drag race engagment

bojisrx

bojisrx

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Aug 25, 2010
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hey guys im looking to get around 6700-7000 engagement on my mod stocker srx 440. I am running new Yamaha apex clutches on her.

What do you guys with experience find works best. IVE been told by some so mill the spider so the roller sits closer to the weight and then add more belt clearance with a colar spacer. Also running a larger roller like a 16.5 will increase my engagement.


But that being said the larger the roller the slower the upshift ??? So why would I do that for drag racing ? Im thinking that just knotching the weights bigger for engagement is the way to go. Anyone else think differently.
the spider milling was said by a big Yamaha guy because it is more correct and accurate every time. But knotching im sure would make this machine come out harder?



LEmme know thanks Yamaha guys !
 
We use to engage our 600 pro stocker up in that range. We tried a couple different things like offset rollers, larger rollers, spider cut and notched weights. I finally settled on using notched weights, it didnt affect the rest of the shift out as much as the other options. I started with a good hard pulling set up that under revved just a bit. Ground my notches multiple times until I reached the engagement I wanted. The final result was a very hard engaging weight that was almost perfectly back a my max power rpm. Once you get a good profile cut they work great! Just make sure all notches are exactly the same!
 
jabber800 said:
We use to engage our 600 pro stocker up in that range. We tried a couple different things like offset rollers, larger rollers, spider cut and notched weights. I finally settled on using notched weights, it didnt affect the rest of the shift out as much as the other options. I started with a good hard pulling set up that under revved just a bit. Ground my notches multiple times until I reached the engagement I wanted. The final result was a very hard engaging weight that was almost perfectly back a my max power rpm. Once you get a good profile cut they work great! Just make sure all notches are exactly the same!
Click to expand...


yes thats what i thought too! cause if you move spider it affects overall shift.
how big of knotches did you guys need to make to get that rpm. big like the old yamaha clutches with 8m6 weights or something. i used a dremil with a circular sander tip and went that route.
 
However you go about it, the best thing to do is build a jig that holds all 3 weights stacked up so the notches are the same. use it on something stationary, drillpress, bridgeport etc...
 
A Jig is mandatory! Its really hard to do without it. I used my milling machine. The size of the notch will depend on the spring and weight combo your using. I started the notch on the centerline of the roller at the rest position. The roller should sit nicely into the notch.
I started small and kept increasing the size.
 
Yes. Do you guys do a sharp edge on knotch or roll it over. Do rollers wear out often from knotch . I know like on my 77 stocker they wear out every race
 
I ran a hauck orange and a big engagement shim to get. 6800 on my improve stock 600 Srx
 
I have seen the notches done two ways. Cut flat with a sharp face and the way I did mine was more like a pocket for the roller. I was worried about damage to the rollers so choose this way. Not sure if it's actually better though. It worked well and I had no roller problems.
 
Engagment shims effect your over all shift on spring I don't think shims are the answer
 
John We Used Notches On The Old Srx,s Years Ago To Increase Engagement. Never Hurt Rollers. The Deeper The Notch, Higher The Engagement. Did It Right Where Roller Comes In Contact. Also Use To Add Slight Flat Spot To Weight To Make It Smooth , But High For Racing. 3:16 (yammie tony)
 
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