nytro stumble

[nate007]

What do you mean by a dripping injector?

 

[mnmt_c08]

Well, when the injector doesn't close all the way, a little extra fuel comes out. I've been talking with Mark Leipiteimer(spelling??) (USA distributor of MCX) He has seen this before.... but not very much. I need to still pull the injectors out of the intercooler (for the turbo system) and watch the spray patterns for them. or to see if the leak a little after suppose to be closed. also on the top end, when I get done pulling a long line, after I drop the throttle it seems like it floods out the motor. Hold the throttle wide open, clear it out. then runs fine. also steering me into a dripping injector (or a not closing injector)...

Other systems are fine. I know i've got a great, strong spark. Great compression. Good fuel pressures. New plugs, fuel filter.... Checked the mapping with the mcx fuel systems, kinda been eliminating the easy stuff.

I was just putting out the "feelers" to see if other people have seen it.

 

[nate007]

I was thinking that's what you were talking about.
I've found some good references regarding injectors and this sort of issue, if I can find the link to it again I'll post it up. It went into the description of how they're made, how they operate and the different ways they fail, etc. Sounds like if there is an issue with them, as far as flow, etc, the best thing to do is to have a fuel injection shop clean them. Over the counter stuff doesn't work very well.
Do you run a separate regulator on your boost injectors? Depending on how your programmer runs them, you could try a later-but-steeper curve for your supplemental injection, or have the fuel pressure come up slower for those as well.
Not sure how your system it's built, but that's just a shot in the dark anyways..

 

[Nytro Nasty]

Mine had slight stumble before and after exhaust was added. This my first 4 stroke sled. Few years back I made the switch in Moto from 2-4 stroke. 2 stroke tachs up quicker with less hesitation and is typical of motor characheristics of the 2 stroke vs 4 stroke. Once I saw that in motocross bikes the switch for sleds was easier to do and easier to understand. Still a bit foreign but getting all dialed in and learning lots fast!

 

[Nytro Nasty]

I never gave it a second thought based on my bike findings and just accepted it. I figure eventually I will be able to work around it or make it a little less but doesn't bother me once I learned a little different throttle English with this old girl!