RS Nytro 'flutter'

[4strokelover87]

A friend of mine has a RS Nytro, and it's not running quite right at idle...it has a little 'flutter', or 'hiccup' every few seconds. It's almost like a momentary miss on one cylinder. We have been through the carbs, new plugs, swapped coils, and I just replaced the exhaust dognuts last night, which weren't too bad, but I did them anyway to make sure...same thing. Any other ideas on what this could be?? It seems like once you take off it's fine, or atleast it isn't really noticeable, but when it's sitting here idling, it sputters around some. I'm at a loss as to what else to look for!!!

 

[theCATman]

Try jetting the pilots up to #50's

They are so lean to meet emissions it's scary.

 

[Angus viper]

sync the carbs.

 

[4strokelover87]

sync the carbs.

Did that too...spot on!! It's really got me stumped... I haven't looked into changing the pilot jets yet...

 

[Metallicat]

Do the carbs have accessable fuel screws or are they plugged like mine? I read somewhere that the pre-2008 carbed engines had accessable screws. You could try adjusting them. 2 turns out is what I read but do some research to be certain. You might want to try the larger pilot jets as suggested. Mine wouldn't idle correct with them but others have had success.

 

[4strokelover87]

I believe the fuel screws are plugged...I'm not sure I've seen any 3-cylinder carbs that aren't plugged really. I may try the other pilot jets and just see if that will do it if it's worked for some. So Metallicat, you just live with yours idling like that??

 

[Metallicat]

Mine idles good with the stock pilot jets once it is warmed up. I think maybe only the 2005 models came with accessable fuel screws, now that I think about it.

 

[jlparker77]

My 05 has accessible screws... but, i've not checked, but my guess is if they are capped, then they did it for emissions so the customer can't change anything. However, they've been doing that on bikes for a long, long time. and on every carb that they updated with a plugged screw, you can just drill it out, and the same screw is then accessible.

 

[lucky1]

My 06 Rage did this...burnt an exhaust valve. Do a compression test and it will show it. Mine had a valve clearance that was too tight...burnt the valve. This was at 12k miles. Fixed it myself...has never run better.

 

[fastdave]

So 4strokelover, did you check compression? The reason I'm asking is my 07 Vector GT does the same thing. That little miss about every 20 seconds or so. Seems to run fine otherwise. I only have 5700 miles on it. I have 2 strokes that have more miles than that, that don't need any engine work yet.