Low idle issue..Round 2

[SXIPro]

2004 SJ, freestyle ported 701,b-pipe, ada head...etc. Stock 38s which were rejetted when b-pipe was added, stock flame arrestors, premium gas.

Mid-range and Top end rips. Rips immediately when I grab a bunch of throttle regardless of what RPM I am at when I squeeze. So, that's all cool. But if I am tooling around slowly, making set up wakes for instance, it idles rough and kinda sounds crappy. It doesn't hesitate, and doesn't stall, but 'sounds' like it wants to. Just not a nice flat feel/sound to it. It seems even worse as of late.

It has been really hot and humid lately, could that add to the issue?

I have not touched it yet. I am gonna change plugs, check any external fuel filters and possibly mess with my low speed adjusters. I can't imagine I would need to rejet or change N&S since up to this point it has been pretty much ok. I am not saying it ever ran perfectly down real low but don't know if a 701 with these mods actually can run completely smooth/flat since this is the only one I have ridden.

Like I said, once I am past 1/4 throttle, it runs like a dream, below that, not so much.

Suggestions?

 

[Mark44]

Read through this thread and others that are posted in it before you start turning mixture screws. I would also suggest reading the Mikuni manual for a good starting point.

http://www.x-h2o.com/threads/39688

Mark44

 

[Rickster]

Read through this thread and others that are posted in it before you start turning mixture screws. I would also suggest reading the Mikuni manual for a good starting point.

http://www.x-h2o.com/threads/39688

Mark44

Do you have a restrictor running in the cooling line to the stinger? Too wet of a waterbox will give you a sluggish bottom end.

Don't ask how I know.
:dunce:
:smashfreakB:

 

[SXIPro]

Do you have a restrictor running in the cooling line to the stinger? Too wet of a waterbox will give you a sluggish bottom end.

Don't ask how I know.
:dunce:
:smashfreakB:

I've got a pro series Jetworks valve, but have it set at how it came from the factory. Maybe I should crank it a bit?

Oh, and how do you know? :swordfight:

 

[Mouthfulloflake]

alot of things will give you a sluggish bottom end.

too much water in the pipe, is one thing that ive been fighting ( and still trying to beat)

 

[Superjet3]

If it is running good and has good throttle response throughout then I wouldent worry about it. How low are you talking when it is running rough? Idle? If so try raising the idle a little bit.

 

[Rickster]

I've got a pro series Jetworks valve, but have it set at how it came from the factory. Maybe I should crank it a bit?

Oh, and how do you know? :swordfight:

I have a Jetworks valve on mine also, but the factory setting had way too low of a pop off for my engine.

I raised the pop-off significantly, and the low end throttle response is now there.

:Thinkingof_:

 

[SXIPro]

If it is running good and has good throttle response throughout then I wouldent worry about it. How low are you talking when it is running rough? Idle? If so try raising the idle a little bit.

Above idle, enough throttle to stand. Pretty much like if you were trying to go through a no-wake zone as slow as possible while still standing. So just putt-putting around. Probably at 1/8-1/4 throttle.

I am with you though, on not messing with it. It doesn't stumble, hesitate, or bog it just basically idles rough at that speed I guess.

I'll do the simple things first. Plugs, check for a crappy filter, maybe play with the Jetworks valve.

I fear messing with carb settings and making things worse, especially where it runs so well in the throttle positions that are important to me.

 

[Ericfox]

it might be something to do with your pipe... I think there is something like a spot right before the pipe "kicks on" that the engine will not sound quite as good... maybe?

 

[Mouthfulloflake]

if you rapidly, work the throttle back and forth, does it clean up and get crisp for a second?

also..

can you idle like that for 60 seconds or so, and then floor it, what does it do? immedialty go or hesitate?

Above idle, enough throttle to stand. Pretty much like if you were trying to go through a no-wake zone as slow as possible while still standing. So just putt-putting around. Probably at 1/8-1/4 throttle.

I am with you though, on not messing with it. It doesn't stumble, hesitate, or bog it just basically idles rough at that speed I guess.

I'll do the simple things first. Plugs, check for a crappy filter, maybe play with the Jetworks valve.

I fear messing with carb settings and making things worse, especially where it runs so well in the throttle positions that are important to me.

 

[SXIPro]

if you rapidly, work the throttle back and forth, does it clean up and get crisp for a second?

also..

can you idle like that for 60 seconds or so, and then floor it, what does it do? immedialty go or hesitate?

A) Never tried it

B)This ski hardly ever hesitates. Once in a great while if I do a WOT run and then shut it down immediately. Then when I re-start and go to take off it will hesitate for a few seconds until I get it rippin again. So, maybe once a month.(since I don't make a habit of doing WOT runs and shutting down) But in your scenario, it doesn't bog.

BUT, I will try out both when I get home to be sure and will report back, as long as the thunderstorms hold off.

 

[SXIPro]

Update

A) Never tried it

B)This ski hardly ever hesitates. Once in a great while if I do a WOT run and then shut it down immediately. Then when I re-start and go to take off it will hesitate for a few seconds until I get it rippin again. So, maybe once a month.(since I don't make a habit of doing WOT runs and shutting down) But in your scenario, it doesn't bog.

BUT, I will try out both when I get home to be sure and will report back, as long as the thunderstorms hold off.

A) didn't change anything
B) No hesitation.

Couple things I am concerned about though. My Jetworks Valve even after adjusting it a bunch of ways, just barely dribbles once it finally opens up no matter how much I rev it. I wonder if I should put a restricior in the line to the pisser (which comes off the same T that the FCV is plumbed into) in order to direct more pressure to the FCV?????

Also, my stock airbox was originally 'modified' in order to fit with the ADA girdled head. The previous owner had covered up the gaping hole that was left with some biaxial. Apparently epoxy resin does not adhere permanently to a plastic airbox....Looks like I need to try another redneck way to close this thing up.

 

[Ericfox]

A) didn't change anything
B) No hesitation.

Couple things I am concerned about though. My Jetworks Valve even after adjusting it a bunch of ways, just barely dribbles once it finally opens up no matter how much I rev it. I wonder if I should put a restricior in the line to the pisser (which comes off the same T that the FCV is plumbed into) in order to direct more pressure to the FCV?????

Also, my stock airbox was originally 'modified' in order to fit with the ADA girdled head. The previous owner had covered up the gaping hole that was left with some biaxial. Apparently epoxy resin does not adhere permanently to a plastic airbox....Looks like I need to try another redneck way to close this thing up.

I put a restrictor in the line on mine... I think about everyone does.... gives the other line a bit more pressure... I tuned mine to start to dribble at about like 2800rpm or something like that....

 

[Mouthfulloflake]

I put the restrictor right before the stinger.

when the FCV is open there is a good stream of water from the bypass, and very little getting into the water box.