Jet Needles

[sicivicdude]

I need experienced tuner knowledge.

I'm looking at looking purchasing new needles for my OKO 30 mil. I'm fat on the bottom end...I need a larger diameter needle. How much difference does .01 mm in diameter make? I don't want to buy a bunch of needles I don't need, at $5 each. Up to about 1/8 throttle, it sputters. I want to fix it by replacing the needle.

 

[brandoz28]

up to 1/8th throttle is pilot jetting

 

[sicivicdude]

I've played with pilot already... My idle is best right now with a 48 pilot and my air screw 1 1/2 turns out (which indicates my pilot jet is perfect) but I still have a little bit of sputter as I take off. I'm pretty well certain that I need a larger diameter needle to fix the trouble I have, I just need to know how much change .010mm is in AFR.

 

[Surfrjag]

go to a bigger pilot and about 2 turns out and save yourself some money on a needle. when i ran my oko i was at a 58 pilot to get it to idle right and not bog on throttle

 

[sicivicdude]

I'm rich on the bottom end. A bigger pilot isn't going to solve the problem.

I tried a smaller pilot and ended up with a hanging idle with the air needle about a half turn out.

If I raise the needle it sputters worse, if I lower the needle it surges...

 

[sicivicdude]

Considering the outpouring of knowledge of this post, I think I'm going to order two smaller needle diameters with the same taper and length and see how it goes.

I'll report back on the difference .01mm in diameter makes!

 

[sicivicdude]

Alright, I order a HFK, HKK, HKL, and a JFL. Two first two are .01mm larger but two different lengths with the same taper. The next one is .02mm larger and a little longer with the same taper. The 4th is .02mm larger with the same length but a little steeper taper.

I'll report back when they arrive (3-5 business days) and see how they do.

 

[slickerthanyou]

I will definitely subscribe to this thread, I was curious on what a needle change will do, to these OKO's

 

[sicivicdude]

Well I just want to get the damn thing right... if I help someone else out in the process GREAT!

I have splooge all down the front of my engine and it sputters something fierce until I reach about 1/4 throttle if I roll on it slowly. I know I'm rich and I know the needle is the culprit. Now to find out which needle makes my problem better...

 

[sicivicdude]

Ok, JETSRUS apparently means JETSonlyRUS

I ordered 4 needles apparently none of which they have in stock. I sent an email to see about the status because I heard nothing back from them after the paypal confirmation cleared...

One of my needles (the HKL) was discontinued. One of them the supplier is out of (the HFK) and they can't get for sometime apparently... personally I would have got that particular information out a little quicker than a week and a half later but minor details.

I'm going to see about getting a LGL instead of the HKL. Maybe the steeper taper with the larger diameter might be the trick.

 

[royalt67]

I ordered direct from www.sudco.com, the westcoast supplier of Keihin, and got some needles in about 4 days. The guy on the phone even suggested I get a couple needle clips cuz you know how screwed you would be if you dropped one and couldn't find it. Helpful and knowledgeable.

I see you are on the east coast, you might try CPW, they are the east coast supplier. Keihin Offroad Carburetors

 

[sicivicdude]

I looked at carbparts.com and couldn't find their needle chart so I didn't order from them.

Oh well, if the part is backordered nobody will be able to get it no matter who I order it from. I'm just going to wait until the stuff arrives and then play with jetting some more.

 

[sicivicdude]

I can't talk too much crap, the man is diligent... I received an email at 10:15 listing all of the needles he had in stock for it (apparently I just picked the wrong few) and I settled on a replacement. So I'm getting three of the ones I ordered originally (the JFL, HKK and HFK) and one different one (a JJL).

I sent him a reply at around 10:30 telling him of my decision about the substitution.

He just printed a shipping label!

 

[slickerthanyou]

I looked at carbparts.com and couldn't find their needle chart so I didn't order from them.

Oh well, if the part is backordered nobody will be able to get it no matter who I order it from. I'm just going to wait until the stuff arrives and then play with jetting some more.

There site is about useless, but if you call them, they know their stuff and will hook ya up! Future reference!

 

[sicivicdude]

Their site isn't about useless, it is useless...

I couldn't find anything what I was looking for so I went elsewhere. Maybe they should throw a couple of bucks at a professional webstie designer. Might make them a few more sales...

Anyway slick, I'm going to have a few needles laying around when I'm all done dialing in my carburetor. I should also have a good firm idea of how much needle diameter, taper and length affect the middle jetting. Want a BF hookup?

 

[slickerthanyou]

Fo sho! I have a stumble that I can't seem to get rid of when at about 1/8 to little over 1/4. And also when you are coming to a stop> I have tried I swear 20 different combo's of pilots/needle positions including air screw positions and it will not go away. from leaner to super rich, just can't get it to disappear so i'm thinking a diffenet needle but i really don't have enough Knowledge to figure out what taper, length, Ect. So I'm tryin to learn from what you do. I feel stupid and do not want to waste another build!-Bob

 

[sicivicdude]

That's exactly my problem... from a little over idle up to just under 1/4 throttle it sputters until BAM! it takes off and the front tires leave the ground. I know it's rich, I've got tons of splooge if I ride it around the yard in the "bad" throttle range. I'm going to try and get a handle on how MUCH difference needle changes make to be able to give you an idea of how much change you'll need (and possibly the needle if it's one of the ones I got)

 

[super noober]

im staying tuned also I:I

 

[sicivicdude]

Noobs, I thought I heard a little stumble in yours at low speed in your video of cruising around busco. Do you have a little stumbling at low throttle?

 

[slickerthanyou]

I'm actually up to a 175 main, the 172 was a hair less than mocha brow and this 175 is nice dark brown almost black( perfect for me) and 60 pilot, air srew is best at 2 1/4turns, if I drop the pilot 2 sizes I still have an air screw at 2+ turns. if i drop it 2 more sizes i can get to 2 turns out but then the surging starts and doesn't matter what needle position it will surge. I was told that is a lean condition. I'm afraid of destroying sh*t again. I will not and cannot do another rebuild this year or the next.