Jetting Question

[Black Sled]

As soon as the rain stops I am pulling the Valk out of storage and installing my new Mark T's pipes - replacing some beat up Cobra 6-6.  Can't wait.  My dilema is that I am currently running the Factory Pro kit with the FP recommended tune for the Cobras (38/100/FP needles 3rd clip).  Also have IS springs and K&N + prefilter.  Questioning if I should go back to OEM needles. 

My question is, has anyone tuned with Mark's pipes using the FP jet kit?  I'll call Factory with the same question, but am hoping someone on the board has experience.

Sure wish I had a dyno in the garage...

Thanks

[98valk]

use FP directions for stock pipes.
re-adjust the idle mixture screws and lower the needle one slot and most likely u will be good. u will gain 10-12hp. the cobras remove approx 5-7 hp so just going back to stock headers will get that back and glass packs will add the rest.

[9Ball]

same advice for moving the clip out one notch....I did the same change.

I believe the Factory Pro kit came with 105 mains...at least mine did.  I was running a bit rich until I rejetted to the stock 100s, at which time I just re-installed the OEM needles.  Pilots at 2 1/4 now back to nice normal plug color.

[Black Sled]

JR - are you running 38 slows or stock 35's?

Thanks 

[Patrick]

2 1/4 turns  on the pilots is fine for 35s,, but,, may be a tad much for 38s.. It appears that 1 1/2 to 1 3/4 works for the 38s..

[9Ball]

JR - are you running 38 slows or stock 35's?

Thanks 

I went back to 35s...completely stock.  My Mark Ts like this setup.  I don't use the trombones, just the glaspaks.

I run the K&N w/ no prefilter as well.

[Robert]

I'm with CA on this one the stock setup is lean and the 38s do real well at idle pipes or no. The other thing that most dont consider is that the mains jets supply the needles meaning if the needles are adjusted to correct the mix at most throttle settings then the mains will only kick in above 3/4 and above throttle. The needles really have to be lifted out of the needle seats for the mains to really kick in. So at full throttle these bikes can really suck up alot of fuel. So with that said My recommendation is take out the pre filter and adjust the needles as needed and that's it. By taking out the pre filter you may find that a needle adjustment may not be needed. You will get good idle good mid and really good high.