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Possible kickback solution?

tnc110

Lifetime Member
Joined
Jan 5, 2015
Messages
317
Age
44
Country
USA
Snowmobile
Sidewinder BTX SE, SRXs
All this talk about kickback causing starter failures...maybe I don't understand what exactly is going on. I have been assuming that the kickback is a sort of misfire that forces the engine to turn over backwards. I assume this is caused by spark just as the key is removed from the start position, causing combustion, but not enough momentum to turn the engine over forward, so the engine turns over backwards instead?

I have always held the key in the start position until I was certain the engine was running, no kick backs...but I've only got 300 miles...

If a person couldn't get their sled to start on the initial attempt and wanted to release the key to try again, would hitting the kill switch prior to releasing the key from the start position eliminate any chance of a kickback???
 

It would but it has not been proven to me that it's a kickback and not just a rollback. For a true kickback there would have to be pre ignition. If it is actually pre ignition then yes kill switch eliminates all spark so problem solved. If it's just a rollback then the damage could still happen since AC in there ultimate wisdom made the starter turn over even with kill switch engaged. If we could figure out how to wire it like all other Yamahas where kill switch also kills starter then yes your idea would definitely work but if we could use Yamaha wiring then we wouldn't have this issue to begin with.
 
The nytro doesn't have a kickback issue right? But the Viper does? This tells me the Viper has a different fuel/air mixture, or timing or some variable causing the partial combustion, causing kickback. If it was a rollback issue then I assume the nytro would be having issues as well. Eliminating spark before the key is released should eliminate misfire/partial fire/kickback.
 
The nytro doesn't have a kickback issue right? But the Viper does? This tells me the Viper has a different fuel/air mixture, or timing or some variable causing the partial combustion, causing kickback. If it was a rollback issue then I assume the nytro would be having issues as well. Eliminating spark before the key is released should eliminate misfire/partial fire/kickback.
Good point. Could very well just be a partial combustion causing this. Never thought of that. I am going to do that. If it doesn't fire just keep key turned and hit kill. Actually we should just use key for power and just install a rocker switch for start just to avoid the reflex to let go instant it fires.
 
All this talk about kickback causing starter failures...maybe I don't understand what exactly is going on. I have been assuming that the kickback is a sort of misfire that forces the engine to turn over backwards. I assume this is caused by spark just as the key is removed from the start position, causing combustion, but not enough momentum to turn the engine over forward, so the engine turns over backwards instead?

I have always held the key in the start position until I was certain the engine was running, no kick backs...but I've only got 300 miles...

If a person couldn't get their sled to start on the initial attempt and wanted to release the key to try again, would hitting the kill switch prior to releasing the key from the start position eliminate any chance of a kickback???

You have a good thought however there is no way to predict when the kickback will occur. It doesn't happen when you let off the key, it happens at random while cranking the engine. You have the opposing forces of the starter cranking the engine and the kickback which causes the teeth to break on the starter gear. The only solution is retard the timing a few degrees at cranking /starting RPM. My starter gear failed after about 5 kickbacks.
 
Guys I have a 2016 Viper and never had a kickback issue. Is this a 2014, 15 issue only?
 
You have a good thought however there is no way to predict when the kickback will occur. It doesn't happen when you let off the key, it happens at random while cranking the engine. You have the opposing forces of the starter cranking the engine and the kickback which causes the teeth to break on the starter gear. The only solution is retard the timing a few degrees at cranking /starting RPM. My starter gear failed after about 5 kickbacks.
Wow, I didn't know it was happening to people while cranking. Whenever this had happened to me with other engines, it was because the battery was week.
 
I have been reading some of the comments today and notice most of the speculation has been on a fuel issue with respect to some type of ignition failure. The failure seems to be some what unpredictable with an equally unpredictable result. There are many differences between the Nytro and the SR Viper. The ECU, fuel management and electrical are only a few but very important when trying to trouble shoot this issue. I'm not convinced there is only one part to this puzzle, more likely multiple issues that at times are result of the problem in a complex way. If the presenting issue was the same every time then the fix would be easy to find.
I trouble shoot for a living, its important to have an expert understanding of the equipment you are trouble shooting. The point at which I begin my evaluation of a problem is based on the knowledge of the system order that needs to perform to work properly (step by step). Start at the beginning and work thru until the system fails. I am not an "expert" Yamaha engine builder however the same should apply with an approach to solving this puzzle.
It seems the approach has been to hear the problem (issue) and then react to the problem rather than to roll back to the beginning, turning the key and following and testing as you go. The root cause of an issue can present its self in many ways and send you in many directions, fuel, air, electrical and mechanical are only some that react to what can be happening many steps prior. The results may be similar but not the same every time the root cause is happening.
"Back to the drawing board"

I posted this a while back and its just a thought:

I have not had any of the issues with starters or kick back that most have reported. I did notice however that the battery is located at the rear of the sled and the low voltage reported by some could be as simple as a voltage drop condition caused by the size and length of the cable between the battery and the engine. The cold conditions in which starting problems occur caused by a voltage drop would be consistent with many if not all of the symptoms reported. I have seen the voltage drop below the required starting voltage only after the starter is engaged, and continue to drop as the starer struggles to turn the engine over. When the key is released the voltage returns to normal with or with out the engine running. The use of a booster eliminates the low voltage condition at extreme cold starts and allows the engine to crank and the ECU to receive the correct voltage for ignition.


I do have an electrical background, it is only an observation and my simple opinion.
 
Ignition timing is crazy if engine kickbacks with opposing forces while cranking? Luckely I never had that issue on my Viper.
 
I have been reading some of the comments today and notice most of the speculation has been on a fuel issue with respect to some type of ignition failure. The failure seems to be some what unpredictable with an equally unpredictable result. There are many differences between the Nytro and the SR Viper. The ECU, fuel management and electrical are only a few but very important when trying to trouble shoot this issue. I'm not convinced there is only one part to this puzzle, more likely multiple issues that at times are result of the problem in a complex way. If the presenting issue was the same every time then the fix would be easy to find.
I trouble shoot for a living, its important to have an expert understanding of the equipment you are trouble shooting. The point at which I begin my evaluation of a problem is based on the knowledge of the system order that needs to perform to work properly (step by step). Start at the beginning and work thru until the system fails. I am not an "expert" Yamaha engine builder however the same should apply with an approach to solving this puzzle.
It seems the approach has been to hear the problem (issue) and then react to the problem rather than to roll back to the beginning, turning the key and following and testing as you go. The root cause of an issue can present its self in many ways and send you in many directions, fuel, air, electrical and mechanical are only some that react to what can be happening many steps prior. The results may be similar but not the same every time the root cause is happening.
"Back to the drawing board"

I posted this a while back and its just a thought:

I have not had any of the issues with starters or kick back that most have reported. I did notice however that the battery is located at the rear of the sled and the low voltage reported by some could be as simple as a voltage drop condition caused by the size and length of the cable between the battery and the engine. The cold conditions in which starting problems occur caused by a voltage drop would be consistent with many if not all of the symptoms reported. I have seen the voltage drop below the required starting voltage only after the starter is engaged, and continue to drop as the starer struggles to turn the engine over. When the key is released the voltage returns to normal with or with out the engine running. The use of a booster eliminates the low voltage condition at extreme cold starts and allows the engine to crank and the ECU to receive the correct voltage for ignition.


I do have an electrical background, it is only an observation and my simple opinion.

Very good point!
 
I have not had a kickback issue myself nor have the other two Viper riders in our group. However I would like to arm myself with as much knowledge as possible. If my sled is having a hard time starting I'm going to hit the kill switch and then release the starter and pull out the blue fuel battery booster. These new lithium battery boosters are pretty small and lightweight, I have got plenty of room in my tunnel bag to store the booster.
 
You have a good thought however there is no way to predict when the kickback will occur. It doesn't happen when you let off the key, it happens at random while cranking the engine. You have the opposing forces of the starter cranking the engine and the kickback which causes the teeth to break on the starter gear. The only solution is retard the timing a few degrees at cranking /starting RPM. My starter gear failed after about 5 kickbacks.
Can you please tell us the conditions that were present when your Kickbacks occurred? Was the sled cold? What was the temperature outside? Did the sled seem slow to turn over verses when the sled was warm?
 
The only time I had a problem is when my battery went bad, with a weak battery it don't have enough power to turn it over properly and that's what ruined my starter.
 
Decomp
Valve clearance
Wiring
Battery
Weak gear and starter
Fuel tune
Ignition tune
Prime start method
No prime start method
Hold key after running
Let go of key early
Throttlebody sync
Map sensor hose routing
Different throttlebodies
Different Ecu

All these and more I am sure are rarely or never discussed in Nytro forum and anyone of them can help or hurt the issue. It's not simple for sure.
 


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