Tweet
Got a puzzle here. I have my '79 1100 down for maintenance. (head and base gasket, clean carbs etc) while I had heads off I measured the bore and it was 3.0 inches. The Clymers manual says it should be 2.8. The numbers work out to 1250cc. I guess what I want to know is, was there a big bore kit that would give you those numbers ? No complaints just would like to know.
-
Ron Moss
1979 xs 1100 yamaha special (sold)
1984 honda v65 magna (sold)
1984 vtr 250 intercepter
1975 250 TL Honda
2006 Kawsaki Concours
1979 R100RT BMW -
Hey there Ron,
There are two flavors of big bore kits, the 1179cc and 1196. The first uses a 74.00mm diameter piston/ring set, the latter a 74.50mm diameter piston/ring set, which measures to 2.93### inches, so if you measured by a simple ruler, then you could be off a bit to get your "3.0" inches diameter vs. using a caliper or micrometer??
To replace your head gasket you'll need to order one from Wiseco, or a distributor, cause a stock Yamaha one won't fit or work, and don't think you can get that size from Yamaha since it's well over the largest size oversize they ever recommended.
Otherwise, congrats on your "big" find! Enjoy.
T.C.T. C. Gresham
81SH "Godzilla" . . .1179cc super-rat.
79SF "The Teacher" . . .basket case!
History shows again and again,
How nature points out the folly of men! -
Check out the yamaha web page, find parts diagrams. There are yamaha oversize piston sizes and stuff. There is other stuff than wiseco...
It might be from a FJ 1200... or something.
LPIf it doesn't have an engine, it's not a sport, it's only a game.
(stole that one from I-dont-know-who)Comment
-
Custom made forged pistons - pick your size. Ron, if those pistons are 76mm, chances are you've got a 'hot' motor. Maybe ported and cammed too! 1250cc = torque monster.Comment
Comment