setting up your suspension

BETHEVIPER

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Setting up your rear skid.

If you are looking for settings to start with, stop reading. Settings from some one else’s sled are just that, some one else’s settings and not yours. Straps stretch, arms bend, springs sag and bushing wear causing adjustments to change from sled to sled. Sleds and their riders are like snowflakes, no two are alike.

First read the rear skid article I wrote on how to tighten up your suspension and the front end alignment article. The links are below my posts.

Please keep in mind I am writing this for everyone, even those who know very little about the suspensions. Also, this is a rough draft and please ask any questions on anything I might have missed. I will add it as I go. Sorry to all you spelling bee winners and school teachers for the grammar and sentence structure.

I will describe a few terms used when talking about suspensions.
Transfer: The moving of the sleds weight toward the rear of the sled.
Pitch: This is the movement of the sled forward or back.
On plane: This is the imaginary flat reference point used to describe an untwisted sled or suspension.
Upper and lower gap: This refers to the gap above and below on the transfer rods on each side of the rear of the sled.
FRA: This is the arm that the front of the rear shock is bolted to. This adjusts the speed and distance the shock and spring travel when the suspension is compressed.
Ride height: The height the sled sits with all the weight it will be used with on the sled when measured.
Spacers: The plastic washers that adjust the gaps on the transfer rods(some sleds have adjustable rods)
Limiter straps: There are two of them, they attach to the W arm and limit it from dropping down.

W arm: The front arm of the rear suspension that is attached to the front track shock and to the rails. This arm does many things. 1. Holds the skid on plane with the frame of the sled. 2. Is the bump stop for the rail to hit against when compressed. 3. Is the bump stop for the FRA shaft to hit against when bottoming. 4. Holds the limiter straps at an exact distance. 5. Holds front shock. 6. Takes weak part, under a lot of load.




The first thing that is necessary to adjust the rear of the sled is to start at the front. The rear of the sled is adjusted to the front of the sled. You will need to guess at what you like your front shocks to be set at. Short travel sleds require preload on the springs, go with the standard setting to start with if you don’t know what you like. On most all long travel sleds you will want the front springs set to no or little preload. This gets the sled as low as it can be, making it handle better and a lot of preload usually means hard on the arms, and back on long rides. For sleds with multi-rate springs, I recommend a venture sway bar. If your sled has sway bar links that have open spots in them, I recommend you change to srx/viper links.
First thing we need to do is to take care of a bad idea, the front track spring in the xt/xtc/venture sleds. Throw it away. Install a stiffer rate spring. One from the front of an srx or sx sled works good. The inside will need to be ground out on the spring so it will fit over the washer of the shock. You will see what I mean when you do this mod. Night and day difference.
You will need to decide what your FRA will be set at. The upper position makes the valving and the spring rate seem softer as it moves slower and not as far for the same suspension travel. The lower does the opposite, making the shock and spring seem stiffer. a lot of it depends on shock valving and each sled is different. In general terms, if your heavy, go for the lower setting that will make it stiffer. If you don’t weigh much, move it to the upper setting so it will be softer.(sounds backward I know) If you use the sled for two up riding some times, set it to the soft setting, upper, then when you ride double, you can just move it to the stiffer setting, this will give you stiffer valving and stiffer spring for the extra rider. If your not sure, guess, that’s what everyone else has been doing when they tell you how to set your skid up for you.

Total transfer rod gap is another thing that is a preference. A good starting point is for short travel sleds, 8-12mm, on long travel sleds, 14-18mm. On long travel sleds this is with a thin spacer on the lower side, 2-4mm. On short travel sleds this is with a thick spacer, 10-15mm.

Now that we have the front height, total gap, and the FRA set, we can move to the part that does all the work. The rear shock and spring. Let your limiters out all the way for now. Set the front track shock preload to 0.

You set your gap with you and all your gear on the sled on a flat surface. Stand up, rock the sled around and then sit down slowly. You are setting the sled to its neutral position. Then lay over the side of it and look at your upper and lower gap on your transfer rods. For the best handling you should have 50/50 spacing.
Do not adjust you height with the FRA, this is for adjusting the speed of the shock/spring through its travel. Using this to adjust height is a band aid. Aluminum bodied shocks in the rear are easier to adjust if you remove them from the suspension. Sounds crappy I know.

*if when you set on the sled the front end of the sled lifts and the gap ends up even (50/50)then the center spring is too stiff, doubtful if it was set to 0 preload. But if it does, try setting the front ski shock preload higher. Then start over.

*if when you set on the sled the front end does not move up and the gap is too large on the top the spring in the rear is too tight. Lessen the preload on it. Then start over.

*if when you set on the sled the front end does not move up and the gap is too large on the bottom the spring is too loose. Increase the preload on the rear shock. Then start over.

The optimal setting is to be able to have the most front track pressure, sit on the sled and not have the front end lift while still having 3-4in of set in and keep the gaps even. Easy enough.

On a side note. I hear a lot of people talking about bottoming their sled and using this to judge if it is set stiff enough. If during the day of riding you have your sled set so it never does then your riding a stiff sled for no reason 99% of the time. If you bottom several or more times in a day increase FRA rate to the next stiffer setting. If it is already there, you either need to re-valve your good shock stiffer, or just have your wore out shock rebuilt.
The tighter the gaps on the top and bottom the flatter your sled will handle during acceleration and de-acceleration.

Your top gap is the amount of transfer or downward travel the rear of the skid can make without taking the front along with it.

Riding with a larger top gap gives a better ride until your driving under power. When under power your sled is closing this gap(dropping the rear of the sled). When you do hit a bump under power you are now hitting it in the lower part of your sleds travel which on a yamaha is rising rate and is a lot stiffer and you are that much closer to bottoming. Another issue with riding with a larger gap is that the front end comes up. yamahas front pro action is really a crappy design that polaris and chaperal threw away along time ago. If you lift the front of your sled, the skis will toe in , as you drop the sled and push down they will toe out, if you run your sled loose then when your on the gas your sled is now toed in, when you let of on the gas to go into a corner now the sled pitches forward and the front end toes out. (this does not apply to the four stroke sleds)
There is a myth about running larger gaps and weight transfer. “Weight transfer=acceleration.” Any time the sled comes off the ground you are wasting acceleration, a sled that has the skis 1mm off the ground has no more traction than a sled with the skis 12in off the ground and in some cases has less as the front of the track starts to lift. just watch any race and you will see that those guys that have the fast sleds almost always have the sleds that just barely lighten the skis all the way down the track. If you run adjustable rods and backed them way off then felt that your sled was hooking up better it was probably just that, felt like it. That little extra feeling of acceleration upward makes you feel like the sled has more power and or traction. It is an illusion. The object is to move the sled forward. Energy used to move the sled in any other direction is wasted. The chicks dig it though.

If your out for the great ride and do not get on the gas hard or go into corners hard then you can set the sled up with loose gaps. The ride will be a little softer. If you want it to handle great in a corner or on the brakes, the tighter the gaps you will need. A stiffer sled this will make.
 

When the sled is set up for height, now you can set your limiters. I like them to be set as long as I can stand in a hard corner. If you have rebuilt the skid the way I have explained in my other thread, you will be surprised at how loose you can run the limiters as they are not used now for keeping the skid from twisting up. This lets the suspension drop out further into holes and makes the whole setup handle better.

When you think about a bump in a trail it is rarely above grade. That means that you usually fall into the bump. The tighter your limiter is the less the front of your skid can fall out into the bump before you do. Your shock wont have as much stroke to absorb the impact. The other effect a shorter limiter has is the sled is allowed to fall into the bump further before the shock can start absorbing the impact.

Now for handling, its another story, the tighter your limiters(to a point) the more of a slot car feel you will have and also the more of a handful you will have to turn your slot car. Do not believe for a second that just pulling up those limiters will make your sled handle flat. If your skid is real loose your will still wrap your sled up in a corner. Loose gaps and a tight limiter will still allow the skid to twist over in a corner making your sled lean. Lift on the front of the sled is best handled by the transfer rods gap in the back. Using this method lets the suspension have as much travel as it can.

A great starting point for limiters to be set at is so when you lift the back of the sled up, the front of the rail should still touch the ground when the back is 1 ½ off the ground. With this setting, you might want it less or more, it is a personal preference that needs to be set to you. To ease this adjustment, buy a 12mm gear wrench, cut it in half and round the end. This will make it very easy to move limiters.

Track adjustment usually means you loosen the rear axle. Tighten or loosen the adjuster bolts while the sled is in the air. Running the sled to see if the track runs centered on the rails. This is called a hanging alignment and is the standard way most people will do an alignment.
Loose suspensions and bent parts are why you can’t trust a hanging alignment. They are great for getting started. Then go out on the lake or flat trail, drive the sled straight, let it roll to a stop. Without getting off, lean over and look to see if the slides are centered between the clips. this is true center. if your sled is hanging and you have straps adjusted a little different side to side, or the skid is wore out which it is when it is new, the suspension can hang lower on one side than the other, this will push the track off.

You want the track as loose as you can get it without jumping cogs and tight enough so it does not run on the guards in the tunnel at top speed. Go out to a place where you can get as much traction as you can. Keep doing launches. Back off the adjuster bolts till the track jumps, then tighten it up two turns. Now, go do some speed runs. Tighten the track up a half turn each run till you see speed fall off then back it up. Some tracks and sleds will want more or less tension as they all balloon a little differently. Loose tracks don’t always mean faster if they are bouncing off the guards.
 
Scott. When I ride my sled it feels like Im riding a bucking bronco. Do you thin k it maybe my preload too stiff launching me back from the bump. I never bottom out so I think I m going to change the fra adjustment to a little softer. ALso is there anyway to straighten a bent frame. Remember a couple of years I bougth some right front end parts from you after I kissed a tree and it broke the bolt off flush in the trailing arm. Ever since then the right side trailing arm sits a little lower causeing the sled to lean to the right. If you are looking from the snowflap the track is a bit off the ground on the left side than the right. (If your looking at it from the back)
 
un twisting a frame always requires loosening all suspension bolts and sometimes un rivoting heat excangers on the side and rear as well as footwells. twisting it back past, or holding it a little past then rerivoting the sled in that position.

really sucks.

could be too stiff and is wacking you in the but not absorbing the bump. what shocks do you have in it?
 
BETHEVIPER did you say that no preload on the front shocks will give you better sterring and to much preload will give you less.
No preload = no tension on springs-less steering
proload= tension on springs-more steering

correct me if i am wrong trying to get this right and understand front shock load settings,thanks

PROGOLD
 
progold said:
BETHEVIPER did you say that no preload on the front shocks will give you better sterring and to much preload will give you less.
No preload = no tension on springs-less steering
proload= tension on springs-more steering

correct me if i am wrong trying to get this right and understand front shock load settings,thanks

PROGOLD
the less preload, the lower the sled will sit. the amount of preload has little to do with better steering but does change the height of the sled in the front. the lower the sled, the better the sled will corner and handle. As the sled gets higher and higher the sled will tend to roll up in a corner. It will also ride hard because it will fall into the bumps, not letting just the suspension fall into the bump.

Steering effort is effected very little by alot of preload or no preload if your adjusting it first and then adjusting the skid to it. Use the front springs to set the height of the sled that you prefer, LOOKS COOL or HANDLES GREAT.
Then adjust the skid to match.

Steering effort is effected by many things, most are not adjustable. The rest can be toyed with in different ways after the initial setup.

Guys, anyone reading this, please, please post any and all questions. I love to rethink what I thought was unthinkable again.
 
Front Spring Setting

BETHEVIPER said:
the less preload, the lower the sled will sit. the amount of preload has little to do with better steering but does change the height of the sled in the front. the lower the sled, the better the sled will corner and handle. As the sled gets higher and higher the sled will tend to roll up in a corner. It will also ride hard because it will fall into the bumps, not letting just the suspension fall into the bump.

Steering effort is effected very little by alot of preload or no preload if your adjusting it first and then adjusting the skid to it. Use the front springs to set the height of the sled that you prefer, LOOKS COOL or HANDLES GREAT.
Then adjust the skid to match.

Steering effort is effected by many things, most are not adjustable. The rest can be toyed with in different ways after the initial setup.

Guys, anyone reading this, please, please post any and all questions. I love to rethink what I thought was unthinkable again.
Well this is interesting this is why i dont bring my sled to thelocal yamaha dealer,they told me just the oposite more preload = more steering less preload= less steering last season i had just minimal preload and found that the sled pushed hard in corners so i cranked up the preload and the sled handled evem worse,maybee with me tightning up the rear skid and taking all the preload out of those front shocks the sled will handle better this season.

THANKS PROGOLD :dunno:
 
Oh by the way BETHEVIPER thank you for all the valuable information that you offer to me and any other member on this site ,hope you dont mind if i call on you if i have any other problems you seem to be the guru of vipers and the things that i have read and tried seem to work out every time ,love my viper and it`s paid for ,hope you have an awsome upcomming smowmobile season,THANKS again.

PROGOLD
 
BETHEVIPER i was about to install the shaft for the upper carriage wheeles fpr the rear suspension and when i had taken the old wheel and bearing of i did at different times i had to pretty buch beat the first one of last week then i just put everything aside because i was frustrated and today my parts arrived so i started to beat the other one off when i finally got the other wheel of the shaft there were two spacers in behind the wheel one small one and one just a bit larger in diameter,but when i removed the first wheel everthing seemed to go flying and i only could find one spacer ,my question is ,is there soposed to be two spacers in behind the carriage wheels?,i checked on the online parts catalogue but it does not show,please help.
 
there are two spacers(washers) behind all four upper idler wheels. the smaller diameter ones go against the bearing, the washer one goes against the bushings thrust surface. make sure if you beat the bearings off you dont cut the thrust surface of the bushing off while your doing it. you should use a puller to do this. remove the snap ring, slowly pound the wheel off the bearing, then use a puller to remove the bearing.
 
these are oringinal wheels they dont have snap rings to hold the bearing in the wheel it`s all one unit but the new ones have snap rings so the bearings can be replace if they go bad.
 
Well i am swapping skis on my 94 vmax 600 from the old steel ones to some Viper skis. My sled has a 2000 venture 600 skid installed as well. I am looking for a general starting point to start setup. I always trail ride with a occasional off trail blast. Nothing Major, usually a potato field or powerline. I want a setup that will work for me it tight twisty trails with some whoopped out crappy trail conditions also because my ride always starts nice but by the time we head home they are all tore up. My weight is around 210 without gear.
 
yes, spring just tightened enough to keep it from rattling. This is a starting point from what I have found usually ver close unless you have a xtc, xt, or venture center shock. They have springs on them that are way too soft for traction and handling.
 
I wish I had BTV in my garage for week to help me set my Viper suspension up.

I gotta stop the rear end from waggin in the turns. The front end turns like it's on rails but I'm fighting the rear ens swinging all over the place.

Any advice BTV?

I've been thinking of playing with the limiter straps to make sure I have the whole track on the snow in the turns.

I always thought that the limiter straps were to control ski pressure, but your comment about dropping into the holes on the trails is something I never thought of.... Interesting.
 
Long Travel front mods

Hey Betheviper,

I know this has been dealt with previously, but I couldn't find it.
I have a 98 SRX 700 with the 2001 Viper longtravel skid installed.

I rebuilt both skid shocks (KYB gas - professionally done) and have ohlins on the front along with the eBay long travel shock mount...nothing else done at the front.

the sled is a little low in the front and the skid sits forward a little far (the rear of the track is off the ground about a half inch.

What else is needed on the front? Please use little words and lots of descriptions because I don't know squat. like what's a spacer and where does it go? and how do I get one and what is the part #.....lol.

I can read the details on the rear set up, and have printed it off, but, I'm not seeing much on the front set up, installation etc.
Jr.
 
Srx

Not Trying To Jump In Front Of Betheviper But I Have A Sled With A Similar Set Up And I Converted The Front To Viper Shocks With Brackets From Betheviper. Also Installed A Wide Kit. Much Better.
 
I recently extended my 02 Viper to 136. I have been fighting an understeer problem. After the extension was done the rear of the skid did not touch the floor. Did some reading. Found out that most people use drop brackets to get the skid flat again. I dropped the rear bolt 2 inches and the mid bolt about an inch. Made a template and used the drive shaft as the swivel to locate the holes. I have the limiters set with 20mm of thread showing. With the front of the skid touching I have a 2 inch gap on the bottom at the rear of the skid. Front shock preload is as per Pioneer Perf. as well as the center and rear springs.I forget what the preload is. The gap on the transfer rods with me sitting on it are top=5mm and bottom=11mm. So I am a little off from 50/50.
I know I can suck up the limiters some more but I really dont want a stiff ride.
Been thinking on how I can get the "bite " of the skis back in the sled. One thot I had would be to move the transfer rod mounts back along with the rear and mid skid bolts.Was thinking of moving these back about 6 inches to put them back to where they were from fatory in relation to the rear of the skid.
What do you think??

http://photobucket.com/steinerPB
 
Jeff..move the engine,gas tank and your seat back.This will get the back end to drop then..lol..Oh yeah.set up for maximum transfer to.I would eat heavier meals and gain some weight and that'll drop the rear..lmao

what are you doing anyways,put the 121 back in and lets ride...
 


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