GP shift pattern
12-17-2006, 12:20 AM
#1
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Squid
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GP shift pattern
has anybody tried running the gp shift pattern on the superhawk. all you have have to do is turn the clamp over on the shift rod coming out of the engine. i marked the shifter to make sure i got it back in the right spot then flipped the clamp over. the rod from the shifter to the clamp rubs on the rear set a little, but it hasn't affected the use. it glides past very smooth and doesn't bind. i've found that its made the up shifting a lot more postive feeling just pressing the shifter down as opposed to lifting it up. i don't miss the 1-2 shift anymore. clutchless shifting is a lot smoother. it took me a couple of days to get used to it, but i find myself liking it.
12-17-2006, 05:44 AM
#3
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I rode a GP shift bike once. I'll never do it again. I understand why it would be helpful on the track when you can't get your foot under the lever on a long sweeper (I've always cured this with proper gearing myself). On the street I see no benefit, so mine is going to stay as-is.
12-17-2006, 08:58 AM
#6
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I rode a GP shift bike once. I'll never do it again. I understand why it would be helpful on the track when you can't get your foot under the lever on a long sweeper (I've always cured this with proper gearing myself). On the street I see no benefit, so mine is going to stay as-is.
12-17-2006, 10:20 AM
#9
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I changed mine for the track but unless you have a real need for it it doesn't much make a differance. if you like it go for it, if not leave it as is. it's completly a matter of preferance. it does take some getting used to.
12-17-2006, 01:55 PM
#10
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We changed all our road race bikes to "road" pattern years ago, after an unfortunate experience on a TZ 350 Yamaha which changed itself down a gear in a fast corner because the lever touched the ground (no foot under it, either).
I'd rather have more positive downshifts, myself, on the road - I use engine braking a lot on the VTR.
I'd rather have more positive downshifts, myself, on the road - I use engine braking a lot on the VTR.
12-17-2006, 04:03 PM
#12
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Yeah, not one of our more spectacular blow-ups, but a blow-up nevertheless. It didn't spit me off; therefore the memory is of an unfortunate event, and not of a painful one.
12-17-2006, 04:06 PM
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12-17-2006, 04:15 PM
#14
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Ah, well, the rear tire needed replacing anyway. And the inside of my leathers was already a bit sweaty. It was a shame, as I was leading a race at the time and there was a championship at stake. The sponsor stayed with me, though.
12-17-2006, 09:36 PM
#15
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I have 3 bikes, so there is no way I would want one different o the others, so mine will stay standard.
As a thought to those of you running the reverse pattern shift, why not buy an aftermarket shifter and fit that directly to the spline like a dirt bike. That will give you the reverse pattern shift you want, and will have the added benefit of removing the linkages and giving you a nicer shift action. I know a guy who has done this and is very happy with the result.
As a thought to those of you running the reverse pattern shift, why not buy an aftermarket shifter and fit that directly to the spline like a dirt bike. That will give you the reverse pattern shift you want, and will have the added benefit of removing the linkages and giving you a nicer shift action. I know a guy who has done this and is very happy with the result.
12-17-2006, 10:50 PM
#17
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For those of you wanting to get better shifting with shorter throws, try the following:
* Loosen the adjusters on the link and extend it out about 4-5 threads. This will move the shifter in the downward direction. Leave it loose.
* Now loosen and remove the shifter arm bolt and remove and replace the arm exactly ONE spline in the clockwise direction. Install and tighten the shifter arm bolt.
* Adjust the shift lever to your liking and tighten the two locknuts.
What this does is gives you less lever travel due to the increased angle of the shifter arm. It works great at the track and street with or without the clutch.
* Loosen the adjusters on the link and extend it out about 4-5 threads. This will move the shifter in the downward direction. Leave it loose.
* Now loosen and remove the shifter arm bolt and remove and replace the arm exactly ONE spline in the clockwise direction. Install and tighten the shifter arm bolt.
* Adjust the shift lever to your liking and tighten the two locknuts.
What this does is gives you less lever travel due to the increased angle of the shifter arm. It works great at the track and street with or without the clutch.
Thanks Greg
12-18-2006, 11:04 AM
#20
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For those of you wanting to get better shifting with shorter throws, try the following:
* Loosen the adjusters on the link and extend it out about 4-5 threads. This will move the shifter in the downward direction. Leave it loose.
* Now loosen and remove the shifter arm bolt and remove and replace the arm exactly ONE spline in the clockwise direction. Install and tighten the shifter arm bolt.
* Adjust the shift lever to your liking and tighten the two locknuts.
What this does is gives you less lever travel due to the increased angle of the shifter arm. It works great at the track and street with or without the clutch.
* Loosen the adjusters on the link and extend it out about 4-5 threads. This will move the shifter in the downward direction. Leave it loose.
* Now loosen and remove the shifter arm bolt and remove and replace the arm exactly ONE spline in the clockwise direction. Install and tighten the shifter arm bolt.
* Adjust the shift lever to your liking and tighten the two locknuts.
What this does is gives you less lever travel due to the increased angle of the shifter arm. It works great at the track and street with or without the clutch.
12-19-2006, 12:25 AM
#22
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Understand that the shifter mechanism is changing linear movement into rotational movement much in the same way our engines work with the piston, connecting rod, and crankshaft. So now picture the piston in your engine at exactly mid stroke, this would be 90° on the crank. For X amount of movement of the piston you will have Y amount of crankshaft rotation. Now move the piston lower in its stroke and the crankshaft is now rotated say 15°, up to 105° on the crank. Now, for every X amount of movement in the piston will give you Z crankshaft rotation, where Z>Y (by some value). If you're really interested in the math, go to http://www.wfu.edu/~rollins/piston/.
12-19-2006, 02:33 PM
#23
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Understand that the shifter mechanism is changing linear movement into rotational movement much in the same way our engines work with the piston, connecting rod, and crankshaft. So now picture the piston in your engine at exactly mid stroke, this would be 90° on the crank. For X amount of movement of the piston you will have Y amount of crankshaft rotation. Now move the piston lower in its stroke and the crankshaft is now rotated say 15°, up to 105° on the crank. Now, for every X amount of movement in the piston will give you Z crankshaft rotation, where Z>Y (by some value). If you're really interested in the math, go to http://www.wfu.edu/~rollins/piston/.
I think you're confusing the idea that the shift rod equals the (engine) connecting rod. In this case, the con-rod is the stationary part of the shifting mechanism. The shift rod is merely a connecting linkage. It always operates in the same way no matter where it is located on the shaft. It's radius always remains the same.
The way to accomplish what you are proposing is to make the radius on the shift lever-shift rod connecting point smaller than the radius where it connects to the shifter. However this would come with a commensurate increase in required force.
Whew!
12-19-2006, 05:54 PM
#24
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hehehe, no, I've got it right. You have to think of it in the sense of distance traveled on the shifter for a given (fixed) angular change (a shift up or down) rather than pistion speed and acceleration. The same basic principles apply. I'm going to try and not complicate this any more than I have to but if you want me to do the math just let me know and I'll work it out for you. Been a while since I looked at my trig/calc stuff. Maybe it'd be a good brain exercise for me. 
12-19-2006, 08:40 PM
#25
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I'd really rather have you explain it in a way that I can understand, if you would. "hehehe" isn't quite doing it for me.
No matter where the shift shaft arm is it travels the same distance per given shift. It's still equally radiant from the shaft whether it's up, down or anywhere in between. What you seem to be indicating is that the radius changes, somehow, depending on where the shaft arm is located. How could this be?
No matter where the shift shaft arm is it travels the same distance per given shift. It's still equally radiant from the shaft whether it's up, down or anywhere in between. What you seem to be indicating is that the radius changes, somehow, depending on where the shaft arm is located. How could this be?
12-19-2006, 09:16 PM
#26
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I think if you are familiar with vector diagrams, you can figure out why Greg is right. Some of the down motion is being converted to forward motion. Look at the average slope of the curve in between 0 and 45 degrees, and 45 and 90 degrees.
It took me a while to work it out in my head. Especially since I refused to go look at the bike in person.
It took me a while to work it out in my head. Especially since I refused to go look at the bike in person.
12-19-2006, 09:17 PM
#27
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I'd really rather have you explain it in a way that I can understand, if you would. "hehehe" isn't quite doing it for me.
No matter where the shift shaft arm is it travels the same distance per given shift. It's still equally radiant from the shaft whether it's up, down or anywhere in between. What you seem to be indicating is that the radius changes, somehow, depending on where the shaft arm is located. How could this be?
No matter where the shift shaft arm is it travels the same distance per given shift. It's still equally radiant from the shaft whether it's up, down or anywhere in between. What you seem to be indicating is that the radius changes, somehow, depending on where the shaft arm is located. How could this be?
Sorry, didn't mean to be flippant or condescending at all.
Okay, forgive the really crude working diagram of what we have as a shift linkage. See attached pic. The pencil is the shift rod. The yellow sticky is the linkage arm and shift shaft. I calibrated the paper with each 1/4" of movement of the "shift rod" pencil in its stroke. Notice how the distances become greater (ie more degrees of angular rotation of the shift shaft) as you get farther in the stroke. That's what we're doing here. We rotate the shift arm one spline clockwise so that the shift arm doesn't need to move as far to reach the same angular rotation for a proper shift, up or down. We lengthen the shifter arm to compensate and keep the shift lever the same height as before the mod.
Lemme know if you have any other questions.
12-20-2006, 12:15 PM
#29
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Sorry, didn't mean to be flippant or condescending at all.
Okay, forgive the really crude working diagram of what we have as a shift linkage. See attached pic. The pencil is the shift rod. The yellow sticky is the linkage arm and shift shaft. I calibrated the paper with each 1/4" of movement of the "shift rod" pencil in its stroke. Notice how the distances become greater (ie more degrees of angular rotation of the shift shaft) as you get farther in the stroke. That's what we're doing here. We rotate the shift arm one spline clockwise so that the shift arm doesn't need to move as far to reach the same angular rotation for a proper shift, up or down. We lengthen the shifter arm to compensate and keep the shift lever the same height as before the mod.
Lemme know if you have any other questions.
Okay, forgive the really crude working diagram of what we have as a shift linkage. See attached pic. The pencil is the shift rod. The yellow sticky is the linkage arm and shift shaft. I calibrated the paper with each 1/4" of movement of the "shift rod" pencil in its stroke. Notice how the distances become greater (ie more degrees of angular rotation of the shift shaft) as you get farther in the stroke. That's what we're doing here. We rotate the shift arm one spline clockwise so that the shift arm doesn't need to move as far to reach the same angular rotation for a proper shift, up or down. We lengthen the shifter arm to compensate and keep the shift lever the same height as before the mod.
Lemme know if you have any other questions.
It transfers the motion along a flat plane.
Theoretically, the shift shaft can be one inch or fifty. Shortening the rod may make it stiffer, but it won't change the number of degrees traveled. The shifter rod is merely a connection between the levers. The eyelets of each lever travel the same linear distance. If they are differing lengths, one or the other will travel more degrees of rotation. If they are the same length, they will travel the same rotation.
The only way to accomplish what you propose is to adjust the relationship between the two lengths of the shifter and shaft levers. As the shift shaft lever is made proportionally longer, though, the amount of force required to move it increases due to lost mechanical advantage.
12-20-2006, 08:23 PM
#30
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Okay, let's get a couple things straight here:
- The shift lever, the thing your toe operates, is not in the equation here. This mod DOES change the distance the shift lever travels (less). This is NOT a variable here. It is affected by the mod, which is exactly the result we're looking for, but it is not a variable.
- The shifter arm, the thing connected between the shift shaft and the adjustable shift rod, is not going to change length. It will change it's angle on the shift shaft, and that's it. Thus radius does not change.
- The required rotation of the shift shaft in order to change gears does not change. It is a constant.
- We DO lose mechanical advantage here, but what we gain is less travel ON THE SHIFT ROD AND THE SHIFT LEVER.
I don't know if I can make this any clearer, especially with the little mockup I made last night. Anyone else who has engineering background please chime in.
- The shift lever, the thing your toe operates, is not in the equation here. This mod DOES change the distance the shift lever travels (less). This is NOT a variable here. It is affected by the mod, which is exactly the result we're looking for, but it is not a variable.
- The shifter arm, the thing connected between the shift shaft and the adjustable shift rod, is not going to change length. It will change it's angle on the shift shaft, and that's it. Thus radius does not change.
- The required rotation of the shift shaft in order to change gears does not change. It is a constant.
- We DO lose mechanical advantage here, but what we gain is less travel ON THE SHIFT ROD AND THE SHIFT LEVER.
I don't know if I can make this any clearer, especially with the little mockup I made last night. Anyone else who has engineering background please chime in.
