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MountainPerformance.com
THE YAMAHA SUPER STORE
Exclusive Manufacturer of the Year 2000 YAMAHA Mountain Max
Snowmobile Update Kit.
MOUNTAIN TUNNEL KITS, GYT PIPES
... and Discount Direct Accessories |
SETUP INFORMATION FOR MY
1998 YAMAHA MOUNTAIN SRX 700cc
Please E-mail me your comments & experiences randolph@macr.com
 | My Conditions:
 | 7000 to 10,000 feet |
| 0F to 40F |
| Factory Optional 2" Track |
| DEEP POWDER RIDING
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| Key Fix for Air Intake In Deep Powder - See 98 Mtn SRX
Mods Page.
|
| Primary Clutch (Drive)
| Roller Diameter 14.5mm 8CA-91 w/ Duralon bushing (stock) |
| Weight P/N 8DN w/Duralon
bushing (stock) |
| Rivet Inner 1 10.3 Al (10.3
Steel stock) |
| Rivet Outer None (stock) |
| Spring
Pink/Silver/Pink (stock)
(Rate 3.0Kg/mm, 35Kg pre-load) |
| Spring Shims 1 (none stock) |
| Engagement 3700 rpm (3500 stock) |
| NOTES: The sled came with a Short Steel Rivet in the inner hole and no shim. This was
really the spec for mid elevation. My R's were low at about 8200.
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| Secondary Clutch (Driven)
| Helix
47deg Yamaha |
| Spring
Green (1 step stiffer than Stock) |
| Pre-Load
70deg
(60deg on Hard Snow) |
| Shift Speed 8600rmp SOLID! |
| NOTES: The sled came with a softer secondary spring (Red). This was fine on hard pack,
but slow to backshift in the Deep Deep powder. The Green spring raised my shift point by
about 150 to 200 rpm and the back shift is GREAT! I am planning to try two or three more
things:
 | Current Green Secondary spring at 70deg with a 10.3 Al Rivet in the outer whole
of the Primary Clutch Weight (in addition to the 10.3 Al Rivet in the inner whole) to
bring rpm down to 8500 and provide more high speed upshift. |
| The softer red spring at 80deg - may have to move up one step on primary spring
rate to keep rmp at 8500. |
| The stiffer green secondary spring at 60deg.
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| Gearing
| Top Gear
22 Tooth (stock 23 - See Note) |
| Bottom Gear 39 Tooth (stock) |
| Chain
70 Link (stock - all the charts show 68L, but are wrong!) |
| NOTES: The sled came with 21/39, but with the optional 2" track call it calls for a
23 tooth replacement of the 21 tooth to compensate for the smaller 8 tooth drive axle that
comes with the 2" track kit. Many of my friends are leaving the 21 tooth gear (really
geared down). I like the 22 tooth and have had no belt problems, etc.
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| Jetting
| Cyl #1 (PTO) 132.5 (chart recommends 133.8 at 20F
and 8K to 10K feet) |
| Cyl #2 (Center) 132.5 (chart recommends 133.8 at 20F and 8K to 10K
feet) |
| Cyl #3 (Mag) 135.0 (chart recommends 136.3 at 20F
and 8K to 10K feet) |
| Pilot Jets (all) 50.0 (stock 8K to 10K feet and 20/40F) |
| Needle Clip (all) 2nd position |
| NOTES: My jetting is perfect. Nice burn rings on each plug (1/2 way down the electrode).
My PTO side is the leanest of the 3, but again, they are all real close. My piston wash
looks great (4 small corners are clean) at Wide Open and mid range; a racer would want to
be a bit leaner on both, but I like a little margin of safety. I HAVE MODIFIED MY AIR BOX,
MY AIR INTAKE and HAVE V-FORCE REEDS -- See my MSRX Mods
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