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Shims, Springs and other Carb things
By Chet Walters

Some exhaust modifications will make the Valk run lean in the midrange. Midrange lean can be corrected with new jets, but that is a lot of work and requires tools and talent. However, midrange flat spots can be lessened with little effort and expense requiring only a few tools (just a phillips screwdriver if you're careful). What you can do is add a shim or two to raise the main jet needles. It's so easy it should take you only 20 minutes or so. (But you really should re-jet, since shims are a qwik fix). If you have a Standard/Tourer, you can replace the springs with a set from an Interstate. And/Or you can replace the needles with a "needles only" jet kit. We will describe how to do each here for you.

3 options
Assorted washers Radio Shack Part #64-3022

Interstate springs for use in Standard Honda Part# 16050-MBY-671

Pro Dyno Needles only Jet Kit Part # V6000-01

Phillips screw driver
(one that fits the soft screws of the caps EXACTLY)
only if you raise the tank will you need:
10mm socket
12mm socket
Needle nose pliers for needle clips
Click any picture to see enlargement
Click resuting picture to see next
Use backspace key for previous
STEP ONE: Remove choke linkage cover
Three screws, one up top between the front and second carb and two on the side of the linkage cover.
STEP TWO: Remove the choke linkage
You can get away with not removing the linkage if you raise your tank. But, it's easier to get everything lined up and there is less danger you will pop a diaphragm or miss a seal if you pull the linkage. Be careful of the springs and washers. Note how they are oriented before you remove them.
STEP THREE: Remove the carb top screws
Take your time here. Remove the top two screws (near the tank) and then hold the carb top in place as you remove the bottom last screw. Use a #2 phillips. These screws are soft! Before you turn loose of the carb top cover, see the pic below of what to expect.
STEP FOUR: Carb top is a two piece item
Remove the carb top and be careful of the spring inside. If you have pulled the choke linkage, these are easier to get off. Make sure they are clean and free of dust and dirt.
STEP FIVE: Remove the spring
Carefully remove the spring. Try not to bend or kink or stretch it. These springs need to match to keep all six of your carbs working properly.
STEP SIX (alternate): Using Interstate springs on a Standard
Many folks have had success by changing to Interstate springs from the Standard kind. This enhances throttle response in the mid range. IS springs are shorter but with more coils. Used in conjunction with shims or new needles, this makes for a nice mod for only about $12.

If you're just swapping out springs, skip to STEP ELEVEN.

STEP SEVEN: Pull the slider straight out
Take one of the screws that held on the carb top and screw it into the needle holder a few turns. Pull the slider straight up and out. Be careful of the needles and jets. You can harm performance by just putting a little nick or scratch in a needle or a jet. Your bike will run very badly if you damage the diaphragm
STEP EIGHT (alternate): Pop the holder out of the slider and (alternate) install shims
Wiggle and pull the screw that you inserted in the holder and pull out the holder. Shown here are the parts of the assembly. Inside the holder is another smaller spring but it should not dislodge. The stock setup comes with one shim already. If you are just adding shims, then grab a matching washer from the assorted washer bag and re-install the needle with the original washer and one of your washers (for .020) or two of your washers (for .040) or more. Re-install the keeper, pushing all the way down until it clicks. Skip to STEP TEN.
STEP NINE (alternate): Changing needles
One can change the needles by using a "needles only" jet kit. All that you change is your needles, not your jets. This requires that you also adjust the pilot screw. Follow the instructions that came with the needle kit. These needles have a steeper taper than the stock ones. The same cautions apply. If you damage a needle, you are Toast! These pricey kits come with just enough parts to do the job. Don't lose a single washer or retainer. The supplied washer goes above if the retainer and the stock washer goes below the retainer. Install the needle and re-install the keeper, pushing all the way down until it clicks. Many recommend putting the clip in the second slot on stock bikes.
STEP TEN: Install the slider
Invert the diaphragm (make a little "umbrella" out of it). Put the slider back in the carb. Here, the diaphragm will hit the top of the carb before the needle goes into the jet. Be gentle. Remember you don't want to mar the needle or the jet. Tip the top of the slide slightly toward yourself to drop in the needle, then straighten it up to seat the diaphragm. The diaphragm must seat properly, or you'll have a vacuum leak and unbalanced carbs (ouch).
STEP ELEVEN: Install the spring and button up
Push the slider down keeping the diaphragm in the groove. Install whichever spring you are going to work with and replace the carb top. Repeat for all six carbs.

To see if you are running lean or rich, check the color of your plug insulators after running a tank or two. Though the picture above is for heat range comparisons, it matches rich and lean for the most part. Your plugs should look like the center one. For more information on pugs, NGK has a nice write up here.

More plug pictures here with lots of info.

My Valk plugs after 30,000 miles

click pic for larger view.

Making a Pilot screw tool from a radio antenna
Remove the intakes and cover the head holes with tape to avoid stuff getting in there.

Where the Pilot screw is located.

Screw all the way in gently and unscrew 2.25 turns and try it out. Unscrew turn each time to futher adjust.

This article was written after working from a FAQ found on the Valkyrie Owners Association web site. Thanks go out to Rikki Dee who alerted me to the IS spring mod some time ago and to Hondatek who detailed it first, I believe. I added springs some time ago and just recently (May of '01) added the needles only jet kit that I had sitting around for a year or so. I'm not sure of the improvement the needles only will do for you if you have a stock exhaust, but by adding the needles and putting three more disks in my Trapps (making 8 each) I love the "fat" feel of the throttle now for sure!

Questions? Contact Chet at Chet says 'Be sure to write!'

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