GibViper
New member
I have spent the last three days searching this post and breaking down my carbs on the Viper. Hoping I can get some guidance and figure this thing out before a trip up north Thursday...
Carbs have been cleaned three times in the last two months and sled was running great up until last week after a WOT lake run. Ran fine for another 10 miles or so then I noticed this...
Starts great, idles nice and runs from mid to WOT like always, however, once you coast to an idle and give it the gas, she bogs and sound like a cylinder isn't firing. Come to a complete stop and accelerate again, all is fine. Have no clue... PVS were cleaned last fall. I am going to pull those tomorrow but wasn't sure if a pull through would cause this???
Also, checked the plug caps..all within spec. Pulled the plugs and the PTO side looked pretty dark but not oily.
Any advise would be greatly appreciated
Carbs have been cleaned three times in the last two months and sled was running great up until last week after a WOT lake run. Ran fine for another 10 miles or so then I noticed this...
Starts great, idles nice and runs from mid to WOT like always, however, once you coast to an idle and give it the gas, she bogs and sound like a cylinder isn't firing. Come to a complete stop and accelerate again, all is fine. Have no clue... PVS were cleaned last fall. I am going to pull those tomorrow but wasn't sure if a pull through would cause this???
Also, checked the plug caps..all within spec. Pulled the plugs and the PTO side looked pretty dark but not oily.
Any advise would be greatly appreciated
viperking
Active member
Is it your tors? make sure both clear bullet connectors on the right side of the carbs are plugged in and throttle cable isn't too tight
If I am understanding it correctly, everything is fine from a dead stop, but if you are at speed and then let off the gas for a few seconds, it won't accelerate very well (kind of like slowing down in a manual transmission car and then forgetting to downshift when it is time to pick up the pace again). If that is what is going on, perhaps one of the clutches isn't springing back properly while it is still rolling but will pop back to "1st gear" once you have stopped completely. Maybe try cleaning the clutches and checking the bushings?
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mopar1rules
Active member
maybe your tors is kicking in?? take your throttle cable, and adjust it so its all the way down, giving maximum free play. then bypass the tors, by simply plugging the 2 wires that go to the sensor under the trottle lever on the carbs, into themselves, to loop the system. sorry, i can't explain it very well.
GibViper
New member
I bypassed TORS, still did it. There is not that much play in the throttle. Adjusted per spec of 2 mm, still seems tight though. I called a Yamaha tech and he said it sure sounds like TORS as well, also recommended unplugging the kill switch as well; said that switch could be bad.
So even if I have the TORS bypassed and my throttle cable is a bit tight, that may still cause this?
Bigreis: Interesting about the clutch. I did change out the helix and secondary spring this fall. Was all fine until that WOT run across the lake. Could it be binding or something? And if so, why would the engine sound like its not running on all cylinders?
So even if I have the TORS bypassed and my throttle cable is a bit tight, that may still cause this?
Bigreis: Interesting about the clutch. I did change out the helix and secondary spring this fall. Was all fine until that WOT run across the lake. Could it be binding or something? And if so, why would the engine sound like its not running on all cylinders?
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If the secondary is getting hung up (not closing all the way) then it is like you are trying to take off in 5th gear in your car when you hit the gas again when you really should be in 2nd or 3rd gear. Your engine will be super overloaded (bogged down) and it will let you know it isn't very happy by sounding funny. Again, just a guess but an easy fix if that is the problem!
ottawaair
New member
check the plastic buttons on the secondary, could be worn & grabbing helix.
GibViper
New member
So...ohm'd out the TORS. At rest the carb switch is closed and the throttle switch is open. Once I engage the throttle the throttle switch closes.
Shouldn't the carb switch be closed as well at rest? And to bypass the TORS, do I disconnect both the carb side and the throttle side and connect both sides to each other to make two separate loops or do I just connect one side? If so, which one? Only reason I ask is when I bypassed TORS yesterday, I made two separate loops and it didn't make a diff.
Shouldn't the carb switch be closed as well at rest? And to bypass the TORS, do I disconnect both the carb side and the throttle side and connect both sides to each other to make two separate loops or do I just connect one side? If so, which one? Only reason I ask is when I bypassed TORS yesterday, I made two separate loops and it didn't make a diff.
grizzlyrunner
New member
Did you check your reeds for cracks or chips make sure reed cages are in good shape and sealing properly, reeds can do weird stuff like that exp at midrange,
sockeyerun
Test Dummy
Un plug them and check them individually.You are describing exactly what I experienced a couple years ago to the "T". Turned out to be the switch on the carbs. Replaced it and all went back to normal. Here's is the thread I started asking how to test the switches:
http://www.totallyamaha.net/forums/showthread.php?t=66514&highlight=torsthis
http://www.totallyamaha.net/forums/showthread.php?t=66514&highlight=torsthis
journeyman
Active member
grizzlyrunner said:
That is true. Mine acted real weird last season until I discovered my reeds were shot.
I would not rule out the clutches though. I have seen even a bad belt give a person false ideas.
BigTimeFarmer
New member
grizzlyrunner said:
x2 on that. had a similer problem on my viper turned out to be a chipped off reed petal
Starts great, idles nice and runs from mid to WOT like always, however, once you coast to an idle and give it the gas, she bogs and sound like a cylinder isn't firing. Come to a complete stop and accelerate again, all is fine. Have no clue...
When you pulled the carbs, did you check the screens under the floats? I had a similar issue and my fuel screens were plugged. I could get a full pull initially out of the sled, and then it would start to "drop" a cylinder, and the longer I tried to run it this way, the more it would not come back. Would have to choke it to make it run again, but then that wouldn't work either after awhile. Plugged screens were preventing the fuel bowls to fill up fast enough for the fuel demands. Just a thought.
When you pulled the carbs, did you check the screens under the floats? I had a similar issue and my fuel screens were plugged. I could get a full pull initially out of the sled, and then it would start to "drop" a cylinder, and the longer I tried to run it this way, the more it would not come back. Would have to choke it to make it run again, but then that wouldn't work either after awhile. Plugged screens were preventing the fuel bowls to fill up fast enough for the fuel demands. Just a thought.
FJViper
New member
Gib, did you adjust your fuel screws at all? I think I know what your talking about. I've had the same issue with my Viper. Normally I have my fuel screws turned out to 2 just to help with an idle hang. Works great. Last week I figured I'd adjust them back to 1 7/8 stock. One lap around the house, let off the gas to take a corner, sled bogs and sounds like it's on one cylinder. Sounds kinda like my one lunger ski doo.( ding..ding) Won't go anywhere, no power. Give it 5 seconds or so and then will act normal until I let off the throttle again, same corner.
Obviously it's a lean condition. But like you, my carbs are spotless. Reeds seem like they are in good shape.
Pulled the carbs, reset the screws back to 2 turns, runs great! Can't figure it out. Carbs are spotless! Sorry to hyjack your thread.
Obviously it's a lean condition. But like you, my carbs are spotless. Reeds seem like they are in good shape.
Pulled the carbs, reset the screws back to 2 turns, runs great! Can't figure it out. Carbs are spotless! Sorry to hyjack your thread.
GibViper
New member
no problem FJ, I originally had the fuel screws out to 2 when this all started. Put them back to 1 7/8 after cleaning and nothing changed. New plugs look dark already like I have a rich condition, but I haven't been able to really give it a good run WOT to test plugs.
I have not cleaned the screens. I tried to get the pin out (with a center punch) that holds the floats in with no luck. I'm back in the garage this morning, after last night's little storm, it looks like a postcard not to mention trails were just groomed last night as well, of course! haha The SledGods are mocking me
I have not cleaned the screens. I tried to get the pin out (with a center punch) that holds the floats in with no luck. I'm back in the garage this morning, after last night's little storm, it looks like a postcard not to mention trails were just groomed last night as well, of course! haha The SledGods are mocking me
GibViper
New member
Okay...
Cleaned carbs AGAIN and cleaned float screens (not plugged)
Cleaned PVs, very dirty...one was completely stuck
Adjusted PV's
Runs like an animal until I coast to almost a stop, then the bog. HAS to be something with the clutch. I know nothing about clutching. I did replace the helix this Fall with Bender 53/43 and green secondary. Other than that, we're completely stock. Clutches never cleaned (will do tomorrow) but what should I be looking for???
Thanks again guys..
Cleaned carbs AGAIN and cleaned float screens (not plugged)
Cleaned PVs, very dirty...one was completely stuck
Adjusted PV's
Runs like an animal until I coast to almost a stop, then the bog. HAS to be something with the clutch. I know nothing about clutching. I did replace the helix this Fall with Bender 53/43 and green secondary. Other than that, we're completely stock. Clutches never cleaned (will do tomorrow) but what should I be looking for???
Thanks again guys..
Sounds like your secondary clutch is not "Back Shifting" properly.
Things to check:
-check spring wrap, sometimes the indexing is incorrect and can fool you if you have never done it before...when you have one end of the spring in the numbered hole in the clutch[example #1] and the other end of the spring in the helix hole[example #6]you should have to rotate the helix approx 60 - 70 degrees under tension when you install the helix
-check buttons in secondary for wear
-belt tension could be incorrect... with the belt installed the top of the belt should be flush to approx 1/8" above the top of the secondary sheaves...a worn belt will run low and can cause bogging...you can search to find instructions on adjusting belt tension
-broken motor mounts or misaligned engine and cllutches...there were some issues with Vipers breaking motor mounts...again a search will give lots of info
Hope this helps:
Bob
Things to check:
-check spring wrap, sometimes the indexing is incorrect and can fool you if you have never done it before...when you have one end of the spring in the numbered hole in the clutch[example #1] and the other end of the spring in the helix hole[example #6]you should have to rotate the helix approx 60 - 70 degrees under tension when you install the helix
-check buttons in secondary for wear
-belt tension could be incorrect... with the belt installed the top of the belt should be flush to approx 1/8" above the top of the secondary sheaves...a worn belt will run low and can cause bogging...you can search to find instructions on adjusting belt tension
-broken motor mounts or misaligned engine and cllutches...there were some issues with Vipers breaking motor mounts...again a search will give lots of info
Hope this helps:
Bob
If was me, I would prop the back of the sled up good and secure and then observe what the clutches are doing as you speed the track up and down. As the track speed increases you should see the secondary sheaves open up and smoothly close as the track speed decreases. I am guessing your secondary is hanging up at some point and is staying open a little until everything stops spinning. It will behave differently under a heavier load (like with the sled on the ground) and do exhibit the same behavior, but you may get lucky and see the clutch hanging up with the track up in the air.
When you have the clutch apart for cleaning, you may want to try putting it back together without the spring and then move the sheave back and forth to see if you can feel a spot where it isn't sliding smoothly.
When you have the clutch apart for cleaning, you may want to try putting it back together without the spring and then move the sheave back and forth to see if you can feel a spot where it isn't sliding smoothly.
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GibViper
New member
Thanks guys...I'll give that a try tomorrow. Buttons look fine, belt has less than 1K miles and sits correct on the secondary when at rest. Worse comes to worse, I'll pop the stock helix and spring in and see if that changes anything...then I'll know for sure its the clutch.
Man, weird being on this end of the posts on here. Everyone's time and experience is very much appreciated. TY is the best forum site on the internet bar none
Man, weird being on this end of the posts on here. Everyone's time and experience is very much appreciated. TY is the best forum site on the internet bar none
sockeyerun
Test Dummy
Dude you are bringing back memories of some some very frustrating times for me personally. My sled acted exactly the way you are describing. I did everything you have done with no change.Carbs 3 times, messed with the carbs, adjusted my throttle must have been a hundred times, I even rebuilt the clutches. Same thing. It turned out to be the TORS switch on the carbs, unplug and test them separately. Here's the thread I started back then. Hope it helps...Soc
http://www.totallyamaha.net/forums/showthread.php?t=66514
http://www.totallyamaha.net/forums/showthread.php?t=66514