1/8 to 1/4 Throttle weirdness

[KB112]

Running the PV flush cleans up the bottom end on my 250RR. Snappier and cleaner just off throttle. Makes logs and step ups easier with little run up. This is with the NEDW clip 3, 168, 38, 1.5 on the AS.

The power valve stays closed at low rpm regardless of the screw setting. Your screw setting should come into play around 4500 rpm.

[aj_mariner]

Running the PV flush cleans up the bottom end on my 250RR. Snappier and cleaner just off throttle. Makes logs and step ups easier with little run up. This is with the NEDW clip 3, 168, 38, 1.5 on the AS.

The power valve stays closed at low rpm regardless of the screw setting. Your screw setting should come into play around 4500 rpm.

Are you referring to the 2015 JD dyno?

[NW_250RR]

Running the PV flush cleans up the bottom end on my 250RR. Snappier and cleaner just off throttle. Makes logs and step ups easier with little run up. This is with the NEDW clip 3, 168, 38, 1.5 on the AS.

The power valve stays closed at low rpm regardless of the screw setting. Your screw setting should come into play around 4500 rpm.

OP is referring to 1/8 to 1/4 throttle. My intentions were to too (may of confused that with stating "just off throttle"). PV flush makes the transition onto the pipe almost instant under throttle. Less hit, cleaner response, smoother power. Basically feels like I'm right on the pipe.

[hawaiidirtrider]

You might be chasing ghosts here... especially if you are talking first 5 minutes in warm up. Spooge means nothing. Bike warms up and it runs good right?? So why try to jet for a cold bike in the first 5 minutes?? Unless Im reading this wrong.

[hawaiidirtrider]

This pet peeve of mine has been rearing its ugly head every now and again...still.

The best way to describe it is a “lean spot” because it sounds like the engine is trying to combust but it’s not a clean sound. It happens on warm up, which is choke on at idle for 10seconds then hopping on the bike and going slow in 2nd or 3rd for 5 minutes. As soon as giving her more throttle (possibly power valve opening point) it’s like a tat-tat-tat sound in the same throttle range. I’ll run it just at the lower edge of this range and it will clean up and no longer make the sound.

I used to think it was carb related because it seemed to improve when switching from NEDx to NECx. But after a day of lazy slow exploratory riding clicking between first and second, it happened when getting back on the road and opening her up. If I’m feeling good and have a trail where I’m clicking between 2nd and 3rd gear then it doesn’t happen.

So now I’m back to thinking that I was not working the engine hard enough to keep the sparky hot and clean, but that should be fixable through jetting. Just a note, there was a small streak of spooge maybe half an inch down the silencer end cap. Any other ideas out there??

[hawaiidirtrider]

You have the choke on too!! Of course it’s not going to run right.you don’t jet your bike with the choke on. Try not using the choke at all. I don’t.

[aj_mariner]

I was trying to describe or place the sound the bike made in the throttle range after a slower luggy trail ride with the same sound that happens during warmup in the same throttle range. Of course the bike is going to run different when cold, not trying to fix that. Just making notes as I go. Sorry if it isn’t concise.

[NW_250RR]

I was trying to describe or place the sound the bike made in the throttle range after a slower luggy trail ride with the same sound that happens during warmup in the same throttle range. Of course the bike is going to run different when cold, not trying to fix that. Just making notes as I go. Sorry if it isn’t concise.

Adam,

It sounds like you are describing a loaded up bike after riding at slow tech speeds for a while.

[aj_mariner]

I agree...but it is pretty wild that I could make it do the same thing on the N2ZJ with a hot engine

[dirtbird]

Is this what the slide mod is supposed to correct?

Maybe but don't rush with it.
I did this to mine...



... and after a small test ride around home, I think that some snap down low has been lost. But I use also an S3 head and a STIC, so maybe I have to ask Kels his opinion.

And maybe I have grind more than what I should be...

How do like the Stic?

It definitely increases hp but jetting around it it's not easy. The HC head has helped a lot but I still get some pipe bangs (which is not normal with the Beta engine). Initially I jetted according to their guidelines and it was very rich.
I have not contacted the inventor for extra set up help and have not done much riding this year so perhaps I can improve it.
Bottom line is yes it gives extra oomph and makes the bike more fun on open spaces or long uphills but I am not so sure that it is needed for tight single paths (I guess a 200 would be the answer).