I definitely appreciate the attempt to make the old Kawi's more competitive. But the reality is that a 30 year old piston port engine is never going to really be competitive with a modern reed or rotary valve engine. Weight reduction will make them closer, but you are working with an engine that doesn't benefit from 30 years of 2-stroke engine development and technology. Even if you did bore it out to be 500cc, it's still an old piston port engine and would still be down on HP and torque compared to a modern 500cc engine.
Personally, I agree with the decision not to allow the overbore. By the time you bore and sleeve and replace pistons, etc., and then make clutching changes, you're going to sink more money into the engine than it's really worth. You also are potentially building a grenade motor that may not last. We know that the crankshafts are the weak point on the Kawi at 440cc, so going to 500cc is just going to kill cranks faster. And since there is such a limited supply of Kawi cranks out there, repairing or replacing a crank is a difficult and expensive proposition. Not to mention the tech nightmare of trying to inspect modified Kawi engines. No disrespect to the scrutineers, but they are volunteers and for the most part they are not very familiar with 2-stroke engines at all. I doubt most regions have scrutineers who have the experience and understanding of 2-strokes to be able to determine compliance of a modified engine. For my money, I'd rather go buy a nice new 493 and be instantly competitive (and reliable), as opposed to pumping a lot of time, money and effort into trying to update an old Kawi to turn it into it something that it's not. Just my $0.02 worth.... and probably not even worth that much money! :-) ---------- Eric D Christensen Proadmin, Inc. > -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On Behalf Of Stan > Sent: Friday, April 21, 2006 7:25 AM > To: [email protected] > Subject: Re: [F500] 440 vs 494 > > John, > > While it is true that a weight break for the 440s was not > among the 18 or so items asked for in Joe Palmer's list, > there were two other suggestions brought up which had the > same intent - give a performance enhancement for cars with > those engines. After considering all of the input on porting > and overboring, as well as soliciting additional input from > experienced 440 guys about how well those options might work, > we decided to go with the weight break. > > That decision won't please everyone, but then neither would > have permitting porting or overboring. Many writers, > including most self-identified 440 guys, pointed out that > porting and overboring run counter to the class philosophy, > and open huge "cans of worms" while complicating the already > considerable clutching challenge. If we were to stick with > the class philosophy of "no internal engine modifications", > then a weight break was the most direct route to giving those > guys a break. The CRB recognizes that not all 440 cars will > be able to make that weight, or at least not without > considerable investment. However, neither porting nor > overboring are free, either, and either would require > potentially considerable cost to "get it right". > > I hope that adequately addresses your concerns. > > Stan Clayton > > John Whitling <[EMAIL PROTECTED]> wrote: I guess > that I'm confused about this process. Won't there be a time of > comment before changing any of these rules? We didn't > even ask for a > weight break for 440s. And because a few guys ask > and write for > porting for kaws the weight get changed? Sorry but I > didn't imagine > rule changes would work like this. Dave Panuef has > already worked on > Ti brake rotors and such. This weight change may be well > intentioned > for bringing out old cars but aside from the no suspension > era cars, I > doubt you could chase 100 lbs out of a chassis without > compromising > safety or greatly increasing the use of exotic > (expensive) materials. > Just my opinion. > John Whitling > > Stan wrote: > > We dropped the weight to 700 lbs after considering all the > input on the subject , especially that from the Kawi guys. > Neither porting nor overboring was consid ered a workable > solution, and since many of the cars which came with those > engi nes date from when the minimum weight was 700 lbs, we > felt that the best choice available was to revert to that > weight. The change isn't going to make the Kaw i a > Rotax-killer, but maybe it'll bring some cars out of garages > and get them b ack into road racing. > > Stan > > > > --------------------------------- > New Yahoo! Messenger with Voice. Call regular phones from > your PC and save big. > _______________________________________________ > 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! *** > _______________________________________________ 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! ***
