Viper idle hang

O2viper700

O2viper700

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Joined
Sep 25, 2012
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489
Location
Ottawa, Ontario,
I bought a 2002 viper this summer and so far am loving it, put 1400km on so far. It seems to run great, installed a new track before the season and rebuilt the skid. Everything is working great. But it has a idle hang, should I clean the carbs? I would like to get some opinions on what to do and go from there I don't want to mess anything up. I've been reading about it and some people say turn the fuel screw from out 2 turns from lightly seated. I don't think it's running lean though, the plugs are black with a little tan in the center does turning the fuel screw just change the low end/idle? sorry for so many questions I just don't want to mess anything up. I have no problem cleaning carbs but im an expert on them. Is it bad if I just run it this way? I've run seafoam through the gas aswell and no change

Thanks in advance.
I love this forum, I don't know what I would do without it.
 

If you have not yet cleaned or had the carbs cleaned this season I think you may be running on borrowed time... An Idle hang is a sign of a lean pilot circuit and could cause fueling issues that could lead towards a burn down... Cleaning the carbs is cheap insurance and todays fuels are loaded with so many combustion enahncers to stretch the fuel as far as the fuel companies can... The fuels of today are NOT like the fuels we used to have(even 5 years ago.
 
As stated above. Clean the carbs. Unfortunatley Seafoam will not cure a dirty carb. All the Vipers that I've worked on seem to idle the best at 2 turns out. Also check the idle rpm. It should be around 1600. If its higher then turn it down. The higher idle will have the same sympton of idle hang.
 
stein700sx said:
As stated above. Clean the carbs. Unfortunatley Seafoam will not cure a dirty carb. All the Vipers that I've worked on seem to idle the best at 2 turns out. Also check the idle rpm. It should be around 1600. If its higher then turn it down. The higher idle will have the same sympton of idle hang.
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The specs say 1800 rpm for idle. But I have it at 1500 right now.
So seems I have to clean the carbs then.
Does turning the fuel screw out only richen the lower end? Like idle and low rpm
 
O2viper700 said:
i dont think it is running lean at midrange, if anything its a little rich looking at the plugs.
so if i clean the carbs and set the fuel screws at 2 turns out will i be ok?
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Clean your carbs good and set the fuel screws to 2 turns out. That should take care of the idle hang. Did you read the links? Good info. there from a guy who know what he's talking about.
 
Thanks for all the input guys i will be taking the carbs off this weekend.
Would it be worth it to adjust the needle? Here's a pic of one of my plugs, they all look the same. They look pretty spot on to me. not an expert though. I just don't want to mess with it if it is running great.
I read the links very informative


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Turning the idle down was the only way I could fix my idle hang--which I messed with for quite a while, even trying bigger pilots. Here is what Betheviper explained to me a while back:

"Put the 45pilots back in, its not that the sled is lean at idle, what is going on is that the pipe is making it idle high. Pipes have more than one rpm where the resonance works out to be efficent. It happens to be on this sled that the stock pipe is also efficent at around 2-2500 when the pipe is hot. so what happens is you ride fast or hard, keeping the pipe hot, then come to a stop and let off the gas. As the engine passes down through that rpm, it is so efficient there that it doesnt need alot of fuel to stay there. the reason flipping the choke makes the rpms drop is it is adding enough fuel to cool the pipe at the same time it is flooding the motor, making less power and allowing the engine to drop rpm."

the only fix is to idle the sled to 12-1500, usually works.

And ya that plug looks pretty good to me(safe).
 
averagesleder said:
What rpm does your idle hang at? I'm in the process of trying to solve the same problem on my viper.
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Somtimes If im slowing to a stop after crushing at 120 -160kmh it will hang at 3500 for a few seconds and then clime up to about 4000, and the clutch will engage for a second. Then it will usually clime down to normal but sometimes it will still hang 2000 - 2500. But sometimes after coming to a stop it will come to to 3000 and then slowly come down to idle.
 
O2viper700 said:
Somtimes If im slowing to a stop after crushing at 120 -160kmh it will hang at 3500 for a few seconds and then clime up to about 4000, and the clutch will engage for a second. Then it will usually clime down to normal but sometimes it will still hang 2000 - 2500. But sometimes after coming to a stop it will come to to 3000 and then slowly come down to idle.
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Thanks, mine hangs at around 4000. It doesn't do it after every stop which is strange. If I'm riding fairly hard, and let right off for a corner it will hang at 4500 with the clutch still engaged, which isn't good at all. Time to go read some tech pages.

Where in Ontario are you?
 
averagesleder said:
Thanks, mine hangs at around 4000. It doesn't do it after every stop which is strange. If I'm riding fairly hard, and let right off for a corner it will hang at 4500 with the clutch still engaged, which isn't good at all. Time to go read some tech pages.

Where in Ontario are you?
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Ya that's dangerous! And mine doesn't do it all the time either.
I'm in ottawa and man the trails are sweet put on 380km last Saturday and have a total of 1400km this year
It was +4 for some reason today though which really sucks
 
:I had the high idle problem on mine. I took it to 3 different repair shops to try to fix it. I ended up researching the problem on here and turned my idle down to 1200. That fixed my problem! :letitsnow
 
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