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[Admin]

I don't understand why you need a cush drive? I run a yamaha dirt bike wheel on my racebike. The sprocket bolts directly to the wheel. The wheel is 11 pounds lighter than the stock suzuki 500 wheel with the cush drive, and it eliminates that sloppy cush drive feel.

Hey Kris,

Maybe it's a lack of understanding on my part of the cush drive's purpose. As I understand it the cush drive is there to cushion the shock to the driveline and reduce wear on the chain, sprockets, tranny output shaft splines, etc... Plus a modern enduro cush drive is a lot smaller and lighter than the ones originally used on the T500. I take it you have not noticed any appreciable wear and tear on your driveline? How has your CR trans held up?

It could be I'm overthinking this as usual but I'm trying to strike a balance between strength, durability, and lightness.

I also don't see the need for a disc rear brake. The rear brake is very seldom used on the track. I use it occasionally to settle the bike coming into a corner, but as far as slowing the bike down, it's all done with the front brake. There are many successful road racers out there who have made a career without ever setting foot on the rear brake. I know racers who purposely use spongy old lines or do a poor bleed job so that there is less chance of the brake locking up. I also think a drum set-up might be lighter than a disc, unless you get some really trick dirtbike stuff.

I want the extra disc to maximize my ability to be an orange vested rolling roadblock on your racing line. Just kidding - I don't seriously have a deathwish. The bike is set-up for a disc already and it's just another avenue I'm exploring. I'd use a full enduro set-up from a mid-nineties machine including the smaller disc and caliper so I figure it should be at least a little lighter than the stock T500 drum. Plus the savings in rotating mass should be decent even with a small steel brake disc attached to the hub.

Thanks for the insight Krash - keep it coming!!!

Jim

[Admin]

Well, judging by Krash's starts, we all have the propencity to be rolling road blocks. Now if we can only master 4 wide into all the turns he will never be able to pass us.

[Admin]

A cush drive is used to ptotect the drivetrain components form shock loads induced during acceleration and deceleration. The reason dirt bikes wouldn't need cush drives is that on a dirt bike the rear tire is acting upon a moveable medium (dirt) that gives when loads are applied. This contrasts to street bikes where the tire grips the road without appreciable slippage.

[Admin]

Here's my take on racing T500's. I decided to race the T500 because I has a street model and loved the bike. I liked that it was different from H1's and RD's, and wanted to build a different racebike.

My TR500 is certainly not competitive on the racetrack, especially with me riding it, compared to the fast guys on H1's and RD's. Does that matter to me? Not at all.

I have a great time being on the track and just being around the racing environment. If I'm the slowest guy on the track, who cares!!! I think Zooke said it best this year at Mid-Ohio when I came in after a race, he said "I think you're going to need a bigger helmet to contain that smile you have on your face!"

As for the danger aspect of racing with AHRMA, I certainly feel safer racing than doing trackdays or certainly road riding the "twisties." AHRMA racers seem to be respectful and I'm sure more than one (me) doesn't want to wad up their pristinely prepared historical machine by taking unecessary risks.

After being on the track I can't believe how dangerous and stupid it is to go ripping down back roads, I've done my fair share in the past. Most tracks are 36 feet wide...compare that to most roads that are 8-10 feet wide. After being on the track you realize there is really not much "racing line" on the street.

Keep in mind that a F-500 machine is also eligible to race in F-Vintage class, in fact I've had more fun racing in that class than in F-500. F-Vintage brings in a variety of machine classes and hence rider abilities and for me there's been more of a chance of racing against someone else instead of being a back marker for F-500.

So for those of you building or wanting to build a F-500 machine, I applaud you and encourage you to do so. I look forwarding to racing with you at Gratten and Mid-Ohio in 2007.

This fairly sums up my experience of racing with AHRMA. I enjoy it imensely and the racers are a great bunch and become an extended family to visit while travelling and racing.

[Admin]

Hey Ralph,

That's what I was thinking. And it follows that using a modern enduro type rear wheel will net me a smaller cush drive than the stock set-up to save a little weight. Plus a lot of mid-nineties enduros used 18 x 2.15 rims right off the showroom floor so that's one less thing I need to do.

I'm interested to hear if Krash has noticed any wear to his driveline from running a dirt bike rear rim. I'm pretty sure he's got a Nova CR trans in his and buying one of those once is enough to convince me to protect it if I can.....

Jim

[Admin]

I would make sure the racing orginazation you want to race with will allow your mods........

[Admin]

I haven't noticed any appreciable wear on the driveline components. The bike is run for such short periods of time that I imagine it would be difficult to quantify any extra wear unless things start breaking. I imagine for those with a stock transmission the most shock would occur on a race start. With the CR tranny, first gear is so friggin' tall my only worry is about frying the clutch, there is hardly any strain on the driveline, because as Zooke pointed out, I am actually moving backwards!!

Ralph is right about the cush drive thing. A friend of mine who used to chop streetbikes into dirtbikes told me that they design off-road bikes with the rear wheel spinning in mind, therefore lightening components that have to be stronger on a roadgoing bike.

With the low horsepower of the 500, I'm not really concerned about not having the cush drive. I figure the tire is doing some flexing under acceleration and taking some of the strain. When I hit the gas, I don't want to have to wait for it to take the slop up in the cush before it goes. I think the components are more than up to the job, but only time will tell. I'd be curious to know what others think.

Kris

[Admin]

I agree with Kris, cush drives are more critical in street bikes than race bikes. Street bikes are continually accelerating from a dead stop and decelerating, thousands of cycles in the life of drive train components, vs the relatively short duty cycle of racetrack duty.

[Admin]

Speaking of fairings - is there a relatively universal mount out there or does everyone custom build their mount?

Thanks,

Jim

[Admin]

These are from clubman racing accessories. Otherswise you have to make your own.

[Admin]

Hey Zook-e,

My frame has the forward facing horizontal tube welded onto it. I'm more concerned with the attachment points on the fairing. I know I'll need three points of attachment around the windscreen area (left, center, right); an attachment point on the nose at the number plate location; and I have to imagine there's attachment points needed on the lower fairing sides but I'm not sure where.

Are there any "fairing mounting 101" documents out there? If not could someone post one?

Jim

[Admin]

Thanks guys - good info!

There's definitely fewer full stops and starts going on in racing (when all is going well anyway) so I would have to think that would decrease the stress on the driveline. On the other hand, you don't cycle from part throttle to WFO as often on the street (well you could but you'd probably do some jail time as a result) as on the race track.

It would simplify things if I don't need a cush drive on the rear wheel and increase my selection of potential donor wheels. Then again I could stop thinking about it, drill a bunch of holes in the stock T500 rear wheel hub, and call it a day.... Nahhh! Too easy!

Hey Krash - are you running the straight cut primaries from Nova along with their cr trans?

Jim

[Admin]

Yes, I've got the straight-cut primaries. Makes a great whirring sound when the gearbox oil gets up to temp. I don't know if I picked up any horsepower with these, but I got them with the tranny, so I've always run them. If I had to buy these seperately, I probably would have skipped it because they are so expensive.

Kris

[Admin]

The primaries are bloody expensive from Nova that's for sure and the crappy exchange rate doesn't help either. I've always thought it was a shame that we can't find someone here in the Us to make a small run of them for anything approaching a sane price. We're talking about a couple of gears here after all....

Jim

[Admin]

OK, I've got the bike bug again....

I'm planning the motor I want to build for my race project. I'm going with the Swarbrick pipes and Zook-e's porting to match. My plan is to definitely give a big boost to horsepower, but not so much that i'm on the ragged edge of blowing up.

I want to have everything planned out before anything gets cut. What size/style/brand carbs would be best suited for this application? Besides porting, what other machining work would give the best results for my application? I'm planning on keeping the bike lighted so I can ride it (though not nearly as practically or economically I know) on the street.

Also, does anyone have a source for connecting rods? After my fiasco with that crank rebuilder, I'd like to get a new set for the crank... Thanks!!