24 replies to this topic

[Daag44]

 Yes!  Adapter was needed.  

 
There you go, that is FANTASTIC news for you!

 

Can't get a high enough compression reading with the schrader valve further away. The added volume takes away some of the compression like turning a 12:1 CR to 11:1 . This is just an example as I didn't bother to calculate it.

 

By the way, the functioning of the schrader valves is very important. Two different gauges should read very close. How close? Let's just say definitely not 20 psi apart. The elevation AND temperature makes a big difference, and so does the oil film. But two gauges should be close enough.

[wileo]

I just had a 09 600tec bog and not re start

The plugs had spark when checking but when I put them back in nothing.

They were wet and wouldn’t fire in starter fluid.


I left the plugs out for the night. Put new plugs in and it Fired right up like nothing ever happened

[Geezjeff]

 
There you go, that is FANTASTIC news for you!

 

Can't get a high enough compression reading with the schrader valve further away. The added volume takes away some of the compression like turning a 12:1 CR to 11:1 . This is just an example as I didn't bother to calculate it.

 

By the way, the functioning of the schrader valves is very important. Two different gauges should read very close. How close? Let's just say definitely not 20 psi apart. The elevation AND temperature makes a big difference, and so does the oil film. But two gauges should be close enough.

That IS great news and solves the mystery I’ve been having with that gauge set.  I’ll test them again and get the delta on the two, but yeah - that’s great news and boy do I appreciate your expertise in clearing that up.  THANK YOU! 

[Geezjeff]

Well I’ll be a monkey’s uncle....

 

Took the sled back apart and got all ready to really dive in, and just quick wanted to see if anything magically improved by letting it sit, so I cranked it over and saw this!  Cracked spark plug.  Definitely didn’t do that when I put the coils in, so curious if either it happened on the trail or the plug was faulty for a while and I just started to see it.  Anyway - I’ll get new ones as soon as possible and let you all know the results, but this is very good (easy/cheap/noticable) news!  Appreciate all the help thus far.  This forum is amazing.  

 

Made a quick vid to share of the issue you can scope out here

[12/3]

Good find, I've been there before where retracing steps can prove to be benefical.

[Spud800]

That’s electricity for you... always finds the path of least resistance.

[Daag44]

In the video, now that's how you troubleshoot ignition troubles. Shut the lights and it becomes that much easier to see.

 

Any idea why the plug cracked? I can't say that i like seeing this. I am guessing last year's gas?

[Geezjeff]

In the video, now that's how you troubleshoot ignition troubles. Shut the lights and it becomes that much easier to see.

 

Any idea why the plug cracked? I can't say that i like seeing this. I am guessing last year's gas?

 Absolutely no idea. I’ve never seen a cracked plug before, personally.  And previous owner says dealer put these in Jan of 2020.  He also says all non-ethanol gas, but not sure of the vintage of the fuel.  Did the sniff test on it when I bought it and it passed the olfactory mustard.  

 

My first ride out was mid RPMs after warming up on a lake with about 4” of snow.  Nothing crazy, as I went from hard pack (lake trails) and some open riding.  Minnesota is insanely low on snow right now, so nothing deep at all.  I rode maybe 15 miles that day with my 4.5 year old in front of me (so not fast at all).  That is the first time the problem showed it’s face, and it got better for a while after letting it cool down.  The more I think it over, the more I think it is a manufacturing defect on the plugs.  I think they slowly failed, and then finally failed on me this last time and that is why I could see it on the outside.  Either way, I’m hoping this doesn’t happen again.  

 

Because I saw a few others telling a similar tale, I’d just advise them to swap plugs regardless of condition at this point.  There are maybe 3-4 other stories on this forum with similar gremlins, and people had various success figuring it out.  I’ll for sure post again if this fixes it after some real mileage.  

[Daag44]

I have heard the same story with light to moderate speeds with kids that ended with engine failures. Tag on my own and I am not convinced that this type of riding should be considered full proof. Under 5000 rpm is the range I assume to be the safest, but rarely if ever does anyone ride in the 4000-5000 range.
 
With a two stroke, it isn't really about running an rpm or load that we believe is safe, but rather an engine that is working right, fueled right, good octane and the exhaust valves are working as they should. Obviously we all want the intake reed boots to be in good condition.
 
For the similar tales, we naturally grasp onto situations that appear the same, hence Confirmation Bias. I find this difficult which is why I have learned to start from scratch thinking this is a new situation. I do this from experience of having been wrong too many times. Conversely the fuel issue has become a broken record.

[Geezjeff]

Great news, crew: 

 

The new plugs fixed it.  I put another 25 or so miles on since the new plugs were put in and it runs like a champ - good as new.  For sake of clarity, I did put new coils and plug wires in during the process as well, but the plugs were really the issue.  

 

Thanks for all the help on here. I got to hit the new 4-6"s of snow this weekend because of all of your help!  

 

Cheers, 

-Jeff