KR1S needles

[wallcraft]

Evening chaps, has any one had complete success with the N68X needles in their carbs with no 4-6000 splutters? I'm running a 4LO mild tune Ramairs detachable can Allspeeds and a Zeeltronic. Carb set up is 42 pilots JJH needles 152 mains 1-1/4 out on the air screw. Bottom end seems ok as is top end it's just that 4-6000 sputter I can't eliminate wether I raise or lower the clip, I assume the splutter is the effect of running rich with JJH needles, the N68X needle has a thinner taper so as I understand is a richer needle, can't work out how the 68x helps? Or is the splutter a weak mixture in which case the 68x is better? Can't get my my head around it!!!!
Help needed.
Thanks Mark.

[bare]

Clearly It doesn't seem the XXX needles Are better.
JJH needles have worked well on a .. lot.. of bikes previously.
Refit them and try again? I'd refit the Airbox too.. using 130 mains

[nikfubar]

Well I've never been able to get my bikes running cleanly on JJH needles unless they were on the dangerous side of lean & consequently I had a melt down in the cold weather. Fitted the N68X on middle clip & the bikes never run better, I think Headcoats came to the same conclusion aswell Try it & see if they are better

[wallcraft]

Am I right in thinking the 68 needle will run richer than the JJH. Has the mid range splutter gone on your set up Nikfubar?
Thanks for your help gents, anyone else?

[johnlc]

Had no success with the jjh needles switched to n99 needles problem solved , all depends on slide cutaway jjh not suited to 4.0 cutaway slides on my 4l0

[nikfubar]

I thought they were a leaner needle than the JJH I used to have to run them on clip 1 or it would bog down all the time , I run the 68s on middle clip

[wallcraft]

Evening chaps, is this correct: N68X has a thinner taper than the JJH needle, so the 68X will be leaner.
Still struggling!! Going to get on to Allens to order equivalent 68x needles so want to make sure as its getting £££ .
Thanks.

[nikfubar]

Think I may be muddying the waters here but I thought the N68X needles were leaner than The JJH which would make them fatter. I was looking to change to a leaner needle from the JJH which I had to run on clip 1 (leanest) & I was going to get JJJ needles until someone suggested I use the original needles, don't hold me to this but I think the JJJ needles are longer than the JJH but the same profile

Just looked at the 3 PWK28s I've got for my KH build & found two of the slides are 35s and one is 4.0 anyone got a 35 they want to swop

[wallcraft]

I have only 1 N68X needle and I compared it next to the JJH needle. The 68 has got a thinner taper so I understand it as being a richer needle which is why I can't understand why the 68 seems to work better over the JJH.

[bare]

Very strange..
But remember that fitted to KR1 PWKS are an OLD superceeded design/version., and likely have seen a fair bit of use/wear to boot.
Clapped out is a less charitable descriptor.
Which in no small part explains inconsistent results/extraordinary difficulties.
My New PWKS in a IUA, moderately modded: ported, squished, reeded, Zeeled, etc etc.. albeit using the airbox, run rich with JJH needles and 130 mains.
Plugs are milk chocolate brown and a bit oily to boot.
The longer life setup :-) I hope.
Mine has NO stumble /miss or ..any... other palpable misbehaviour, pulling usably strongly from ~3k/3.5k rpms on up.
It ran Perfectly on the First 'suggested' jetting instal. Yipeee!
It also left me with a sizable and apparently redundant investment in 'Genuine' Keihin jets and needles.. purchased for the naively assumed PWK jetting ordeal ahead.
That was /is the beauty of Keihins, they work surprisingly well on a 'close enough' jetting. Smoooth power delivery being their real life signature.
Major! improvement over Mikunis, even brand new ones, should one be daft enough to buy such.
IF not working well.. Easily.. then there really is something Basic.. wrong... In the engine or the carbs themselves.

[nikfubar]

Bare, you are lucky to be able to get new PWKs cheap on your side of the pond, they are fortunes over here which is why we use KR1s ones, but as we end up having to replace all the jets etc they are not too bad even if they are old.

Quote
"I have only 1 N68X needle and I compared it next to the JJH needle. The 68 has got a thinner taper so I understand it as being a richer needle which is why I can't understand why the 68 seems to work better over the JJH."


Yup your right if it's thinner then it's a richer needle, sorry,think I need to butt out of this as I'm just confusing things. All I can tell you is my bike was on pod filters with 42 pilots & 152 mains JJH needles & the only way I could get it to run cleanly was to have the needles on clip 1, it consequently melted the pistons on a very cold March morning. I have now got the N68A needles on middle clip which means I must have a richer mixture & it pulls cleanly throughout the rev range. I had previously tried 150 mains & it was far to lean & 155 mains which were far too rich & it just bogged down throughout the rev range so I think the 152 mains work well but not with the JJH needles

This is what happened when it leaned out, still at least there was no damage to the bores or head on the plus side I could accurately measure the squish at 9K by the squashed ali on the crown of the piston which is 0.8mm

[wallcraft]

nikfubar thanks for your help no need to butt at all much appreciated,just can't get my thick head around these needles!! Dose'nt make sense to use a richer needle(68) to make it run weaker when it's running rich in my case but I'll give it a go, think I going to try the opersite and try a thicker needle as well,
seems logical
Mark.

[wallcraft]

Sept 2, 2013 21:15:21 GMT 1 wallcraft said:

nikfubar thanks for your help no need to butt out at all much appreciated,just can't get my thick head around these needles!! Dose'nt make sense to use a richer needle(68) to make it run weaker when it's running rich in my case but I'll give it a go, think I going to try the opersite and try a thicker needle as well,
seems logical
Mark.

[muttsnuts]

just finished doing a load of work on the dyno with the PWK's and there are a few surprises which gives food for thought.

The pilot jets affect the whole rev range, we proved this by fitting larger 52 pilots over some 48's, this richened the whole bike up across the rev range including when on full throttle, so it is better to work on the assumption that the PWK's have a much finer calibration.

Also, we found that adjusting the air screw has a large affect as well, one full turn out or in, in broad terms adjusts the richness/weakness by about 2/3's of an A/F ratio point, adjusting the air screw by 4 turns out weakened the mixture by 2.5 points on the A/F ratio.

The mains affect the mid to full throttle rev range and therefore a combination of pilots and mains need to be considered.

I have yet to play with needles, but I am running N99 needles and so far have managed to work around any short comings with the profile by adjusting the pilots, mains and air screws. I have some N68's and also some JJH's so will try and have a go with them if time and money allows, but its all very expensive this Dyno lark, I've spent a small fortune recently ...........

[seahorse83]

mutts nuts, nick and blokes, thankyou so much for the past and current info re the PWK's, ihave a new set waiting to go on either a ypvs or a 4lo, still have the original NAPF what came with the carbs but have bought both mains and pilots in preparation., so reading with great interest. Have not committed to buying needles yet, still leaning towards N68x if I can find a set that don't cost drug money. Cheers again guys

[muttsnuts]

hehe, yeah mine did the machine gun impression as well !!

I am running 120 mains and 48 pilots, with N99 needles (clip at the top position) and 1.5 turns out, still running rich at top end (costing approx 2bhp) and weak mid range, so going to 50 pilots and 117.5 mains and see what happens, we know its about 2bhp at the top as it went onto reserve during one of the runs and we hit just under 55bhp !! instead of the 53bhp we where constantly getting

[alext]

Sept 3, 2013 10:52:18 GMT 1 seahorse83 said:

mutts nuts, nick and blokes, thankyou so much for the past and current info re the PWK's, ihave a new set waiting to go on either a ypvs or a 4lo, still have the original NAPF what came with the carbs but have bought both mains and pilots in preparation., so reading with great interest. Have not committed to buying needles yet, still leaning towards N68x if I can find a set that don't cost drug money. Cheers again guys

see when you do find some N68x needles, let me knwo where you got them from.

I cant get them anywhere.....

Im told a KX85 kawa uses this needle (not confirmed this yet) and I cna get rebuild kits with needle from the US, but havent been able to confirm the needle type yet.

My symptoms are almost exaclty the same as yours...it wont run at all well at more than half throttle in the midrange - its OK at partial and full, but not half.

runs great up to about 5.5K then will burp and splutter and miss and generally not be happy...... seems OK once past it at 8.5k+

want to ry a set of N68 needles to see if they are any better...

ALex.

[nikfubar]

Try the KR1s forum, they are standard fitment on their bikes, that's where I picked up my 3 PWKs for my KH build.

[wallcraft]

Going to try Allens sure they can match up very close

[midlifecrisisrd]

What's the difference between 68X and 68A then? Managed to acquire 1 68X and 2 68A

I still have a slight machine gun holding 3 - 5k on tiny throttle openings. Only does it in the warm, not when cold so going to try messing with the air screws.

Strangely going down on the pilots cured my 5.5k stutter/stumble

Still running the JJH needle on mine and pulls clean on all positive throttle openings so don't know if they are better suited when keeping the airbox.

Steve

[wallcraft]

Steve, what pilots-mains-air screw out settings are you runin
Mark

[midlifecrisisrd]

Sept 3, 2013 17:49:05 GMT 1 wallcraft said:

Steve, what pilots-mains-air screw out settings are you runin
Mark

mine uses the ypvs airbox with snorkels out and lid drilled

36 pilots, 140 mains and think airscrew is 1 3/4 turns out. was on 135 mains but a/f at top end was over 13

need to get it done again to check wot top end and steady cruising at 70

mine would not tolerate bigger pilots, tried 42/40/38's and it machine gunned on neutral throttle, progressively better each time i dropped them. will pull full throttle without a stumble from 2k

steve

[bare]

Mine have 40 pilots 130 mains JJH needles (middle clip) and work absolutely perfectly. The thing runs as if Fuel injected.
No missfire /stumble from idle to Rev limiter (now set at 10k instead of it's risky/dumb 10.5k previous setting :-).
Crack the throttle and it pulls smoothly.. not overly strongly just off idle :-) but neither does it Miss OR Stumble at wot during stupidly low revs.
Again either the carbs are clogged (there are a couple of V tiny orifices in the rascals) or otherwise fubar'd OR the later (current) design has markedly improved performance.

As addendum : NON genuine Keihin Jetting bits are ..NOT.. the same as genuine.
Buy cheap= Buy repeatedly.

[wallcraft]

Thanks chaps for all your info and pointers just need to go through the process of trying different set ups, very time consuming as we all know. Hope they are worth it as my mikunis are set up very good!!

Mark