hey guys
what jetting will you recommend for a good flowing 4-1 system. eagle bla bla system-
thanks in advance
What is your intake filter setup? Stock, foam pods, other? What part of the globe do you live in and at what elevation level? Are your carbs currently stock?
Excellent questions Eric :good2:
I heard that it's all about intake set up.
Once upon a time I had a Supertrapp four into one with Uni Pods and for that RPM fattened up the jetting.
It ran great.
Then the welds split on the Supertrapp and it was back to the standard 4 into 2.
I didn't do anything with the jetting and it runs great.
Quote from: 86FJNJ on October 27, 2025, 04:02:06 PMWhat is your intake filter setup? Stock, foam pods, other? What part of the globe do you live in and at what elevation level? Are your carbs currently stock?
modded airbox hiflo filter. insanely lean in the bottom. live in sweden 0-1200 ft elevation
Ok, thanks for your info.... :good:
New #42.5 pilot jets (from #37.5) new #117.5 main jets (from #110) stock 155 air jets, if you have adjustable needles, raise up 1 clip....or if you have non adjustable needles, shim needles up 1/2 step.
Yes, FJ's were set very lean from the factory.
Cheers
Pat
For comparison my FJ1200 has high flowing pod air filters, stock headers and open wide mouth mini-mufflers. I'm running 45 pilots and 120 mains. I admit I'm rich on the pilots but I had trouble getting the 42.5's dialed in and the 45's are working fine. The 120 mains are great, I could probably go up a size from there but rarely riding in that throttle range. I run HSR Dyna springs and HSR tapered needles with needles on the 3rd clip from the top, bike runs great and for me it's most important the bike is dialed in for the mid range between 3k-6k rpm and this set up is spot on for me. I rarely let the bike idle except at stop lights and rarely go past 3/4 throttle except for maybe a few seconds, the bike has so much torque I have no need to twist the throttle that much.
Pat is right in his starting point and then you can dial it in from there based on symptoms.