Why Aren't You Guys staying on Topic?

[carhartted]

Boy I got you I got you all beat. Just wait till I roll up on my '90 JAG. Its bone stock but the flames make it go a lot faster.

 

[bwalker]

Rotary valve motors have the highest specific output of these three common types.

Thats not really true Doug. Piston port motors actually have the potential for highest output due to that fact that they have no restriction caused by valve systems in the intake.. This, of course is with the assumption that peak hp is the only concern. A piston port motor tuned for max hp would have a razor thin powercurve.

 

[dbabcock]

I guess I learn something new every day, but it may be that a rotary valve motor is more tractible, therefore having more useable HP, as you infer.

 

[eyolf]

I just love it when I get to jump on somebody over completely meaningless trivia:
Doug Babcock sez:

all '99 and previous Rotax twins were rotary valve

The first rotax twin I know of was the 370 opposed twin, starting in about 1966 or 67 on the Alpine, 1968 saw limited production of this engine on the "super 370". (I have two of these, plus one spare engine)
Interesting engine; one plain jug, one piston-ported jug with wide carb flange to take a Tillotsen HD. Opposed cylinders share common crankcase. Enterprising racers could put a 2nd carb jug on, even weld and machine crankcase to accept 35hp Johnson-Evvie reed valve cages, but it was pointless: engine would grenade spectacularly at high RPM's. I know. My uncle has shrapnel in his knee from this.

First inline twin was the 371 used in '70 wide track sleds, and its sister, the 399 twin used in the '70 TNT. This engine was eventually available in both piston-port and case reed versions.

In 1971 my uncle went racing for Scorpion snomobiles, and I got to come along sometimes as a sort of Jr wrench (gopher). I don't know from ski-doo much after that.

Mercury outboards used it for reverse in the late 50's.

I live in a resort area with lots of lakes: I am aquainted with a fellow that owns a little homemade 9' "pumpkinseed" hydroplane with a 90 hp Merc 6 cyl like you mention on it. I helped him shorten the shaft using some of the machine tools at work. I've been on it once. Worse than wicked.

 

[dbabcock]

Perhaps I should have said something clever like, "with respect to my limited knowlege", or,"modern day twins" or something like that. I've never even heard about these older sleds. I stand corrected. You win, eyolf.

 

[bwalker]

QUOTE] but it may be that a rotary valve motor is more tractible, therefore having more useable HP, as you infer.[/QUOTE]

Doug,Thats 100% correct. Piston ports when tuned to max power have much narrower powerbands than an rotaryvalve or a reed valve motor.

 

[eyolf]

Maybe I should keep my mouth,...er, keyboard?...shut. I had hoped to blunt the negative effect of my last post with my opening remark, but was perhaps too obscure.

Now I feel like I was being offensive. I apologize, Doug. As penance I will put a 20" bar on my 395xp tomorrow, and buck up some big burr oak logs for firewood.

 

[dbabcock]

No offense taken. I have no problem admitting that I don't know anything absolutely.

 

[dbabcock]

Yes, another example of Brian's posting of the best pictures on AS. Too bad Fish is at work. I doubt that this will last until he gets home. Too bad.

 

[mikek711]

This ones for Fish

18.99 a gallon.....4.75 a quart....Cant beat it.

 

[dbabcock]

I gotta find someone who I can instruct on how to take action shots. Until then, here's a picture that I manipulated by inserting myself next to a fake Ski Doo 7c REV today up at Lake Winnepesauke.

 

[jokers]

Nice looking fake sled, bet you have some fake fun with that one.

 

[bwalker]

18.99 a gallon.....4.75 a quart....Cant beat it.

Thats up for debate!

 

[v6bill]

Topic ????????

I have a problem>>>>>>>>>>>> went to Cumberland on Sat. to drink beer with Rotax no beer<<<<<<<<<<< im thinking them guys from Canada must have gotten across.the boarder again

 

[bwalker]

I think Flannery's is

Flannery is a engine builder from MI. I believe he is located somewhere around Cadillac. He has a very good reputation tuning Polaris engines for the soo 500 and other enduro races. I dont know if he builds doo's or not.

 

[Gypo Logger]

Ken, Ole Buddy, did my 346 KDP ship yet?
John