Any 82 GS 550M Katana experts out there? What makes this bike so unique?

[bmt]

I've been restoring an 82 GS550 M (US model) and wanted to know what the differences are between the 82 550M and an 81 550L. I'm looking to buy an 81 550L parts bike to help repair my M. Beyond cosmetic differences are there mechanical ones that aren't readily apparent?

-I know the 550 M has dual front disc over the 550 L single disc
-550 M uses a slightly different head over the 550 L
-cosmetic differences like gas tank, seat, plastic, handlebar.

Are the frames interchangeable? I have a sneaky suspiscion that my 550M took a lateral hit and the frame is out of alignment (based on visual inspection anyway of the rear swing arm, rear wheel alignment).

anything else that would say, "hey dummy that 550L won't help you"?

I would for sure like to pull the transmission, cylinder block, and pistons out of the L to put into my M, which is a bit ragged out (low compression, little metal bits in oil sump from engagement dogs). Did these bikes share a common crankcase?

The parts bike is $250US, so a relative bargin (i think anyway) if i get an engine out of the deal. and it comes with a clean title, always a bonus!
Thanks for any advice.

[Old Colt]

Part of the answer is the L frame is not the same geometry.

[doctorgonzo]

Aside from the frame (which is different), is the M a 16 valve engine? If so, the L isn't going to you much good.

[hampshirehog]

The engine is an 8 valve - same as the later 550E model (those fitted with CV carbs). You should be able to swap quite a lot of bits - obviously forks / wheels / body bits would 'change' your bike though.

[Nessism]

$250 for a parts bike seems reasonable. You can pull down both engines and use the best parts from both to assemble one good one. As far as I know, almost all the engine bits will exchange.

Regarding the frame, since it's steel, it most likely can be tweaked back into shape. The race track guys throw there bikes on the ground all the time so if you have a race track near, check around for a frame repair shop.

[Bill C.]

550m

I bought one brand new in 82. The only problem I had at the time was the Yosh header that I bought for a standard 550 had to be tweaked a little to get it to fit the M. I loved my M and wish I had never sold it.

[Zooks]

If you change the frame you will lose the '550M' numbers won't you? The chassis number is what makes it a genuine Katana.

[Shin-Ken 1074]

Hi Dave (are we mates yet?) Could you post a pic of your 550M Katana for the pagans (me that is) to see what one looks like ? Got any details/specs on these Oz models to share? Cheers.

[Zooks]

My Kats in the shed in about 4 million pieces. It effectively looks like this -



Except that someone has painted the tank, side covers & front fender black at some stage.

[emjay]

My Kats in the shed in about 4 million pieces. It effectively looks like this -



Except that someone has painted the tank, side covers & front fender black at some stage.

That's exactly what mine looks like, and it only has 1800 miles on it! I also picked up a second one for parts. It's my understanding that there were less of these shipped to the US than almost any other GS, and I have two. Now I just need to finish my restoration.

[emjay]

You can go to Alpha Sports website and check part numbers to see what can be swapped.

[bmt]

Thanks everyone for your advice. Good call regarding the geometry differences between the L and M models. I was under the false impression that the M was just an L with some cosmetic changes, and the dual front discs. Good to know they do not share a frame. with any luck I'll be able to just get the engine from the parts bike and pull the best engine bits of both and build a nice reliable unit.

Because of the bike rarity in the US I've been very excited about returning it to the road, and ideally keeping it as close to stock as possible. Finding parts has been pretty difficult. I get a lot of 'there is no such bike as a an 82 550M' or 'sure it will fit, all the 550 are the same.' Z1 and CRC have had a lot though and have been easy to work with.

microfiche research has been somewhat helpful but also shows that many parts are not interchangeable, when in fact they are, i.e. common stators among 550L and M, so it has come down to a lot of measuring and visual inspection.

luckily, I have access to a fabrication/machinist friend who can repair the frame if it actually is bent. one step at a time...thanks again!
~BMT

[Zooks]

Check out this page for lots of info. It's a Brit site but it has lots of Kat info that is relevant worldwide. http://www.katanacentral.co.uk/index.asp