Ok, I use to live in MT and ride at elevations around 5700' to 8200'. When I moved to CA for work 
......I moved my sleds (3 - 144" Mountain Vipers) to my brothers' place in CO. i would visit them and ride a few times a year there. The elevations we were riding at were 8000' to 11000' In CO, one of my vipers was having a slight problem last year.
Due to the elevation change, I knew the machines were running too rich, but since they weren't being run that much, I didn't bother to re-jet them. The problem I was experiencing, and only with one of them (they're all jetted the same) was that I would get the DCS light at wot in the powder (no snow blockage). However, I wouldn't get it on the trail. I had rebuilt this viper engine two seasons prior and had no problems. I go thru the carbs every year, and all the normal maintenance. Rpm at wot in the powder or on the trail was holding 8500rpm. When DCS light came on I would hear just a slight difference in sound. I would back off the throttle and the light would instantly go out at around 8200 to 8300 rpm.
I haven't come up with a reason for the DCS light in powder at that elevation (around 9500'). Any thoughts would be appreciated.
I've finally moved the sleds out to where I live
here in CA I plan on leaving the jetting as is since I'll be back at the MT elevations. I'm just wondering if anyone had any theories as to the DCS light.
......I moved my sleds (3 - 144" Mountain Vipers) to my brothers' place in CO. i would visit them and ride a few times a year there. The elevations we were riding at were 8000' to 11000' In CO, one of my vipers was having a slight problem last year. Due to the elevation change, I knew the machines were running too rich, but since they weren't being run that much, I didn't bother to re-jet them. The problem I was experiencing, and only with one of them (they're all jetted the same) was that I would get the DCS light at wot in the powder (no snow blockage). However, I wouldn't get it on the trail. I had rebuilt this viper engine two seasons prior and had no problems. I go thru the carbs every year, and all the normal maintenance. Rpm at wot in the powder or on the trail was holding 8500rpm. When DCS light came on I would hear just a slight difference in sound. I would back off the throttle and the light would instantly go out at around 8200 to 8300 rpm.
I haven't come up with a reason for the DCS light in powder at that elevation (around 9500'). Any thoughts would be appreciated.
I've finally moved the sleds out to where I live
here in CA I plan on leaving the jetting as is since I'll be back at the MT elevations. I'm just wondering if anyone had any theories as to the DCS light.
Check for exhaust leakage and/or broken powervalve cable/ stuck PV.
staggs65
Moderator
Do the other 2 have DCS?
check and see if the manifold has hairline cracks in the top or more commonly in the bottom of the manifold, youll need a mirror on a stick to check. they crack in the seams where all 3 merge to 1.
The other two have DCS also. I'll be re-adjusting the PVs so I'll take a look. Unfortunately, I think they are fine.
Looks like I'll break out the mirror and check the exhaust for cracks. I honestly can't say I've ever looked for cracks on them.
Thanks for the suggestions everyone.
Looks like I'll break out the mirror and check the exhaust for cracks. I honestly can't say I've ever looked for cracks on them.
Thanks for the suggestions everyone.
Took a look at the manifold tonight. I didn't see any cracks. The manifold mating surface looked good also. Just slightly damp under the Mag side. I actually don't know if it's just moisture or a very little amount of exhaust spooge. It's been really foggy and raining like cats and dogs here. And the machine is slightly tipped for moisture to run to that side.
I also looked in the cylinders with my borescope. Everything looked ok, except the pistons had a lot of build due to running so rich in CO.
I'm starting to think my carbs might have been the problem. I cleaned them last year but the gas in CO seems really bad. A lot worse then I've ever seen. Even though, they seemed to be clogged. Or at least partially clogged.
I think I'll clean the carbs, adj. power valves and run it. Hopefully it was just bad fuel, clogged carbs.
I also looked in the cylinders with my borescope. Everything looked ok, except the pistons had a lot of build due to running so rich in CO.
I'm starting to think my carbs might have been the problem. I cleaned them last year but the gas in CO seems really bad. A lot worse then I've ever seen. Even though, they seemed to be clogged. Or at least partially clogged.
I think I'll clean the carbs, adj. power valves and run it. Hopefully it was just bad fuel, clogged carbs.