MM700
New member
- Joined
- Nov 3, 2003
- Messages
- 15
I need some help with a low-end hesitation or bog when I crack the throttle. The clutches are over heating when I hill climbing. The sled is a 2002 Viper. This is list of mods that have been done to this sled. 2000 MM skid frame w/141” 2” track, 8 tooth drivers, 3-1” holes drilled in every pitch of the track and 22-38 gearing. Engine spec’s. 2 layers of head gasket removed, reed spacers, Wolfe Pack reeds, SLP triple pipe, Holtzman ATACC, 162.5 mains, 47.5 pilots, needles 3 ½ and air screw 1 7/8 turns. Clutch setup for 8000’. Yamaha primary 8DN10 w/10.3 rivet in outer hole, Green white Green spring, 2 shims and 14.5 rollers. Secondary, 43 degree helix. I have tried Maxx Roller Secondary w/green spring, 80 degrees and a 48/40 helix. The stock Yamaha Secondary with the above spec’s works better. I have also tried SLP clutch setup for the roller secondary 13.3 rivets in the inner. The engine is spinning around 9100 RPM’s, it drops below 9000 when I put the Yamaha secondary on it. I am also running a Yamaha 8DN belt. A couple of other items I would like to get an answer on. I can’t keep the motor aligned is there a torque rod for this sled? I also ride in the 1600’-2000’ level so I would like to get a setup for that elevation also. The sled pulls well once I get rolling and then peters out I think from belts slippage. I forgot to mention 120-125 PSI across all cyl’s nice tan plugs and great piston wash. How can get rid of the bog and clutch heating?
The bog is probably from running too small pilots at elevation. Your mains are way too rich for 6000' too. Try running a 47 helix with a silver spring or maybe even a silver with the other helix,s. The SLP pipes here seem to work better at around 8800 rpm.
Bogging
I would also change the gearing if you want to cool off the clutches. I would go to the stock MTN Viper gearing, 21-40. Belt life will also increase, heat kills a belt. I would also try turning out your gas screws half a turn if you don't want to buy new pilot jets. Half a turn makes a lot of difference. A roller clutch also helps with belt life and running cooler clutches. However, I have found that a 48/40 helix does not work very well in the mountains. I would think that you need a helix along the lines of 41/35 with the green spring.
I would also change the gearing if you want to cool off the clutches. I would go to the stock MTN Viper gearing, 21-40. Belt life will also increase, heat kills a belt. I would also try turning out your gas screws half a turn if you don't want to buy new pilot jets. Half a turn makes a lot of difference. A roller clutch also helps with belt life and running cooler clutches. However, I have found that a 48/40 helix does not work very well in the mountains. I would think that you need a helix along the lines of 41/35 with the green spring.
Bogging
PS Yamaha also makes a kit for a motor brace. It is the same as on the SRX's. Retails for around $38.00. A couple of other aftermarket companies sell them.
PS Yamaha also makes a kit for a motor brace. It is the same as on the SRX's. Retails for around $38.00. A couple of other aftermarket companies sell them.
LoneViper
New member
I'm even a little lower yet in gearing, 20/40 . I swear by Ultra Max 3 belts, not much slip with them and no belt dust.
..SNAKEBIT..
VIP Member
GEARING?
are you running 8 tooth drivers?
I'm running 9 tooth 136 x 1-1/2 and need to gear down!
running 21 - 38 now. what can I run with stock chain? 20 40?
are you running 8 tooth drivers?
I'm running 9 tooth 136 x 1-1/2 and need to gear down!
running 21 - 38 now. what can I run with stock chain? 20 40?
clutch heat
I am also running nine tooth divers, I have not had any problems with the 21/40 gearing with a 151x2 track. Sled ran about 1900 miles on the stock belt in the mountains. If you have the 68 link chain you can change to gearing.
I am also running nine tooth divers, I have not had any problems with the 21/40 gearing with a 151x2 track. Sled ran about 1900 miles on the stock belt in the mountains. If you have the 68 link chain you can change to gearing.