Part One: The Exhaust Port

[Lightning Performance]

The the entry and exit angles of new 2smoke jugs speak volumes, literally.

 

[Deets066]

Stock port, 084

Lots of arch

 

[Deets066]

More gooder port

 

[Dub11]

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More gooder port

Nice. How much weight did that remove lol.

 

[Deets066]

Nice. How much weight did that remove lol.

Lots

 

[Lightning Performance]

Double check that floor and tare some of the center down on the chamfer/bevel. Easy on those rigs.

 

[Deets066]

Double check that floor and tare some of the center down on the chamfer/bevel. Easy on those rigs.

Floor is mostly untouched, may have gotten a little in the corners but that's it. I gave it a good bevel. I don't plan on goin any further until I get my new piston.

 

[BonScott46]

View attachment 116148 View attachment 116149

More gooder port

Purdy.

 

[lauren]

 

[smokey7]

What do we have going on here. Very interesting tell me more.

 

[Deets066]

View attachment 116193

You used to play with snowmobiles?

 

[lauren]

Yes Deets that and kawasaki h2s, had retired from porting about 10 years ago, started in 1988

 

[Deets066]

Yes Deets that and kawasaki h2s, had retired from porting about 10 years ago, started in 1988

I like the taper from the top of the port to the bottom. I did a little of that on my 84 jug, can't see it from the outside pic though. I'll get one from the inside.

How much of the top of the port did you close off?

 

[Deets066]

And I'm guessing your gunna free port a lot

 

[lauren]

No free porting. I made that upper wedge out of 3/8 plate, lets also remember that all my research over the years was done using chambers, still having a hard time using mufflers but i will keep at it to come up with a program using a pressure gauge

 

[Mastermind]

Looks like you've created a Husky style downward flowing exhaust outlet on a Stihl jug.

Very interesting.

 

[Deets066]

No free porting. I made that upper wedge out of 3/8 plate, lets also remember that all my research over the years was done using chambers, still having a hard time using mufflers but i will keep at it to come up with a program using a pressure gauge

Rpm is a lot different too, short stroke on the saws is way different than what works on bikes and sleds.
Interested to see how this one works for ya.

 

[lauren]

When I had the race shop, I did a flow bench work and came up with certain angles that worked the best, again using a chamber, and backed all my findings with my dyno, now will this work Im not sure, I bought this saw back in December and it was a slug as far as I was concerned, early D cylinder, so I figured I would try a A M cylinder for 20.00, put that cylinder on and the saw picked up a great deal, still was not satisfied and probably never will be, so I made some more changes this past week and way more power, got to run it for a little bit yesterday against my brother in laws 460 and it miles ahead

 

[Deets066]

 

[Deets066]

Tapered ex was big with snowmobile guys, I like the concept and it's better for ring wear I think