Jetting and Clutching help...quick

SXlover

SXlover

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Minot, ND
Might be headed to Bear Lodge, WY (8000 feet) on the 2nd or 3rd. I need some clutching and jetting advice for the Viper Mtn's. They are completely stock. Got any ideas?
 
On a stock MTN viper, I would only follow the jetting and clutching specs out of you manual for hill climbing at elevation you are riding at. I heard horror stories of people wanting to lean out their sleds for the elevation and they burn it down just out of the parking lot down low. I would do the head gasket mod for sure. when your doing a pull up hill, look at the tach and make sure your RPM's are 8500 when in deep stuff. If its a little under have to take a little weight out of tip of fly weights. Be you you have proper secondary srping tension so you have good back shift when you get in the throttle again after you let off so it doesnt bog down. Mountain riders tend to run a little stiffer secondary tension for that purpose
 
Stock Mt. Viper for up-to 8500:
Primary Spring G-W-G w/ 8DN-10 weights 10.3 out, 13.3 inner
Secondary Spring Green @ 70 or 80 twist
Jetting MJ 143.8, PJ 52.5, PS 2-5/8, JN 2.5
If you are doing most of your riding above 8500, you can go to 141.3 on main.
This is a safe by the book.........however I usually run leaner jets than the book calls for.
 
Thanks guys for your input...but I just got the jetting chart and cluctching chart from a Yamaha dealer. We are going to go with MJ 143.8, PJ 55, PS 3 1/8, JN 2.0, because that is what the chart says.
 
You will probably be OK, cause the forcast for those days are warming trend. But other wise you aren't going to be riding much above 8000ft. in the Big Horns. Most of the higher stuff in the Big Horns is out of bounds, (Wilderness).
Bearlodge Resort is only 7800' , and Bald Mt. is only 9000'. Not that much snow up there any way only about 28" average, not much snow when riding over 60" rocks. Have fun and watch the trash.
 
snomoguy said:
Stock Mt. Viper for up-to 8500:
Primary Spring G-W-G w/ 8DN-10 weights 10.3 out, 13.3 inner
Secondary Spring Green @ 70 or 80 twist
Jetting MJ 143.8, PJ 52.5, PS 2-5/8, JN 2.5
If you are doing most of your riding above 8500, you can go to 141.3 on main.
This is a safe by the book.........however I usually run leaner jets than the book calls for.
Click to expand...
Can you help me out? I have a 2002 viper with bender pipes and bender clutch kit. I am going out to the LineShack in Wyoming (8500ft?) Do you know what I should be running for jets and clutching?
 
Viper48
Sorry, I don't have much todo with mod stuff. You might give A K Mtviper a shout or send him a PM. He has the modded stuff. The Lineshack is only around that 8000' level but most of your riding will be 8500' and up.
Good Luck and Have Fun
Welcome to Wyoming...........bring the avalanche gear!!!!!!!!!!!!
 
SX Viper 144 said:
This is my first shot at posting, so please bear with me.

I have an '02 SX Viper that had the Hauck Venom pipe & cluth kit installed before I bought it when it had just 200 miles. Then proceeded to add a Mountain Performance Products 144 extension and 1.5" Camoplast crossover track. It runs great in the flats (Minnesota), but our local dealer has tried to jet and clutch it effectively for riding out west but with poor results. I want to try one more time, and wanted to see if anyone had any suggestions. We typically ride the Taylors Fork area in MT at about 10,000 feet, starting out at about 7,500 feet and heading up. It seems to be dumping alot of unburned fuel and I really use it up (like having to use up all of the extra gas my buddies bring with)! This last go around they changed the jets slightly and adjusted the secondary clutch and it was better, but still not good. On hard pack it goes pretty good, but as soon as I'm in the deep powder it looses power and bogs down.

It still has the stock Viper gears, should I switch to the Mtn Viper gears? As set up it runs about 9000-9200 with the triple pipes and the dealers claims that's okay.

Any suggestions would be greatly appreciated.

Thanks.
Click to expand...

You should probably start your own thread. You might get more replies.
 
I have the same question as the first guy, i have a 2004 viper mountain and heading out to bear lodge on the 8th. I was wondering if i should jet for 8-10000 feet, and clutch for that as well. Also, how do you know what twist is on your secondary and how do you change that? thanks
 
Are you going to Bearlodge Resort or Meadowlark? Meadowlark is about 6500 and Bearlodge is about 7800. If your Viper is stock, you can jet for 8000-10,000. The stock Vipers will stand a little leaner jetting than factory says.....the factory jetting is way safe. However I would go with the 20 degree jetting and that will be OK. You won't be riding much above 8000-8500. If you haven't changed the secondary, it is set from factory at 70 degrees. If you want to change the twist, remove the 3 small bolts from the secondary, change the spring to different holes, re-twist and replace the bolts. You can do this without removing from sled if you want ........will need a second hand to help with twist and replace bolts. If you are stock I wouldn't go over 80 degrees.
 
Hey SXlover, How did the trip to Bear lodge? We are going there the end of Feb and was wondering how the setup worked.
 
jlebrun_05 said:
I have the same question as the first guy, i have a 2004 viper mountain and heading out to bear lodge on the 8th. I was wondering if i should jet for 8-10000 feet, and clutch for that as well. Also, how do you know what twist is on your secondary and how do you change that? thanks
Click to expand...

To calculate the twist, you add up the numbers.
There are three holes in the sheave, which are labeled: 1-2-3.
There are four holes in the helix, labeled: 0-3-6-9

For example, if you put the spring in 1 on the sheave & 6 on the helix, you'll be at 70*

If you've never had the clutch apart before, be careful when you put it back together. I've seen several people not get the helix ramps back on the buttons, instead they have the bottom of the ramps behind the buttons. Like snomoguy said, a helper is nice to have to start the nuts while you hold down on the helix, there is quite a bit of tension on the spring when you put it back together correctly.
 
I know this is kinda bringing the topic back from the dead, but what about clutching for around 1700 feet on the 05 Viper Mtn. Right now we are running too high of rpms and since there is no mountains are we better off to change gearing too?
 
Book is kinda confussing, it shows for 2500'
17.2mm steel out
17.2mm steel in
but shows
2000' to 4500' shows:
13.9mm steel out
13.9mm steel in?????????????????????
 
Daaa
Finally understand the book; the 17.2 are for anything UNDER 2500'. So I would think that is what you need for weights. All else is the same.
 
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