K&N filter and dynojet kit problems

[Tadpole]

when fitting the K&N filter should you take out the snorkel in the airbox? or leave it in?... I've put a quill end can on, dynojet kit and K&N filter.. goes like stink in gears 1-4 but when in 5th & 6th at about 12,ooo rpm it won't pull through. could this be because the snorkel has been removed?



we've had a play around since.. re-balanced the carbs, adjusted the mixture screws and lowered the needles one notch from what dynojet recommend.. As the re-dyno run showed the bike to be running rich up to about 10,000 rpm

We're contemplating cutting the snorkel back a bit to allow that little bit more airflow.. but canot take it out completely as we feel the air flow above 100mph must be pressurising the airbox too much and means the bike won't pull through.

i'd be interested to know from any of you that have tried a few tweeks (k&n, dynojet and end can improvements) and what troubles you may have had, or quick wins..

The bike sounds great by the way... Just it runs a bit rough through the rev range until it's fully on song

I think it's a bit more responsive in the mid range - but on the dyno runs i've only gained from 60.15 to 62.8 hp. the bike was spot on fueling wise before i started,and now it's not as smooth. To be honest i wish i'd never started messing around, butnow the dynojet's in it's too late so we're trying to make the best of things.Tadpole

[jake]

Zimm know of ways to use a k/n, but he aint been on a while. Im pretty sure he said take the snorkel off, as you have already.

Imo, it sounds like things have been done a weird way. If its problems are around 12k, messing with the needles is not the way to go.
Put the standard ones back, or at least put the clip on the leanest (top) on the dj's, you may actually find the standard ones better. Now get your mains right, they wont go up much from standard as you have only put a can on....

[Tadpole]

Cheers for that..

how much time did you spend trying things before it worked itself out?

I take it you have a race can on yours as well then.

We've lowered the needles to the lowest setting but we only placed one washer on top of the needles as not really any space left on the dynojet needles.. it kept falling off.. unless it's worth the 2nd one.
the mixture screws about 2 turns out and carb's balanced..
we've kept with the 96 main jets

did you try the K&N 1st or did you keep the standard filter in? I take it the snorkel stayed in as well then? or did you experiment like i've done, taken it out and had the same problems.. it's around 110mph it started having problems but at lower speeds it sounded better and appeared more powerful..

I'm curious to know from anyone else who's tinkered and found an answer...

[zimm]

is the bike an L or an H

bear in mind the DJ needles are developed for the Uk spec L model, and dont play well with H airboxes or the restricted 30mm carbs.

either way it sounds like the main jets are too small @ #96's, and you may well get better midrange fuelling with your standard needles

if its an L i'd fit #102 mains, and ditch the snorkel

if its an H either #102 mains and ditch the snorkel, or #100 mains and leave the snorkel in place.



I have tried cutting a snorkel down by a third on an H, the bike revved out better, but lost power from 10-11k

[Tadpole]

Cheers Zimm

mine's an old L model - on an H plate - black frame so i guess an l1 or l2

So you have played round with the snorkel - cool

But is that only with the H model?

to get this right - with the #96 jets in and snorkel out my bike pulled like crazy accelerating thru the gears say 2-4 2-5 up till about 105 110 mph and pulled right thru the rev range and into the red... However when doing about 110 say in 5th or 6th the bike just wouldn't want to pull through...

We put the snorkel back in and like my friend who fitted the dynojet kit suggested we lost some of that raw power in the lower gears but the restriction at the top end dissapeared and it does pull through it.. He's of the opinion that if we take say the bottom third off, just above where the snorkel restricts down to two chambers we may find a compramise?

We have had it dyno'd and did query the snorkel idea with them. Problem is they cannot recreate anywhere near the air blast you get at high speeds (as if a type of ram air affect is created) to check the fuelling at the top end.they can only create about 60mph wind max, which doesn't help.

On the dyno it was running rich all below 10,000rpm - so we lowered the needle one notch to try and smooth out the mid range.. The dyno showed fuelling to be ok above 10k but again cannot recreate the air blast effect...

others have suggested putting the standrd filter back in may cure it... But surely a K&N working properly would be better?
Question now is did you have very similar problems to me & is sodid the fitting of 102 main jets cure the problem and make the bike go better through the whole rev range and show it's merits on a dyno run or track

Had the bike apart few times now so trying not to have to fiddle too much more unless we're confident its going to work.

Cheers

[zimm]

sounds like its leaning out at the topend with the snorkel out, and ok up top with it fitted albeit rich in the midrange,

given that its an L, and the kn filter differs to the OE design in that it only draws air from round the edge, obscuring the snorkel to a degree, I'd run without the snorkel, and fit bigger mains, #102's being about right.

Once it'll pull clearly through to the top, start to worry about the needles

I wouldnt worry about modifying the length of the snorkel, it'll mainly change the resonant tuning of the airbox rather than affect the fuel-air ratio

[Tadpole]

Cheers Zimm..

In theory then you feel the K&N is worth persevering with and should make a performance gain.

With the 102 mainjets in - am i likely to have it pull through straight away?

I'm guessing the needles will have to be at there leanest too? which they currently are with the 96jets

We struggled to balance the 2nd washer on top of the dynojet needles when we lowered (meaning 1st position) them so left it with just the one.
A chap named Rich posted a reply on the other forum link suggesting it's worth the effort trying to squeeze the 2nd washer on and i wouldn't regret it..

Do you concur Zimm?

Any chance i could call you tomorrow to discuss matters? As so far it appears you're one of the only members whose had a similar issue and persevred with the K&N set up

If so let me know by text.

Cheers