gs 650 engine in a gs550 frame

[johny]

Hi there my name is john from coventry west midlands 

quite new to this type of work 

during the lockdown i bought a 1983  gs550m katana  in bits and only now do i realise why the lad sold it many problems and missing parts .buy hey thats life 

i need a new engine for my gs550 i have managed to find a reasonable priced 1985  gs650 .does anyone know if this will fit in my frame with minimal issues .

thanks ride safe 

john

[Swiss Toni]

Hi John. Welcome to OSS! @wraithwill be along in a mo. He’ll let you know!

[wraith]

Hi and welcome to OSS

Unless you have found a important chain drive gs650 (bit rare in the UK) the answer on no it won't fit, as most of the gs650 are shaft drive and completely different. 

The other 650cc GS looking engine was the NX85 which is a turbo charge gs650 chain drive but again won't be a straight swap because of the turbo bit.

You can put any other gs550 in the gs550kat frame with no problems, or if you don't mind a bit more of a project which will mean a bit more messing, is putting a bandit/gsxf 600 engine or gsx750f engine in it, been done meany times  or the other option depends on what's up with your 550 engine is to put the gs650 top end on the 550 bottom end.

[TonyGee]

what about a GS/GSX 750 engine to keep it old school ? 

Edited March 30, 2021 by TonyGee

[johny]

thanks wraith

its the bottom end thats the problem the gear selector shaft was bent and has broken of the case on the clutch side .

so if this gs650 is a chain drive you think it may fit 

also someone has just offered me a gs 750 engine do you think that may fit 

with the type of messing you spoke of does that involve welding in engine mounts .

thanks john

[vizman]

Without some serious frame mods you won’t fit a gs750 or gsx750et motor in there.

[wraith]

As Viz says a gs750 motor will not fit 

To put a oil cooled motor in b6/gsx600f, you can use the standard bottom rear engine mounts, make new (bolt on top front and rear, the bottom middle ones, one is a make a plate to bolt on the other is Tec a weld on but not a must have.

Have a good look through the projects pages, as it's been done meany times you will find some project build in there.

Don't forget the oil cooled engine's are getting to be 15+ years old now and the air cooled 30+ years old and a lot of the air cooled may need work done on them 

For easy way it's a case of getting a running gs550 engine and putting that in. All depends on how much of a project you want and how original you want to keep the bike, and don't forget some gs550 came with CV carbs and the early one's came with slide carbs which have different carb rubbers and heads which could give you some matching of carbs as you gs550kat I would think are CV carbs ?

The down side of putting a oil cooled motor in (depends on your budget) is you will also need complete engine, carbs, harness and exhaust.

Like I said, have a good look through the projects pages to get some information of how involved it all is 

Once you have the magic 50 posts you can put up a wanted thread in the market place, which will be closed to you at the moment. 

[johny]

thank you 

most helpfull  

[Poldark]

We had a discussion not to long ago:

550/650 Swap - Page 2 - Air Cooled - Oldskoolsuzuki.info

As stated above, your most expedient route, other than another 550 engine, would be to swap in an oil cooled 600. 

[wraith]

Get a b6 for about £300 ish use the engine, carbs, electrical bits and running gear. Get some to weld mounts on the swing arm to keep it twin shock, get a rf600 bottom yoke for the b6 forks etc and away you go. Or the same but with a gax750f 

Then if on the b6 route, keep your eyes only for some gsx600f fork springs to go in the b6 fork to make them stiffer, 

[Poldark]

Which 550 engine in the Katana?  Two valve per cylinder or four?  The link I provided for the 650 top end on a 550 lower applies to the two valve per cylinder engines.  The four valve per cylinder engine from the mid 80's, often labeled TSCC, were a different engine.  If that's what you have, you need a direct replacement engine or an oil cooled 600 as Wraith described.  If you aren't sure what you have, take a picture and we can help you figure it out. 

[johnr]

gs550e engine is the same as the kat 550 motor and there are loads of them around.

 

Edited April 7, 2021 by johnr

[Tosha]

Maybe if you find gsx550es engine i think it will fit ...

It's more old school air cooled engine and litlle more horse power than gs 550

[Poldark]

I don't think we ever had the Kat 550 here in the US, so I'm not sure which 550 engine it had.  Certain model designations differ between different markets.  Certain new products were not introduced the same year here and there.