Jetting specs that I have used

[spud]

We are looking forward to hearing your results Fercho.

Art set up my OEM modified to Black Jack 48's and jetted them:

110 pilots

2.5 N&S Black 80 gram springs

150 main jets

This is to go on a Lowell ported 1390

I don't know anything about Blackjacks so I am really interested

[Fercho]

Razzbo wil be working straight for 2 weeks so I will have to wait till then

[RX951]

I've ridden Razzbo's XLT1390 w/Blackjacks...all I can say is tha it HITS ! and its still running rich.

[Fercho]

We need to reinforce that pump tunnel somehow.!!!

I've ridden Razzbo's XLT1390 w/Blackjacks...all I can say is tha it HITS ! and its still running rich.

[spud]

Can we condense this information and make it a sticky, or just make it a stick in the how-to section? I plan to add when the BJ 48 "I" body conversions are dialed in.

Jetting that has worked very well for me with Fercho's recommendation:

Lowell ported 1300, single pipe, stock carbs, Prok F/A's, Advent Yam 59

115 pilots

2.0 N&S 95 G springs

135 mains

Lows 1 turn out

highs 1.5 turns out


Stock 1200 choke plates in:

110 pilots

1.5 N&S 95 G springs

120 mains

Lows 1 turn out
Highs 1.5 turns out

Stock 1200 choke plates removed

110 pilots

1.5 N&S 95 G springs

125 mains

Lows 1 turn out
Highs 1.5 turns out

Lowell Ported 1390 single pipe, Blackjack 48 I body carbs, Prok F/A's

Update: I ran the 1390 at Senator's Wash today. The ski ran great the water level was too low to get any runs in much over 1/4 mile. Temp was about 75 degrees

115 pilots

2.0 N&S Black springs

150 mains

low screws 1 turn out

High screws 1 1/2 turns out.

Ski was crisp and accellerated very hard. There might be additional fine tuning, but this works good.

[Hydrotherapy]

Nando, what do you recommend for a 1300 with no to little porting, head, single pipe, stock carbs with F/A's and VF3.

any ideas for 1300 not ported with d plate and 150 psi head 1200 timming stock reeds,stock carbs with flame arrestors

[RDH]

1200 GPR single piper ported or not, Flame arrestors, Advent CDI Yam 84 Engine, No accelerator pump

Stock, Novi modified, Prok Atomizers or RPM modified (Stock Bore)

110 Pilots
120 Mains
1.5 N/s
95 Gram Spring


For a Triple Piper 1200 add 20 to the main jets.

should i keep the same 95 gram spring for triples or go to the 115 ?

[spud]

I updated an earlier thread to include what I believe to be good Lowell ported 1390 jetting.

That ski is pulling like a freight train.

[Full Throttle]

Are the jetting specs provided here still valid? I have a ported 1300 w/Novis I'm ordering jets for.

[cmherrera]

what jettings, 2000 GPR Novi 48, LH ported 1300 single pipe with jetwork mod, Advent yam 84, Head 150psi,IR case porting, VF3's with spacer, fly F/A.Did I miss anything