GS6 and MC5 motor differences

[mx503]

What is the difference between a GS6 400 motor versus a MC5 400 motor? Is the transmission the big difference? The bike is a 77 model and I was curious if the motor would work fo vintage motocross. Thanks for your help!

Thanks, Bob

[Steve Minor]

Welcome aboard Bob......

I think the biggest difference is the GS6 is a 6 speed and the MC5 is a 5 speed.....actually both are 6 speeds but one gear on the MC5 is "pinned", making it a 5 speed....BUT it can be "un-pinned" making it a functional 6 speed. As far a ratios go, I believe 2nd gear on a GS6 is 1st gear on a MC5...

Maybe someone with more knowledge can jump in now......

[John Ehrhart]

I am certain someone else will come through with technical differences, but I can tell you from a lot of time riding them, there isn't much difference in power.
I ran a desert race on a friend's MC5 and ran some enduros and two-day qualifiers on my GS6. Apart from being lighter, the MC5 was slightly more crisp with the less-restrictive MX exhaust. Having said that, the GS6 would still wheelie in 5th! Oh, that is, after I finally got the jetting figured out.

1969 Husqvarna 400 Cross
1974 Monark
1975 Jackpiner
1978 GS6 400
1981 250 MX

[mx503]

Thanks to all who have replied! I have a couple of MC5 250s and I also have an extra chassis. I am looking at a GS6 and thought I could make a pretty good mx bike with all of the parts for the open class for vintage racing. I had a new 76 MC5 250 with Fox Airshox which was awesome! I will keep everyone updated on this progect and I really appreciate everyones input and help!

Thanks, Bob