I found that I was re-gripping the stock throttle excessively during track days, especially on tracks with a few long straights. I scavenged the site for as much information as I could get and got to work on installing a quick throttle. Although the site contains valuable information on the HRC quick throttle install, it wasn't easy to track it down. I figured it was time to do a tutorial.
PREAMBLE 1 : My track F4i has a PCIII and full yosh exhaust. I'm not sure how well the quick throttle would work on a stock system. I've had no problems with mine but your mileage may vary.
Requirements for this specific tutorial :
- HRC quick throttle kit (pictures below)
- RC51 Starter Switch (picture below)
- Long (10 inches in this example) Philips head screw driver
- Locktite medium strength (suggested but not *really* required)
RC51 starter switch and wire assembly :
HRC quick throttle parts, which should include both pull/push throttle cables, a new grip, throttle housing and mounting clamp and screws (which occupy the stock starter switch location).
Put the bike on the rear stand if available.
Disconnect the wires for the front brake switch indicator and remove brake master cylinder holder bracket from the right handlebar. Keep the master cylinder as upright as possible and slightly out of the way.
Remove the bar end screw, bar end weight and the start/kill switch screws and remove the throttle cable ends from the throttle housing. This last step might be a bit tricky. I found that using a set of needle nose pliers helped.
Slide the throttle housing and old grip off the bar. This will be replaced by the new HRC housing and grip. Remove the old starter/kill switch from the bar and disconnect it from the wire harness.
Now lift the tank, remove the air filter cover (10 screws and the grey electrical connector), the air filter and the air funnels (6 screws).
Next, disconnect the hoses from the air filter housing (3 to the rear, one at the front, and one on the left side). Disconnect the electrical connectors to the left and right side. NOTE : be very careful removing and reattaching the two small air suction hoses located at the rear of the filter. The plastic knob they attach to can break off very easily. I discovered this first hand.
Partially remove the throttle body assembly (the top portion, 8 screws), which is probably the most difficult part.
The tank bungeed up :
Partial throttle body removal, four screws when facing the bike from the front. You'll need an angled screw driver, or a very small one.
Partial throttle body removal, the tricky four screws at the rear. A long (10 inch or more) Phillips screwdriver will need to be used. It will need to go through the frame hole and angled such that it can reach these screws, from both the left and right side of the bike. Picture below from the right side. The left was difficult to picture with the wires in the way. NOTE : the screws do NOT need to be removed -- only loosened enough so that the clamp that they are attached to gives enough wiggle to pull the assembly off.
And put something over the cylinder head intake openings! This suddenly becomes a much more difficult procedure if you drop something in one of these.
Now wiggle the upper throttle body assembly until it comes off the bike.
The pull and push throttle cables need to be removed from the assembly. There isn't a lot of room for fingers here, but with a pair of pliers it is possible to remove the throttle cable ends from the throttle drum (the wheel that will spin to open and close the throttle bodies). It's best to attack the job from below the assembly and have an assistant hold the assembly up as the old cables are removed and replaced by the new ones.
Don't attach the throttle cables to the bracket in the above picture just yet. The right handlebar needs to be setup correctly first.
The HRC throttle housing mount is designed differently than the stock starter/kill switch. There is a notch located on the bottom side of the handlebars. If the same notch is used for the new throttle, the cables will exit directly up rather than just above the brake lever, and will hinder the ability to turn the bars to the left since they will come in contact with the windshield.
To remedy this, find a drill bit that fits the existing hole (or is just a bit bigger), and drill another hole slightly up so that the new housing mount directs the throttle cables just above the brake lever -- ideally they should be angled the same as the stock throttle cables. The picture below shows the original hole and the newly drilled hole. The new hole could have been drilled just a bit higher. As it stands, the throttle cables need to be angled slightly down so that they don't come in contact with the windshield.
Make sure the new housing fits properly first, and then remove it from the handlebar and attach the throttle cable ends of the pull and push cables. Make sure to position the throttle cables at the throttle body assembly end to give as much slack as possible (the reason why the throttle cables were not mounted at the throttle body end yet!).
After slipping the ends onto the new throttle housing, place it back on the handlebars positioned on the newly drilled notch. At this point attach the throttle cables to the bracket at the throttle assembly end. Bolt it down tight and add some Locktite medium strength for good measure. I had the throttle cable come apart at this bracket during a track day the first time I installed it due to the bolts not securely holding it to the bracket. Now spin the throttle and make sure it all works properly. Adjust the throttle slack and then reassemble it all.
The next step is the installation of the RC51 switch. I used abadfish's RC51 to 600 tutorial (
http://cbrworld.net/forums/thread/258009.aspx) as my reference, and it was a perfect match for the F4i with one caveat. Although it is a perfect match to the actual wiring, it differs from what the wiring diagram in the Clymer manual shows. The White/Green of the RC51 should match up to the White/Green in the wiring diagram. But there is no white green on the actual switch when you pull it off the bike?! It does however have a black/yellow which doesn't appear in the wiring diagram but does match up as per abadfish's mapping.
Here's a shot of the RC51 and F4i connectors. They are identical. I removed all the RC51 connector pins since none of them match up by default, and then used the mapping above to poke them back in. You'll need a thin flat head screw driver (something you'd use for working with eye glasses for example) to poke the connectors out. Before poking them back in, re-extend the lock flap to ensure they don't pop out after installation.
Now attach the RC51 switch to the handlebar and connect the rewired end. Then reconnect the master cylinder bracket. There will be very little space between the brake light switch connectors and the RC51 switch, but enough to get them connected.
Get the bike on the track and enjoy not having to re-grip on those long straights!