throttle stutter

[cooper]

Hi I have a blackbird 97 vintage which has a KN air filter installed the problem is it has a stutter at about 85/95 when I try to roll on the throttle in top is this due to the non standard air filter ? if it is how do I cure this I have been told to fit a stage 1 dynojet kit but I am not sure what to do as the bike is standard through out apart from the filter if it is going to cause me grief should I put a standard filter back in?
regards Percy

 

[Bird Info guy]

Mess with any part of the carburation....

... and you stand to upset something. You might not think that an air filter would have that much effect, but it does. Any change from stock and you should have a check that it hasn't upset the 'breathing' of the engine, and the usual way is on a rolling road. If you're going to do this then you should be prepared to consider a dynojet jobbie to make sure everything is pukka.

Sorry, but Mr Honda puts mega-bucks into designing a superb engine and people then go and tinker - what do you expect

 

[Trumpet]

It's almost certainly the filter making matters worse. Most bikes tend to have a bit of a flatspot right at the revs the noise test is taken when they are being type approved, it used to help the noise figure. And usually unluckily for us, its around legal (ish) speeds. Running a K&N on a carbed bike without making any adjustments to the carbs will make that dip into a crater. Your friend is right, a stage one kit and a dyno setup with the filter would be the ultimate, but if you are unsure when you can do this. revert back to the original filter, your bike is running lean on the K&N.

 

[Trumpet]

Wow Clive, you replied at the same time ! and it was roughly the same answer .. Saw my new bird today, just out of the crate being built up. Pick her up thursday.

 

[Bird Info guy]

Wow, really exciting Trumpet

Bet ya can't wait. Hope it turns out the way ya expect, sure it will.

See ya at Rivington Barn with a great big grin across ya face:}

What colour're ya going for?

 

[Trumpet]

.. it was either black or Blue. Just had a Black Sprint ST for 3 years, so had to be Blue. Although the black ones look ace as well ! If I dont get banned in the first few weeks of ownership, will see you and your missus at the Barn !

 

[Trumpet]

Wanted to go back to Honda, wanted it to be fast, and had to have a comfy pillion, the other half is not in a size eight anymore ..

 

[Bird Info guy]

Ya know what's next....

... ya gointa have ta get a decent seat for your (size 9) pillion - a Corbin, or maybe a Melvin, or whatever, but ya must keep her happy

BTW, we'll let ya off the colour What! No red option?

 

[CBR1100 Nutter]

Just to clarify something

Well guys i have to say that you are sort of right and also sortof wrong Im afraid. I also have a carbed version and have fitted the K&N, Dynojet stage1 and Erion race cans. ( along with shit loads of tarty bits lol )

Now ref the K&N. I think you will find there are no gains in fitting one in the 1st place ( other than its re-usable ). The stock air filter has a very simular flow rate as the K&N so this shouldnt have any effect on the running of the bike at all. The only reason i went for the K&N was so that I can just take it out, clean it, re-oil and re-fit without the expence of a new stock one every time. Other peeps have fitted K&N, put it on the dyno and no difference was noted at all over stock.

With ref to the problem you have, I bet its a flat spot around the 5K mark? Some people notice this more than others. I had it and it used to wind me up bigstyle hence the Dynojet kit and race cans. Hey presto the flat spot is minimised to near on non-exsistence ( it still shows a very small drop off on the Dyno )

So really its up to you weather you splash out and go for the full montey to get rid of the problem. I wouldnt bin the K&N as i think you will still have the same probs with the stock filter. Pays ya money, takes ya choice

Just my opinion based on persanal experience with mine thats all

 

[Wolfie]

got mine booked in on the 13th sept, going to play with some jets, filters etc, will let you know which comes out best, my cans got rid of some of the stutter/flatspot but not all.

 

[cooper]

Hi guys thanks for the replys I would not have noticed the stutter so much but tried one or two orther bikes before and this one has the KN fitted which I did not find out till I had got used to the bike then when I opened up to try some quick overtaking I got this hesitancy go from about 85/90 if I use the gears it is obviously not noticeable so is the considered opion that a standard filter and perhaps a carb balance will put it back OK? as a second query from other owners what do you use oil wise do you use semi of fully synthetic

Thanks PC

 

[CBR1100 Nutter]

Oil

Now theres another can of worms LOL

Persanaly I use semi as I have heard others mention that a full synthetic doesnt do your clutch plates much good ( no good those being coated in a friction reducing product lol )

Honda recoment a mineral based oil but again i think its persanal choice. As long as its wet and slippery it should be ok ( story of my life :} ) And regular changes dont go a miss lol

 

[Trumpet]

I've found K&N's flow slightly more air than a standard filter, thats one of their selling points - fuller flow, as well as washable. Most bikes I've ever ridden in the last 30 odd years have minor flat spots at around the 5.5k mark to help em pass the noise and emissions test when they are being type approved. It's crap really, as they are all checked at one RPM setting, so they frig the bikes. They run weak deliberatly. I've fitted K&N 's in the past to several Bikes and it has made a large hole in the power delivery. K&N have always said no modification is necessary, but in my experience thats bollocks.

As we have all agreed on previously, K&N filters, the correct jetting and a dyno check/setup is the only way to improve an already awesome bike. I dont care what K&N say.

 

[cooper]

re stutter

who's what 's LOL

 

[XXscraper]

Lots of lovelies

Are you asking what LOL is?

Laugh out loud

but could also be loads of larger....LOL

 

[Mechanic2001]

HI All

RE Stutter and K&N.
I can say 100% that the filter is the root of the problem my bird had a wicked flat spot so I thought I would fit a dyna jet kit and K&N Filter, When the parts arived striped bike down to fit parts and it already had a K&N fitted (O f**K) old owner did not tell me it had one anyway all new bits fitted Bird flys no flat spot just pull pull pull pull all the way.
So I sold old filter to a mate with a bird with no flat spot he fitted the filter a he had a flat spot so filter to blame !

Get a jet kit and you wont be sorry

 

[cooper]

Mechanic2001

When you say fit a jet kit is this a dynojet kit as I was told to fit a stage one dynojet kit, but previous threads say it needs to be done on a rolling road what have you done with your bird ?

regards PC