Installing LA ChopRods Internal Throttle

Published In The August 2014 Issue Of Cycle Source

Article & Photos By: Will Ramsey www.faithforgotten.com

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here is no denying the fact that internal throttles are just cool. Clean looking handlebars, hidden throttle cable, what could possibly be the down side? Well, some internal throttles have gotten a bad rap due to performance issues and dependability. Cheap materials and poor designs have led to sticking throttles and broken cables. But with time and a little extra R&D there are a few companies producing Internal Throttles that perform as well as they look. I have always used LA Choprods Internal Throttle on all Faith Forgotten Choppers builds. No. I do not have a deal with LA Choprods, and in fact I have never even met Gard. My choice to use his product is strictly based on my opinion that this throttle is very well designed and has performed exceptionally well on all of my builds. It is also made entirely in the USA.

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The LA Choprods Internal Throttle is well packaged and accompanied by a very detailed and easy to follow instruction sheet.

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The first order of business is to cut 4” off the right side end of the handlebar. This can be done in many ways, but it is most important to make the cut as square as possible. I usually use a cold saw but in this picture you can see I am using a vertical band saw with a square guide.

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Be sure to debur the edge of the cut.

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The next step is to drill and tap the set screw hole that holds the throttle in place. I usually do this in the vertical mill because it is fast and exact but as you can see in the next 5 pictures this can be done accurately by hand if your technique is precise.

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Using layout dye and a set of dial calipers, a line is scribed precisely 1.5” from the end of the tubing. Make sure the scribe line is on the bottom of the handlebars so that the mounting set screw will be hidden.

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A hardened punch is used to accurately locate the drill hole along the scribed line. Take your time with this step to ensure accuracy.

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A 9/64 drill bit will follow the punch mark. Care must be taken to hold the drill bit perpendicular to the tubing.

CSM-AUG2014.pg61_Page_1_Image_0004A shallow counter sink makes an excellent lead in to any tapped hole

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Using an 8-32 tap, the setscrew hole is threaded.

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All of our handlebars are made using .095” wall DOM steel. The inside diameter must be sanded in order for the internal throttle to fit. With some patience, this allows for a tight fit and eliminates excessive play in the throttle. I simply use a piece of aluminum chucked in a drill and wrapped in adhesive sand paper to achieve the desired fit.

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A universal throttle cable is used. After being routed from the carb and through the handlebars, the vinyl cable housing is cut to the desired length. With the entire cable attached to the carburetor, the inner cable should be cut 1-11/16” past the end of the vinyl sheath.

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The Internal Throttle can now be disassembled and installed during final assembly.

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The silver cable guide must slide onto the cable before installing the orange slide plunger. Be sure that the counter bored side of the guide is facing toward the cable housing. The slide plunger contains a brass sleeve which the last ¾? of inner cable is inserted into. Two opposing set screws are torqued equally as they compress the cable. The brass sleeve protects the cable from being damaged by the twisting compression of the set screws and greatly reduces the chance of a broken throttle cable at this point.

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The slide plunger and cable guide are now inserted into the black inner sleeve of the throttle. Be sure to secure the guide with the short set screw before inserting the inner sleeve into the handlebars. Once the inner sleeve is lined up with the threaded hole, the long set screw is inserted through the bottom of the handlebars, securing the entire assembly.

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The two opposing bearings are installed. This design by LA Choprods offers excellent balance and smooth performance of the throttle assembly.

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Make sure the cable is secured to the carburetor and that the spring return functions without a hitch.

 

CSM-AUG2014.pg61_Page_1_Image_0013 Finally the grip is installed and the system is checked. Make certain that the throttle moves smoothly and returns quickly when released. I’m sure the debate will continue over the use of internal throttles. Ultimately the decision is up to you but I strongly suggest that you think about the design, and choose a throttle that has been engineered and manufactured to perform without cutting corners. Personally, I will continuing using the LA Choprods throttles. As always please contact me if you have any questions.

For More Information About LA Chords be sure to check out their website at www.choprods.com

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