Spark plug insulator around electrode broke off in the motor

[Doc Brown]

The leaking base gasket could have been the reason. At least I really hope that.

If you are not sure about the sound due to the fact its your first two stroke I recommend you to do what I did. I asked a two stroke nerd to listen how my bike sounded and he gave me good advice how to detect possible errors in jetting.
Though this was many years ago I am still grateful.

I really keep my fingers crossed for you.

 

[TGM_OFFROAD]

Ok so rebulid is done. Pressure test is good now after some gasket sealer with the base gasket. It held 6psi solid for 10 minutes. Sprayed water all around the base of the cylinder and left side crank seal since I already had the flywheel off and no bubbles.

I reinstalled the stock pipe and my turbine core 2.1 silencer.

I am using the stock head which in my case is the gp head since that was what came on my bike when I bought it used.

Reset my jetting back to stock
42p
A/S 1.5
N1EF needle at #3
175 main jet

Rode around in my parking lot since I was jot able to get to the OHV park today. Had to take my dog to the vet

First impressions, pilot is too rich but the needle is slightly lean around 1/3 to 1/2 throttle and main is too rich. It will sputter at WOT.

Here is two videos of cruising around, let me know if that sounds right to you

https://youtu.be/cfMVjM9BCQw

https://youtu.be/vi1GraiXyZY

 

[TGM_OFFROAD]

Even at 44 seconds on the downhill she sounds likes shes lean with erratic idle. Like others said.. check your engine for air leaks.

Also take the time to cc the trapped volume.. especially if you've had a failure. Double check timing.. and I wouldn't bother with iridium plugs in a 2 banger.

How do I check timing on this bike? The timing is fixed also so I am not sure how it would get out of adjustment. Even at stock everything it does sound off compared to other bikes I have heard in videos. Could the CDI cause this.

 

[Jakobi]

Where was the base gasket leaking? I always use some sealant at the front and back where the cases meet. Did the cases show any signs of leaking on disassembly?

By timing, I was suggesting that the flywheel was retained properly and woodruf key not sheared, etc.

 

[TGM_OFFROAD]

Where was the base gasket leaking? I always use some sealant at the front and back where the cases meet. Did the cases show any signs of leaking on disassembly?

By timing, I was suggesting that the flywheel was retained properly and woodruf key not sheared, etc.

Gotcha, the flywheel and everything looks good. I did have an issue with the woodruff key shearing when I first got the bike due to the flywheel not being properly torqued but I replaced the key, luckily the ktm key is the same dimensions because the gas gas one was not available at the time.

When I pulled the jug the base gasket was damp and torn at the rear. After the rebuild the rear was where the leak was coming from until I reassembled with some sealant.

 

[TGM_OFFROAD]

Went to 1.75 on the a/s and raised the needle 1 position to richen it up. It feels better but still doesnt sound right to me.

https://youtu.be/A-OFq-ObXPk

 

[hannesd]

Went to 1.75 on the a/s and raised the needle 1 position to richen it up. It feels better but still doesnt sound right to me.

https://youtu.be/A-OFq-ObXPk

sounds very rich, but your engine should be warm before judging your jetting.
in the clip it says you have needle at clip #4? why so high/rich?
this is not standard setting.

 

[Jakobi]

What temp and altitude are you running at?

 

[Jakobi]

Went to 1.75 on the a/s and raised the needle 1 position to richen it up. It feels better but still doesnt sound right to me.

https://youtu.be/A-OFq-ObXPk

So rich.. moister than a wet fart at the moment.

As per my last post, what temps, altitude and humidity are you running at?

 

[TGM_OFFROAD]

So rich.. moister than a wet fart at the moment.

As per my last post, what temps, altitude and humidity are you running at?

Where I live is 15 feet above sea level, where I ride 80% of the time is 500 to 2500 feet. Temp was about 60 F with 70% humidity.

 

[Doc Brown]

N1EF needle at #3
175 main jet

.... and main is too rich. It will sputter at WOT.

... and raised the needle 1 position to richen it up.

I admit I am puzzled now. It's to rich at WOT and you raise the needle further? Doesn't make sense to me.
Whatever!

Whats wrong with your dog. Hope its not serious

 

[TGM_OFFROAD]

I admit I am puzzled now. It's to rich at WOT and you raise the needle further? Doesn't make sense to me.
Whatever!

Whats wrong with your dog. Hope its not serious

Just a urinary tract infection, she is ok.

I raised the needle because it had a lean spot round 1/3 throttle and bogged with quick throttle input and still had some detonation. I put the nech needle on #4 and it felt 100% better than the stock needle but seemed to lean still due to detonation when trying to purposely lug up the little hills I have here. I am getting a hold of a new cdi box to plug in next week just to cross that off the list.

 

[Doc Brown]

I listened to the videos again.

First two it blubbers down low as they all do. Thats caused by the NE1F which is very rich down low. It sounds much better through the rev range but I am not sure if that hesitation at WOT is caused by an overly rich mixture. I dont know the sound that good....

I don't want to be a pita and sorry if I annoy you but I think you change too many things at a time. From video 2 I had opened the air screw to 2 turns just to see if the blubber down low gets better. If it does not get much better, DROPPING the needle to clip 2 had been my next step. I am pretty sure that could have cured the blubber down low and the hesitation at WOT (if caused by richness).

Cheers
Doc

PS: your idle seems to be too high. Set it as low as possible, accept that it may stall from time to time. I cant judge the third video....

 

[Doc Brown]

Just a urinary tract infection, she is ok.

I raised the needle because it had a lean spot round 1/3 throttle and bogged with quick throttle input and still had some detonation. I put the nech needle on #4 and it felt 100% better than the stock needle but seemed to lean still due to detonation when trying to purposely lug up the little hills I have here. I am getting a hold of a new cdi box to plug in next week just to cross that off the list.

Glad she'll be fine soon. That's good news. I had dogs myself and I know how hard it can be when they suffer.

Could not hear detonation but I trust your words, no doubt. Its very strange that it detonates with the OEM set up. That really puzzles me as this set up is known to be rich. Maybe the problem is ignition related but if the woodruff key is ok and the flywheel hasn't moved on the crank....and the pick up isn't loose.... I have no idea. Has your CDI been updated. I can remember that we had to bring ours to the dealer who updated them. No clue what has changed...

edit: missed that you used the NECH instead of the NE1F. Is the NECH richer than the NECW? Cant find my notes at the mo.

 

[TGM_OFFROAD]

Glad she'll be fine soon. That's good news. I had dogs myself and I know how hard it can be when they suffer.

Could not hear detonation but I trust your words, no doubt. Its very strange that it detonates with the OEM set up. That really puzzles me as this set up is known to be rich. Maybe the problem is ignition related but if the woodruff key is ok and the flywheel hasn't moved on the crank....and the pick up isn't loose.... I have no idea. Has your CDI been updated. I can remember that we had to bring ours to the dealer who updated them. No clue what has changed...

edit: missed that you used the NECH instead of the NE1F. Is the NECH richer than the NECW? Cant find my notes at the mo.

All the videos after the rebuild were still the stock N1EF. I might take it out tomorrow depending on the weather to actually do some testing. The parking lot test is very limiting. I dont feel like jetting in the rain.

 

[TGM_OFFROAD]

I may be over sensitive due to recent events and think I am hearing detonation when I am not. But the times I heard it were off camera I think.

I dont know if the CDI was ever updated, I tried to find out when I got the bike but the closest dealer was 200 miles away and were not helpful. They also have dropped the Gas Gas line at this point. The guy I bought the bike from had a couple 19 CDI left over from the race team and he is going to give me one to see if it helps.

 

[TGM_OFFROAD]

Took another crack at it today and it looks like the morning is going to be clear tomorrow so I am gonna go out for a quick trail ride. I put my jd jetting blue needle back in and it feels pretty good, a little rich still but will know for sure tomorrow when I can actually open her up and clear it out.

Here is how it sounds. Opinions?

https://youtu.be/ec07rdf4-10

 

[Doc Brown]

I may be over sensitive due to recent events and think I am hearing detonation when I am not. But the times I heard it were off camera I think.

I dont know if the CDI was ever updated, I tried to find out when I got the bike but the closest dealer was 200 miles away and were not helpful. They also have dropped the Gas Gas line at this point. The guy I bought the bike from had a couple 19 CDI left over from the race team and he is going to give me one to see if it helps.

Sounds good to me. I'd try the other CDI without changing anything. Swap them a few times and do a short lap if possible. I am really curious if that will change anything.

Here is how it sounds. Opinions?

https://youtu.be/ec07rdf4-10

Its the first time I can say it sounds perfect. At least at all throttle openings you tried. The engine was not fully warmed, I can hear that it slightly hesitates down low but this is absolutely normal and nothing to worry about. It will disappear when engine and exhaust are hot.

When the bike is ridden with cold or not fully warmed engine the pipe stays cool and gets wet from fuel residue. As long as the pipe is wet and oily you'll hear it splutter a bit but that will go away once it is hot and has been revved.

Yes, riding it hard in shorts on wet tarmac isn't a good idea. Hope your neighbours wont be too upset when you ride around their houses numerous times Good Luck!

 

[Zman]

Once you get the jetting correct you may want to give yourself a little detonation safety margin. You can retard the ignition timing by rotating the stator plate in the same direction that the engine spins. You will get about 1 degree of ignition timing for each 1mm of rotation measured on the circumference (outer diameter) of the stator plate.

That being said, I do not remember if the new bikes allow for ignition timing adjustment.

 

[TGM_OFFROAD]

Once you get the jetting correct you may want to give yourself a little detonation safety margin. You can retard the ignition timing by rotating the stator plate in the same direction that the engine spins. You will get about 1 degree of ignition timing for each 1mm of rotation measured on the circumference (outer diameter) of the stator plate.

That being said, I do not remember if the new bikes allow for ignition timing adjustment.

The 18+ bikes are not adjustable unfortunately