Gearing on a Viper

E

ExpertXViper

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I want to get a lil better MPG with my Piped Viper. And was wondering, do I need to add or subtract for topend on the top gear? And how many teeth can I go up or down with the stock chain?
 
you can go up to a 23/38 from the stock 22/38 but you will also need a 70L chain. stock chain is 68L

But im not sure if you would see much of a gain in mileage just going up one tooth on the top.. IMO not worth it
 
machine the primary and seconday for overdrive. quite a few speed shops will do fairly cheap. exellent mod for the money. have someone that knows what there doing, cut it for you.
 
What will this mod do for me? I know what overdrive does for cars and trucks but not a clue how it works for a sled clutch.
 
easier on belt and clutchs at engagement, primary shifts out (belt closer to the top giving you od. you need to gear the other way though, gear down, so the motor can pull primary into overdrive. sleds are gear way to high from factory to pull big od #'s. you will have a quicker sled and less friction so improved mileage.
 
Overdrive will do nothing for mileage. Trail riding you never use overdrive anyway, only running WFO across a lake or railbed will this be benificial.

Expert,what pipes do you have?
 
well thats a lot of the riding that puts the miles on for me. if you go for 200-300 miles a day you, this mod would benifit you. also smoke people that arnt ready for you. ;)s!
 
theres a big misconception that overdrive will be the fastest, thats not always true, you see when your in overdrive your bending the belt alot further in the secondary now then in the primary, this increased bending of the belt causes friction and heat, this in turns lowers the clutch's efficency. its basicly the same as with the sled sitting still only reversed.You can simply take a spare belt and try rolling it on a table, first, push the belt down in a tight radius and try to rollit across the table, hard to roll right, now bend it only so its the half of the original radius, much easier to do right? thats because the more you bend a belt,track, gear chain, etc. the more frictional loss you have.

Heres a easy way to understand this, go out and look at your sled, take a black magic marker and mark the belt in the area where it touches the front clutch surface only, will be a fairly small area because the belt is bent in a tight bend in the front clutch at start, now remove the belt and install your spare belt but without placing it in the secondary clutch, now bend the belt in a prefect oval shape so you have the same radius in the front and rear, this will be around half way up to 5/8 the way up the front sheave surface. while holding this belt this way, have someone mark the belt with a marker where it touches the sheave faces of the clutch, you will notice this will be more then double the distance of the first belt you marked. This is the same exact concept of running in overdrive but reversed at sitting still, you have a large radius in front and a tight radius in secondary clutch when in overdrive.

You see running in 1:1 ratio in your clutching will make for the fastest speed and the best you can get as far as clutch efficency, because the radius the belt is being bent is the same in both the front and the rear clutch, the amount of belt to sheave contact area is greater, thus less slippage and less heat/friction buildup. Now what you must do to run your sled in this ratio is play with your gearing and clutching combo's, pick your paticular speed your aiming for and watch where your belt rides in the primary/secondary clutch's by using a magic marker to see the distance the belt travels up the sheaves. It will take some tuning to find the sweet spot, but you will end up with better performance, mileage and clutch efficency. Some sleds you actually gear down to get there, some you gear up, it all depends upon clutching, gearing and your speed your running at mostly.

As far as getting good gas mpg with a piped viper goes, wont happen!!! 9-10 if you have perfect jetting, perfect clutching/set up,unless you install a whole srx engine,pipes,cdi ,jetting, you get the idea, not worth the hassle. the pipe design isnt what yamaha put into their srx pipe design and thats just it in a nutshell, but at least you can gain something from having efficent clutching, because lousy clutching effiency eats fuel too, your just making noise and heat not using the power to propel the snowmobile.
 
mrviper: You dont think addin 2 teeth on top will make a diff. then? Just tryin to save money on gas but if this is not goin to help there no reasons to spend the extra money sense gas prices have dropped majorly anyway.
 
ya, sure it makes a differance but it might be better or worse performance. nothing I dont think your looking for in the way of gas mpg. You see to get your clutchs and such to run efficent with your paticlar set up may require you to gear down, you dont know till you start checking all that stuff out like I was trying to explain earlier. each sled is differnt because of clutch weights, springs, motor rpm, add ons etc, distance run, speed run at rpm run at in the distance etc, you get the idea.
 
mrviper700 said:
theres a big misconception that overdrive will be the fastest, thats not always true, you see when your in overdrive your bending the belt alot further in the secondary now then in the primary, this increased bending of the belt causes friction and heat, this in turns lowers the clutch's efficency. its basicly the same as with the sled sitting still only reversed.You can simply take a spare belt and try rolling it on a table, first, push the belt down in a tight radius and try to rollit across the table, hard to roll right, now bend it only so its the half of the original radius, much easier to do right? thats because the more you bend a belt,track, gear chain, etc. the more frictional loss you have.

Heres a easy way to understand this, go out and look at your sled, take a black magic marker and mark the belt in the area where it touches the front clutch surface only, will be a fairly small area because the belt is bent in a tight bend in the front clutch at start, now remove the belt and install your spare belt but without placing it in the secondary clutch, now bend the belt in a prefect oval shape so you have the same radius in the front and rear, this will be around half way up to 5/8 the way up the front sheave surface. while holding this belt this way, have someone mark the belt with a marker where it touches the sheave faces of the clutch, you will notice this will be more then double the distance of the first belt you marked. This is the same exact concept of running in overdrive but reversed at sitting still, you have a large radius in front and a tight radius in secondary clutch when in overdrive.

You see running in 1:1 ratio in your clutching will make for the fastest speed and the best you can get as far as clutch efficency, because the radius the belt is being bent is the same in both the front and the rear clutch, the amount of belt to sheave contact area is greater, thus less slippage and less heat/friction buildup. Now what you must do to run your sled in this ratio is play with your gearing and clutching combo's, pick your paticular speed your aiming for and watch where your belt rides in the primary/secondary clutch's by using a magic marker to see the distance the belt travels up the sheaves. It will take some tuning to find the sweet spot, but you will end up with better performance, mileage and clutch efficency. Some sleds you actually gear down to get there, some you gear up, it all depends upon clutching, gearing and your speed your running at mostly.

As far as getting good gas mpg with a piped viper goes, wont happen!!! 9-10 if you have perfect jetting, perfect clutching/set up,unless you install a whole srx engine,pipes,cdi ,jetting, you get the idea, not worth the hassle. the pipe design isnt what yamaha put into their srx pipe design and thats just it in a nutshell, but at least you can gain something from having efficent clutching, because lousy clutching effiency eats fuel too, your just making noise and heat not using the power to propel the snowmobile.
Click to expand...

wow that a lot of writing to defend something that you dont even have. mr.
:rofl:
ok in other words have perfect clutching like on mine. way to spell out the long form. eviper its your sled try clutching/gearing combos, you wont gain one mile without trying. take notes you can always go back. people say it wont work, i know it works. difference is i tried it, the other guys didnt. i would take a 150hp sled thats clutched this way, over a 150hp out the box.
 
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