Just changed to a K&N filter in my stock 2003 superhawk and it is sluggish and sputters in takeoff and when in lower rpm's. Any advice?

 

just a wild guess. put the original filter back and see what happens.

 

I was about to start my search on this too.
I got mine stock and it ran OK
Seafoamed it and got crap in the carbs and it didn't run
Cleaned carbs and installed a K&N and it ran kinda like you describe.
Installed a DynoJet Jet kit set for K&N and high flow pipes and it ran well, no hick-ups.
Installed Yoshi Pipes and it still runs well with the exception of very little throttle low down in the rev range where it hesitates a little (plus a fair bit of popping on deceleration)

Much as the SH intruiges me, this is why I love the Power Commander III's on my other 3 bikes.

 

Lots of information on this forum about K&N filters and Superhawks. Not a good combo.

 

Nah, your other three bikes are too slow

Searching through the site will tell you that general consensus is that the K&N for the Superhawk is rubbish. Many have tried and few have got it to work as successfully as the stock filter. This goes for us "seat of the pants" types as well as those on a dyno.

So, ditch the filter, perhaps go though 8542Hawk's "carb setup" thread. As a side note my (ex)mechanic pretty much scolded me for putting the stock filter back in and not using a jet kit, even after I explained the online research and uniqueness of people's suggestions on this particular bike.

 

I've got a K&N filter and a Micron (not for road use) exhaust + a dynojet and have seen an improvement. Sounds like you need to some carb fettling and dyno time to get it running right. Fitting a K&N isn't a necessarily a 'plug-'n-play' mod esp if you have made other changes.

 

There are a couple things you need to do to get it to run right.

#1, Jet kit.
#2, Remove the air damn on the top half of the air box.
#3, Carb Synch, and fiddle with it a little.


I have a '98. It has a K&N, Jardine High Mounts, and I think an ign advancer. It runs fine. Power everywhere from about 3k all the way to the rev limiter.

 

 

Yep

 

Not to put too finer point on this but I have run K&N filters on almost all of the 10 bikes I have had in the last few years and they work great. Has anybody actually tied to work out what the problem is. Do they flow too well? To they disturb the airflow in a certain way that could be improved by adding a baffle etc. ?

Doing some reading, I wonder if this problem would have been solved if the SH had some sort of accelerator pump in it's carbs.

 

Nope. Everyone just put it in and it didn't run correctly right away so they just gave up. No one in 13 years tried to make it work

But for reals, plenty have tried, all of us wondering why the hell a "better" aftermarket filter worked worse than the stock one. Plenty of people on here have tried to make it work on a dyno (and tuned with jet kits)... types who wouldn't take no for an answer. Tweety, Mikster, 8541Hawk, all people who know this bike better than general motorcycle mechanics don't run the K&N. Speaking of that, my mechanic scolded me for taking mine out; I did try to run it for awhile, but the stock felt better and the info on here confirmed what I suspected.

It seems that the K&N either runs too lean in the top end, or WAY to rich in the low end, depending on which side you tune it for. Also, the lack of an air dam messes with the airflow (this can be fixed by making your own though... which I also tried). In certain racing conditions you could tune it for the top end, but sacrifice street ridability.


Airbox lid= On
K&N= Trash

 

I have a K&N filter in my 98 Superhawk and it runs great, although it wouldn't surprise me it it's running a bit rich (based on my gas mileage).

It came that way when I bought it, and I'm adhering to the "if it ain't broke don't fix it" principle. It came with Yoshimura pipes, the K&N filter, and according to a dyno printout from the previous owner the main jets are 188 and 192.

Max power: 106.1 hp, max torque: 70.1. According to the before and after figures, that's not much more than before the filter and rejetting, but the torque curve is much more level and hits close to 60 lbs much earlier than it did before.

 

Well to be clear, my 2003 has:
RS3 Yoshis on a stock header
Freshly cleaned and oiled K&N
a DynoJet kit set per instructions for high flow air filter and muffler.
(Holes drilled in slides, 190 Front & 195 Rear Jet and needle set on groove #5 from the top)
I'm 600 ft above sea level, running on 87 octane fuel and it's not cold here.
I haven't messed with the mixture screw at all. The bike starts easily, doesn't require much if any choke and seems to run just fine across the rev range with the small exception of when I apply a small amount of throttle at low revs. Then it hick-ups a little. Last tank which was a mixture of before and after I got 114 miles and obviously I didn't run it dry.

Sorry for T.M.I. but I wonder if we compare all variables if we can find some patterns.

 

Well, you have much more experience than me it sounds like, all I have is what I've read on here and my little bit of tinkering...

That being said, you're not the first to question the validity of the stock filter recommendation. There are also a number of people like Tormoz on here who do get the filters to work... All I'd suggest is that you poke around the forum a little bit, b/c those questions have all been looked into...

Punching out!

 

See this post. And a search will reveal others like it. Some may get the Superhawk to run OK with a K&N, but it will never be as good as with a stock filter.

https://www.superhawkforum.com/forum...45/#post310018

 

Well I guess this is where I have to say something......lol

First of all I have spent a "little" time mess with the carbs on these bikes.

So first of all, as this is over the 'net, one persons idea or impression of "running good" might not be the same as someone else.

On your set up I see, what would be to me, 2 problems (or 2 symptoms of the same problem) right from the start.

First is the no need for the choke when you start it. The second is the stumble at low RPMs.

These both point to being way rich on the bottom end. IMHO the point of a "jet kit" should be to make the bike run better, not worse than stock.

Now it didn't take long after picking up the bike in 9\97 before i started messing with the carbs.

Like you I had been around bike for sometime and had always had good luck with a DynoJet kit and a K&N filter.

Well after around 2 years of messing with it..... yeah I'm one of the stubborn guys and I don't just give up easy..... I finally pulled both out as i was never able to get it to run clean over the entire rev range.

There was always a hole or a flat spot somewhere.

Now some have said they have had good luck with the set up you have and without hearing or riding their bike I can only go on what they write here.

Another problem is when you get a bike with a jet kit already installed. In that case you really don't have an idea what it was like stock and don't really know if there is a problem.

To give you an example my bike is a '98 ( or a '97 anywhere except in North America) with close to 90K mikes now..... the last time on the dyno was 10-15K ago but it was putting out 112RWHP and the torque was in the 70's somewhere.

This is with stock main jets, 48 pilots and yeah I have HRC needles but the stock ones do a damn fine job and that's what I would run if I had a second bike to set up.

Yes I have had the heads cleaned up but besides that it's just the standard mods.

But that is not the point. What mine does do is pull cleanly from any gear (yes even 6th) from 2K RPM. It migh lug a bit in the high gears but no stumble, no mis-fire, it just pulls.

It is all in what you are willing to settle for.

Now you asked what the problem with the K&N filter is. First you have to remember the old rule of tuning CV carbs...... The larger the CV carb, the harder it is to get it tuned correctly.

That is just the way it is. So IMHO the issue with the K&N is it causes too much turbulence in the air box which causes issues with the vacuum signal to the carb.

An example of this problem is the Moriwaki race bikes. When they did ram air or airbox mods their carb set up was to block the air bleeds and run smaller mains. They were willing to deal with the atomization issues running no air bleeds cause, as there was no other way to compensate for the fueling issues that the fluctuating airbox pressure caused.

Yes, it is taking it to the extreme but the K&N causes the same issues, just to a bit lower degree.

So IMHO a K&N is good if you are on;y looking for peak HP numbers. For any other application, it has been my experience, you get the best "rideablity" from a stock air filter.

 

i replaced my stock filter with a stock filter. funny because it made the PAIR decel stumble crackle pop funny. i just redid cct's and removed PAIR and

"What mine does do is pull cleanly from any gear (yes even 6th) from 2K RPM. It migh (sp? t) lug a bit in the high gears but no stumble, no mis-fire, it just pulls."

i dont know who set my carbs up before i got it.. but its spot on

i do believe after going manual cct, i feel a greater difference in engine stability on and off throttle. and the decel clicking i was hearing last week is long gone..

now my rear tire skips the ground @7k ... back to buisness

and anything ive ever done has been stock OEM parts.. exceptions only for cosmetics.

stick with OEM! it just works

 

 

did you do the bass4dude 's advise? ! you need to man, its very worthwhile

love to bathe in oils and bath salts in the ocean