Dan, You bring up some excellent points. I hadn't even thought about checking the ignition timing, but if the valve is opening ATDC, then the ignition may be firing ATDC. I'll check that when I tear into the motor this weekend.
I've got most of my 1997 SkiDoo shop manual scanned in and riding around on a flash drive for perusal at work. I'd like to see scans of what you've got, but don't strain anything to do it. I've gotten my mind wrapped around the procedure for setting the valve timing by doing some reading this morning. Thanks again, Kenneth --- dan hester <[EMAIL PROTECTED]> wrote: > ken, > you outa just pull the front rotary cover and look. > or you can look in the > pto side carb with a flashlight, actually in my > own terms one port is > opening and the other is closing, on the mag side > port > there is a mark scribed on there from the factory, > go to tdc back it up to > where the book says and look at where the edge of > the plate is in relation > to that line, the mag side port is totally closed at > this point, you are > looking at what they say is the opening starting > point, whicjh doesnt really > make any sense since it is not right on the edge of > the port, on the same > note if you are where you supposed to be degree > wheel the, if i remeber > correctly the pto side of the rotary is just > starting to close on that port, > you should be able to look in with a flashlight and > see it starting to > close. > my book has a diagram of how to scribe a line in the > proper place on the > case for you to line it up, unfortunately i just > leared our scanner/ fax > machine is broke here, i will take it back home and > scan it there tonight, > im looking at the ski doo racing team manual for the > 494 it goes into a bit > more detail. > like checking the timing mark on the flywheel, if > you set your rotary off > the mark and that mark is off, not only will your > ignition be off slightly > but your rotary will be out a bit too. > ill have to find that section also , you need a > guage to get to tdc then you > back it off xx amount and remark the flywheel. > i will copy these pages as well , its a good way to > pick up some hp if you > really want to take the time to get it perfect. i > really noticed a > difference after i did this several times. > > dan / clarkston mi. > > > > > >From: Kenneth Kirkland <[EMAIL PROTECTED]> > >Reply-To: [email protected] > >To: [email protected] > >Subject: Re: [F500] 494 Rotary valve question > >Date: Thu, 1 Mar 2007 12:46:45 -0800 (PST) > > > >Dave, > > > >Getting back to your first post, this is a motor > that > >was running until an overheat and stick last > August. > >It turned out to only need a top end job, but the > case > >was cracked open to confirm the health of the > crank. > > > >I dug out my SkiDoo manual while I was home at > lunch. > >For the 494, the technical data lists valve timing > as > >opening 135 deg BTDC and closing 64 deg BTDC. Does > >"opening" and "closing" indicate when the valve > BEGINS > >to open or close? > > > >I'll confirm yesterday's observations after work > today > >and get more specific about what the valve is doing > >and when it's doing it. > > > >Thanks, > >Kenneth ________________________________ FormulaCar Magazine - A Proud Supporter of Formula 500 The Official Publication of Junior Formula Car Racing Subscribe Today! www.formulacarmag.com or 519-624-2003 _________________________________ _______________________________________________ F500 mailing list - [email protected] To unsubscribe or change options please visit: http://f500.org/mailman/listinfo/f500 *** Please, DO NOT send unsubscribe requests to the mailing list! ***
