GR650 top end on GS450 bottom end?

[Mekanix]

There is one other option

http://www.thegsresources.com/_forum/showthread.php?t=172422

I'm in the middle of installing just the Sleeves out of a gr650 in my 400's barrels.

I have the 8 valve head but this seems to work on any two valve as well.

Starting out at with a 77mm stock and later going to 80mm.

Head and base gasket for the GR.

For removing sleeves ( place in oven 425 10-15 minutes ) and they just fall out :P

The sleeves are longer as well. So have to machine them down...


An engine with a base starting at 400, 425, 450, 500 could jump to:

bore stroke displacement

77 56.6 527.1cc

78 56.6 540.9cc

79 56.6 554.9cc

80 56.6 569.0cc

81 56.6 583.3cc

82 56.6 587.8cc


Several big bore kits for the 750 or 1100 could be used for the 4xx base.
Mine will be from a 1981 GSX1100 big bore kit. ( half of it that is :P)

There's lots on E-bay.


Fyi:

In my research I've found that gs4xx and gs5xx have the same base crank case (at least 1980 up)

They all use an 18mm pin.

So does the GS750 and GSX750 and 1000 and 1100. The GS1150 uses a 20mm pin.

In theory all their big bore kits should work.

Stock stroke is 56.6.

GS400 are 67mm bore 56.6mm stroke 18mm pin

GS500 are 71mm bore 56.6mm stroke 18mm pin

GR650 are 77mm bore 70mm stroke 18mm pin

GS750 are 65mm bore 56.4mm stroke 18mm pin and have many overbore kits.

GS850 are 69mm bore 56.4mm stroke 18mm pin

GS1000 are 70mm bore 64.8mm stroke 18mm pin

Gs1100 are 72mm bore 67.5mm stroke (I think) 18mm pin and have kits available that go up to 85mm

I'm wondering how far to go with this. As in how much room there is for a larger sleeve.

I know installing the GR sleeves will require machining of the case for the sleeves to slide in and machining of the cylinder block to allow the new sleeve to fit.

Stock sleeves have 4 mm thick sidewalls. (on the 400 and GR650 at least)

Going from 77mm stock GR sleeve to 80mm isn't too much but its as far as I would go.

Gs 400 450 425 have the same cylinder block I believe. The 500 is just larger but still fits in the same way a 4xx would but it has more surface area on the fins.

That's what I know for the moment.

If I missed something or wrote something horribly wrong please feel free to point it out. I'm still learning myself.

[hjfisk]

So, I have a nice dependable 81 GS450S and I want to make it into a 650. Short of finding a GR650 engine, what are my best choices? I do have a GS500 engine, complete. I know the exhaust ports are different causing frame interference, but I've heard the cylinder will fit the 450 bottom. Will the 650 head fit the 500 cylinder? Can I install a complete GR650 top end onto my GS450 bottom end? I would guess I'd need cylinders, pistons, head, carbs? Should I stop thinking like this and just ride the 450?

Where are you located; found this just poking around;
1985 Suzuki GS650 GS 650 Engine Motor - $150 (milan NY)

Date: 2011-03-23, 10:00PM EDT
Reply to: sale-6bnud-2282969583@craigslist.org [Errors when replying to ads?]

I have a motor that is in excellent condition with 1300 miles on it for $150. Dont waste my time with stupid low ball offers! Will trade for a shotgun to keep away cheap people!

• Location: milan NY
• it's NOT ok to contact this poster with services or other commercial interests

PostingID: 2282969583

[Mekanix]

GS650 is a 4 cyl.

That would be fun to do but it is a little more work.

[Mekanix]

Some fyi

GR650 is not a direct swap onto a GS4xx or GS5xx base.

Cylinder barrel is too tall 17.32mm more than stock

, oil drain is on the wrong side in the front of the cylinder near the cam chain.

GS4xx and 5xx have a 56.6mm stroke, GR needs a 70 stroke

Cannot be done IMO.

GS 500 cylinder and head can be put on a GS4xx and cylinders can be bored out to 77mm like the GR but that's pushing it to the point of not having any overbores.

4 mm sidewall at 74mm
2.5mm sidewall at 77mm.

Please correct me if I'm wrong!

[Collo]

Hi all,

Haven't put comment or question on here for months! Anyway, the GR650 is a little more common below the equator and so my question is...

Has anyone heard of putting a GR650 engine (complete) into a GS450 frame?
I know the engine is taller and the mounts may be different, but seems a logical way of gaining some size.

Thanks in advance.

[pete]

Hi all,

Haven't put comment or question on here for months! Anyway, the GR650 is a little more common below the equator and so my question is...

Has anyone heard of putting a GR650 engine (complete) into a GS450 frame?
I know the engine is taller and the mounts may be different, but seems a logical way of gaining some size.

Thanks in advance.

Hey Collo, good to see you back on here finally! I got my 450 all done and complete while you been gone and nearly 6000km's on the clock since the rebuild

I'm pretty sure someone has looked and ascertained that it would be a very tight squeeze into the 450 frame but it would be possible with a lot of careful planning and effort...

You need to upgrade your 450 thread too, keen to see how she's looking!

[Collo]

Hi Pete,

Your right, it's been a while. I've kept an eye on your bike over the past few months and it's looking great, you've done a good job with it.

I was close to buying an old BMW R100 the other day but I couldn't let go of the GS450 in return and so I'm keeping the project going...slowly. This being the case, I would be interested to see what size donk would fit in it's frame. The GR650 seemed logical but it's quite a tall motor as you say. Would be good all the same to see if someone has done the conversion or attempted it.

Anyways, will try and update the thread soon. (bike currently collecting dust).

[pete]

Cheers mate, she's a fun ride now

The GR into the GS frame is one conversion I've never seen done before, which is not to say it hasn't been, just not on the GSR I expect.

I think the biggest drama will be maintenance if it's much taller than the 450 motor.

As it is right now there's not a huge amount of room to get the valve cover off, so if you lose much more room under the top frame rails I dare say you'd need to remove the motor just to do a valve clearance check!

Mind you, if it can be done that would be very cool...

Glad to hear you've kept the 450 too and looking forward to seeing her come along a bit more.

[Mekanix]

I believe its a full inch taller than a 450.

[pete]

I believe its a full inch taller than a 450.

that's gonna make for some interesting valve clearance checks

[Big Rich]

Instead of subscribing to this thread, I may as well add to it........

When I wanted a 2-1 exhaust for my GR650, the first choice was the MAC system made for the GS450. I had to cut the headers and add about 1.5" so it would clear the GR's oil pan. There is a moderator on the GSTwins site that put a GR motor in a GS500 frame, and he said it actually fits better than the original motor.........however, he has to take out the motor mount bolts to allow the motor to swing down for valve clearance checks.

With any luck, I will be acquiring a GS450 soon, and I will have a GR motor laying around. If I do attempt to fit the GR motor into the GS frame, I will be sure to report back here (won't be for a while though........).

[olddaddy]

Big Rich, keep us, and me posted about your progress on a GR/GS bike. I currently have a GR 650 sitting in it's own frame with a GS 750 swingarm, rear disc set up and a twin front disc fork setup. I want to move it all over onto a GS 750 frame if I can find one. I do have a GS550 frame that might end up being used. Twins are good!

[Big Rich]

The GS750 swingarm, huh? I've been looking into that too actually. What wheels are you running front and rear?

[olddaddy]

I used the stock GS 750 front and a 16" matching wheel style on the rear. My reasoning was to keep the same rear wheel diameter the engine/tranny were geared for and keep the rear low since I'm short. I dropped the triples trees an inch up front also.