Motor and Frame fitting...or lack there of:(

[Kwest187]

Hey guys/gals...
I'm looking for some help here on fitting my 1981 GS550E motor into a 1980 GS550 frame.
A quick overview of my story-
I'm building a bike for a friend of mine. I picked up a nice 550 motor and last weekend picked up a bike (550) that had a (450) motor in it.
I pulled the old motor and then spent all of a day trying to get the 550 motor to fit in the 550 frame.
It just doesn't seem to line up-
I've double triple checked the numbers...the Frame VIN on the neck stem Starts with GS550
the motor is stamped 549 on the case-
I'm pretty sure this motor should fit in the frame...but I just can't get it to go-
It doesn't look like the mounting tabs were altered for the 450 motor...but there are differences in the front and and front bottom mounting holes on the engine-
I'm waiting on a shop manual-hopefully that will give me some answers-
But I found this forum and am guessing people on here have gone through what I'm doing-
Any help. tips advice would be great-

[Nessism]

Most likely the engine mounts are different for the 450. Bet if you get some 550 mounting plates the engine would fit.

[Kwest187]

Great help on the GS550 frame question-

So-the 550 frame I have...most likely is equipped with the 450 mounting plates-
That would explain why I figured I needed a different spacer on the top rear mounting bolt and why I guessed I'd need to use spacers on the top front mounting bolt...
and these 550 mounting plates should then assist in the bottom front and rear tabs lining up...
This is great news-thanks very much for the quick response-
I'll start shopping around online tomorrow...Thanks again...I was pretty bummed until now!

[Nessism]

I parted out a 550 a couple of years ago and tossed the hardware in a box...along with the hardware from a couple of other bikes. I most likely have those 550 mounts only I don't know what they look like. I'll dig though the box tomorrow and see what's hanging around. Anything I find you can have.

[Kwest187]

That would be great-

Those mounting plates would be great to have...I've searched ebay and haven't found a whole lot...
What I am finding are the front brackets and the bolts, spacers, and the one rear bracket that goes on the left side top rear...if that makes any sense-
My issue yesterday was that the distance on the frame from the bottom rear holes and to the tabs that stick up on the frame rails is off...
The engine case has an indentation on the bottom for the tabs...and the bolts for those tabs have a weird little triangle shaped nut that wedges in there-
I am thinking of cutting those tabs off if I can find brackets to make it fit...
I wish I knew what was done to the frame to make that 450 fit...so that I can undo it-

[Kwest187]

Downloaded 2 manuals-

I downloaded the 450 and the 550 manuals...
I definitely have the 550 frame...since the pics of the 450 frame show a single down tube and the 550 frame is a double wishbone...my frame is a double wish bone-
I'm going to triple quadruple check the numbers tonight-
But I believe the frame and cases from 77 to like 82 are pretty much the same-
Why those lower rail mounts are giving me such a headache I don't know...
worse case scenario I cut them off...attach engine using the other 3 mount locations...then mark and reweld the tabs on the rails where I need them...
But...the frame has divots on the tubes next to the tabs...which tells me the tabs were never relocated for the 450 motor-
ahh....
I've had many Japanese bikes...but got spoiled working on HD's...they are like tractors and everything lines up so smoothly-
Also If I were stronger I could muscle the motor around more which might make it easier for me to see what is and isn't lining up-
the old back is killing me today, hahahahah

[mike_of_bbg]

does this help?

Here's a shot of the rear right-hand mounting bracket. Just don't make fun of my sucky rattle can paint job on the frame there This is from an 82 GS550 L. This bolt goes through the block, a spacer, then the left hand side of the frame - there's no bracket on the LH side.

BTW, the edge of the triange you can't see here has an indent cut.

[mike_of_bbg]

and this

Here's the lower mid bracket on the RH side. BTW, sorry I tried to use a high-contrast ruler but the flash was still washing it out. The LH side has a tab welded to the frame. Those go to the frame pockets into the cam nuts. I recall those cams being a bit of a struggle.

[Suzuki_Don]

KWEST did you get the photos I sent you via email. Let me know. They should explain a lot.

[Kwest187]

Yes I got the pics!

I got the pics...thanks a bunch very helpfull...also the pics posted on this thread were great too-
So, here is where I'm at.
Last night I cut out the two mounting tabs on the rails of the frame...
I've come up with a hoist style system to swing the motor in so that helps a lot...that 550 is back breakingly heavy-
Anyway I cut out the rail tabs, swing the motor in and still no dice-
The rear lower tabs are still off, and after pulling the motor-I realize this is one point the frame was altered by the previous owner....It almost looks like he cut out the piece of the frame that held the lower rear mounting tabs (that the center stand mounts to also) and flipped it, then welded it back in place-
Who ever did it did a good job because it was very hard to tell these were not factory welds...
Now looking at the pics posted on this thread about the rear upper mounts...It may appear mine were altered here as well, cut out and lowered about an inch and a half, then rewelded....
I guess I'll find out tonight when I cut out the lower rear mounting tabs and see how close it lines up....
Damn...I hope I don't have to reweld in all the mounting tabs. But I guess I'll find out...
Thanks again for all the help-I'd be lost right now without this Forum-