Still not running right.....

Yamaha_Chuck

Yamaha_Chuck

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Joined
Mar 18, 2011
Messages
62
Age
41
Location
Keswick Ridge, N.B.
Well here in Atlantic Canada we got about an inch of snow today so I had to take out the Viper (new to me) to see how it was working after doing some pre season maintenance. I took my carbs off initially because it wouldn't idle properly....really didn't find any garbage in them but it would start better after this. However when I took it for a ride today it would sputter at higher RPM and would only go as high as 7000RPM. Originally I thought I had compression problems because my gauge would only read 75 but I checked it with a different gauge and am getting between 100-105 but it is the same all across. Could this be my problem or would my power valves be so bad as to cause this?
 

A lot of guys will tell you that as long as your compression numbers are within 10% of each other don't get too excited if the number seems low,it could be the gauge especially seeings as how you got a higher number with a different one.
As far as the sputtering it could very well be the pv's not opening up correctly.Did you have them apart for pre season maintenance?Are they set to spec?Are you sure the servo is working properly?
Another area that seems to be overlooked is the flywheel because it will rust up and cause some pretty odd running issues.It's a pain to get at because you have to take the recoil off to see it but that would eliminate that as a possible cause .I'm sure other guys will chime in here with some other things to look at too.
 
It won't go over 40MPH and sounds like crap when I open it up....if there was something wrong with the power valves would it cause it to run this bad? Also, it still doesn't sound just right at idle either.
 
Check powervalve cables make sure they are not broken. Fuel filter but the tank? Floats not set right. A lot of options to check.
 
You're absolutely sure that your carbs are spotless including the top hat filters, pilots, all orifices clean and blown out? How are the reeds? Plugs and plug caps? Lights and/or speedo doing any funky things while it's running. Did you drain all of the old crap fuel out of it before you put fresh stuff in or just add to the tank?
 
Yamaha_Chuck said:
Originally I thought I had compression problems because my gauge would only read 75 but I checked it with a different gauge and am getting between 100-105 but it is the same all across. Could this be my problem or would my power valves be so bad as to cause this?
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If the Viper is stock you may want to check your compression numbers again, because they shouldn't be the same all across. The PTO cylinder should be approx 10-15% lower than the other 2.
 
When you cleaned the carbs did you:

1.) remove the pilot jets from the carb and able to see light thru them after you cleaned them???

2.) spray carb cleaner up thru the orfice where the pilot jet threads in and it would squirt out the little orfice in the front side of the carb??

3.) remove the float pin and check the screens under the needle seat, you had to remove the seat by a small screw and pop it out to check theese.????

add:FYI- if it were the powervalves not even working or all 3 pulled thru it would idle fine, and it would run fine but not rev anymore then 7800-8000rpm, so i will say its not the powervalves with your description, sounds like a carbs circuit not open.
 
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reeds chipped reeds? dirty carbs? i just cleaned an enticers that looked fine but wouldn't run right until i cleaned it, doesn't take much. plugged exhaust? possibly a nest in it? nice blue spark when pulling it over? plug caps are at spec? fouled plugs from blowing out fogging oil or something? power valves like said before? start with the easy stuff that wont cost you money!!
 
FJViper said:
You're absolutely sure that your carbs are spotless including the top hat filters, pilots, all orifices clean and blown out? How are the reeds? Plugs and plug caps? Lights and/or speedo doing any funky things while it's running. Did you drain all of the old crap fuel out of it before you put fresh stuff in or just add to the tank?
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I do not know about the top hat filters. I blew out the main and pilot jets. Reeds were in good shape, I took all of them out. The plugs are new and I even tried an old set with no difference. Nothing unusual with the speedo or dummy lights. There was such little fuel in the tank that I couldn't syphon it out but the carbs showed no evidence of bad fuel anyway.
 
mrviper700 said:
When you cleaned the carbs did you:

1.) remove the pilot jets from the carb and able to see light thru them after you cleaned them???

2.) spray carb cleaner up thru the orfice where the pilot jet threads in and it would squirt out the little orfice in the front side of the carb??

3.) remove the float pin and check the screens under the needle seat, you had to remove the seat by a small screw and pop it out to check theese.????

add:FYI- if it were the powervalves not even working or all 3 pulled thru it would idle fine, and it would run fine but not rev anymore then 7800-8000rpm, so i will say its not the powervalves with your description, sounds like a carbs circuit not open.
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I've made up my mind that I will pull the carbs again and do a more thorough job. I did not spray carb cleaner through the pilot orifice or remove my floats. Hopefully this will work.
 
check out the carb cleaning 101 I put in the tech section with pics on what to look for.

Do this carb clean and see how it runs, if it doesnt run right i will guide you to the next thing to look for, hang in there we can find the issue.

Just have to remember i might ask a question you think is dumb but I cant see it or hear it so your my eyes and ears for description.
 
Thanks a lot mrviper700 AND to everyone else on this forum. I've posted a couple other questions on here and always get a fast and accurate response.
 
Yamaha_Chuck said:
I've made up my mind that I will pull the carbs again and do a more thorough job. I did not spray carb cleaner through the pilot orifice or remove my floats. Hopefully this will work.

If it will run better with choke still half way that's usually an indicator of dirty carbs. For what its worth my girlfriend burnt down the center cylinder on a SxR because I skipped pulling the floats......Had crap restricting fuel flow......which also restricts oil flow.........L E A N B U R N D O W N
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Took my carbs off tonight and followed the procedure except for the float removal....they were all in extremely hard and I didn't want to put anymore force on it because I was afraid of breaking off the tang that it goes into. Anyways the carbs did not look to be at all dirty but I will know more when I fire it back up. Right now I'm in the process of cleaning the power valves which also do not appear to be that dirty which brings me to my next couple questions. Do I have to buy new gaskets for putting them back together or will high temp silicon work? My closest dealer is an hour away so I hope I don't have to make a trip there just for that. Also when I removed the valve I pulled the cable manually to get slack so I could disconnect it but I could hear the servo operating when doing this....in hind sight I should have removed the cables from the servo but its just from lack of better knowledge.....did I damage anything by doing it this way?
 
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