Nytro rtx idleing problem....

[YAMAHOWIE]

Trying to help out a friend with a Nytro rtx. Cold start, idles fine, no issues. once warmed up seems like its running on 2-cylinders at idle. if you bring it up around 3000 rpm it clears out and runs fine. Trail riding is fine as long as you keep the speed up. once you slow down it drops back down to 2-cylinders again. I'm thinking there may be a partially clogged injector. I pulled the plugs and they looked fine. I replaced them anyway. Didn't help..... any ideas ???
Thanks, Howie

 

[mike3577]

Try some seafoam or some type of injector cleaner,might just be a bad injector,or coil,plug cap?sorry not much help,look in the electrical section someone may have had this same problem,i would say coil since it does it when warm and at low rpm

 

[canoehead]

When it's acting up pull the coils off one by one and see what cylinder it is. You can then swap the coils around to see if it's a coil or injector.

 

[sorenson1610]

Might as well check the plugs too

 

[YAMAHOWIE]

Thanks for the tips ! I'll try checking the coils tomorrow

 

[grizztracks]

Any codes being displayed? The idle speed control valve (ISC) may be malfunctioning. You could try running the diagnostics to see if it picks up a problem. http://www.ty4stroke.com/viewtopic.php?t=83992

 

[westbaycustoms]

do a cylinder leak down test or what ever you call compressed air down the spark plug hole , i know of a nytro that would not idle very good, sled had great power , leak down test showed couple leaking valves, once valves where re shimmed, it idled just fine, sure there are many more common causes for your problem but if all else fails

 

[YAMAHOWIE]

No codes being displayed. I determined its the center cylinder thats missing at warm idle. I switched the coils around and it made no difference so the coilpacks seem ok. It idles perfectly at cold start. after 4-5 minutes when the idle steps down it starts to miss. raising the idle when warm does not help. Raising the rpm's to 20-30 mph on the stand and it runs fine. Still thinking clogged injector ??....