Quick Throttle? - Page 2

Shu · #11 21st November 2009

So I checked out XLXR's link, what exactly is the difference from the stock one? Any chance you did a side by side comparision photo before installing? That one looks basically the same as the one I have in my bike. I have marked it several times for rotation to tune my Mikuni but never measured the overall rotation.

XLXR · #12 21st November 2009

They change the cam profile that changes the mechanical leverage between the throttle tube on the handle bars and throttle plate in the carb. In other words, they regrind the ramp the throttle cable is pulled over just before it attaches to the throttle tube.

This mod is very common in the dirt bike world, and is very effective in how the motor jumps into the power curve. Motocross dirt bike riders want the rpm curve to hit hard and come on fast. Harley's are opposite, the lower rpm curve is not affected, but the upper rpm curve comes on quicker.

Shu · #13 21st November 2009

Weird I just measured the twist on mine...90 degrees exactly and I know mine is the stock HD throttle sleeve.

PistolPete · #14 21st November 2009

Quote:

Originally Posted by flashedwards

This is to update my original post. First, I want to thank everybody that replied and gave me direction. Second, I want to tell you what I found out. Most of the sites that list throttles have them for dirt bike applications and thyey
really wouldn't work on a Sportster. The exception to this is the outfit that XLXR found (yeh, the post directly above this ^^) G2 Ergonomics makes replacement throttles that are straight drop-ins for Harley-Davidson. They fit into the stock switch houseing with zero modifications. The reason that I replaced the original throttle was that I had to regrip sometimes to twist it to wide open throttle. The stock throttle rotates 100+ degrees from idle to WOT, this was just a little more than was comfortable for me without rotating my wrist too far forward. G2 offers a throttle that is 90 degrees or less. I'll grant you that a 10 to 12 degree reduction in rotation isn't a whole lot but it did help and it is noticeable. The way that they have it designed is that for the first half of the rotation it is about the same as stock but it ramps up quicker in the second half. So far it has worked well and I do notice the difference when I'm getting on the freeway or pulling away from a stop sign.

I see that they recommend it for 74-06 models, any mods to get it to work on your nightster?

flashedwards · #15 22nd November 2009

Addendum to my addendum: I wish that I had taken a photo of the two throttles side by side because there is a noticeable difference in the way that they are shaped. The throttle fits my '09 Nightster (as to differentiate it from your lowly run of the mill Sportsters because we all know that the parts are not interchangeable) just fine. Somewhere I read that you must remove the stock throttle friction screw to make the G2 throttle to fit... this was true of the older ones...the new ones work with the screw in place. Don't get me wrong, this throttle isn't magic..like I said it only reduced the rotation by 10 degrees...that's not a lot..1/36th of a rotation...on a stock Sportster that's only a fat 1/8th of an inch (3.5 mm). My nephew keeps his Kawa R6 at my place and his throttle only turns 1/5th of a rev...that's 72 degrees...that's almost scary. Anyway, if you have a throttle that is on a newer Sportster (100+ degrees) this replacement isn't that big of a deal...if your throttle turns more, you might want to check these things out. Oh and by the way, the website doesn't show it but they do have grips that look alot like the plain grips that came stock on my scooter.
I hope that this helped some,
Flash

flashedwards · #16 22nd November 2009

Since I didn't take photos earlier and I can't now because the camera is 20 miles away, I did the best that I could and traced the profiles of the stock and G2 throttles. What I tried to represent is the difference in the cam profiles... on the stock throttle the pull cable rides on the right side of the profile and the cam is at the 3 o'clock position. The throttle would rotate CCW. On the G2 throttle the cam is much more pronounced so that as it rotates and the cable is lifted by the cam the pull is increased. I hope that I haven't confused anybody further but without a camera this is the best that I could do.

XLXR · #17 22nd November 2009

I assume the arrows indicates the throttle cable that pulls the throttle plate open. The end of the cable is fastened on top where the "S" is Stock and "G" in G2 is.

flashedwards · #18 22nd November 2009

Lemme see if I can get my hands on a camera in the next day or so...I kinda figured that the profiles of the throttle cams might be confusing and I guess that they are. I'll get some photos and maybe they will clarify things.
Flash

flashedwards · #19 23rd November 2009

OK, I got hold of a camera but unfortunetly the macro is nonfunctional..so you once again you may have to use your imagination. The throttle barrel made of black plastic is the stock one off of my Sportster. The grey plastic one is the G2 replacement. In the 9 o'clock position is a cam that the throttle cable passes over. The cam profile on the G2 is much larger than the stock one. This is what takes up the cable faster and reduces the needed rotation. I hope that this helps.

Shu · #20 23rd November 2009

Quote:

Originally Posted by flashedwards

OK, I got hold of a camera but unfortunetly the macro is nonfunctional..so you once again you may have to use your imagination. The throttle barrel made of black plastic is the stock one off of my Sportster. The grey plastic one is the G2 replacement. In the 9 o'clock position is a cam that the throttle cable passes over. The cam profile on the G2 is much larger than the stock one. This is what takes up the cable faster and reduces the needed rotation. I hope that this helps.

Yeah that helps a ton. Very interesting. Mine only turns 90 degrees but with the hump it seems it would do exactly as it clams and ramp up the speed of the action progressively. Do they offer one that fits under grips?