Gs400 engine into GSX250 frame

[jave101]

Hey guys, I'm looking to convert my 1980 gs400 to a hard tail bobber. Not so keen on chopping down the original frame though.
I've found a 1980 GSX250 frame for sale for fairly cheap, I was wondering if anyone had any idea if my motor will bolt into that frame?

 

[Guest]

Without seeing a 250 in the flesh it's hard to say for sure, but from everything I've seen the crankcases appear to be a similar size if not quite the same.

That would lead me to believe it's doable with some engine mount modifications...

Probably the biggest difference is that I'm pretty sure the front of the 250 frame is a single tube rather than the twin tube cradle of the 400's.

 

[Guest]

i think all the bottom ends are the same, i have a gsx 250 with the engine out at the moment, if you can wait a week i'll get dimensions, like pete say's they're single down tube frames. off the top of my head they have 4 engine mounts, front, bottom, & 2 x rear. not sure what a bobber is but if its some kind of chopper, you could do with the gsx250t as itsl a custom model already, the gsx 250e is more a race style.

 

[jave101]

This is the frame I'm looking at. Not sure what model exactly it is. He is asking $100 so I don't think it will be too much of a loss if it doesn't fit. View attachment 18594

 

[Guest]

Looks like early '80's GSX250 to me, same bodywork as the 450E/S with the 4 valve 250 engine. You should be able to make it fit without too much hassle I would think... the bottom and rear mounts definitely look similar if not the same as the 450 mounts.

 

[jfman]

That tank alone is worth the 100$

 

[wera90ex]

I tried the better part of a weekend to shoehorn a GS 450 into one of those GS 250L frames. I had a bare engine case,cylinder and head to work with and concluded that the only way I was going to get that motor in there was cut the frame and lengthen the engine cradle and backbone.
I think about an inch would have done it.