Re: Suzuki GR650- 2-6-11
Hey if you're going to keep the pentagram wheels, might I suggest that you engrave a goat's head on the drum brake plate? Back in their day these bikes had a very heavy metal kind of vibe. Soo very 80's. I was thinking this should be a no-brainer, I even thought you were a little thick in the head until I realized it was a shaftie. Yeah, shaft wheels are a tough one to swap. I'm doing a wire wheel swap on an '82 Cb750F, using a GL1000 front and a KZ1000 rear. Pretty simple. But while I have everything I need, I hesitate to move forward until I have 18" rims, 3.50 in front for a 120/70 and 4.50 in the back for a 160/60. Sport touring spec tires, like you see on pannier clad beemers and the like. So, to that end I've sourced out some good Harley style chromed steel rims on Fleabay, and I've also noted that Buchanan's will trim down your existing spoke set for twenty bucks. Piece of cake. Lots of guys are doing up floating rotors, and I'm hung up on drilling some to suit or pairing up an exact match of rotor bolt pattern. I have a good resource for that over on the CB1100F.net site. A catalogue of aftermarket rotors with all dimensions listed, ergo all OEM dimensions for many many bikes.
Anyway, I did a lot of reading about spoked wheel swaps around the CB-F and CB-C sites, and found a good one on the custom site. On my beloved CB750C.com, there's this fellow sixpackrunner did a shaftie wire wheel swap on his 900C, by taking a drum brake hub and lathing out the drum, then lathing down the shaft hub he wanted in there, off the CB comstar wheel that's stock on his bike, and he had them welded together. A disc brake model, and I believe he wound up using the rotor mount for a sprocket. Now, I dunno what the cush drive looks like on your Suzy wheel, but I have always thought a lot about cush drives and wondered why they're built this way and that. Turns out that a heavy cush is more or less necessary on bikes where the internal lash compensation is less than optimum. But looking at modern sport bikes and aftermarket rims, some of them have bolt on cush drives. It's just a thought. But I think you could probably have the wheel you want modded with respect to the cush drive, rather than dicking around with this or that. Sixpackrunner's swap is unique in his approach to the problem, in that so many others are hung up on what wheels are a bolt on swap, with the correct gear ratios, etc. You hear a lot of that talk on the shaft drive forums. Now, there are plenty of different shaft drive hubs out there, but if you're looking at keeping the drum brake you're gonna narrow down that selection. That said, the type of lathed out hub with inserted cush drive and accompanying pumpkin pinion doesn't necessarily work well for you when you want the drum brake intact. Unless, of course, you look at the side where the sprocket normally mounts up as where you want to mount in that cush drive. I think that he used a CB750 SOHC wheel with his DOHC 900C pinion/cush parts. Looked great by the way. Yours would be a little different, but follow the same basic plan. The existing cush becomes your cush, and you keep the drum and all it's parts. Which, frankly, look a lot more classy on the CB than on the other big four bikes. My KZ440ltd, which I hope to put some KZ400B wheels on some day, has an ugly assed brake plate, just like yours I might add. Sorry. It's just a flat assed plate. And now you've decorated it with a drill I might add. Ha ha. To each their own. But we all lust for those CB brakes. That is, until Carpy takes his damn drill to them and makes a colander out of them. Best ventilation I've seen is on "cafe overkill" CB500, but it needs a screened scoop on it lest it become attractive to a nesting bird or a whole mess of road grit for that matter. I'm ventilating some drums for my kid's C70 right now, and I happened upon those alloy drinking water bottles. You could do a cool air scoop with those things, and screen the opening so they look like old 60's GP drum brakes. That's what I'm hoping to do. Gonna go through all sorts of them alloy brazing rods by the time I'm done. Might as well buy a TIG, for the price, ha ha. Back to your wheel swap though. There are ways to get it done, and I've only mentioned one of them so far.
There are wire wheeled drum braked shaft drive bikes. Usually classic European, as in, expensive. And you would have to play around with the ratios.
Now, here's another approach. I hit upon this idea when I first was thinking about my wheel swap, and before I hit upon the axle diameter chart which is such a must for a straight up chain driven wheel swap. This has been done on a CX500/650, and I've got photos someplace. Everybody told me it would be dangerous, etc. Using a pair of drilled rings on each wheel, basically creating the flange for the spokes to hook up to. And you could have your wheels lathed down to as small a hub as you dare, and the flanges would be press fitted then welded to stick. The comstar wheels are uniquely suitable for this, because of their modular nature, and that's how I've seen them done, with the existing bolt holes on the comstars. But if you suspend disbelief along with the notion that the wheel must be modular and bolted together, as opposed to -da da ta-da!!!!- WELDED, then this is a technique which can transfer to any shaft drive bike, it doesn't only apply to the comstars. Though, the comstars with their five transverse bolt lugs have the convenience of being a straight up job to align the two flanges with respect to one another, the holes needing to be off-set on each side by one half inter-hole distance. Duhhh. Man, do I feel stupid now. I am sure the CX guy feels like an ass too, if his rear comstar hub weighs anything near what my CB750/900F rear comstar hub weighs. I am now using a KZ hub that is pressed together one half chromed steel and the cush half alloy, sort of a conical design, if you will. It's off a KZ750B, but everybody knows what a KZ1000 is, and it's the same wheel. You can have a really good look at such hubs in "MAD MAX" on Toecutter's bike and Bubba Zanetti's bike. Not on the Goose's though, he had cast mags. Yeah, anyway. What I am getting at, is the comstar hub I removed and polished despite the fact it is a turd and they say you can't polish a turd; the comstar hub weighed as much as the entire KZ wheel. Too bad the damn rotors make up for the difference, they're double the weight of the comstar rotors on the GL front wheel. but the wire wheels weigh waaay less, which will wear with why whither where-for when ... Yields a greater transfer of power to the tarmac, as you're not fighting the wheel's mass. Another thing that sucks, is the skinny rims the GL/KZ wheels have. They're one size less than the comstars.
Now. Why do it? Well, if you're gonna stick with the same old tire spec, I would say it comes down to weight. But, and this is important especially with a shaftie, you can put waaay fatter rubber on without the five hundred dollar a wheel Kosman weld-up rim approach. And with the chrome steel rims I have found on fleabay for some sixty to eighty bucks each, (18" x 4.5, 3.5, etc. She says she may even get some 17") even with new spokes which you don't have to get, that's not so expensive compared to welded up Kosmans.
You could grab any GS, GL, KZ or even GT front dual rotor hub, preferably six bolt if you want modern rotors and don't want to drill them for a new pattern (lots of guys do that and it works, check out Melchiro on CB1100F.net, his track bikes, his CX500 project, with the Kosman welded up rear 18" CB and CX rims and GL1100 18" x 2.50" alloy rimmed matching comstar front wheels.... Which leads me to a rather lame suggestion, that you use comstar wheels of which there are shaft drive and drum and dual 18" types available yadda yadda yadda Ughhh. Right when I started doing my wheel swap, a guy in my neighborhood stuck comstars on his CB550K! Another man's trash....)
Now, here is a more radical idea I have been cooking up. I was thinking. So you accept for a moment that there are people running around out there who have not died because they rebuilt their VF1000R modular wheels with nylon lock nuts, a dude riding a very cool wire wheeled CB900C shaftie around New Brunswick, some other character I believe in Der Nederlanden riding a wire wheeled CX with bolted steel plates that make his comstars even heavier than they already were despite the conversion of the actually very light-weight star sections to wire spokes.... If you can handle all of that. Then wrap your head around this.
I look at the D.I.D. alloy rim I got with my GL1000 front wheel, and I ask myself whether there is a person out there who would pay a couple of bucks to convert their CB750K sohc front wheel's rim to the same specification only in shouldered alloy. Instead of doing the right thing and putting an 18" or even 17" wheel on that damn thing. 19" wheels make a bike look like ass. Maybe that's just me. Anyway, the existing rim, and remember this thing was used on the GL1000 as well as the CB750A, it seems about as rugged as the rims on my kid's mountain bike. Compared to the rims that bolt up to the comstar rear I tore apart, for that matter compared to all of the cast mag wheels out there, it's light as a feather and correspondingly less ... over-built. And there are a lot of wheels out there with a very nice specification that are cheap as borscht because they are cast skinny "mags" and have only one application, or are just plain butt ugly. Nobody wants them. If you have a 90's ZX1000, you want modern rubber on it, a six inch rim instead of four and a half, seventeen instead of eighteen. If you put "modern", which is to say 17" sport spec rubber on my dohc CB it will look like shit, many bikes on the 1100 site to prove that point. The CR750 though, had matching 18" wheels, as do old Ducs and Guzzis, the better looking classic Brit racers which for the moment have slipped off their 19' front and rear hula hoops, etc. Many examples of cool, classic bikes, matching rim diameters, 18" more often than not, on the good looking ones at least....
Anyway. What makes a rim a wire spoked rim? The holes, right? And what makes a rim on a cast wheel a cast wheel? The three to five or even six lumps of heavy crap that hold them to the hub, right? Same goes for the hub. What makes a cast hub different from a wire hub? The presence or absence of said lumps of metal or two plate flanges with anywhere from thirty-two to forty holes in them.
Now, I don't know if the thick assed cast rims are going to weigh a whole lot less than the chromed steel ones. Looking at a 2.15x18 steel and 2.50x18 alloy comstar modular rim with a ridge inside it with ten rivet holes in it, there's some indication that the comstar type at least, would weigh substantially less at the size of 4.25-4.50" x 18" I am looking for. I don't know about the type on the ZX1000 wheel though, it could be thicker than your finger, when rims made for wire spokes seem to be thinner than a cardboard box. This should lend itself towards rugged reliability, and also lend itself to some cupped countersunk holes as opposed to dimples punched in as with steel or even alloy rims. I should add, my GL1000 wheel came with little cupped washers on each spoke nipple. I wouldn't use alloy rims without these. I would think they prevent some galvanic welding or galling, as well as serve as a tougher socket for wear protection as each spoke plays in it's socket however slightly with each rotation.
For the price, I think I feel myself leaning toward the chromed steel. If only because I might have to pay somebody to lathe the damn thing. Could probably be done with judicious use of a hack saw, a detail sander, and a drill. If they more or less balance out weight wise, imperfections would only be cosmetic. And careful use of a detail sander could "plane" the material down to the bed level of the rest of the interior rim. However you screw up with the hole pattern, it probably wouldn't be so bad as to not be fixable through the true-ing of the spokes. We want a balanced, true, rigid yet flexible wheel, we're not decking the head or triple grinding the valve seats here. Just think of each spoke as a nut and bolt, rather than thinking of the wheel as some type of helicoptor rotor. I would bet that even a helicopter rotor needn't have the level of accuracy to which the most paranoid of my detractors would have you keep your wheel to.
And the whole "don't fuck with it" approach is no good either. Don't even get me started on the "leave it to the professionals". Lots of guys are leaving thirty year old wheels as they have sat. When you're talking about the spoke nipple seats, I don't think rust is very helpful, and it's still there no matter how much engine enamel or even powdercoat you throw at it. Any old wire wheel ought to be rebuilt, if the bike will see highway speeds. Hell, I am rebuilding my old C70 passport wheels, if only because my little girl is gonna be riding it. So approach the problem logically. If a manufactured rim to be used as intended, then why? What makes it appropriate? Because it's forged, and a cast wheel will have pitts and holes? Well, I have polished both wire and cast wheels, and let me tell you. usually, both are forged. Especially anything but the earliest ones. That said, both types also have pits and holes in the material. And fatigue, well if metal fatigue worries you what the hell are you doing with a thirty year old motorcycle. Many many folks will say "When it comes to wheels and brakes, these are things that MUST work" What then, of the hundred or so parts which may or may not cause your rear wheel to lock up? The dozen or so welds that keep your bike from becoming two unicycles? Or the two bars that keep that twin-shock bike from eating your crotch like a venus fly-trap? 'Nuff said.
Now, that 'Nuff said, the steel rims I mentioned also have a drop center in them, which may not look great, but it could lend itself to an internal seal job for going tubeless. Lots of cruiser people doing this with their wire wheels now. Plenty of ways of doing it. Seen the mountain bike method with the slit tube? I for one intend to use tubes inside of radials, as was done when radials were new even on cars, until I see an condition of overheating on the surface of my tires and then I will consider a seal. I regard it as one more layer of back-up against a blow-out when I am cruising slowly across the country and back at mostly vaguely legal speeds. Nothing requiring relinquishment of my license, let's put it that way. On a track day I might see it differently. But I want sport touring rubber, for sport touring, nothing more nothing less. To me, tubes are a plus, not a minus.
I have everything laid out - tires even, old and ratty though they may be - to swap these wheels out from 110/90x19 + 120/90x18 to the slightly narrower 100/90x19 + 110/90x18. In this small a range of differences, I could probably use the same tires. Then again, with so small a tire, it could be a big deal. Both sets of tires I have, by the way, came off the same '82 DOHC CB750F wheels, one pair off my old rider and one pair off a transplant donor. Now, I don't have to follow suggested rim to tire charts to the letter. Few people do. But I thought about the prospect of 120/70ZR18 on the front mind you, not the back ha ha, and 160/60ZR18 or even 170/55ZR17 on the back, and it's like I'm not kicking the performance possibly back a decade from where it was I'm bringing the bike forward in tire technology at least a decade or even two.
That said. Your bike, this GR650 Tempter. Hmmm. Tempting, isn't it? Well, it is when you think about how such a light bike would do with either 17" or even the more rare and hard to find rubber for yet ubiquitous on the chopper scene in terms of rims, Sixteen inch wheels! If I recall, there were some cool 130 spec front tires in 16", and fatter still in the back. I wonder what the rim widths are for those. I read about a Harris Magnum with 16" tires a while back. So it's not just classic Harleys and Indians, or 80's cruisers or customs, that have these sizes of rims, diameter wise at least, width being the determining factor of whether it can be done, let alone tire availability. But yeah, there are lots of sixteen inch wheels on sportbikes. The transition bikes, between 19/18" tires and the 17/17 we see today, there were many with 16" front, many more with 16" rear. And if you look at the most common spoked wheel rim conversion kits out there the 16" by 3.00" kits for CB750 are very very common. I dare say you could find a rim and spokes in that size for fifty bucks. A slightly wider or narrower rim can also be sourced, i am sure, from the chopper or classic V-twin scene. If you can't get sport spec rubber ala VF1000R, then you could certainly find some white walled balloon tires, ha ha ha.
I would suggest that whichever approach you take, that you use as a basis the spoke flange size, spoke hole pattern, and hub width ... better yet the very thing itself, of the CB750K sohc. It may be cheaper, or more expensive, depending on what you can do or have a friend help with, to either make up flange plates, or cut your existing wheel down to a cush drive section which you could have welded in, though I would say far better to measure out that cush drive and fab up a new one and sell the old wheel which ever is cheaper... and have that inserted into the gaping wide butt that is the cush drive of the sohc CB's rear hub.
The CB supersport rear hub, the disc unit, sells for ridiculous money nowadays, because anybody doing any type of disc brake swap uses it for all sorts of purposes. K bikes that need a disc, F bikes that need wire wheels, customs of all sorts of applications. But it's not without reason. Like I say, the CB has had custom rims with spoke sets made for it since the late 60's, as in right out of the gate. But, Buchanan's will make a custom set for you, provided they want anything to do with the death-trap you are making. So, chose a wheel of a type which they or some other spoke maker already lists, like the KZ unit I bought for pennies on the dollar compared to what a supersport hub goes for, and then you won't be bothering with any custom measurements or designs. The KZ is listed for spoke sets to build 16" and 18" wheels, which leads me to believe that a 17" set could also be made. Existing rims are made to fit only certain types of hub, the hole pattern is relevant to how far out there you can go. For instance, when I asked about a set to put a 17" rim on my GL1000 front hub, specifically the 17" x 2.50" rim on the GL1000 rear hub, they told me it could not be done. Sounds to me like they don't want to do a custom bent spoke head, only a custom length spoke "leg".
Another note. The Harley rims I mention, may require a different size of nipple. They could set you back fifty bucks. Slightly larger diameter, due to slightly larger holes. All the more reason to chop up some cast mag wheels, I say. But crunch the numbers. If you can get spokes with the hub you buy, great. But not if you have to pay to ship the whole wheel. That said, twenty bucks to cut spokes to length and roll on the threads as opposed to a tap and die method which weakens the spoke and will cause premature failure, plus fifty for nipples, and you're only saving fifty bucks off a whole new set. So crunch the numbers. It's still a cheaper thing, to buy an eighty dollar rim and a hundred and twenty dollar custom spoke set, than to even contemplate a four hundred dollar alloy rim from Sun, Akront, or others. At that rate, my cast wheel hacksaw idea even has allowances for some work in a machine shop, to have things made to exacting standards. Providing they want anything to do with the death trap you are building. Buchanan's will also drill and even dimple, a "customer supplied rim". Will they drill one such a rim? I doubt it. But tell your machinist your an art student, and you are building a clock, then they might just help you.
All of what I am getting at, is I believe there are alternatives to paying anywhere upwards of three to five hundred bucks per wheel to go with the wire. I don't know what your budget is. Just keep in mind all the trendy little cafe racer girls who's knees unlock for a guy who has wire wheels on his bike. Cross those wire wheels with a decades newer four valve per head DOHC engine that makes power like a bored out and ported SOHC version with a MOPAR cam, and you could put together a winning combination. Sort of a top-down versus bottom-up kind of thinking about the problem. So the next time you see that gal (/twink, depending on your prediliction) with the Fonzee jacket and the white silk scarf sitting around reading Kierkegaard, or better still Pirsig, at your local Starbucks and you want get down her top and up her bottom, you need to have a cool looking bike that also kicks ass on all of the bikes out there on the coffee shop sidewalk. It makes a heck of a lot of sense to take these unappreciated bikes and make them beautiful. In most cases, they're better bikes with only an ambiguous name in the case of your bike or Battlestar-Galactica inspired bodywork and paint in the case of mine, keeping them from stealing the show. Dress them up? And you can take them anywhere. Certain classic design features would save any bike. Look at what they've done for Harley. Looking at the Ducati sport-classic, there is even further, non Harley no less, argument for a seat shaped like an antique John Deere tractor's seat. There I draw the line. But several other elements I do enjoy. Wire wheels of course. Candy paint. Polished alloy. Duck-tail seat. Bubble type half fairings. Simple tinware fenders. Shock covers, fork covers, headlight "ears", indicator lights you can see from more than ten feet away. Clip-ons/clubmans, or for that matter top clamps in cast alloy with bar mount clamps. Classic design elements are a good thing. But so is the ability to go fast. I don't think that to enjoy such things you should give up the expectation that your bike can perform like a porn star.
Which is why the next time I stick wire wheels, a classic tank and side panels on something, it's gonna be a plastic crotch rocket. It might even get to keep it's hubs and rims, other than all the plastic and black paint, it's just those three blades per wheel that have to go....
-Sigh.
