2006 Hayabusa Problems with new exhaust AFR maybe?

[Kosz216]

I have an 06 Busa LE with K&N Filter and 16/42 sprockets. Stock exhaust. Bike was running fine, no issues what so ever. Last month I purchased Two Brothers VALE M-2s dual slip ons for it and PCV then installed them. I used the map that was 4-2 Two Brothers Exhaust with Stock/Aftermarket airfilter off Dynojets website. So with K&N and Two Brothers M-2 Slip ons and PCV if I was just cruising around 40 mph at roughly 4000 RPM the bike would feel like it was stumbling or falling and picking itself back up. I was racing a friend from 60 around 6k RPM and as soon as we took off my bike like fell on its face before taking off, once it did and anytime I punch it around 6k and go rev limit it will cut out or buck maybe 2-3 times. Anytime I full throttle from around 6k rpm it will do this. If I go slow into it and eventually reach rev then it won't cut out/buck. At first I thought the problem was my kickstand not being able to fully press the kickstand switch due to where the midpipes were placed but that wasn't the problem. I can't think of a fuel pump/filter or an injector being clogged or even gas I bought could cause this issue because the timing was so perfect. It didn't have any problems before the slip ons.. But afterwards it did. And I can't throw the stock pipes back to see because I already got rid of them. Honestly my only thought is AFR and that its running too lean not getting enough fuel due to the amount of airflow the exhaust is letting out unlike the stock pipes which I would assume have more back pressure? Idk, I'm still really new to the bike world just curious as to what others think! Should I just have it dynotuned?

Thanks for the help!

[mjl3truck]

Short answer YES! Try disconnecting the PCV first and go for a short ride, that may be more to blame than the exhaust.

[Quiksilver]

I have a 2002 turbo busa and I switched turbos it acted similar to yours. It would fall on its face and buck if I wrapped it too fast but would be a lot smoother rolling into it. Got dyno Tune and smooth sailing now.

[Kosz216]

I forgot to mention I rode it for about a week off and on without PCV because it hadn't shown up in the mail yet and it was still cutting out! I figured the PCV and a map off their website would fix the problem but nope! I guess I'll have it dyno tuned now tho. Thanks again.

[GoldenChild]

Simple, You need a tune... You will hear no you don't it will be fine, now you see it's not fine. when you change the intake or exhaust flow of anything, fueling needs to be checked. it's not about rich or lean, it's about engine efficiency. some just don't get it regardless how much of a rocket scientist they (think) they are.

[dadofthree]

Maybe it's something simple like an over oiled K&N air filter

[dadofthree]

If you still have the stocker, put it back in and see what happens

[Kosz216]

Alright GoldenChild, thank you! I called Smithers Customs out of Olathe KS and basically they told me something was "wrong" with my bike and it had nothing to do with mods I added. I called BS. I listened to them but what they said was ridic. It wouldn't be coincidental that as soon as I install exhaust it starts cutting out and it's some serious internal problem where they need to run diagnostics to figure out what it is before they write a custom map. I'm sure they were just wanting to take my money. Lol Anyways, I've read many threads and you always seem to give great positive feedback, GoldenChild, so once you said something it really gave me reassurance and I'm going to setup a time to have it dyno tuned either by Justune or Smithers. I prefer Justune but we'll see.. Whoever has time since those are the only two I know of in the KC Area.

[Kosz216]

I already got rid of it dadofthree otherwise I definitely would! Bad mistake on my part. Ah well.. Learned my lesson lol

[dadofthree]

Tune it brother, just don't normally have that issue with a pipe, even the Brocks that makes 12-15 RWHP. Spend the additional money and get the ECU unleashed.

[dadofthree]

By the way, how many miles are on it and do you keep the maintenance up ? I have really extended the replacement periods on the air filter and spark plugs. Getting ready to replace both with about 25K miles on the bike. Bikes running fine, I'm just getting ready for the Bash and figured three times the factory spec was enough. $40 set of spark plugs will make you think about these things. Can't wait to see what the plugs look like.

[Kosz216]

I do keep up with maintenance! It's got 36k on it. Put the k&n on when I bought it with 29k, still clean, and stock was clean when I swapped it out. It's had valves adjusted as well. Oil changed every season. Spark plugs I thought could be the issue, so changed them about a week ago it didn't change the way it ran tho. Still like crap before and after with ngk iridiums.. And they looked ok. Like when they do when it's regular time to change them! My only other concern would be ignition coils that looked "decent." Lol Justune text me tho and he's gonna look at it and create a custom map sometime next week. I'll keep ya posted.