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1\4 mile drags

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Never would have thought of this on my own, but now I can't stop thinking about it. A friend of mine called me Sunday night to tell me he had his 520EXC out at the drag strip! I didn't know you could do that!

He said it ran a 14.1 at 94 mph with stock knobbies(sounds slippery to me). He has never raced before and freely admits he could have done way better with some experience. I have limited experience with racing to but I bet 13's would not be a problem and 12's with some setup. Guess I am just wondering If anybody else has tried this? probably not.

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I don't think slipping is a problem with these bikes on any type of pavement. Keeping the front wheel down is the issue due to the high CG. I suppose slicks would be slightly more effecient than knobs so maybe a slight gain there - but mostly I think technique to keep the perfect balance of power vs wheelie. My limited mock drag race experience (on a straight piece of backroad pavement) with my stock 520exc has been that in third gear acceleration is still limited by a wheelie and sometimes even in 4th.

Interesting to see that he got 94 mph. I remember seeing a KTM 620 dual sport tested in Cycle world (with good drag race riders I would assume) at just over 100 mph and I thought that was impressive - kind of surprized that the 520 is that close on top.

Mathew

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This is also a topic I have wondered about to myself. Especially when I pull up at the lights next to a hotted up car.

I think you would have to change the gearing. I know my 520 will hit top speed way before 400 metres. I have been in cars that cut a 13 second quarter, and my bike goes way harder than that car.

So, what is everyone’s thought on the following.

Time for 0-60mhp

Possible quarter time, without to many modifications.

I think it could hit 60mph in about 4.5 seconds and the best quarter would be around 12.5 seconds.

This is my totally un-educated guess.

It doesn’t make much difference at the end of the day, just interesting.

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I have coinsidered this in the past. The equation gets real interesting when you start figuring out the hp per pound. A corvette makes what, 350hp? and weighs 3200 or so pounds, which puts it at about 9.142 lb per hp. A 520 makes about 52-55 grin.gif hp at 250lbs. This is an astounding 4.5 lb per hp. So you factor in wind resistance, gearing and traction, and the sky is the limit. I should imagine that swapping to the proper sprockets would get you into the low 12's . I dont think tires would play a critical role either, as these bikes are so light that there is more of a wheelie problem than a spinning problem.

And now for some useful information. I got my EE handguards installed, and the fit is fantastic, just bolt them on. No muss, no fuss.

Steve

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im thinking that slicks would only help if wheel spin was a problem and from what i heard it isn't on the pavement. But if you did fit a slick, you could launch the bike harder and thats where the time could be cut down, but then i guess you will flip the thing.

Not to sure about cutting a low 12 though. What does a new GSXR1300 do?

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How many transmissions has this guy gone thru? Puts alot of stress on the drivetrain without a cush in the rear hub.

------------------

TWIST&SHOUT

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Couple of points:

- for lb/hp comparisons - the RIDER weight is a big factor on a bike. About the lightest typical rider would be 150lb - which gives a 400lb overall weight with ~52hp. So somewhere around 7.7 lb/hp. Still good but not THAT good.

- the wheelie factor is really a big deal for quick acceleration. Unfortunately - nice offroad suspension puts the CG waaay too high for good acceleration.

- while a dirt bike might do OK from 0 to about 50 - 60 due to the good power to weight - as you get much above that wind resistance starts to be the dominating factor and that is where you need mongo HP and good aerodynamics. This is where street bikes with 120+HP and better aerodynamics really run away. With only 50ish HP and poor launching due the high CG - I can't see ever getting in the 12s.

I believe the GSXR1300 holds the current cycle world record for a stock bike at 9.9 sec @ 130+mph.

When had a WR400 I dragged it against my dads V-max (rolling start - pavement) and the V-max absolutely killed it - so bad that we quit at maybe 50 mph.

Mathew

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brn2rde,

What type of hand guards are you using? how much did you pay for them, and is there a web site i can see them at?

thanks.

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My handguards are made by Enduro Engineering. I don't have the web address handy, maybe someone else has it? Anyways EE seems to pretty good to work with, quality made stuff.

------------------

Steve (degeyter@cpros.com) 01' 520MXC 1992 Oregon cross country & ISDE 4stroke state champ (When 4strokes were made with solid 24carat lead)

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Mathew,

you are spot on with all of your points, well done! good to see. Just wondering if the GSXR that did the 9.9 was straight from the dealer. If so, they shouldn't be allowed to sell the things! even a 11 second car is thrill to drive. Can't help wondering....

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Here's the EE site:http://www.enduroeng.com./index.htm

By the way, I've got to believe that the knobbies are going to make a big difference in the 1/4 mile times just because of the increased rolling resistance on the pavement as the speed picks up. I remember a while back going on a roadbike ride with a friend who was on a mountain bike with knobbies. As the speed picked up, those knobbies made more noise and he couldn't keep up with the guys on the "slick" road bike tires because of the energy it took out of him just to keep those tires rolling. On the next ride, he had slicks on his mountain bike and it made a HUGE difference. He kept up with us - no problem. I would think that the same would apply to motorcycle tires. It takes a lot of energy to roll those knobbies around - energy that could be better converted to speed on the top end. Again, no proof of anything here - just my observations.

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Yes the knobbies would have more drag for sure, but there is a big difference between the effect at bicycle speeds and motorcycle speeds. At 15-20mph, tires (or rolling resistance) is a big part of the total drag. At nearly 100mph, wind resistance is the dominating factor in overall drag. Just a guess here but if it takes 50hp to go 100mph - probably 5-10 would be going to the rolling resistance, 40-45 to wind resistance. So if you could take ALL of the rolling drag out - the gain is some but not huge.

Would be interesting to know the real world difference - anybody have a supermotard setup to try with a slick and then a knobby?

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Need a 4 foot swing arm to really see what she'll do. I suspect if he ran 14 at 94 he did top out well before the end of the strip. I would suspect low 12's to be pretty easy if somebody REALLY wanted to spend the money to do it. Bet we'll never know...

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