FZ1 Holeshot Stage 1 Kit, part II: Jet Kit Install

December 31, 2014

Day 2 of the project was the actual carburetor work:  installing new jets, checking float levels, adjusting mixture screws, and installing carb shims.  As complicated as it sounds, with the exception of nervously drilling out the mixture screw plugs the kit install was much easier than removing the carbs from the bike.

Installing New Main Jets

The first step is to turn the carbs upside down and open the float bowls to get to the floats and main jets.  The instructions recommend to do this one bowl at a time, although this is not possible given the new jet sizes.

Note: This should be done in an extremely clean, dust-free environment.  A spec of dust can clog jets or float needles and render the bike inoperative.

Each float bowl has a cover with 4 screws holding it on.  The screws are extremely difficult to remove.  I ended up whacking all of them with an impact screwdriver, and ruined a couple screws.  Fortunately the Holeshot kit provides replacement hex bolts which are used to secure the covers after new jets are installed.

Floats and jets

The main jets are the largest of the round slotted brass fittings sticking up between the pink floats.

FZ1 carburetors are odd in that the main jet sizes are not all the same.  In #1 and #4 (outer) the stock size is 132.5 and #2 and #3 (inner) the stock size is 130.

The Holeshot kit calls for a 130 jet in #1 and #4, and 127.5 in #2 and #3.  However the kit does not include 130 jets, so the 130s from #2 and #3 end up being swapped into carbs #1 and #4.  Then the 127.5 jets from the kit go in #2 and #3.

Actual jet replacement is easy, just hold the base with an 8mm open end wrench and unscrew the jet with a large flat screwdriver.

At this point it's a good idea to check the float levels.  Pat's Ivan's Jet Kit install page has some guidelines for how to measure and set float levels, and Holeshot sells a nice float gauge which I bought, that makes this easier. Suffice to say I've never adjusted float levels from their stock positions when installing a Stage 1 kit, and one can spend quite a long time bending float tabs random amounts trying to get the levels perfect.  I did measure the levels and found them to be within a mm of spec, and decided not to mess with it.  That way lies madness.

After the jet swapping is done the covers should be put back and the screws replaced with the hex bolts from the Holeshot kit.

Mixture Screw Adjustment

This is the hardest part of the kit. There are brass plugs covering the mixture screws that must be drilled out and removed.  The kit includes a drill bit and self-tapping screw to help with removal of the plugs.

The brass plugs can be seen in the first photo, they are the brownish-colored circular metal disks with a tiny hole in the middle.

The hazard here is that if one drills too far one can drill through the mixture screw underneath the brass plug, thus ruining it. The best way to avoid this is to create a drill stop by cutting a ball-point pen in half and then sliding the pen half over the drill bit.  That way the drill bit can only go a small distance.  Did I do that?  No.  Stupid, stupid.

There is a lot of brass dust created that is best vacuumed up with a shop vac after drilling.  It is hazardous to get any debris near the carburetors.

So 3 of the 4 plugs came out perfectly and I managed to drill into the mixture screw in carb #3 almost enough to ruin it.  Fortunately there was just enough of the screw left to turn it delicately with a jeweler's screwdriver.  The base setting is 3.5 turns out from bottom.  Turn the screw in all the way (clockwise) until it doesn't turn anymore, then back out 3.5 turns.

Brass plugs drilled out

Shims

The next step is to turn the carburetors right-side up and unscrew the black caps on top to install shims, one cap at a time.

The caps are spring-loaded and there is a tiny o-ring and spacer that can fly out, so they need to be removed carefully.  Take note of the position of the o-ring and spacer.

Cap removed, showing spring and o-ring

Underneath the cap is a delicate rubber diaphragm that needs to be gently peeled off the carb, while removing the plastic needle cap in the center of the diaphragm.  There is a tiny spring that can go flying.

The base setting is 3 shims (they look like steel washers), which get slid over the pointy end of the needle.  Then reinstall the needle and diaphragm and move on to the next carb.

Needle with shims:

After the shims are done the carbs are ready to be reinstalled in the bike.

Air Box Mod

This can be done anytime before the tank goes back on.

The air box has a rubber cover which gets discarded, except for tabs on the right and left side that fit over posts on the frame.  The rubber tabs are needed to secure the tops of the plastic side panels.  This is another one of those steps that can't be undone.  So I very tentatively cut up my air box cover with a scissors.

A 1" hole saw is needed to drill a hole in the air box lid.  The drill bit in my hole saw became detached somehow and I had a heck of a time getting the hole saw not to drift all over the place.  But eventually I got the hole drilled in the center of the lid.

After drilling through the air box lid it's a good idea to clean up the air box hole with sandpaper to prevent plastic shavings from entering the air box.

1" air box mod

So ended day 2 after 5 hours or so.  Up next, carb reinstallation.

FZ1 Holeshot Stage 1 Kit, part I: Carb Removal

December 30, 2014

I was generously gifted a Holeshot Stage 1 kit and comp1 slip-on for X-mas this year.  While I greatly appreciated the gifts and was very eager to get rid of the OEM muffler, in spite of the fact that I've installed 2 Bandit Stage 1 kits (with help), I had a fair amount of apprehension about this install.  The FZ1 is a more complicated bike and more difficult to work on, the carburetors had never been out, and procedures of this complexity always offer plenty of opportunities to turn a decently-running bike into salvage.  I had a 4-day weekend over the New Year's holiday to do the install so I convinced myself now or never.  My schedule allowed plenty of time to proceed slowly and cautiously: day 1 for carb removal, day 2 for kit install, day 3 for carb reinstall, and day 4 for the slip-on.

Prep

To prepare I read the Holeshot kit instructions, the carb removal and disassembly procedures in my Clymer manual, and the excellent carb removal and Ivan's Jet Kit installation procedures on Pat's FZ1 site. The Holeshot Stage 1 kit appears to be easier to install than Ivan's with less drilling required. While it appears less comprehensive I was mainly interested in adjusting the mixture to safely run the Holeshot slip-on, with peak performance being a secondary consideration. I didn't feel I needed the added performance or complexity of Ivan's kit.

Stage 1 kit and instructions

Carb Removal

Even with Pat's excellent instructions this proved quite time-consuming.  The FZ1 is tightly packed and doesn't allow a lot of room to work.  There are a total of 6 vent hoses and 2 coolant hoses into the carburetor, as well as fuel tank vent hoses, AIS, etc.  A lot to keep track of.  One of the air box bolts is inconveniently behind the fuel pump, and Yamaha likes to threadlock everything.  Not to mention that my FZ1 has a lot of miles and has been to the Salt Flats twice so there is corrosion to deal with.

First the easy stuff:  remove seat, side panels, tank, battery, and air box covers.  I got stuck early on, apparently Yamaha used red threadlock on the 3 screws retaining each air box cover.  Why??? The air box covers were nearly impossible to remove and I stripped one of the screws trying to get it out.  Note to self, use impact screwdriver next time.  Fortunately I had long ago been gifted a Desmoparts stainless steel fastener kit which had replacement air box cover bolts I never installed.  Saved a trip to the hardware store.

Tank, battery, and side panels removed

Next, label and remove top R/L vent hoses, AIS hose, and carb fuel hose.  Hoses removed:

Top hoses removed

Next up, loosen air box and move it as far back as possible.  There are 3 bolts total, one on top and one on either side, plus the 4 clamps that hold it to the carburetor.

Fuel pump, air box with side cover removed

Next, the coolant hoses, one on each side.  The manual says to drain the coolant, but Pat's procedure said the hoses could be blocked instead.  I clamped them with binder clips before pulling them off the brass carburetor fittings.

Right side coolant hose, binder clamp

After the upper hoses are out of the way the choke cable can be disconnected.

Next, two lower vent hoses on the left side of the bike.  I carefully marked one of the hoses and its fitting with white-out to make sure I got them back on in the right order.

Left side vent hoses

Next, the throttle cables have to be loosened, both at the control end and the carburetor end.  Pat notes only the top adjuster on each cable needs to be loosened at the carb end.  I put a piece of masking tape on the rear cable, although they are color-coded and the adjusters are different from each other.

There is a big white electrical connector that has to be disconnected, then I loosened the intake boot clamps.  This required a special long-handled hex driver to reach the inner clamps.  I used the Holeshot driver which works really well.  Then sprayed a generous quantity of Tri-Flow at the opening of each boot.

Finally there are two vent hoses clamped to the underside of the carbs.  I was able to reach under there with a long needle-nose pliars to slide the clamps down the 2 hoses.  This was difficult and took a long time.

After all that the carbs were ready to slide out the left, note that the throttle cables and 2 lower vent hoses are still connected.  Per experience with the Bandit kits carburetors can scratch off frame & engine paint as they're moved around so I covered all surfaces with soft rags.

Carefully sliding carbs out the left side

There is not a lot of room to slide the carbs out, and it still seems like there is a lot of plumbing in the way.  As the carbs come out the final 2 vent hoses can be disconnected from the bottom, and once out the throttle cables can be disconnected, front first.

Carbs out, finally

As per suggestion I stuffed clean rags in the intake boots to prevent dirt from getting in there.

In total it was about 4.5 hours to get to the point where I could open up the carbs to install the kit.  But I was beat so I decided to get a fresh start the next day.  So ended day one.  Note that the Holeshot instructions say the kit can be installed right next to the bike without removing the throttle cables.  This sounded precarious to me so I fully disconnected the carbs and brought them to my work bench.  Note that the float bowls are full of gas and will vent gas everywhere as the carbs are rotated.  They can be manually drained by opening the drain screws, or by rocking the carbs back and forth, which will drain the carbs out the two vent hoses.

Carbs out, engine side