NC23 1988 - New Downpipes / Endcan - Rejetting

[Html33]

Hi all, i'm new here hopefully should be sticking around

Right basically i have recently bought new Stainless Steel down pipes from Sandy Bike Spares, and a newish second hand Scorpion end can.

Previously, with my old down pipes and endcan i could pull all the way to high RPM's (dont actually have a rev counter) but GPS on my phone clocked me at 135mph, with constant pull. - Don't think i could get a lot more...

Now, with my new down pipes and end can i can only hit about 114mph (Gps) and struggle to pull through high RPM's in 4th+. The symptoms im having are;

If i am throttling hard, then back off ... and then go back on throttle hard again threes a few seconds of hesitation before the power comes back.

Not as much pull at higher RPM at full throttle, hesitations and flat spots, if i open slower so im on the pilliot jet it is more responsive.

Spitting and popping on de-acceleration after hard acceleration (although after reading is quite natural)

I presume i have standard jets (115) I think its an RRJ, 1988.

As a guess i would go for 118 jets? And a needle notch down?

Next question where do i get jets? Wemoto have them measured in MM's?

Thanks in advance!!



(before endcan change)

http://i152.photobucket.com/albums/s183 ... 5467_o.jpg

[jetblack]

Allens performace should be able to help wih the jets...

http://www.allensperformance.co.uk/

[Html33]

I've looked on Carb Kits, is it a MIKUNI or KEIHIN?

Thanks

EDIT: I think it's KEIHIN KITS for DownDraft carbs? Correct me if im wrong please.

"CBR400RR 33 FCRD-33-453"

Edit again, i've also found Keihin jets on the left, but which size would it be?
And what roughly would you go for to try first? 118?

Thanks.

[jetblack]

give them a call.

They'll be able to tell you what you need, you just need to tell them what size jets you want.

[Html33]

give them a call.

They'll be able to tell you what you need, you just need to tell them what size jets you want.

Okay than, thanks. I'll do that in the morning - I'm sure they've had lots of people ask the same thing.
Anyone else feel free to put forth suggestions?

Thanks.
Thanks jetblack.

[Html33]

No other replys other than JetBlack?
I've seen 100's of NC23's with different exahusts...somone must have some ideas?

[The Novice]

I had the same issue. Hesitation at high revs, had stainless headers and a carbon can, swapped the can for a quill end can now though as it was too loud for me.

I simply emailed graeme france and he sent me a set of new jets (dynojets i think). Swapped the old ones out - for some reason it had smaller jets than standard - anyway, all good after changing and it pulls like hell now.

I recommend you get in touch with Graeme - he knows what he is talking about with these bikes. I do recall however there may be an issue with the stainless pipes you bought at lower revs, do a search on them.

[Html33]

Hi, Thanks for your responce.
I've sent him a message so let's see what he says back.

What size jets did you put in do you know? Thanks.

[The Novice]

Graeme told me what size I needed for the mods it had, I paid, he sent. best thing I did to the bike, made a marked difference.

[Dowensy]

Hi, I currently have a full yoshimura system on my bike and i got just new jets and swapped them out cant remember on the size though and that sorted everything out and only issues with it are when your ridding the bike and it isnt warm the bottom end will be a bit laggy and will bike fire, but once up to temperature for some reason everything is fine.