pod filters and carb jetting

[carsick]

I love a thread hijack flavored fascicle. Very cooling on a hot day.

[Alf]

With individual filters I run 125 mains in my FJ 1100. Don´t miss to raise the needles with a little shim under the clip

[RichBaker]

On a WFO plug chop, I wouldn't want the easily visible part of the insulator to be tan.  Ideally, you'll need to cut it in half and read the ceramic portion down near where it attaches to the metal portion of the plug.  

Wait, you're saying you have to destroy your plugs to read them??!!  A bit like the Heisenberg uncertainty principle -no?

Dan

Hmmm.
Perhaps Schrödinger's Cat would serve as a better analogy?

So you put in new plugs, run them WFO, shut it down on the interstate, pull the plugs, cut them open, measure their present position but are unable to predict their future velocity, then put them in a box with a cat of indeterminate mortality? Is this a Harley thing or Voodoo? Also starting to sound like some rustic advice from the Haynes manual.

The "Black Art" of tuning a 2-stroke......   

[weymouth399]

That's what Yamaha told me back in 1989 when I was at school. What would they know?

Bob W

Well, if they knew what they were doing we wouldn't have to rejet, right? Oh wait, we screwed with the bike, never mind.
While we're on this topic, anybody know why my needles have 6 grooves? I've seen 4 and 5 clip grooves, is this some strange brand of jet kit?

Not all FJs are jetted the same all over the world. Yamaha got it close where they didn't have to pass EPA standards.
They had to be so lean they would barley run right out of the box. It was a big problem at the time. To get it to run right, it would never pass the EPA test.
The 6 clip needle is what all mine have, I run HSR kits.
My 08 KLX 450 has the same problem, not for long.

Bob W

[simi_ed]

Ask your plugs what they think! 

Try this for reading your plugs!
http://www.pjmotorsports.com/spark-plug-info.html

[Lotsokids]

I'm glad I saw this thread as I'm considering buying pod filters for my bike. I saw RPM's website had the jets I think I need. I would like to order #115 mains and #42.5 pilots. My bike has 4-into-1 Vance & Hines exhuast without the baffle material in the can (if that matters).

Are there any special tools required? Can I just unscrew the old and screw in the new?

[andyb]

No special tools required.  A couple of flathead screwdrivers that fit pretty well, and you're done.

[Lotsokids]

No special tools required.  A couple of flathead screwdrivers that fit pretty well, and you're done.

Awesome. Thanks.
Why do I keep seeing drill bits and sheet metal screws in jet kits on Ebay? What are those for?

[andyb]

The drill is to make holes, silly!  The screw is then threaded in and used to remove the blocking plugs over the idle mixture screws.  Occasionally, an additional drill is included for slightly opening the air bleed in the carb slide.

If you can see your idle mixture screws, you shouldn't need a drill when working on your carbs.  Just a properly fitting screwdriver will suffice, do be careful as it's occasionally easy to bugger up the nice soft brass jets.

If you're running pod filters and a full exhaust, I am not entirely certain that 115's and 42.5's will be ideal.  I'd suggest closer to a 120-125 main and a 40 pilot.  That being said I have 42.5 pilots as I couldn't get quite enough adjustment from the 40's.

[Alf]

I made a lot of experiments with my FJ 1100 and 125 mains were the correct ones with a Muzzy race 4/1 exhaust & 5º ignition advancer . Mine was an european model with OE 40 pilots fitted

[RichBaker]

It does help to use a cabinet-style screwdriver, the one with straight sides all the way to the tip.... and they should fit the jet properly, filling the slot with little-to-no slop. Damaged jets don't flow to spec.....

[Flying Scotsman]

Recently removed Kerker 4-1-2 pipe and installed 4-1 V&H SS2R.Did not change anything in carbs.Bike ran good but very hot so I raised my needles 2 slots to richen her up.Went to far so lowered them 1 slot.All good except just on the throttle bike was surging.I have a DJ kit in with 144 pilot air jets so i tried some 155 jets I had on hand.Initial testing which was not long enough due to rain was good I could run in 3rd at low rpm without surging when i ease on the gas.
With the old Kerker pipe I had my needles lowered all the way DJ124 mains,144 pilot air,pilot looks like 52,long springs.
With the V&H pipe needles are set on 2nd slot from top,DJ124 mains,52 pilot,155 pilot air.long springs.

Got to take a longer ride to see what needs changed but I seem to be geting close.
I might try a smaller pilot jet next I will decide after another test ride.

[jykkeh]

With 36Y inlets and open exhaus and k&n it is this way Main jet 125, needle middle, LEDAR air corrector jet smaller and thats it.

look here   http://www.fjcatalogue.com/catalog/item/7214426/7422355.htm

[andyb]

It does help to use a cabinet-style screwdriver, the one with straight sides all the way to the tip.... and they should fit the jet properly, filling the slot with little-to-no slop. Damaged jets don't flow to spec.....

I specifically dedicated a screwdriver to the task.  10s with a bench grinder shaped it appropriately, but remember to round the sharp edges off of the sides or you'll cut clearance in the soft aluminum castings...

[Lotsokids]

I noticed some discussion of a 5 degree ignition advance plate. Wouldn't that make it harder to start? I know that's the effect of advancing the ignition on a Chevy V-8.

If my bike gets harder to start, it won't.

Usually:
Advanced ignition = Harder starting, but better power (depending on cam).
Retarded ignition = Quicker starting, but less power + more heat.