Mid range hesitation

[mbarclay]

im sticking with the stock airbox I put that back on even with the big jets and the needle on the 4th clip and its running great it goes like a raped ape. the ulmer clutch kit and 21 tooth gear pulls very hard out of the hole its hard to keep the skis on the ground. The clutching is dead on. Im going to put the stock jets back in and move the needle back to the 3rd clip and be happy. post up your results when you figure it out, im curious as to what the problem was.

 

[dhkr123]

.... I think I know what it is..............

Springs.
The ones that go on the top of the carb and push the slides down.

You need lighter springs in order for the slides to lift at the appropriate time, opening the needles, and letting the fuel flow.

http://www.holtzmaneng.com/page2.html

 

[mbarclay]

I have holtzman red and silver springs that I tried no luck with either

 

[Stillsmokey]

So my slides came in today, tried dropping the needle(leaning it out) made it worse, raised the needle(clip on 4) and it made it a bit better. Under acceleration it's cleared up, but it's still terrible at 1/4 throttle which seems to be right around cruising speed, if bigger pilot jets dont fix it i'll be going back to stock airbox as well.

 

[dhkr123]

Did you try loosening out the pilot screw yet?

 

[Stillsmokey]

Checked the pilot screws today, they were all 6 turns out. I`m putting a stock airbox on it tomorrow, i`m sick of throwing money at this thing trying to just get it to run right.

 

[dhkr123]

6 turns out??!?!?!!?
There's your problem!
WAY too far out.
Stock is 2.

 

[Stillsmokey]

Fixed the pilot screws to 2 turns out, still no difference. I put the stock airbox on, i'm done messing with it. Works perfect now.

 

[DV8]

You have to change your pilots jets out, go to a 20 or 22, Return the needles to stock position. Set a/f screw to 2 turns with the new pilot jets.

 

[jd0270]

With 165's and a modded air box I couldn't get enough fuel into it in the mid range without plugging some holes... You probably need 170 mains, larger pilots might not hurt either, 2 or 2-1/4 turns out should work.

I tried going back to stock and now have a different problem myself... Feels like I am hitting a limiter of some sort around 6000-7000rpm I am thinking I may have damaged the TPS? Is there such a thing as a knock sensor on these engines(senses detonation/retards timing ect?)

 

[DV8]

The pilot jet does supply fuel during part of the mid range, you will have hesitation and possible rpm limit if pilots are plugged. or too small.
When you say you put it back to stock? all jets, and needle settings? stock air box?

TPS sensor, did you remove it or just unplug it from the harness?

 

[Stillsmokey]

Back to stock, stock jets, needles on 3, stock springs, stock airbox, runs excellent and notice no loss of power over the K&N setup.

 

[DV8]

What octane gas are you running?

What does it do when you reach 6-7000 rpm, just doesnt rev or starts to miss? backfire?

 

[Sled Dog]

I am running my airbox mod and have run the k&n's as well with 165 mains then went to 170's without touching the pilots or the springs with no hesitation at all. Fuel screws set at two turns out. I am thinking of going to 20's for the pilots just to try it with two turns out on the screws.