Gs 550 with 650 head swap

[alexl]

I had a look around, but couldn't find any builds which have done the swap, or much info. anyone point me in the right direction?

[gsx]

Had a 550 few years back with big bore  , sorry can't remember what size but was definitely over 600 with bandit 6 carbs , went like stink .well it did compared to the standard bike .

not much help to you though

[alexl]

13 hours ago, gsx said:

Had a 550 few years back with big bore  , sorry can't remember what size but was definitely over 600 with bandit 6 carbs , went like stink .well it did compared to the standard bike .

not much help to you though

Good to know the carbs fit. I was going to put a GSXR 750 in the frame, but I thought it may be a bit too much, so will try with the old GS 550 first. I think the 650 swap gives about the same power as the standard GS750, but much lighter so should go well. I have GSXR front and back end to go on, just looking for some bodywork and should be good to go.

[wraith]

Yes, I have done this  you need pistons and barrels off the 650 head off the 650 (kat one is best but hard to get but standard 650 is good) 650 cams or you can use the 550 one, one off the 550 cams are better than the 650, I think the exhaust. You need to use the 550 can sprockets which ever cams you use as cam chains are different (or the I did was but I was using the Early 550 slide carb motor). You may need to open the crank case up where the barrels sit but not by much? Apx 1-2mm

B6/gsx6f carbs fit the gs650 head the latter gsx600f carbs where 33mm instead of 32mm on the b6 the 550 and 650 zorsts will fit never tried it but the b6/gsx600f zorsts may fit the GS? More oppositions?

And away you go 

Edited January 13, 2017 by wraith
Added a bit.

[wraith]

PS, there was quite a bit of info on gs resources site.

[alexl]

1 hour ago, wraith said:

Yes, I have done this  you need pistons and barrels off the 650 head off the 650 (kat one is best but hard to get but standard 650 is good) 650 cams or you can use the 550 one, one off the 550 cams are better than the 650, I think the exhaust. You need to use the 550 can sprockets which ever cams you use as cam chains are different (or the I did was but I was using the Early 550 slide carb motor). You may need to open the crank case up where the barrels sit but not by much? Apx 1-2mm

B6/gsx6f carbs fit the gs650 head the latter gsx600f carbs where 33mm instead of 32mm on the b6 the 550 and 650 zorsts will fit never tried it but the b6/gsx600f zorsts may fit the GS? More oppositions?

And away you go 

You make it sound so simple! I will take a look over at the gs resources site, cheers

[wraith]

It's all U.S stuff but good for Ted stuff 

[wraith]

Just been in the shed and having a sort out and came across some gs550 gaskets and points cover. If you need/want them let me know and I will send them to you.

[johnr]

top end off gs650 katana will drop onto thee 550 bottom end, and give a healthy boost. btw, the 650 kat, whilst being called a 650 was actually iirc 673cc so thats even more of a  boost! plenty of 650 kat bits kicking round. i know there are plenty of engines knocking round in the owners club. ive given at least 2 of them away in the last couple of years.

 

[johnr]

theres a 550 kat in the owners club fitted with a 600 bandit engine, with no issues, so i suppose the 750 engine will probably fit in there too.

 

[alexl]

9 hours ago, johnr said:

top end off gs650 katana will drop onto thee 550 bottom end, and give a healthy boost. btw, the 650 kat, whilst being called a 650 was actually iirc 673cc so thats even more of a  boost! plenty of 650 kat bits kicking round. i know there are plenty of engines knocking round in the owners club. ive given at least 2 of them away in the last couple of years.

 

I like the idea of trying out the 650 (673cc) as It will still retain the GS character. Thanks for the tip about the owners club

[alexl]

9 hours ago, johnr said:

theres a 550 kat in the owners club fitted with a 600 bandit engine, with no issues, so i suppose the 750 engine will probably fit in there too.

 

I have a GSXR 750 donor bike to build up the GS, but although i originally thought the 750 was a good idea, I think I may try the 550 upgrade first and get on the road with the modern suspension etc. before I do the big 750 swap. I also wondered about it changing to an oil cooled 750 in terms of MOT, insurance etc. as it really wont look much like a gs to anyone who knows their stuff and I can imagine some MOT testers being a bit nosey about it too.

[alexl]

Did Suzuki make a gs 550 for the U.S market with a gsx style top end, or is it a home brew gs/gsx mix? 

[johnr]

makes no difference what engine you have in there. the vehicles identity is all about the chassis, so the frame is its id, fit a gsxr engine, fit a gs1000, fit a rev and go it matters not a jot, it keeps its reg number from the frame.
ok, as for your picture, i think you are labouring under a misaprehension. thats not a gs550 enigne. its a gsx750. suzuki did build a 16 valve gsx550 but it was a totally different engine in looks to the original or to this. that motor appears to be a 16 valve gsx750 engine fitted into a gs550 frame, and done rather well id say. if it were me, the only mod i would do is to fit  a second front disk to help make stopping a less fraught procedure. and if the performance of this engine isnt enough, then where a gsx750 engine fits, so does a gsx1100 engine, though your problem then will be finding one.

 

[johnr]

gsxr flatslide carbs are worth a couple of hundred quid on their own. (assuming the bike in the pic is yours)

Edited January 15, 2017 by johnr

[alexl]

56 minutes ago, johnr said:

makes no difference what engine you have in there. the vehicles identity is all about the chassis, so the frame is its id, fit a gsxr engine, fit a gs1000, fit a rev and go it matters not a jot, it keeps its reg number from the frame.
ok, as for your picture, i think you are labouring under a misaprehension. thats not a gs550 enigne. its a gsx750. suzuki did build a 16 valve gsx550 but it was a totally different engine in looks to the original or to this. that motor appears to be a 16 valve gsx750 engine fitted into a gs550 frame, and done rather well id say. if it were me, the only mod i would do is to fit  a second front disk to help make stopping a less fraught procedure. and if the performance of this engine isnt enough, then where a gsx750 engine fits, so does a gsx1100 engine, though your problem then will be finding one.

 

No, the pic is not my bike, just one I saw. It certainly looks like a gsx head, but It fits the frame really well, I thought the GSX750 motor may be too large for the GS frame. As you say, the gsx 550 looks totally different with its 2 carbs.

I was under the same impression as you on the bike frame/identity, but I read somewhere on the DVLA/VOSA sites that, "legaly" it should retain the frame and one other major component i.e suspension/ engine. But this may well be only for cars and not apply to bikes.  

I think that ultimately, my choice of engine will be based on my own air cooled vs oil air cooled argument. Is putting a totally different, albiet  much more powerful engine, in a frame moving too far away from the original bike?  What I am after building is the bike I wanted my old gs550 to be, back in the day, something that is nice to ride, looks good and can handle the power.  I am quite keen to try the 550/650 conversion as it gives a hefty power increase.  maybe I need two bikes!, or three......or......

[DanielHD]

Alittle late to yalls party but ill be trying this build soon im looking at porting the 650 heads and running 550 cams and a 750 exhaust system to make 85 horsepower at 8k rpm! the thing I wonder is can a 750 lower fit into a 550 frame without modifications? Not to mention the 750 and 850 share the same cylinder stud spacing so you could do a 850 on top of a 750 lower to make 940cc in a 550 frame but for now its just a thought!

[wraith]

No the 750 won't fit in the 550 frame without doing quite a lot of work. 

How do you get 940cc just by putting the 850 top end on a 750? 

They both have the same stroke. Putting the 850 top end on the 750 bottom is a old 750 power increase job (back in the day) when both bikes where easy found and cheep (bit like srads are now) and it just gives you a 850cc chain drive. 

If you really want fun on your gs550 with power put a gsxr1100 (1052cc engine) in it