700 Viper not revving out

[KatMan]

I've got a 04 700 viper which is'nt revving out(about 7500 tops when climbing). The pto cyclyder is running rich compared to other two(plug check). Comp is 110 in two, 90 in pto side(same as when i bought it three years ago).

Was running good last year. Any thoughts?

 

[mrjck]

I've got a 04 700 viper which is'nt revving out(about 7500 tops when climbing). The pto cyclyder is running rich compared to other two(plug check). Comp is 110 in two, 90 in pto side(same as when i bought it three years ago).

Was running good last year. Any thoughts?

Try cleaning out your powervalves. Do you get an engine light when you have it pinned? If you do, whats the flashing sequence?

 

[KatMan]

no lights, nothing unusual, other than maybe harder starting(cold pull 7-8 times), needing a bit of throttle to start hot.

I did tip it afew times on the hill on sat, and starting afterwards was really brutal, along with no rev pick up for about 5-10 seconds(like it was flooding really bad), lots of blue smoke(not belt)

 

[mrjck]

no lights, nothing unusual, other than maybe harder starting(cold pull 7-8 times), needing a bit of throttle to start hot.

I did tip it afew times on the hill on sat, and starting afterwards was really brutal, along with no rev pick up for about 5-10 seconds(like it was flooding really bad), lots of blue smoke(not belt)

Alright, you can give this a try, I've found it works on mine: When she's cold, put on full choke, no throttle, and she fires on the 3rd pull pretty much every time, then a crack of gas and let it warm up for 45s-1min before taking the choke off and it will idle on its own after that. Mine always takes a crack of throttle to start hot too, not sure why, it just likes it.

You could try checking to see that your choke hasn't come on and stuck, use a screwdriver to make sure all the little choke knobs on the carbs are all fully in once the engine's hot, and see if that makes a difference.

I've found that after I roll mine, even if I can shut if off while its still running upside down, it still floods. (Just fills up the carbs anyway) but if I put on full throttle and no choke, it fires up after about 7 or 8 pulls...

How's your jetting? What altitude are you running at? Will it run better at different altitudes? I've got the ATACC system which was the best $$ I've put into my sled, would recommend it. Also I always put in some gasline antifreeze in my tank with each fill because my sled lives outside in the cold (if you could bring it in and warm it up overnight that might clear it up too if you have ice in the system somewhere).

Thats all I can tell you except to maybe clean out your carbs and powervalves! Good luck, let me know if any of that helps.

 

[KatMan]

thanks for the tips. Will try all.

I've had 0 problems to date. Really like the sled, never let me down, so it's a bit odd.

I bought a m1000 last spring to get a bit more track/upgrade. My only bitch with the yammy was not enough track(144) so power/revving was never an issue.

 

[CountryRider]

110psi in one and 90 in another thts not good... Your are supposed to have 10psi within each other max anything beyond that your just askin for trouble... Dont care how long you had it like that its not good... I would do a rebuild

 

[Vipertonytro]

Check your oil cable. About half way down there is a piece that can pull apart. You can use this too put extra oil in engine for storage. It's where you adjust the oil pump cable. Anyway if it is pulled apart and sitting on the edge it will over oil. Hence the blue smoke. Also if it's pulled apart you cannot open the throttle all the way. Hence not revving out. And hard starting. Hope this helps. And yes. Next step would be check your power valves.

 

[twincam88]

did you clean your carbs this fall? thouroughly clean them?

 

[sxv]

I have two 2003 700 mountain Vipers, the head is designed so that compression on number 1 PTO cylinder is lower then number 2 and three, I questioned it as well, so called the dealer to find out, the dealer said the viper 700 engines are designed from the factory that way, I just can't remember why

 

[KatMan]

Not surprised about the compression numbers from the dealer. Maybe because of the added heat from the clutch, not to cause a meltdown clutchside. Didn't have any intension of opening up the motor.
Cleaned the power valves, readjusted the track(loosened a bit). Failed to mention that I did tighten this year. Back in buisness, getting 8900-9300.

That 700 motor has got to be one of the most bulletproof, no trouble engines ever built(2 stroke anyways). I've heard of sleds with 9000K original with no wrenches to the motor. This was my first mountain sled, and it still impresses. We went to forester two weekends ago, the exhaust on my cat burnt a hole through a rad hose, so me & my 300lb fatazz buddy doubled that day. We easily doubled the wieght of the sled. Climbed the wall(doubled), rode all day. What a great sled. Too bad yammy went 4 stroke so soon.