needles

mike brannon · Posted: Thu Aug 03, 2006 5:51 am Post subject: needles

whats the difference in the k22,k27,k98 which one to use? and why and when?...thanks for any help...mike

Janne Rsn · Joined: 31 Jul 2006 Posts: 24

well here is my theory how i have understood it...

k98 is a bigger needle and allows less fuel to enter, and k27 are smaller and allows more fuel to enter... So, i think k98 lets you go a bit leaner and k27 allows you go a bit richer!

What i have heard, that k98.. is better..

Tom Barth · Posted: Thu Aug 03, 2006 5:31 pm Post subject:

Yes, the K98 is larger at the A dimension (2.52mm or straight section) and takes up more area in the atomizer tube compared to the K27 (2.50mm). The A section of the needle affects throttle opening from idle to about 1/4 of total. This is where acceleration is happening. Switch to the K27 and the and now the space between the tube and needle increases by .02mm, richer.

But the K27 has 44mm taper length compared to the 41mm length of the K98. This means that when the throttle is opened with the K27 installed the fuel gets to the venturi sooner, also richer. Sooner, richer - later, leaner.

Both C dimensions (tip) are 1.80mm so wide open throttle jetting is the same for both needles with the same main jet.

http://greenflag.net/dell/delneedle.html
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Tom Barth
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Andy Seesemann · Joined: 16 Jul 2001 Posts: 3187

Excellent explanation, Tom.

This is how I explain it to a average karter.....

When we ran the K27, we always seemed to run the clip in the top setting (leanest) and wished that we could go higher.

When we run the K98, we get more range, as we run the clip further down the needle (richer) to have the same throttle response as the K27.

So, the K98 simply gives us more range. Its easier to put this in, instead of trying to figure out how to make a K27 needle have 7 clip notches.

A
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Joey Gennari · Posted: Thu Aug 03, 2006 6:10 pm Post subject:

Jim Holland · Posted: Thu Aug 03, 2006 6:15 pm Post subject:

So true -

Tim Megenbier · Joined: 25 Jul 2001 Posts: 572

Well you could just....Ah, no that will just get me in trouble, but then....forget it.

Joey Gennari · Posted: Thu Aug 03, 2006 8:15 pm Post subject:

Ahhh ... the real reason your hand was trembling?

It's funny how many contradicting quotes I've heard about the needle change:

"The K98 is so much better off the bottom."
"I'd never run the K98 in the Sr. MAX motor."

"The K27 just never ran in the MiniMAX."
"I never ran anything but the K27 in the MiniMAX."

(I'll only admit to two of those quotes.)
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