Aftermarket can and K&N fitted, not fuelling properly - help!

[papercutout]

So over the weekend I fitted a different end can to the bike, as show on the 'headlight finished' thread, and I fitted a K&N. Now the can flows VERY well, and when I fitted the K&N I hole sawed 3 holes in the airbox. (possible oops. I was careful to put some drainage in the bottom though).


Now she runs really badly, she's obviously not getting enough fuel as she bogs down all the time. I'm being extremely gentle, as I have owned cars where DET is a proper problem, and I know what running lean can do to her. I don't want to replace an engine, afterall!




I spoke to a garage earlier who do bike setups etc, and after describing a few things, they said 'you'll need a dynojet kit, that'd be £125 on top of setting up'. To which I thought 'GULP'.






Has anyone got any advice? I'm prepared to buy a dynojet kit, but fit it myself and then possibly get it tweaked later - I am mechanically proficient. But I can't afford to be shelling out lots of money.


Could there be something else causing it to run so lean? It's never been fantastic, always a very dead through the mid range until about 7K, where it really opened up.

[papercutout]

Oh, and the last post on here, on the old forum show's someone having changed the jets on their carbs with stated sizes. Can someone confirm what the standard jet sizes are?

http://fazerowners.yuku.com/reply/216863#.UzGAi-jcjd0

[johna6968]

Never heard of modding the airbox on the fazer6 unless i missed somethin.. I would have said remove the parts one by one to see which one is the main culprit, but would struggle now with the holes in the airbox to achieve that.. Known quite a few bikes to run like a pig just with the K&N.. Yes to the dynojet kit just to get some more fuel through to even up the mix..

[Mattsplat]

Dyno jet plus dyno time for best results.

[noggythenog]

Loads of us...plus 100's if not thousands of fzs600's have aftermarket end cans & k&n filters fitted....it is just fit & ride....no need for re jetting..im sure a dyno setup would be good but doing these mods shouldnt be enough to mess your bikes riding experience.


This bad running...i take it you mean whilst under way...not just ticking over coz obviously you might be picking up on noise that is now more audible with the can....ok so maybe my bike doesnt always start on the button alone after doing these mods but once going it is faultless.....a few burbles but i prob need my carbs balanced...still isnt enough to worry me overly.


Check silly things like you havent put the filter on upside down, an oily rag hasn't gone down the air intake , pop the tank & make sure the fuel pipe isnt kinked & the fuel tap is fully on.


I dont know...but ive got a feeling that drilling holes in the box wasnt a good idea......i dont think the box is there just to keep rain & dust out....swap the original end can back on or just take off the new can (dont ride about with that out though )....this will narrow it down to perhaps being related to the filter & box.

[fazersharp]

You dont need to narrow anything down --- just put some gaffer tape over those holes

[Dead Eye]

You dont need to narrow anything down --- just put some gaffer tape over those holes

This is what I would do as my first go to option - its cheap and will confirm whether you've accidentally messed up the air flow as so far its the only "non-standard" mod you've done. As noggy pointed out, the majority on here run with a free flowing air-filter (typically K&N) and an aftermarket exhaust without any issues.

If you still have a problem then try to switch back to the original filter (if you still have it) and the OEM exhaust after as well.

Finally, its back to basics; check air, fuel and spark

[unfazed]

Classic mistake, changing to many items at the one time. As previously stated, put the air box back the way it was.

[papercutout]

You dont need to narrow anything down --- just put some gaffer tape over those holes

This is the first port of call.




For anyone who says 'why would you drill holes in the airbox?', well, quite logically, you're fitting an aftermarket filter for more air flow. Want more air in, give the filter more air. That means a bigger area to draw air from. I'm far more used to injection vehicles than carbs, so hadn't figured it'd throw everything out so much.


You can call me stupid if you want, but I can deal with that!

[Dead Eye]

Newer injection engines are smart enough to compensate increased air flow with more fuel - carbs don't work that way unfortunately and it becomes a balancing game of one or the other to get it to run right.

If the problem really is a simple air to fuel ratio problem you either need less air or more fuel. The cheaper of the two is less air

[stevierst]

Newer injection engines are smart enough to compensate increased air flow with more fuel - carbs don't work that way unfortunately and it becomes a balancing game of one or the other to get it to run right.

Just as Deadeye said, it's air/fuel inbalance. I've modded cars for the last couple of decades, and I thought that bikes would react the same. Erm.... No!
 I tried to 'tune' my sons bandit 400 years ago the same way by drilling some holes in the box, and it ran like a pig! Stuck tape over the holes, and voilla. It ran great (ish) after that.

[His Dudeness]

 

[Buzz]

she's obviously not getting enough fuel

... for the enormous amount of air now flowing through.

[esetest]

What size holes , if 20mm or 25mm you could fit blind grommets ( either sparky mate or wholesaler) plug the holes and see if that cures the problem .

So over the weekend I fitted a different end can to the bike, as show on the 'headlight finished' thread, and I fitted a K&N. Now the can flows VERY well, and when I fitted the K&N I hole sawed 3 holes in the airbox. (possible oops. I was careful to put some drainage in the bottom though).


Now she runs really badly, she's obviously not getting enough fuel as she bogs down all the time. I'm being extremely gentle, as I have owned cars where DET is a proper problem, and I know what running lean can do to her. I don't want to replace an engine, afterall!




I spoke to a garage earlier who do bike setups etc, and after describing a few things, they said 'you'll need a dynojet kit, that'd be £125 on top of setting up'. To which I thought 'GULP'.






Has anyone got any advice? I'm prepared to buy a dynojet kit, but fit it myself and then possibly get it tweaked later - I am mechanically proficient. But I can't afford to be shelling out lots of money.


Could there be something else causing it to run so lean? It's never been fantastic, always a very dead through the mid range until about 7K, where it really opened up.

[J_Dub]

I'm also with taping / sealing the modded air box. My boxeye has a Simmi end can (no baffle) and K&N air filter, runs fine with no rejetting.
My lad Karl, has a GSXR 750 with K&N air filter and full Arrow exhaust system, this runs well. He found a race set up for modifying the air box lid (cut the lid to bits) so he bought a spare air box lid on ebay and did the mod - result - the bike ran shit and would need rejetting. Original lid back on problem solved.

[papercutout]

You'll all be glad to hear it worked. A decent bit of taping, and she's back to normal, just louder than before.


Thanks guys. Still debating getting some jets off ebay, they're pretty cheap

[darrsi]

You'll all be glad to hear it worked. A decent bit of taping, and she's back to normal, just louder than before.


Thanks guys. Still debating getting some jets off ebay, they're pretty cheap

Shouldn't really need to though, i had mine re-jetted years back but then it didn't feel quite right so they put the original ones back in when i took it back to the Dyno centre. After that it ran okay again.