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ULT LTWT BIKE

941 Views 7 Replies 5 Participants Last post by  joe c
Branson,
I've started gathering stuff for for ultra lightweight bike. I know your going to be doing a 250 some day and I think I'm going to head in the other direction. I have a very cool rolling chassis and hopefully this thing will weigh between 185 and 190. To be competive with an MT, its probably going to need atleast 25-27 horspower. The class is design for 200cc bikes but I think I'll need a little more cc to get the horspower I want. Is there more info on that class in the new rule book. Has anyone received a new rule book?

Aaron
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Yeah...dumb to spend $80 to lose two times.


Aaron, I think ULWSV is the bump class for 250gp. Of course you'd have to have a drum to run in GP. But you could run 250cc and get the hp you need.
In my opinion you'd have to go two stroke to be competitive at 200cc and far as I know there is no handicap for 4 strokes....except running a 250cc GP machine.
Right now there is like nobody running ULWSV, Turk runs his MT, Marty runs his MT sometimes but lately has been justing doing laps in the class and pulling off before the finish and running for real in LWSV. The MT's run about 1:29...about 7 seconds faster than my best times.

It would be very nice if they gave air cooled 4 strokes 250cc and disk brakes to run in the class. Be aware that in AHRMA or WERA (not sure which) you can't run a disk brake on the MT's in the class they run in....which I assume applies to any bike in the class.

I know the guys like Turk and Marty wouldn't care if you ran 250cc and disk brake...they'd appreciated the competition.

The reason I was going 250gp was so I could run either 250 or ULWSV. But without some real hp (MT's are about 28hp) and an excellent brake, and a 200 lbs bike it would be hard to be competitive.
JohnnyB
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Aaron,
Great, thanks for ordering the stuff. Time is getting short.

Marty says his MT is heavier that you think...but Marty loves to talk his bike down...I don't see where it would be heavy..theres nothing there. The 77 MT had 26hp and the 78 had 28hp....according to Honda...not sure how accurate that is. Marty on an MT is a tough combintation to beat...he only weighs about 130 lbs...he's smooth, fast, but won't really go balls to the wall from what I've seen. He really really hates crashing and it keeps him slower than he could be.

Guys that run the 78 juice brake on the MT can haul them down pretty quick, the 77 mechanical brake sucks ass. I think a fast rider on a 180 lb, 210cc four stroke with a disk brake would be in the mix but it would take a small rider...Turks probably about 160 lbs max. If you could get the bike weight down to around 180, with a light disk on the front you could drop fork size down to 31-33mm for sure and save some more weight...the MT's have 27mm forks, nothing special that I know of, just 27mm damper rod.

An MT that's tuned right has some serious balls. I had a big fat ass on an MT passing me down the straight at Mosport...the guy had to be 230 lbs. The deal with MT's is a well tuned bike has probably 5hp over one that's just thrown together.

I expect to eventually get 25hp out of my bike at 210cc. It would be an interesting experiment to see how light I could go with it...down to braced 27mm forks, really chop up the chassis to save a few pounds, go with a disk to drop 5 lbs up front. Matt has already built me a tank and seat than can seriously be no lighter, PVL and toss out the battery, alloy body shocks, tapered spokes, alloy fork clamps...but damn...I think getting below 185 would be real tough. Other route is keep some of the weight and go with a 260cc engine for about 30hp in GP trim.

Rider weight is such a tough nut to crack....think if Mary rode like Marty at 130 lbs....freakin 70 lbs lighter than me...that's about 7hp, how you gonna top that. I honestly think with my bike the way it is if I was 70 lbs lighter I'd be running competitive ULWSV times.
JohnnyB
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