ZX6R J: new carbon muffler + K&N - will the carby need w

ZX6R_CBR954RR · Post by **ZX6R_CBR954RR** » Sun Feb 18, 2007 9:43 pm

Hi all,

I have a 2000 ZX6R and I want to fit a carbon muffler and a K&N filter to free up a few horses. Will the carby need rejetting etc?

Thanks for any advice,
cheers

I-K · Post by **I-K** » Mon Feb 19, 2007 7:01 pm

In a word, no. I have a 2001 ZX6 that I've run with a full Akrapovic exhaust and a BMC filter for the past 55,000km on stock jetting.

Rejetting will give you a couple more hp here and there at the expense of 30% higher fuel consumption everywhere.

Not worth it.

NovaCoder · Post by **NovaCoder** » Tue Feb 20, 2007 7:41 am

I-K wrote:In a word, no. I have a 2001 ZX6 that I've run with a full Akrapovic exhaust and a BMC filter for the past 55,000km on stock jetting.

Rejetting will give you a couple more hp here and there at the expense of 30% higher fuel consumption everywhere.

Not worth it.

Not so sure about that

It's not so much about the top-end power increase but an improvement across the rev-range, also if it's running lean you could damage your motor.

If a motor is tuned correctly it 'should' use less fuel not more.

christianzx6 · Post by **christianzx6** » Tue Feb 20, 2007 9:57 am

I completely disagree with I-K, if you want the most out of your mods, go for it, running the engine lean will do more damage to your wallet in the long run than the added fuel consumption costs anyway.

I have a J1, bmc RACE air filter, full yoshi and 4 degree's of ignition advance. The jetting on my bike was from a 99, so they were running like 142.5 and 145 mains i think, something tiny. Anyway, I found that the most power came from 160's and 162.5's, the stock jetting on the j1 is like 152.5's and 155's. I recommend a jet kit, my bike (as it had tiny mains) was a joke to ride, almost unrideable. Once i got the jet kit it woke it up, and it canes pretty hard.

I've heard great things about factory pro jet kits, social security recommended them, i've installed one and i recommend it also. mine cost me about 185 from wolf racing up here in brisvegas. Why shell out all that money for a zorst then not rejet for a relatively low cost in comparison.

As nova said, rejetting will give you added torque across the whole rev range, it'll make the bike pull harder everywhere (once its setup right). I recon you should get a jet kit, its not expensive, easy to install and setup yourself assuming your not afraid of taking your bike and carbs apart, just write down after each run how it acted, use the same/similar road each time for equality in testing etc. when u get the main jets right (or even when you start to get close) you wont be able to stop smiling.

Post by **MadKaw** » Tue Feb 20, 2007 10:55 am

I'd get it tuned and re jetted. Probly wouldn't bother with a jet kit though.
I also wouldn't bother with the K&N unless you want a filter that lasts. They don't add any power but do last a long time.
Not sure what the set up is in the zx6 but with my 9 and 7 the best results were with the stock filter with the mesh removed. I put the K&N back in the box and it sat on the shelf for 2 years...

mfzx6r · Post by **mfzx6r** » Tue Feb 20, 2007 2:48 pm

I've got a slip-on and the stock air filter and its runs fine

Gosling1 · Post by **Gosling1** » Tue Feb 20, 2007 7:13 pm

mfzx6r wrote:I've got a slip-on and the stock air filter and its runs fine

agree 100%. I have a bolt-on Yoshi and some BMC's, and at the recent dyno session, my a/f ratio was almost spot-on.

Don't forget that most factories (Kawasaki included), jet the bikes 'rich' right from the factory floor. A freer-breathing exhaust and good filter may simply reduce the richness to a more effective setting (ie slightly leaner), as has been the case with I-K's bike. I don't doubt that if you want to extract every possible HP from your bike, then hire a dyno for a day, grab a big box of jets, and knock yourself out. You will get *perfect* jetting, but the question is, does your everyday riding requirements need *perfect* jetting ??

ZX6R_CBR954RR · Post by **ZX6R_CBR954RR** » Sun Feb 25, 2007 10:05 pm

Many thanks to all those who replied. Now to find the exhaust!

paul-s · Post by **paul-s** » Mon Mar 05, 2007 7:27 pm

rejet lean=hole in piston.check how your plugs are burning.you want a light tan.

BikerBoy · Post by **BikerBoy** » Wed Apr 04, 2007 1:37 pm

i've a carbon slip on and just installed a K&N, runs well, didn't notice any increase in throttle response or power.

Actually, i'm lying, maybe a little in throttle responce.

My bike runs lean though, my exhaust 'pops' a lot.

rejetting is an expense, so just depneds how how long you want to hang on to your ride i guess.. i'm looking to upgrade in the next year so i'm not bothering with re-jetting - even though its recommended.