Thanks in advance.

View attachment 200833

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a different style boost port not used much anymore

 

[Shane10]

Any theory on how it’s supposed to work. I’m assuming it’s a performance mod? I originally saw that in that post about 6 months ago and have thought about how it might work on and off since and can’t seem to make any sense of it. I’m an auto mechanic for a living with 25 years under the hood of a vehicle but that doesn’t mean I know squat about a chain saw lol.


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[dall]

supposed to help feed from the intake side of the piston so less raw fuel out the muffler
more cleaner burn

 

[Nutball]

I haven't checked, but I think it would not fit on most modern saws considering how the piston goes down so far the rings about show through the intake port, so you'd have an intake free porting issue due to the port in the piston.

 

[Dub11]

What’s the circled recessed area do and what do you call it? I’m curious. Sorry if this has been answered somewhere else or if this is the wrong place to ask but I don’t even know what to call it to do any research. Thanks in advance.

View attachment 200833


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Thats the POS port.

As in dudes a pos that needs to ship some saws out.