Cho90

[Deets066]

Are you saying two piece head?

 

[species8472]

@farley9n's chinese 090

View attachment 158007 View attachment 158008 View attachment 158009 View attachment 158010 View attachment 158012

How mine bolts on. Bracket bolts on cylinder then the rest bolts.

 

[sawracr]

Have to remove lots off bottom if you don't have a removable head, years ago stihl had a 090 go cart engine that had rotary valve intake, wouldn't you like to get you hand on one of those ? Hey EJ I have another cylinder with removable head, if this doesen't work I minght go to bigger bore.

 

[Chainsaw Jim]

Have to remove lots off bottom if you don't have a removable head

Yup .040" off. It isn't fun pulling over.

 

[EJ mcnamara]

I'm in California right now heading to Redding ca maybe we could look at what you got

 

[sawracr]

EJ what you saw in the picture is what I've got just looking for enough to put that saw together, have sold most everything else, if your in the general area maybe we could meet somewhere for some BS.

 

[EJ mcnamara]

Sounds good I brought my saws with me too

 

[Chainsaw Jim]

Wuhhhhh?!!


Before...


After...

 

[Deets066]

Wuhhhhh?!!


Before...View attachment 161035


After...View attachment 161036

Cold start saw?

 

[Chainsaw Jim]

Cold start saw?

The only cold start I've seen around here is in the bike saw class. Is your question based on the pics or just general?

 

[Deets066]

The only cold start I've seen around here is in the bike saw class. Is your question based on the pics or just general?

Based on the baby flywheel
Usually that’s for the cold start guys who want to get to max rpm fast as possible.

Think it helps much in the cut?

 

[Chainsaw Jim]

Based on the baby flywheel
Usually that’s for the cold start guys who want to get to max rpm fast as possible.

Think it helps much in the cut?

42.8oz vs 16oz, it's definitely going to help. The way I see it, you got more time to spool up between the ground and the top of the log vs that fraction of a second on a down/up changeover. At higher rpm cutting I believe the weight of the flywheel is so great that the motor has to expend too much energy on it while under load. I also believe the excessive weight lowers the max rpm.

 

[Chainsaw Jim]

I'm assuming the question of what to do with the gap that now exists between the recoil spool and starter pawl cup on the flywheel will come up. I'm keeping my fingers crossed that this will hold up.


I machined a longer axle to butt two spools together, anchoring them with a metal dowel. Since the pic was taken I drilled a hole where the arrow points so the dowel will be anchored better.


Then there's more! Always effing more no matter how well you think it's been mocked up and measured twice.
The excessive length of the stub now blocks the recoil housing from settling in place...

Never fear!... this little mf'er is here!, lol...


The only reason I'd ever attempt threading this kind of shaft with one of these is the fact that there is already a set of threads established to keep it perfect for me to continue on with.

 

[sawracr]

Hey Jim how about kinetic energy once you get a heavier item moving its harder to stop, would be very interested to know if you cut faster with lighter fan. Let us know.

 

[Chainsaw Jim]

Hey Jim how about kinetic energy once you get a heavier item moving its harder to stop, would be very interested to know if you cut faster with lighter fan. Let us know.

Wouldn't you think being harder to stop would equate to also being hard to get moving? It's practically a snowmobile flywheel, lol.

 

[sawracr]

So I'am trying to get you to tell me if it works before I drill holes in my flywheel.

 

[Chainsaw Jim]

So I'am trying to get you to tell me if it works before I drill holes in my flywheel.

You mean literally drill holes in your flywheel?

I'm 99% sure in my mind it'll work, but you gotta sacrifice a crank to do it because I'm not sure if there will be enough threaded stub left to put a stock flywheel back on.
I had to cut it shorter because it butts up against the end of the longer recoil spool axle. The 394 flywheel is another direct fitting taper for this crank stub and might actually be an easier mod for matching up the recoil pawls.

 

[Brewz]

Loving this Jim.... great work mate.
I have a china 070 I have put a 66mm top end on and an 090 clutch etc and ported.
Also retro fitted up an old OEM AV handle and it rock and rolls.
keen to see what you end up doing with the coil etc

 

[Chainsaw-57]

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

 

[Chainsaw Jim]

Here's the latest result of a few quick changes. Crappy wood, I know, but I hope to get a better log soon.
Also the Chinese oil pumps for these things are horrible. Two out of three had badly damaged diaphragms. It seemed to slow down on oiling the chain almost completely and needed thumb pumped. I also believe the reason it quit oiling automatically is because the membrane split open. That would probably explain why it started smoking so strong since that membrane is the only thing that prevents the oil from getting sucked into the case. I'll have to plug the impulse hose entirely and just pump the hell out of it before each cut.