R100GSPD Throttle Tube/Grip, Cable Mechanism

To remove the throttle tube/grip or lube the throttle grip gears, can I simply unbolt the Type C front master cylinder and slide it off in order to remove the cable pull mechanism cover? I haven't looked at it much yet and the sparse documentation about this creates my question.

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leafman60 said:

To remove the throttle tube/grip or lube the throttle grip gears, can I simply unbolt the Type C front master cylinder and slide it off in order to remove the cable pull mechanism cover? I haven't looked at it much yet and the sparse documentation about this creates my question.

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Click to expand...

You only need to remove the top cover over the gear/chain mechanism. That allows access to lube the gear and chain, and if you want to lube the grip tube assembly itself it will just slide off the bar once that top cover is removed. The throttle tube teeth and the rotating gear have index marks to help correctly align things on reassembly.

Best,
DeVern

I have experience with airheads, done a lot of work on the older models. This Type C set-up, however, is my first. Casually looking at it from the rider's seat, the throttle gear mechanism cover and it's single hold-down screw appeared encumbered by the master cylinder reservoir sitting on top.

This afternoon, I had a closer look and now see the seam that defines a separate cover over the cogs. Once I get to that slotted screw, I assume that small cap will come off and reveal the guts.

I still am not yet sure how the cable pulls are attached inside since that reservoir covers up the area that I would expect to find all of that.

This is basic stuff, though. I'll try to post some pics when I get things apart. May help someone in the future.

Pic made today-

I struggled with the little chain and making adjustments. I still can’t get it right

IIRC there is an arrow on the throttle tube that should line up with a mark on the toothed wheel that the cable attaches to. I (vaguely) remember having to fiddle with it for a long while the first time I took it apart.

Other thiings to check

First question is why do you need to get in there? Thottle hard to turn? Crunchy feeling when it does turn? Time to change the cables?

To do this right, yes you need to remove the master cyclinder and the starter switch assembly..grand total of 1 screw and 2 bolts. Swing the switch out of the way and push the master cylinder out of the throttle assembly. Make sure you watch for the larger brass washer and little rubber bumper that goes on the end of the master cylinder plunger..may still be in the assembly..if so leave them or take them out and clean.

Now you can really check what's going on.

if you have another set of hands, have them push the throttle levers on each carb up to give you some slack at the master cylinder to get the throttle cables out of the holder..or just crack loose the 10mm nut on the carb top, pull up on the throttle cable and unscrew the furrrel all the way out. do both sides. But then you have to take a short ride to heat up the engine and do a proper carb balance.

Now you can lift out the throttle gear and clean, then inspect it. Hopefully you have some grease to clean off so you can find the line on top of the gear that aligns with the line between the teeth on the hand grip.

Look at the gear teeth directly under the line..and 3-4 in a row. Compare them to the teeth further away. Nice and sharp or do a couple look like they've been blown over in a storm and worn at an angle? Check for the same on the throttle tube. You might see the same problem.

That's the cause of the crunchy feeling when you first turn the throttle grip. Not smooth and can sometimes hang up. There's something like 14 variations of the throttle tube and gear so you should order a new set based on the last 7 diigits of your VIN.

Lube up and replace. Installation is the same as de-installation (like that term). Now you're have a smooth throttle response and easier time balancing the carbs.Check it again in another 30-40K miles.

One of the most overlook wear items on a bike with over 40k miles.