Speed & Gearing

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BornYamaha

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Oct 8, 2006
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348
Location
Northern IL
I Have a 2003 Viper, Studded, Ported, 8DN20 Weights, No Pipes. I am strongly considering dropping down to a 21/38 gear from the stock 22/38.
I don't know how far these speedos are off (Alot I Know). So Far I have seen 117 MPH in about 1/2 mile and it was still gaining when I had to shut down. I'm still dialing in the clutches and I haven't clipped the high cones that line up with the protectors yet on the track. I'm not sure if I am going to loose any appreciable top end with the gearing change. I Know stock is geared for about 108 mph Radar at 1 to 1 clutch and 21/38 is about 103 mph at 1 to 1. My primary concern is hard acceleration but I don't want to short change my top end. I do more trail riding than lake racing but the lakes are fun too. Will they go past 1 to 1 with any regularity? Experienced Advise Welcome!
 

you might lose a little bit of top end with dropping the top gear one tooth, but not much. You will defiantely notice that it accelerates harder, pulling quicker to 100 mph. If top end is very important though, stick with what you have and look for ways to reduce driveline drag.
 
yamaholic22 said:
you might lose a little bit of top end with dropping the top gear one tooth, but not much. You will defiantely notice that it accelerates harder, pulling quicker to 100 mph. If top end is very important though, stick with what you have and look for ways to reduce driveline drag.
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will a 23 top tooth hurt a viper alot on bottom if you clutch it for it?
 
Concept Carbon said:
what he said. and do you have to go up to a 70l chain with a 23 casue it looks like theres room
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the stock chain will work fine if you have some slack on your chain now. My sled spins alot right now, i'm assuming that the smaller the top gear the more force your going to be putting on the driveline so a smaller gear is out of the question for me. I would think with a larger top gear , the less force on bottom which in theory would "help" my spinning issue on bottom.I'm looking to gain a few mph on top. Any other guys out there tried a larger driven gear?
 
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I read some where on hear i think mrviper said he ran lik e130+mph on a 22, so gearing to a 21 or 20 you shouldnt loose to much, if any.
 
I Guess to some extent what I an really asking is what kind of top speed are you guys getting on the speedo with 21/38 gears and your rpm at that speed.
Also any Idea what my 117 or maybe 120 = in Radar or GPS Numbers.
 
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