jboutdoorguy
New member
Hi guys,
I have an 02 viper that I bought new with now 9,400 miles. Always used yamalube. Starting last year it would idle really high and high enough to engage the clutch. This year its the same thing and also some back firing. Over the years I have had to numerous times clean the pilot jets because of low/no idle and backfiring. I cleaned them now and when I was done thought I fixed the issue because it idled perfect afterward. When I cleaned up my tools after the job I noticed I left out one of the pilot jets. I took it back apart and put the jet back in and my lean/high idle came back. So..., If I give it choke the idle will come down but go right back up when I turn the choke off. If a pilot jet is out completely it idles perfect. Could a stuck power valve cause the high idle? I actually have never cleaned them. I dont notice a loss of high end power. Could it be just the throttle cable it out of adjustment? I dont think there is any leaking at the airbox. The carbs were pretty clean and the pilot jets were not clogged initially. The air screws are About 2 turns.
I have an 02 viper that I bought new with now 9,400 miles. Always used yamalube. Starting last year it would idle really high and high enough to engage the clutch. This year its the same thing and also some back firing. Over the years I have had to numerous times clean the pilot jets because of low/no idle and backfiring. I cleaned them now and when I was done thought I fixed the issue because it idled perfect afterward. When I cleaned up my tools after the job I noticed I left out one of the pilot jets. I took it back apart and put the jet back in and my lean/high idle came back. So..., If I give it choke the idle will come down but go right back up when I turn the choke off. If a pilot jet is out completely it idles perfect. Could a stuck power valve cause the high idle? I actually have never cleaned them. I dont notice a loss of high end power. Could it be just the throttle cable it out of adjustment? I dont think there is any leaking at the airbox. The carbs were pretty clean and the pilot jets were not clogged initially. The air screws are About 2 turns.
Mortagleus
New member
For the backfiring have you pulled the plug caps and made sure the connections havent become loose? I had some really bad backfiring caused by that couple years ago. Once I trimmed about a cm off and reattached all the backfiring went away.
Your not getting enough fuel at idle, or, cable is out of adjustment.
Did you clean everything? Or just pilots?
Throttle cable is easiest to start with.
There is a jam nut, loosen it first, then adjust the longer hex part next to the jam nut just so you have a tiny bit of slack.
Did you clean everything? Or just pilots?
Throttle cable is easiest to start with.
There is a jam nut, loosen it first, then adjust the longer hex part next to the jam nut just so you have a tiny bit of slack.
jboutdoorguy
New member
I only cleaned pilots
I did not pull plug caps
If not throttle cable adjustment is it definitely a fuel flow issue in the carbs?
If it was something like an air leak somewhere I'm thinking I would notice a power difference? The plugs look ok.
Air leak causes a lean condition. Crank seal, base gasket, or reed gasket.
My guess would be dirty carbs or throttle cable.
My guess would be dirty carbs or throttle cable.
A couple of bucks
VIP Member
Stoich is 14.7:1 for the air fuel ratio. This is optimum .... I.E. - on the bubble. No margin for error in temp, conditions or fuel.
Safe AFR is @ 12:1.
I'd venture to guess your are 16:1 at idle. Ripe for a burn down.
Safe AFR is @ 12:1.
I'd venture to guess your are 16:1 at idle. Ripe for a burn down.
A couple of bucks
VIP Member
Ethanol snot gumming up the works.
could be time for a set of carb boots as they do come apart with age.
A couple of bucks
VIP Member
Something else to try.... spray carb cleaner on the boots and pto side main bearing. And anywhere else suspect. RPM or tone change and you've found your problem.
I think CoB is on track. It sure sounds like an un-metered air leak (i.e. crank seal, carb boot) and could be catastrophic if not corrected.
jboutdoorguy
New member
I took it apart again last night and cleaned the power valves and carbs. The power valves were terrible dirty. The carbs I had apart a couple weeks ago and they again looked clean. There is no gummed up gas that I can see anyway. I did not pull every little piece apart. I did pull pilot jets again and they were clean. I sprayed carb cleaner through pilot port and it came out other end. Sprayed in main jet and it came out other end. Sprayed where fuel goes in and it came out other end. After putting it all together with fresh gas and seafoam I thought we had cured the high idle but after riding it around for 5 minutes when we pulled it up to the garage the idle did not go down and it did engage the clutch. There was no backfiring now but instead an occasional cough if that makes sense. I guess I will try sparying carb cleaner on the boots and crank bearing seal and see if I notice a change. Also there is some slack in the throttle cable. I really want to run it now and see if it will clean itself out but from reading the posts here I am afraid of burning it up. Because I ran it last winter with the high idle that has me a little less worried about burning it up. Thanks all for your help. If you have any more tips please share.
Dont run it, there is no magic gremlins that will fix it while you ride. How far out are your fuel screws? Did you spray carb cleaner around the boots, are the carbs seated fully in the boots(a sure way to burn it up)?
mod-it
Member
I also think you might be hunting an air leak. Do the spray trick and see what you get.