DIY throttle for testing?

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knightscape

Member
Jul 29, 2013
340
1
16
Maine
My project bike is an old kit I got second hand and it's definitely seen some better days, I've got the engine remounted, and aside from waiting for a new chain (the one thing I've spent $ on), I'm almost to the point of being able to test it. The one piece I'm unsure of is the throttle cable. I have an old cable that's missing the lever end and a 90° noodle (does that go on the lever end?) and I'd like to fab up a throttle lever out of parts for testing. I don't really want to spend money on new parts until I prove it's capable of running, otherwise if it needs enough it might be more worth it to just buy a new kit. So I'm looking for your best suggestions for a temporary throttle pull. I have bins full of bike parts like shifters, cables, brake levers etc at my disposal, so is there any particular kind of lever/cable that works better than others for a testing basis? Thanks.
 

mapbike

Well-Known Member
Mar 14, 2010
5,502
109
63
Central Area of Texas
id just take a brake lever and the cable and make up a throttle.

The easiest way to make the throttle cable from a brake cable in my opinion would be to find a good cable that has the ball or barrel shaped lead/whatever the metal is on one end and to grind it down so that it is much smaller, probably just under 1/8" in diameter, this will be the end that will go into carb and attach to the carb throttle slide, after this has been attached and the threaded cap that goes on carb has been slid over the cable all the way down to the carb and screwed back on, then you can slide the cable sheath over the cable until it rest down it the adjuster sleeve/screw that screws down into the carb cap, once you know how long the sheath needs to be for reaching up to the Throttle/brake lever, I would mark it, remove it from over the cable and then cut it to the measured length, slide it back over the cable, now you will only need a simple brass cable stop so that you can add this to the cable on the lever end once the cable has been routed through th proper area of the lever so that once the cable stop is installed the lever can be pulled and the cable will lift the slide in the carb.

Sorry about my description of (how to) on the brake/throttle cable, its kinda hard to put all this into words but is actually something that would be very simple to do with a way to grind down the one end and a simple pair of side cutters for cutting the cable to length and also for cutting sheath to length.

If you do this just remember to work from the carb up to the lever, this is the only way you will likely get the length of the cable and the sheath correct.

Hope this helps

cable end on the far right will be what you want the end to look like once it is ground down but it will need to be a bit smaller in dia, when you look at bottom of carb slide you will see where the cable end will rest and have an idea of what he finished dia of the cable end should be.


Here is pic that shows cable stops I spoke of, most all auto parts dealers have these on the HELP racks.




map
reddd
 
Last edited:

knightscape

Member
Jul 29, 2013
340
1
16
Maine
Is the carb end the same size as a regular bike shifter cable end? In your pic on teh right it looks just like a shifter cable to me. If so I could just use a shift cable into the carb end and then clip an adjustable stop onto the lever end and avoid grinding. I think I even have an adjustable stop in my parts bins, just have to find it... LOL
 

mapbike

Well-Known Member
Mar 14, 2010
5,502
109
63
Central Area of Texas
Is the carb end the same size as a regular bike shifter cable end? In your pic on teh right it looks just like a shifter cable to me. If so I could just use a shift cable into the carb end and then clip an adjustable stop onto the lever end and avoid grinding. I think I even have an adjustable stop in my parts bins, just have to find it... LOL
Read my post again carefully and your question will be answered, the reason I said you would need to grind it down smaller is because it isn't the same.

Map
 

mapbike

Well-Known Member
Mar 14, 2010
5,502
109
63
Central Area of Texas
The pic is not a pic of the correct cable it is just to show what end I was talking about that you would need to grind down smaller.

If the cable you used has a barrel on both ends one of them will need to be cut off.
 

knightscape

Member
Jul 29, 2013
340
1
16
Maine
Gotcha, thanks, I had misread your post before. I got home tonight and took it apart and found the smaller size, so I dremeled down the cable end on a shifter cable to fit and ran it up to a makeshift throttle thumb lever I made out of some old downtube shifter parts. It's janky as anything, but I think it'll work for testing. Getting close, a few more bits of tinkering and I'll be ready to hit it.
 

mapbike

Well-Known Member
Mar 14, 2010
5,502
109
63
Central Area of Texas
Gotcha, thanks, I had misread your post before. I got home tonight and took it apart and found the smaller size, so I dremeled down the cable end on a shifter cable to fit and ran it up to a makeshift throttle thumb lever I made out of some old downtube shifter parts. It's janky as anything, but I think it'll work for testing. Getting close, a few more bits of tinkering and I'll be ready to hit it.
Hey thats great, glad you found some stuff to piece something together for the testing, ill bet it'll work out and then you know whether or not to invest a few bucks in a proper cable and twist throttle if thats what you want on it.

Be glad to hear the results of the testing.

Map
reddd