wont idle, bad piston rings?

[caveman]

I recently traded my dual sport for a couple blasters, pretty stoked.

One of them wont idle, the guy i bought it from said he thinks its cause it has bad rings.

Im not completely sold on that since it starts right up and runs fine.

My first step after reading on here was to order a carburetor cap kit eliminator thing.

It hasnt arrived yet but when it does i will install it and see if that fixes the idle.

My question is, on a two stroke will bad rings really cause any problems with the idle?

Any help is greatly appreciated, i look foreword to learning a lot more on this forum.

If anyone lives in the black hills of SD give me a shout we should go riding I:I.

 

[Luni]

Well, yeah, if the rings are toast on a 2 stroke it WILL cause issues with the idle, HOWEVER, it will also cause issues with it starting up.

If it has enough compression to start right up, then I personally dont think your rings are the problem. I think you need to play with the carbs idle circuit.

What carb is on it? What kind of modifications are done to it as far as you know? Do you have to choke it when the engine is cold to get it to start (you SHOULD have to).

 

[caveman]

Well, yeah, if the rings are toast on a 2 stroke it WILL cause issues with the idle, HOWEVER, it will also cause issues with it starting up.

If it has enough compression to start right up, then I personally dont think your rings are the problem. I think you need to play with the carbs idle circuit.

What carb is on it? What kind of modifications are done to it as far as you know? Do you have to choke it when the engine is cold to get it to start (you SHOULD have to).

Its a banshee carb but they are the same as far as understand. the idle circuit? are you saying that these carbs have some sort of electrical tied into them?

The choke doesnt really like to stay on so its hard to say if it needs the choke or not.

 

[Zwiser]

Try to turn your idle up with the idle screw, does it idle after its warmed up?

 

[Luni]

No, theres no "circuit" on it other than the TORS system, but if TORS was causing issues, Im not sure if it would even start. Im referring to the section inside the carb thats responsible for idling the quad, the pilot circuit. Part of the pilot circuit is an air bypass screw that allows even more air into the pilot circuit to help the engine idle.

Ive never had to mess with TORS, mine was bypassed when I bought my bike.

But your carb DOES have an idle screw on it. Try screwing it all the way out, and try it all the way in.

Could just be a dirty carb assembly too. Have you torn the carb apart and cleaned it all out?

 

[caveman]

its kind of all over the place really, it needs to be featherd or it will die, but then if your riding around sometimes it will idle really high like the throttle is tuck, which leads me to believe its a air leak. I just dont know anything about two strokes so my main concern was weather or not the rings would cause problems with idle.

I am going to dive into it next week after finals are over, clean the carb out, install the cap eliminator thing ect. If i still have idle problems after that i guess i will just replace the piston rings.

 

[Luni]

Well, I just told you, if it cold starts just fine, but you cant get it to idle properly its NOT your rings.

Im not saying this to have you NOT replace your rings, cause maybe yours are kinda tired and needing replaced, but Im saying this cause youll do it, and it will still have problems cause you avoided the issue in the first place.

You have an airleak, or an issue with your carb circuit. You need to fix that. It isnt your rings. It could be something as stupid as a clogged up air filter. It could be a loose coupler from the airbox to the carb. It could be a hole in the rubber tube between the airbox and the carb. It could be a clogged pilot jet. It could be a problem with your reedcage even.

What Id do if this was my quad is before I rode it and caused even more damage, Id do a compression test. That right there will tell you if you need rings. Once I did that, if I could, Id do a leak-down test. That will tell you if you have a seal in the crankcase going bad. If you do, it will create an airleak and cause problems. Id also pull the carb off, clean the outside with some brake cleaner and compressed air, and Id take it apart. Id remove the jets, clean all the passages out, etc. Id check the float level (you can search on here how to check and adjust the float level), etc. Id go through the carb. Id inspect the rubber passage from the airbox to the carb. Id check for leaks, cracking, failed clamp. Id pull the intake manifold off (the rubber thing the carb connects to on the engine side), and check THAT for any cracks, failed metal coupler etc. Id pull the reedcage out and inspect them all and make sure the petals are closing like they should. Make sure theyre not cracked.

Theres a lot you can do to it to test, that wont cost you any money. If you want to just throw money and parts at it, be my guest, its your wallet, but usually idle issues are caused stuff other than rings (again, assuming the bike starts up just fine and runs if you give it gas).

Most of the time, if your rings are shot, you cant get it to kickstart. You have to pullstart it with another quad or a car to get it to run, and it will ONLY run if you hold the throttle. It wont change, it wont surge, it just wont idle.

Your description of the issue doesnt sound like that at all. I dont think its your rings.

 

[caveman]

Ok, well sounds good. I was planning on doing all of those things except for the leak down test.

I will have to look more up on that. But yeah i am planning on pulling everything apart and cleaning the carb out, checking for any leaks in the intakes, compression test ect.

Thanks for the help i really appreciate it. Like i said this is the first two stroke i have worked on.

 

[Paulie B]

Do a compression test that will positivly rule out the rings or not.
A banshee carb doesn't have an idle speed adjustment just an air screw.

 

[Luni]

The air screw will adjust the idle. The air screw is part of the pilot circuit. The pilot circuit is pretty much responsible for idle.