how can I improve backshift

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WATCHMAKER

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Mar 23, 2005
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I know I can improve the backshift if I tighten the secondary. What about a helix change? Lets say I have a 52/42, what would be a logical choice? I was told once that the finish angle has more affect on backshift, is this correct? Do I choose a helix with both angles lower such as a 50/40 or would a 50/42 help? That way I have not changed my finish angle, which from what I understand would change shift rpm.
 
I think more twist on secondary improves back shift. There was a good right up somewhere on here
Dual angle helix is for upshift i think. Better holeshot then tapers off. I have a dual angle helix on my wish list.
I have been wrong a few times in my life also.
 
yep, smaller angles and tighter spring pre-loads, all yield better backshift. so does lighter wieghts. if you went from a 52/42 helix, to a 50/42 helix, your initial rpms outta the hole, should be a little higher, due to the shallower angle, causing the secondary to not upshift as fast. if you want to get rid of that 52/42 helix, let me know. what brand is it? what spring are you currently using too and what's the preload on it?
 
I"m keeping the 52/42. Yamaha Silver and I have tried 60 up to 90 wrap. So if I switched to a 50/42 the rpm's would jump to maybe 83-8400 and then climb the rest of the way to 85?
 
WATCHMAKER said:
I"m keeping the 52/42. Yamaha Silver and I have tried 60 up to 90 wrap. So if I switched to a 50/42 the rpm's would jump to maybe 83-8400 and then climb the rest of the way to 85?
Click to expand...

what does it do now w/52/42 helix and silver spring @ 60? you shouldn't need a spring more than green @ 70 and the red @ 80 works fine too w/that helix.
 
You should be tuning top end rpms with the weights. Backshifting is letting gas and jumping back into it and how the clutch reacts to it. You seem to be describing full shift out rpms.



WATCHMAKER said:
I"m keeping the 52/42. Yamaha Silver and I have tried 60 up to 90 wrap. So if I switched to a 50/42 the rpm's would jump to maybe 83-8400 and then climb the rest of the way to 85?
Click to expand...
 
A roller secondary can help with backshift also. Part of the resistance against upshifting is in the friction of the helix on the buttons. Unfortunately this same friction occurs during backshifting as well. With rollers you lose almost all of the friction which has to be offset with more spring twist for upshifting. The benefit is that you don't have the friction any more during backshift, and it reacts much better to off the throttle and back on. This difference can be as much as 30%. One thing to note however is that rollers can be a little harder to tune. Tradeoffs, tradeoffs.
 
Mopar...Right now it is 8bu-00 4.5 tip, 52/42, Silver @ 70 and the set up works fine for what it is intended. More of a race set up. Don gave me the whole set up and he told me it would not have very good backshift. Right now it hits about 81-8200 then climbs to 8500, just like it is supposed to do.

jwiedmayer...I know a shallower helix will improve backshift but I guess I am thinking ahead to how a shallower helix is going to effect rpm's. If I change the helix should I expect to have to change rivets in the weights.
 
its those 8bu-00 weights. they backshift for $%^&. they work for their intended purpose.....drags. if you want a weight for aggressive trail, that upshifts hard and backshifts great, then get heavy hitters. i just trued/tried a setup this weekend, that put my buddies heel clicker setup to shame. also, the clutch temps w/this heavy hitter setup are the coolest i've ever gotten on any setup. you can put a bunch of hard drag runs on them, open the hood, and the clutches are sooooo cooool to the touch. what primary spring are you using? hauck orange?
 
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