Factory Jet Kit?

[fj1289]

Who has experience with the Factory Jet Kit for the FJ?

Compared to jetting most people are running, the Factory Jet Kit seems to be jetted very rich on both the pilot and main circuits.  Does the needle design part of this?  i.e., doew the Factory needle obstruct the main jet somewhat?  Also, maybe has a fat tip that makes the slow speed stuff leaner than would otherwise be?

Factory uses Mikuni jets (or duplicates of those jets) - from the Factory Pro website:
"Factory Mikuni Main Jets are designed to be direct replacements for Genuine Mikuni jets.  Original "0,2.5,5, 7.5, 10" numbering system for "Mikuni style"
Designed to flow on the OEM fuel flow scale - not an arbitrary scale that locks tuners to hard to find brand. "

It seems the 132.5 main jet recommended seems HUGE compared to what most people are running with pipes and pods (generally 115 - 117.5)

Also the 42.5 pilot jet (with an optional 45!) seems to be big too - most folks bump up to a 40 and are happy with the low end response.

The only thing I can figure is the needle design somehow requires rich jetting on the top and bottom?

Who has used Factory Jet Kits on their FJ?  What were your results?  Your final settings?  What type of gas mileage did you end up with too?

Thanks,
Chris

[Harvy]

Chris...... I've got the kit and new FP emulsion tubes ready to go in......just can't take the FJ of the road long enough to do the job yet.

Will give you a shout when I finally get around to putting them in.

Harvy

[fj1289]

Thanks Harvy

I sent an email to Factory Pro asking for suggested settings for my higher altitude.  Also asked about what seemsed to be excessively rich jetting on both the pilot and main circuits. 

What set me down this path is the fact I chose to keep the stock 37.5 pilot jet vice the 42.5 due to the altitude here.  I'm lean off idle right now - just started tuning it.  I raised the needle a half notch first - that puts me richer than the recommended settings which seems odd to me at 4300' altitude.  I'm guessing the needles are meant to be used with richer pilot jetting - will probably order some 40's and see how that does for this altitude.  I also installed the new emulsion tubes at the same time. 

Also due to the altitude, I opted for a 125 main jet vice the 132.5 they recommend (130, 132.5 and 135's are included in the kit).  I haven't done any testing yet to see how it runs with richer or leaner mains. 

Chris

[the fan]

I installed jet Kits in both of Deans 93 FJ's. The first got a dyno Jet kit, was a pain to tune in and never really ran as well as I had hoped.

I installed a Factory pro kit per instructions and it ran really well. as far as I know no adjustments were made after the install and sync. Elevation in Cincinnati is 500-1000 ft depending on where you are in the city. during the fall rally we get as high as 5500 ft and there are no issues I am aware of other than being slightly rich. Certainally not enough to cause problems. I suspect dropping 1 size on the mains would clean it right up.

The needles definitely alter the jet sizes needed to reach the proper fuel/air mixture.

[andyb]

The biggest main used in a config10 kit is a 120 (optional, 117 rec'd).

V&H wants a 125 main, but with a stock needle.

A 132 seems on the big side, but the FJ motor seems pretty easy to please as far as jetting goes.  I'm running a 42 pilot if memory serves, as the 40 was a step in the right direction, but not enough of one.


Wouldn't suprise me if they're using a very large bore needle and trying to smooth out the transition from cruise to needle throttle by running big pilots and a relatively tight needle jet. 

[ccsct203]

I have a fj1100 with a wiseco 10.5 to 1 fj1200 kit
I have megacycle cams (268x2)
Ape springs
titanium retainers
Mikuni rs32 flats
17/43 sprockets
Dyna 2000
Pingel

I can't run 132 mains on my bike without it running too rich
I run 122.5-125.0 and it runs great
35-45 mpg

Stay with 120-122.5 max

Or listen to what the rest here tell you, they know better in the real world then anyone...
they have saved my sanity many times.

[Dan Filetti]

I routinely rode my FJ well up to and above 10,000 + feet with no real noticeable running issues when I lived in CO, and rode up into the mountains.  Power did seem down a bit at the higher altitudes but it was fairly minor.  When I brought the bike east, it was not particularly lean either.

To me anyway, the FJ was fairly easy with fairly significant altitude adjustments. 

FYI,

Dan

[racerrad8]

Factory uses Mikuni jets (or duplicates of those jets) - from the Factory Pro website:
"Factory Mikuni Main Jets are designed to be direct replacements for Genuine Mikuni jets.  Original "0,2.5,5, 7.5, 10" numbering system for "Mikuni style"
Designed to flow on the OEM fuel flow scale - not an arbitrary scale that locks tuners to hard to find brand. "

Chris

FYI,
       All of the jets I sell are the Mikuni sized/rated jets and are a direct replacement and identical to the Mikuni jet in everyway.

Randy - RPM

[fj1289]

Got a reply back from Marc at Factory Pro - they do use a needle that is much thicker than the dynojet I was previously tuned with.  A quote from Marc - "The needle tip type makes a big difference in what you end up with as far as main jets sizes are concerned. Anybody running 117.5 might have a skinny dynojet needle?"  Just like thefan and andyb said, about the needle design effecting the jetting at both the bottom and top end. 

Bottom line - I'll be setting it up as per the kit instructions using the optional 130 vice 132.5.  Might have to go down to a 127.5 -- I'll definately get those from Randy like the rest of the jets I needed for the intial rebuild (new seats and needles, new pilot air jets (stock to replace the dynojet ones), and smaller main jets based on my previous experience with "skinny" dynojet needles. 

Seems we need to keep track of three jetting setups for the stock carbs - stock needles, dynojet, and factory...

Thanks all,
Chris

[Harvy]

Seems we need to keep track of three jetting setups for the stock carbs - stock needles, dynojet, and factory...

Thanks all,
Chris

Agreed Chris........ and just for good measure, I also have to play with the fact that I'm changing from DJ to FP....and the consequences of drilling the slide (all be it only a gnats eyelash) for the DJ kit for Euro and Japan spec bikes.

Harvy

[fj1289]

Well, reset the carbs back to the base settings recommended by Factory Pro - 130 Mains and 42.5 Pilots.  After a couple days riding to work and tweaking the carbs, I'm at 1.5 turns out on the mixture screws and may need to go a hair richer.  The needles are at 3 1/2, may try 3 after I tweak the idle.  Gas mileage seems reasonable at 31 mpg (that tank was mostly on the high side of 85 on STRAIGHT 2 lane highway in very windy and gusty conditions) - sure that would come up at closer to legal speeds. 

With the mixture screws at 1 turn out they were definately lean.  Also started with the needles at 2 1/2 and had a slight lean stumble just at the transition to the needle. 

Chris