Charlie P
Member
Working on a buddies 2002 Viper. He's cleaned the carbs a couple times. Today I went thru the carbs, we replace the fuel filter, and line in the tank. Primed the carbs before starting with premix, and left the hose off the PTO carb to check how much gas was being pumped, pump seems OK. This sled will pull 8000 rpm but won't idle. Just dies, pilots set at 1 7/8 out. I unplugged the throttle sensor and watched the servo motor for the valves, but I don't know a thing about them. It will idle a bit better but not like my SX700r. Don't have a manual for the machine. Will this machine run good with the servo motor disconnected? What to check next? Thanks for any help .
well i do know 8000 rpm is low for yamaha tripples. they like seeing 8500 rpm. might want to try to idle it with the belt off to see if clutch is staying engaged and killing the sled.
Charlie P
Member
Thanks for the reply. The sled may very well pull the correct RPMs, but I was running it in my back yard, and don't have the room to stretch out. clutch isn't staying engaged. It really acts like fuel problem, but I've been thru it carefully. Can the power valves cause this? When I unplugged the throttle sensor it runs better, but not right. We hauled it to the North woods last week and it wouldn't even run. Had to rent a sled. Even bypassed the tors, didn't make a difference. The sled does have electric start and reverse.
Sounds like pilot jets plugged
Spray brake clean into the pilot jets, bowls off, carbs held upside down.
It should flow through
It should flow through
stuck power valves would rob it on top end but i check the sled in the family with them every year and clean them.
battery is good? heard of it causing issues on other sleds when it is too bad to take a charge. need it on any sled after 02 with e start as they do not have the smoothing condensor that was on the pull start only sleds. battery replaces it.
with springs out, clutches all move freely i hope.
super1c
Super Moderator
PV won’t effect idle. Did u check plug caps? Is the idle adjusted proper? Did you clean the top hats under the needles in carbs. Weak stator?
Charlie P
Member
The carbs are clean as can be. My buddy has had them apart 2 or 3 times. I had them apart yesterday, even checked the inlet filters. pilot jets are not plugged. First thing I thought of was fuel problem, it's not a fuel problem.
Charlie P
Member
Didn't check the plug caps yet. The carbs are clean, for sure. It runs better after I unplugged the throttle sensor, but not right. Has a brand new battery. Starting to think stator or CDI box.
mod-it
Member
Power valves that don't open impede top end rpm, but they are closed at idle.
Will it idle if the choke is on?
Nothing against your buddy's carb cleaning knowledge, but I've seen many a pilot jet plugged with gunk that will not come out unless a wire is ran into them to knock it loose. Air doesn't clear them, nor carb cleaner. I always hold them up to a light and ensure a nice round hole can be seen through them before calling them clean. I've opened up carbs that have been cleaned "several times" for others and found blocked pilot jets multiple times. Were the fuel screws completely removed and carb cleaner sprayed from the pilot jet passage through and out the fuel screw opening to ensure that whole passage is clear on each carb?
Air leak somewhere?
Reed pedals look good?
Super1c's suggestion of checking the top hat filters by the needles is also a good idea. Very few actually open the top when carb cleaning. There have been many posts the last few years where it is found that those screens finally plugged up with enough gunk over the years that they are the cause of a running issue.
Is this a sled your buddy has had for a while and ran fine last year? Or a new to him sled?
Will it idle if the choke is on?
Nothing against your buddy's carb cleaning knowledge, but I've seen many a pilot jet plugged with gunk that will not come out unless a wire is ran into them to knock it loose. Air doesn't clear them, nor carb cleaner. I always hold them up to a light and ensure a nice round hole can be seen through them before calling them clean. I've opened up carbs that have been cleaned "several times" for others and found blocked pilot jets multiple times. Were the fuel screws completely removed and carb cleaner sprayed from the pilot jet passage through and out the fuel screw opening to ensure that whole passage is clear on each carb?
Air leak somewhere?
Reed pedals look good?
Super1c's suggestion of checking the top hat filters by the needles is also a good idea. Very few actually open the top when carb cleaning. There have been many posts the last few years where it is found that those screens finally plugged up with enough gunk over the years that they are the cause of a running issue.
Is this a sled your buddy has had for a while and ran fine last year? Or a new to him sled?
Charlie P
Member
He's had the sled for a while but hasn't ridden it. We went thru the whole thing the last couple a days. I cleaned the carbs yesterday. We adjusted the power valves today, cut about 1/2 off of each plug wire and have the sled running pretty good. Not misfiring anymore. It is a cold natured beast though. He told me this morning he has seafoam in the gas. Now I think with some fresh 91 it'll run pretty good. I look thru all jets with a light, been fooled before. Guess I don't understand why the power valves open up when shut down. I wouldn't trade my SX700R for one of these, it's not that much stronger. Thanks for all the help guys !!
good you got it running. it will run well on 87 too, just not recomended for storage.
Charlie P
Member
Thanks, but we both run premium fuel, always have . We've both been out of it for some time. He's 76, and I'm headed for 72. I quit riding in 2001 after an injury, couldn't ride a bike or snowmobile. Let me tell ya though, these AIN'T the GOLDEN YEARS.
Mac
Member
Charlie P
Member
Have you checked the stator? My buddies srx wouldn't get top rpms and the stator was shot.
Charlie P
Member
Top RPM wasn't the problem. We have the machine running pretty good. We rode about 85 trail miles around St Germain on the 1st. Think it was several things.