I think you're right dimlight, I don't think the GX engine was originally available in the US. I have heard that there were alot of them available from those Japanese engine exchanges.
I'm sure the A15 will work just fine. There's no replacement for displacement

I am proposing to build an A15 aswell. I'm on the fence with building an A14 though, because they can rev more.
Assuming I were to use a genuine GX head with 44mm carbs, which one would give more power? With one the torque would come at low revs, but the other would rev more and give more top end.
Any comments?

i didnt know about that, i pressumed someone had taken a GX head off a 1200 and used it on an a-15

jb1200 - If its a good gx it will have twin SU carbs and double valve springs, you may be able to see through oil filler whether there is a second sprind inside the first on the valve stems just inside the rocker cover

Quote:

Did the A-15 GX come out of a B-210GX? If so, I may have bad news for you. It is my understanding that the B-210GX was nothing more than a sticker package on a five-speed economy model B-210. If so, the engine isn't anything special. In fact, correct me if I'm wrong guys, wasn't the "real" GX engine an A-12? Also, didn't the "real" GX have dual SU carbs?
Having said that, I'd still say you made the right choice. Or at least didn't make a wrong choice. Both engines are good and will really wake up a 1200. No, your smile should not fade too much.
Sorry to be a downer, hope I'm wrong.

nah still good move, check the revs the motor makes power at, there is a big diffence there which is the main diffrence between the two engines, maybe you need to remove some emmision gear to get back lost power but if its got gx head it probably doesnt have the gear anyway and the gx head is a big improvement over others already so you hp will be diffrent

Ok, first post for me but.....tell me that when I had an a14 sitting there next to an a15gx and I chose the a15 that I did not make a mistake. This engine is built and ready to put in. Isn't the stroke/crank the only difference? Cam size not withstanding? Should my smile be fading now?

Doh!
A15 has less power AND less torque?
How does that work?
Please tell me that with all the anti polution stuff taken off that I should be faster than an A14!

An EA/EB/or something falcon tried to take me at the lights today on the way home from work I planted it and he back off and I got to the form one lane heaps ahead of him.
He then backed off heaps, I think to pretend that he wasn't trying to get in front of me.
He he he... Made me happy....

dont forget the A15 had about 10kg of emissions gear on it and a pissy carb. take it all off and fit something decent and you'd easily be looking at 90

whoops thought that one had revs
try this one, but your back down to 69hp

hp and revs and torque too

Wohoo I got 80hp apparently...

Any idea at what RPm this would be at (For A15?)