Edelbroke throttle twist grip pulley ratio

My 1994 XR600R twist grip has too much rotation for me . Does anyone know or use a 1/4 turn or less with a quicksilver carb?

I believe the throttle assembly that comes with the Edelbrock 650R kit has a quicker turn throttle assembly with it. One of the upgrades that people used to do to the Edelbrock XR250 and XR400 kits was to buy the Edelbrock XR650R throttle assembly because it was a quicker turn assembly, but maybe Edelbrock has since changed this to include a quicker turn throttle assembly in their other kits. I'll check one of my 650R's tomorrow morning and let you know how much turn it has so you can compare and see if your XR600 is the same or not. Motion Pro made (actually distributed) or possibly still makes / distributes the throttle tube assembly for the Edelbrock XR650R kit.

The throttle tube on my Edelbrock 650R makes 1/4 turn from closed to WOT. Simply installing the Edelbrock 650R throttle tube assembly may or may not give you the same results. If the throttle cam on your Edelbrock XR600 carb is different than the 650R carb's throttle cam, then you'll get a different ratio.

Here's the link to the throttle tube assembly from Motion Pro that I believe is used on the XR650R...


Here's the specs on this throttle tube assembly...

Max Twist = 109º

Rate = 3.00

Max Travel = 36

In order to figure out approximately how many degrees 'THIS' throttle tube assembly will turn with 'YOUR' carb, you'll need to measure the amount of throttle cable travel in millimeters and multiply it by the throttle's rate to determine your approximate twist rate.

Here's what I do. Open the throttle tube assembly, but leave the cables installed. Mark the pull cable with a permanent marker or tape from a given reference point. Twist the throttle to WOT and measure the amount of travel in the pull cable in millimeters. If you've taken that measurement in inches, then multiply it by 25.4 to convert it to millimeters. Now multiply the carb's travel by the rate of the throttle tube assembly you're considering (3.00 in the case above) and the result will be an aproximation of the number of degrees 'THIS' throttle tube assembly will turn from idle to WOT with 'YOUR' carb.


Cable Travel is = 30mm

Throttle Rate = 3.00

So if the travel of your throttle cable is 30mm and you wanted to use this throttle tube assembly, then you should expect about 1/4 turn (AKA 90º) from idle to WOT (30mm * 3.00 = 90º).

If the travel of your throttle cable is 46mm and you wanted to use this throttle tube assembly, then you should expect a little more than 1/3 turn (AKA 138º) from idle to WOT (30mm * 3.00 = 138º).

Thanks, I called Motion Pro & they are looking into this for me.I might have to get new cables. Thats what they are checking.

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