77 srx crank cases

SR643

SR643

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Nov 13, 2006
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Age
45
Location
MI
I need some help with identifing a 77 srx case. I have 4 cases without cranks. I need to how to tell them apart from 78 79 80. Any help would be great.

Thanks
 
FOR STARTERS ARE THE STUDS IN THEM ? ALSO IF MY MEMORIES IS CORRECT, THERE WAS A DEFFERENCE WITH THE WAY STATOR MOUNTED TO CASES. 3:16 (yammie tony)
 
Tony,
I think the crank cases where the same part number. 77,78,79,80. The flywheel housings except 80 where different. The cranks where all different to. 76 was completetly different all around. Dean
 
76 srx case is not the same as a gpx...... 77 has 2 pulse fitting and small studs for the cylinders. no holes to mount the oil pump on the pto side . slot for the timing is wider on the mag side. 77 to 80 crank with fit in a 77 case but not the 76 case.
 
YAMMIEGOD3:16 said:
1975 GPX - TOP 888-15100-02-00
BOTTOM 889-15100-02-00
1976 SRX - TOP 8A8-15100-00-00
BOTTOM 8A7-15100-00-00
3:16 (yammie tony)
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like i said ,different cases. humor me and try putting a gpx cylinder on the 76 srx case. I have both in front of me as i type this.
 
Well!!!! I still say the 77 srx rules hands down. Ha. Who wants to correct me on that. 78 SSR doesn't count. They rule on there own....Dean-o
 
76 & 77 cases use 8 mm studs for the cylinders 77 crank uses a extra brearing on the mag end (2 of them) thats the difference 76 to 77 The only difference between 77 and 78-80 is the size of the studs 78-80 use 10 mm studs. 77 crank will fit in the newer cases. newer crank will fit the 77 cases
 
I noticed the studs and the 8f2 heads will not fit the newer ones.

Thanks for all the info.
 
STUD SIZE WAS CHANGED IN 1978. ALTHOUGH SOME EARLY 78 SRX,s still had small studs. I HAVE ONE FOR YOU EXPERTS. WHAT ABOUT DUAL RING PISTONS. ANYBODY! 3:16 (yammie tony)
 
snopro said:
Aaen has single ring wiseco 18mm wrist pin pistons for sale for the 76/77 440 srx's. he had wiseco produce a batch for him.
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purists will still cry foul claiming nothing is better than oem. i call bs on that though make due with what you can get... if aaen has wisecos they will probably work just as good when clearanced right.
 
I have all years of SRX pistons 76-81 brand new in the Yamaha box. 78 has dual rings. 79 and 80 have single ring. As for the engine cases, every year 76-80 were different. 76 340 (small cylinder bore) 76 440, 77 (extra bearing) 78 (small studs) 79 large studs (one elbow) 80 large studs (two elbows). Jeff Wurl
 
AHood said:
purists will still cry foul claiming nothing is better than oem. i call bs on that though make due with what you can get... if aaen has wisecos they will probably work just as good when clearanced right.
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if the purists are actualy racing their 77 srx's, they need pistons for them. unless you have a hoard of OEM stashed away...no where else to get 'em other than Aaen.
 
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