Making a quick turn throttle, DIY w/pics

[Z1R rider]

I wanted a quick turn throttle but didn't have an R6 throttle tube, so I decided to do it myself

First I cut a piece of 1½" sch 40 PVC a little wider than the slot that the cable pulls on the tube fit into

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I then ground it to fit juuuuust right, not so wide as to bind and not so narrow as to let the cables fall off and get jammed

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I then cut a piece out and heated it with a hair drier to form it to fit on the throttle tube where the cables attach (not glued just a pinch fit)

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I had to do some grinding inside the track in the housing and the cable end to make room for the extra circumference of the PVC spacer


before

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and after

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also had to grind the cable mounting bracket on the carbs to give the cables enough slack to not bind

before

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and after

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and reattached

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this takes the throttle from about 100º stock to around 80º of rotation to get to full throttle. To do this mod you do NOT have to take the throttle tube off, (I took this one off to get better pics) which can be a pain in the donkey, getting the bar end off can be all but impossible, I couldn't get this one off with an impact driver, I had to use heat from a propane torch. 1¼" or even 1" might have worked, but I had 1½" in the shop at the time.

[Triple Jim]

Very nicely done and well documented, thanks. A friend of mine does something almost exactly the same for the old Kaw triples.

[Cra1g]

Is it difficult to obtain an R6 throttle tube? I'm thinking about doing a quick turn throttle as well, but if R6 throttle tubes are cheap and easy to come by, I may as well just go that route.

[csmith12]

[Z1R rider]

Originally Posted by Cra1g

Is it difficult to obtain an R6 throttle tube? I'm thinking about doing a quick turn throttle as well, but if R6 throttle tubes are cheap and easy to come by, I may as well just go that route.

I think they're easy enough to come by, I just had some time to mess with it and didn't have an R6 tube. Like I said in the write up, with the spacer there is no need to remove the bar end to switch the tubes. With the R6 tube you still have to do something about the cable length and clearance inside the housing. It's also my understanding that there are two R6 tubes, one is bigger (quicker) than the other, but I don't know the years that they changed them.

[Ram Jet]

Originally Posted by Cra1g

Is it difficult to obtain an R6 throttle tube? I'm thinking about doing a quick turn throttle as well, but if R6 throttle tubes are cheap and easy to come by, I may as well just go that route.

Motion Pro makes some quick turn twist grips. I'm not sure if they make one for the 250.

Bill

[Triple Jim]

I got a cheapie quick throttle made by Emgo. It's amazingly decent quality, too. It's going on my DT100. They make a couple different ones.

[sparkcycle]

Originally Posted by Z1R rider

I think they're easy enough to come by, I just had some time to mess with it and didn't have an R6 tube. Like I said in the write up, with the spacer there is no need to remove the bar end to switch the tubes. With the R6 tube you still have to do something about the cable length and clearance inside the housing. It's also my understanding that there are two R6 tubes, one is bigger (quicker) than the other, but I don't know the years that they changed them.

I installed the quicker version of the R6 tube and had no issues swapping it out on my Ninja 300. I didn't even have to adjust the cable length... it just fit YMMV.

[bruce71198]

[IMG][/IMG]

I beveled the edges and for clearance.

[cbreater]

Just did this, following 99% of it and it worked great. Wonderful post. Thanks for sharing! \

Confirmed that I did use 1" and expanded with hair dryer. Worked fantastic!

As a point of reference this is now almost exactly the same rotation from full closed to full open as my S1000RR.

[Ram Jet]

Originally Posted by Triple Jim

I got a cheapie quick throttle made by Emgo. It's amazingly decent quality, too. It's going on my DT100. They make a couple different ones.

I think I'm missing something here. What benefit would a quick turn twist grip be on a motorcycle with a constant velocity carburetor. You can twist yourself silly but the carb slide is only going to open as fast as the engine can ingest the fuel/air mix. That is, you don't control the throttle slide the carburetor does.
"Let's twist again like we did last summer."

Bill

[Singh2jz]

Originally Posted by Ram Jet

I think I'm missing something here. What benefit would a quick turn twist grip be on a motorcycle with a constant velocity carburetor. You can twist yourself silly but the carb slide is only going to open as fast as the engine can ingest the fuel/air mix. That is, you don't control the throttle slide the carburetor does.
"Let's twist again like we did last summer."

Bill

I installed one so I could obtain WOT in one motion and keep my wrist in a comfortable spot. It makes banging gears a lot easier too.

[DannoXYZ]

Originally Posted by Ram Jet

I think I'm missing something here. What benefit would a quick turn twist grip be on a motorcycle with a constant velocity carburetor. You can twist yourself silly but the carb slide is only going to open as fast as the engine can ingest the fuel/air mix. That is, you don't control the throttle slide the carburetor does.
"Let's twist again like we did last summer."

Bill

The butterflies comes first though as they determine how much air-volume flows through engine. Then the slides adjusts to that volume to maintain a constant velocity through for the metering circuits. Cause and effect, sure slides open by themselves and they do so based upon volume of air-flow the butterflies dictates. This usually occurs fairly quickly anyway, just a couple of engine-revolutions. At high-RPMs, it's pretty much instant.

So 25.5bhp max-HP requires wide-open 90-degree butterfly position. There's absolutely no way, nada, zip, zilch possibility slides will open all the way at less than that butterfly opening. Trick is how to get there easily for the rider.

What the throttle-mod does is reduces the effort, not necessarily time to get to that max butterfly opening. If you do over 1000 gear-shifts in a single race, that 100-degrees of throttle-twist, requires A LOT of energy and effort. Some people can't even do that with a single-twist and have to walk their hand over grip. Changing that to just 80-degrees makes it easier to do and less fatiguing.

[Ram Jet]

Originally Posted by JacRyann

The butterflies comes first though as they determine how much air-volume flows through engine. Then the slides adjusts to that volume to maintain a constant velocity through for the metering circuits. Cause and effect, sure slides open by themselves and they do so based upon volume of air-flow the butterflies dictates. This usually occurs fairly quickly anyway, just a couple of engine-revolutions. At high-RPMs, it's pretty much instant.

So 25.5bhp max-HP requires wide-open 90-degree butterfly position. There's absolutely no way, nada, zip, zilch possibility slides will open all the way at less than that butterfly opening. Trick is how to get there easily for the rider.

What the throttle-mod does is reduces the effort, not necessarily time to get to that max butterfly opening. If you do over 1000 gear-shifts in a single race, that 100-degrees of throttle-twist, requires A LOT of energy and effort. Some people can't even do that with a single-twist and have to walk their hand over grip. Changing that to just 80-degrees makes it easier to do and less fatiguing.

Ummm, OK. Thanks.

Bill