81 SRX crank case questions

davet · Post by **davet** » Mon Dec 10, 2007 2:36 pm

Can anyone give me the full scoop on what lead to many 81 SRX's having new Crank Cases and Bell housings?

I heard 2 things

1) Crank Shaft Failure/Bottom end troubles, hence new cranks and New Cases etc
2) Stator / Electrical issues leading to a new part via recall needing a different bell housing.

whats the scoop? how would i tell whats been done to my SRX's and whats not ??

i have 3 motors, 4 sleds, and am building 2 good ones.

thanks for the help

Post by **tyler440** » Mon Dec 10, 2007 7:36 pm

from what i know the problem has to do with the crank being longer on the side of the clutch supposedly this amplifies any off balanceness of the clutch therefore toasting bearings, but im not claming to be completely right

davet · Post by **davet** » Tue Dec 11, 2007 2:29 pm

Thanks, any one else know about the so call electrical issues?

what are the Crank Case ID numbers that tell me an original from a Recall Replacement ? are the originals a 437 ? what are the Replacements Numbered ?

anyone ?

davet · Post by **davet** » Thu Dec 13, 2007 4:29 pm

no one ?

Post by **tyler440** » Thu Dec 13, 2007 8:17 pm

ummm yeah? where are the numbers on the crank??

davet · Post by **davet** » Thu Dec 13, 2007 10:07 pm

Believe i Typed "Crank Case ID Numbers" there are number on the Case right ? maybe on the bell housing ?

sorry for the confusion

Post by **Vmax540** » Fri Dec 14, 2007 12:54 am

Dave if you go to Yamaha parts at http://www.yamaha-motor.com/sport/parts/home.aspx and select the 81SRX then scroll to the bottom you'll find a ton of info. on the Technical updates of the 81 !

81 SRX without Vin # and a 83 Vmax housing

davet · Post by **davet** » Fri Dec 14, 2007 12:22 pm

Thanks alot !

vmax-540 · Post by **vmax-540** » Sun Dec 23, 2007 6:14 pm

The reason for the bell and ignition change was that the original ignition didn't have an advance curve in it . When the 82 were built they had an advance curve very similar to the Vmax's they did that to give it more bottom end & midrange , so Yamaha updated the 81's to the new ignition but to do that they had to change the bell or gear case what ever you want to call it as the new stator would not fit into the old case , some dealers re stamped the # 's and some didn't. The crank problems had to do with to small of bearings and crank diameter .

davet · Post by **davet** » Mon Dec 24, 2007 10:30 am

Thanks alot !!! thats exactly what i needed. I appreciate the Info