One of the more endearing features of Suzuki GS and GSX's is the compatibility of many parts between machines. The term "UJM", meaning "Universal Japanese Motorcycle" has been levelled at the GS range many times for this reason.

It follows, then, that engines can be swapped around - for example if you have a good engine but a crashed bike, or an A1 bike with a blown engine (Mind you, you do have work pretty hard to blow up a GS motor!) But most often it is to get more power by fitting in a bigger motor.

Here we are talking about things that go in without any major frame mods - of course if you get into frame mods you can get anything in there (There are quite a few Katana's about with GSX-R 11 motors in). Also be advised of the GS and GSX difference (see Translation page if not sure)

We'll start with complete engine swaps:

GS 550, GSX 550 - No swaps

GS 650 - again no real swaps - the GS 650 Katana motor can be pressed into service in the stocker 650 but no real gain there.

GS 750, GSX 750 - I THINK early GSX 750 motors (pre E series) can be persuaded into the old GS frames. GS 850 isn't worth the hassle as you have to get the shaft drive in but the head can be grafted on - see below.

GS 850 - as we go up, the fun gets better. GS 1000 G (shaft drive) motor goes straight in - but try finding one! GS 1100 G (shaft drive) also goes in but you will need the 1100 swingarm as the drive shaft is longer.

GS 1000 - Happy families can be played with all the GS 1000 chain drive models - e.g. 1000S into 1000 E. But the most common hybrid around is the early ('80 - '81) GSX 1100 16-valve motor which also goes pretty much straight in.

GSX 1100 - early and late GSX 11's don't mix easily, but swapping around models within the same model years will usually work.

GS 1150 / GSX 1100 EFE - No swaps (Why would you want to?!?)

***CORRECTION*** I have had a mail from Down Under stating that the 1074cc lumps bolt straight in to the 1150 / EFE frame. (Which also means that a GS 1000 lump would go in too)...as to why you would want to is that 1150 motors are much more scarce and expensive than the 1074 lumps, especially in Oz, apparently.

Now. What I want to know is how he managed to blow the 1150 bottom end in the first place...:o)))



Jan 2002 - More wisdom from down under...

Hi - All GSX 750 , 1100 and 1150 chain drive motors from 1980 will swap in to any 750 or 1100 frame from 1980 on that is chain drive , the only engine mount that does not line up on the 750 to 1100 is the bottom engine mount under the crank - have to make your own brackets.

I've got a 1982 750 Katana running a GSX1150 motor and had no probs fitting it , my gsx1100et framed drag bike has had in it both the 1072cc and 1150cc motors in it - again no prob in swapping the motors around In all this engine swapping the only thing that u have to change is the wiring a bit to make the 1150 black box match the older wire looms, or u could just run with the older model sender unit on the end of the crank and also fit the older model engine cover as well.

Hope this helps

Alex Paterson, Canterbury New Zealand

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Further wisdom, again from Oz...

Hi, just a quick one; GSX11 motor will fit into a gs1000 frame, only if the lower left crankcase is modified by removing about 10mm. I have just done this!

Gary

Now onto the ONLY hop up that I am aware of by grafting 2 engines together:

GS 750 - The GS 850 G (up to '82) cylinder head goes straight on to the GS 750 bottom end.

NOTE: This is the GS 750, not the GSX 750 - we are talking the '76 - '80, 2-valve per cylinder models ONLY - putting 16 valve heads onto bottom ends from anything with 8 valves won't work.

You will need the carbs too, but basically the whole plot bolts straight on with no crank or case mods.



Finally, a cheap performance tip if you want some extra cubes for your GSX 1100 EFE / GS 1150.

Ever seen a custom EFE badged as "1170" somewhere? If you bore the stock barrels out to the maximum stock oversize (2mm) this takes the capacity up to 1170cc!

All you need to do is get the barrels bored out and then reassemble using the stock oversize pistons and rings - but be advised that if you wreck the barrels after doing this then you will have no rebore margin left and will be looking at new liners, or barrels from the junkyard...