crashing aint so bad
Join Date: Nov 2006
Location: santa barbara, ca.
Bike: 2005 red r6
Re: Graves Progessive throttle tube...
In any class of racing your allowed to alter the throttle housing and respective throttle tube. Graves is smoking some serious stuff selling that thing at that price. You can get throttle tubes from Motion Pro for $20 bucks that are progressive. Just not for an R1, or R6. In either case I can also buy an entire throttle kit for this price that comes with 3 different cams to get the ratio I want. That thing is made of plastic even. The bean counters at graves or , graves in general are full of themselves for pulling that crap. I realize that they do R&D for predominately Yamaha products, but that is no excuse to charge ridiculous amounts of money for a relatively inexpensive part. There has to be a 500% mark up on that thing. There is no way you can convince me it cost a ton of money to create that cam profile.
I took a stock throttle and created a progressive cam on it too. I used zip ties that I bonded to the throttle tube. I shaved the back side for the return line much like the pic of the Graves unit. Mine is about a 1/5 throttle ratio and is set up to ramp up in the middle of it's travel. Mine is set up for an easy onset, then aggressive in the middle and then smooths out as the throttle is nearly full open. Mine also fits in the stock housing. Where it looks as if graves is set up to ramp up after the throttle is opened a little and is aggressive all the way. The graves design is great for those that like to get to full throttle, like right now. There is nothing wrong with the graves design, but I feel it's too expensive for what it is. Mine cost me about 2 hours of work and a couple bucks in zip ties and super glue.
All you have to do to make your own custom throttle tube cam is get a few of the medium sized zip ties and glue them to the throttle tube. I suggest using plastic model glue to permanently bond the plastics together. Then build the zip ties up with the zip side out ( so the cable can run in the grove ) and create your desired profile. I cut under the the boss for the pull side cable so I could fit a zip tie to get it closer to the start of the cables pull. I then layered that zip tie over two others that created the profile I wanted. The center zip tie was the shortest and the outside zip tie was the longest. The first zip tie laid down went up against the cable boss and to about half the cams circumference. The outside zip tie went into the slot I cut in the cable boss to go over the end of the first zip tie starting the cam profile. The second zip tie ramps it up even more in the middle and then tapers back again at the end. You can do a two zip tie version as well where the outside zip tie goes over the first one to create a more subdued profile. You will have to grind out a couple of tabs inside of the throttle housing in order for a three tie cam to fit. The beauty of the zip ties is that you can grind them down to any desired profile once they are in place. It's also not a big deal if you want to start over. Just grind them off and redo the zip tie layout to your desired cam profile. Here is a crappy windows paint of how I did it:
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As you can see with a little ingenuity you can easily come up with any profile you desire. I choose one that started off mild and then went aggressive and tapered back again towards the end. You can make one that is straight rate by simply making the cam bigger in circumference. or you can make one like the graves unit that is pretty much all or nothing. The Graves profile is very aggressive and will be very twitchy with part throttle applications since a little input equals a very large throttle cable movement. Their profile also looks to be a 1/6 throttle cam. Which means a very short twist from closed to full open. I'm not certain as to the exact profile and ratio of the graves, but that is what it looks like to me.
I decided to make my own after having purchased a throttle kit. The different ratios were nice but I wanted something more. I decided that I would be crafty and give it a shot. It took a couple of tries to get what I wanted, but once I nailed it down and got the return and pull cables adjusted properly I never looked back. It's been 2 years and the cam that I am using is still together and working just as I want it to. I replaced the stock throttle set up on my 05 with the stock housing from an 06 R6 and then custom made throttle cables to fit the change. I now have a custom contoured cam that is 1/5 ratio.
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Last edited by luke geis; 02-18-2011 at 05:20 PM.