Over run issue

D

Datjake

New member
Joined
Jan 21, 2013
Messages
5
Age
54
Location
Washington
I have an 02 viper I start it and it idles fine I rev it a few times and idle wont back down from over 4000 rpm unless I choke it then it is fine until I blip the throttle again. I have went through over a can of brake clean looking for an air leak I am pretty convinced it is not an air leak. Anyone has any ideas I am all ears. Throttle position sensor? Power valve adjustment? Internal carb issue? I am totally at a loss and want to ride. Thanks in advance
 

Welcome to the site! Common problem on viper. What are your fuel screws set at. Stock is 1 7/8 turns out. Increase that to 2 even 2 1/4 turns out and lower your idle to about 1100 - 1200. Should cure it. Do a search on viper idle hang and it will tell ya all about why.
 
If it is that easy I will have to find a way to send beer via forum!!! While I was down there I went through the carbs several times cleaned power valves, reed and the excess of brake clean has cleaned everything else. Thanks I will try in the morning.
 
PPS. inc said:
Open air screws to 2 turns, back off idle rpm. Clean carbs while ur down there.
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Remember....If it's on the engine side of the carb slide, it's a fuel screw. If it's on the airbox side of the carb slide, it's an air screw. Like Super said, it's a fuel screw.
Have you cleaned your carbs? Gotta make sure those pilots are CLEAN.Should have a nice round hole looking through them. Any leaks in the exhaust? Exhaust donuts in good shape?
 
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I just got my brothers Viper going that hasn't run for 2 years and when I started it up after cleaning the carbs it was doing the same thing. I ended up adjusting the TORS, I just backed it off a little and it runs perfect and idles down nice.
 
superfan75 said:
I just got my brothers Viper going that hasn't run for 2 years and when I started it up after cleaning the carbs it was doing the same thing. I ended up adjusting the TORS, I just backed it off a little and it runs perfect and idles down nice.
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How do u back the tors off? I've been having the same problem
 
My understanding is tors is either working or not there is no adjustment...I have been through the carbs a couple times now....so fuel screw..air screw.. Which one should I adjust I set the air screw at 2.25 turns should that have been the fuel screw?
 
I had an idle hang up last year (3500-4000 rpm),on my 04 viper. it went away with the changing of the throttle position sensor. The old one failed the voltage test.
 
viperSbob said:
I had an idle hang up last year (3500-4000 rpm),on my 04 viper. it went away with the changing of the throttle position sensor. The old one failed the voltage test.
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!!! I think This post cleared things up for me!! I google throttle position sensor and aparently they had a recall on them for the sx viper and a few other yamaha products!
So would I be able to get one for free from yamaha since it was a recall?
Cuz mine also hangs at 3500-4500
 
I just backed off the screw which holds the TORS in place. It is supposed to be adjusted so it just touches the throttle linkage when you let off.
 
I believe it's 1-2 mm of freeplay at the throttle lever. If you have no freeplay, that will cause the TORS to go off.
 
superfan75 said:
I just backed off the screw which holds the TORS in place. It is supposed to be adjusted so it just touches the throttle linkage when you let off.
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sounds like you are talking about the idle speed adjustment. thats not for adjusting the tors. you set the tors by cable freeplay like said above. you do that with the cable adjuster where the cable threads into the carb bracket.
 
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