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post #1 of (permalink) Old 01-08-2001, 09:46 PM
portgrinder
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4stroke hillclimber

We(university of alberta) are building a hillclimber with a 98 gsxr600 motor (running primary off the crank). Does anyone have a clue of where to start with clutch weights and springs. it makes approx 100hp at 12grand and hardly any until 4grand. its for the c.s.c challenge in jackson hole a week before the big event. it only has to go to the first catwalk.

thanx for any advice, my &$$ is riding on this thing doing well

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post #2 of (permalink) Old 01-09-2001, 01:27 AM
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Re: 4stroke hillclimber

I never really heard of anyone trying a four stroker in a hill climber. Let us know how good it goes. For clutching I would say your going to have to play around a lot. Might go really good. Since it has to rev so high I would think you would need too much weight. You must need a different tack to get a 12000 rpm reading. with the clutch spinning that fast I would for sure use a clutch cover. keep playing around with clutching. Good luck.

What's the weight of this monster and what chassis is it going into..

post #3 of (permalink) Old 01-09-2001, 01:48 AM
portgrinder
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Re: 4stroke hillclimber

were using a 98 xcr440 chassis.
the hillclimber part is just one aspect, the whole goal is to build a sled that still goes like stink but pollutes less. i don't know how much i like the idea of a 4stroke sled buy it sounds awesome on the dyno
we're using the tach off the bike. we're also using (push)cable steering to adress motor clearance

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post #4 of (permalink) Old 01-09-2001, 05:50 PM
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Re: 4stroke hillclimber

Interesting project! Did you cut the transmission off and close up the crankcase with a plate or did you leave it on?
The challenge here is the oiling system. If that engine uses a wet-sump lube system some kind of sump would have to be built. Getting rid of the tranny would sure save a lot of weight obviously.

As far as clutching goes, I run an SLP Orange spring in the primary (Polaris) along with #10 weights. This gives an engagement speed of @5000 RPM and a shift out around 8600. The latter is a bit low considering your power peak is 12000. I *think* a 10M weight is 49.5 grams so that would give you a higher shift and enagagement RPM. Do you know the RPM at which peak torque is made? I would also be wary of running any OEM clutch at 12000 RPM for any length of time. A billet quad cam clutch (HRP or Microbelmont) would be safer. If you do run an OEM clutch, I agree with the other poster that said a clutch cover would be a good idea.

As far as the secondary goes, if you run a polaris secondary maybe an R11 helix (45-36 compound angle) with a Silver spring. This would give you a fairly agressive upshift and good backshift. The 45 degree initial angle may be a bit too much. If it is, try something like a 42-34 from SLP or some such.

Just my .05 worth.

Please keep this note updated as to your progress. I am very interested in knowing how it works out!

Regards,
Dan

post #5 of (permalink) Old 01-09-2001, 09:33 PM
portgrinder
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Re: 4stroke hillclimber

Ya we cut off the whole tranny and are right now machining a new plate to seal er up. It should run in feb. we have to run a water, oil pump and an alternator off our motor also, but i think we have it figured out. The mounts got sliced off. Tourqe peaks at 6grand and then again at 9grand, anything above 9 and this motor screams! we are supposed to be concerned with noise but I think we're going to keep it loud just to turn some heads

we have a polari clutch and will probly just end up using it and making a huge clutch guard. it only has to run for 2 hours top at competition. we are more focused on sealing it up and making sure it will run, and finding cat converter material right now at this point.

As soon as i find out the web address for our page i will post it here.

thanx for your advice

post #6 of (permalink) Old 01-10-2001, 12:10 PM
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Re: 4stroke hillclimber

FYI Artic Cat has several 4 stroke sleds in use by the park guys in Yellowstone this year, don't know what dealer in West is supporting them but they may be able to give you some insight. You might also check with Cat direct.

post #7 of (permalink) Old 01-10-2001, 06:16 PM
portgrinder
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Re: 4stroke hillclimber

ya we've looked into their project a bit, but they are using a relitively low reving motor used in japanese cars compared to our high-strung race bike motor. so not too much crosses over.

post #8 of (permalink) Old 01-10-2001, 09:03 PM
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Re: 4stroke hillclimber

Since the RPM range is extremmely high compared to the 2-stroke you may have to goto a Comet clutch with 4 towers. Then use only two towers with weights and this would give you less mass as compared to the normal 3 tower clutch. this would be necessary as you will develop a lot of shift force at your projected RPM's. Be sure clutch is well balanced and tested for cracks. Use a clutch guard! You might want to look for some help on amsnow's racing forum and possibly some conversation with maybe one of the Erlandson's or Aaen would be in order. I am sure they would share some of their knowledge for a worthwhile cause (experiment :-)

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post #9 of (permalink) Old 01-11-2001, 12:41 AM
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Re: 4stroke hillclimber

Sounds really cool portgrinder. It would be interesting to know how much the motor weighs when you get it sealed up. For comparison, I just bought a used Polaris Ultra 680 triple. Without the carbs it weighs right at 90 lbs.

I also recently read an article in Snow Tech by Olav Aaen where he theorized how hi-performance sleds of the future could be powered by four-strokes. He even talked about how Yamaha could do exactly what your doing - chop the tranny off of their 1000c five-valve mill and drop it into a sled chassis.

Keep us posted!

post #10 of (permalink) Old 01-17-2001, 03:05 PM
portgrinder
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Re: 4stroke hillclimber

ya, next year we are looking at doing the same to an R1 motor or direct injecting a 440 liquid

thanx for your feedback. we're coming along quite well. for those who asked, our motor actually weighs within a pound of the original 440 liquid. the cg is just much higher. Anybody out there have a business that would want to sponsor us? our sponsors get their logo on our hood, 27ft trailer, tax receipts, and in the summer we are probly going to let each business have it in their office for a week, plus other perks. Big Rock Distilleries gave us 5 kegs!

anybody know the exact elevation of jackson hole?

thanx again



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