Suzuki GR650 - back to work...

[Big Rich]

This is my first motorcycle that was far too near and dear to cut up. But recently I found a damn-near mint GR close to me......and if I get my grubby hands on it this is what's going under the sawzall. Luckily I've already "restored" it, so the paint, wheels, motor, etc. is already good to go. But here's a little history: It was only sold in the US for 1- almost 2 years. After being a bomb in the market, Suzuki decided to sell it every where else (Canada, Australia, the Netherlands) until 1989. Almost the same bike as the GS450's minus the dual shocks, 6 speed tranny, and it has a longer stroke. Obviously there's some other stuff (but not much).

1st day in the garage:


About 1 month later:


To give you an example of the PO's "fix-all" for rust:


Coming back together (I know, "Tempter" is the probably the worst name for a cycle. Probably one of the reasons it bombed in the US):


And here's one of the most recent shots of it. Some stuff has changed since then, but this bike has been my "ride comfortably wherever" bike.

[Big Rich]

Just wanted to add: big thanks to Beatnic for cleaning up the front end for me. World of difference!!

I've posted both of these pics before elsewhere, but these 2 are the inspiration bikes for what I want to do (and these are both GR650's):

[stik70]

Boy, there's some killer potential there. That blue bike is outta sight COOL! Have fun with this project and take oodles of pictures.
Kev

[thompsonmx100]

So thats the bike you were asking about the gs head for. From the pics you have it looks to be about the same as the gs500 head. I will get some more pics and send them to you.

[chris73cb175]

the new project huh  it looks like this will be another good thread from ya

[Big Rich]

So thats the bike you were asking about the gs head for. From the pics you have it looks to be about the same as the gs500 head. I will get some more pics and send them to you.

I was actually doing the research on GStwins (and its been suggested here quite a few times as well) and the exhaust wont clear the frame. Something would have to be modded - i have plenty of time to straighten it out.

This would be a long term project and it wont be down for any length of time. I always want to have 1 bike running at any given time.

[Curbcast]

If you could hide all that electrics junk under the solo seat, thatd be a cool route.  I see why your 175 went red, you had a blue bike already.

Cool man, excited for updates.

[Big Rich]

Ok, here's the plan: right now the wheels are 19 up front and 16 in the rear. But the X model has spoked wheels. So it should be possible to swap out the wheels for a 18 front and 17 for the rear. I know, it's gonna throw the geometry off, but a little never hurt, right?

Speaking of the wheels - the gs650's of the same generation use a dual disc setup. Direct swap. Easy peasy.

After doing some research, there's no advantage to using any gs500 parts. The heads will give me 3000 more rpms before redline but the valves are made for 150 less cc's. The cams are hotter in the GR650, and the exhaust already fits my frame. The ONLY better part to the GS motors is the 6 speed tranny. And availability of parts of course. But i'm still trying to find out if it's possible to swap out the tranny (i know, a guy can dream).

So after all that, there is still the issue of clip ons / clubmans, seat, tank, getting rid of the original gauge cluster, lighting, exhaust, etc.
Any other ideas / suggestions?

[ehdave]

Hey Big Rich,

As you already know I have been playing with my gr650 for a while now, I found with mine that the rear upright piece on the back of the frame was a pain in the butt to try and set up a rear cowl on so I ground mine off on the weekend. I think it would be very hard to make a good looking cowl with this part still attached (I spent a lot of time thinking about this as I didn't want to cut the frame).

Although I dont know a lot about bike geometry, personally I'd try and get a set of "x" model wheels (thankfully mine is an x model) and just use them but they may be a little hard to find seeing as they aren't a common bike. I was told that the brake upgrade probably wasn't necissary if you use a braided front hose and rebuilt the brakes. Personally I'm going to rebuild the stock brakes and if there not good enough I will upgrade them.

I would love to know if the six speed fits as well as it would make it a totally different bike to ride. I wonder if you could use the gr valves in the gs head? Although they might end up too close together. Might be worth looking at but I suspect the bottom end probably wouldn't take the extra revs.

Keep us updated, I will be watching this build
Cheers
Dave

[Big Rich]

Yeah, the rear of the frame is going to be kinda tough to work with. I'd like to see about using the original seat pan and just glass it to suit.

I have seen the X hubs a lot on eBay, so im not terribly worried about that. I think the bigger obstacle will be finding proper wheels to lace up.
Far as the dual discs go, there's no such thing as too much stopping power, right?

The whole GS conversion seems kinds iffy. All the info I've seen points to the GS owners taking parts from the GR650 and using little from their original motors. But the 6 speed would be great. These things are well known to be geared WAY too low. I'll see what i can find out and keep you up to date!

[Big Rich]

Well, the guys over at GSTwins squashed my dreams of converting the 5 speed to a 6 speed (and saved me from a lot of work). It was pointed out that there are very precise tolerances around the bearings, gears, shift forks, etc and the chances of everything lining up just right is pretty much slim to none.

I do have a spare GR motor that needs rebuilt anyway, so if i can get the tranny from a gs it might be worth taking a look. But that may be all it's worth - a look.

Oh well, may be time to look into some cusrom sprockets......

[jlgace]

Looks like the makings of an awesome project.  Just wondering, why are the GS500 heads worth 3000rpm?  Also, are you saying the bike is geared too low as in acceleration is reduced or top speed is reduced?  I think you're on the right track playing around with sprocket sizes - usually with a twin 5 speeds is plenty unless you're dealing with a really peaky motor (thinking two-stroke-like powerband). 

[Big Rich]

The GS 500 has an 11,000 rpm redline while a GR 650 reaches red at 8,500. So its actually a 2500 difference. 3000 is just easier to type.

Everybody that owns these bikes complains about the stock gearing - you can reach 5th gear by around 35 mph. And there's no readily available gearing changes. I can buy a 52 tooth sprocket for the back, but cant for the life of me find a 36 or 34 for it! It has plenty of pull off the line but develops a "vibration" at 65 mph.

[dcmspikes]

i like that box swingarm.  i say cut the rear off and show it off, like the red example you showed.  different seat and cut the exhaust short.  good luck

[ehdave]

Hey Big Rich,

I have only ever seen the dual disc front on the alloy style wheels and didn't think it would work on the x series front hub but I have just looked at my front wheel and realised that the holes are on the other side pre-tapped and they only have a plastic cover over them

I agree that it probably would be better to have the dual discs for a few various reasons but the standard one will do the job once rebuilt if a dual set up cant be found. I would try to find complete wheels rather than just hubs, at least that way you get all the parts in one go. I know that the bloke that owns that blue bike had a gt250 rear wheel modified to suit the gr so he may be worth emailing for more info.

If you have a look on the gr650 message board there are some links for places that sell the different sprockets for these bikes, I am planning on having some shipped here to oz from o/s for my bike if I can't find any over here as my bike will be frequently on the highway.

Cheers
Dave