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Discussion Starter #1
I recently picked up this:

If you were to call it a Virago you'd only be a little wrong. In truth the major difference between the more plentiful 'Virago' and the European model XV920/TR1 is the chain drive vs. the US model's shaft, and the slightly odd looking rear end. What this is in truth is a good, all around motorcycle. This particular unit is in outstanding shape for it's vintage. It's an 81 with a shit-ton of miles on the clock (68k!) but the engine was recently treated to a fresh top-end rebuild and sounds/runs like brand new. That 68K kinda worried be at first but the bike was obviously owned by someone who did maintenance as it SHOULD be done. There are no rattles, no clunks or squeaks or any other odd noise for that matter. It's had paint recently but shows a fair amount of 'garage wear' in the form of subtle scratches and scuffs. I'm not worried about that at all as it's it such fantastic mechanical shape. Other than changing to tires of a brand I recognize (these are some kind of chinese death tire) the only place it *NEEDS* attention really is the suspension.
Typical of an 80's bike, it's squishy and wobbly and handles like a drunken hobby horse.
For all that though, due to it's exceptionally low center of gravity (note how low in the chassis the engine is) it feels tremendously light and agile for 480-some pounds(til the wallowing starts) so potential is there.

I've been happily involved in conversation with a couple guys who raced them in the 80s in the BOTT series. (for those not in the know)Battle of the Twins was just that....a racing series for twin cylinder bikes. Neat. Like most racers these kats are full of tall tales about their bikes but once past the enthusiasm a vast amount of knowledge was laid on me in large chunks. From that info-dump formed a plan of attack for this bike, which will be built in phases since this is a clean tagged rider.

The end result will flesh out in one of two ways:


....or this:


Regardless of how it ends, this build will go in phases so as to keep this on the road as continuously as possible.

Phase 1: Weight-loss

Let's be honest shall we? This shit just ain't gonna work........
We're going start by taking heavy shit off and either just pitching it or replacing with something less weighty. In typical 80's fashion, there's a lot of crap hung on the bike for the sake of the prevailing fashion and perhaps a little misspent creative thinking.

On the chopping block currently:
1) Heavy cast alloy grab rail, "luggage rack" and tail light assembly.
Generally speaking, 'Heavy' and 'Alloy' don't go together, however in this case I think they alloyed the aluminum and zinc with lead or tungsten. Regardless this is just a heavy piece of metal with little real value as far as I'm concerned. The rack portion is good for a whopping 11lb (5kg for you Euro types) so totally useless and I don't intend to carry anything on this bike that can't be handled with a backpack or soft bags/tank bag anyway. The silly plastic "trunk" bit that's built into the rack? Dumb. Gone. Lastly the tail light; I'm a little torn as it's actually not bad for an 80's unit, it's not HUGE or particularly ugly so who know...it may remain we shall see.

2) That ridiculous enclosure for the chain:
So.......great idea! It makes an otherwise generic non-oring, non-spiffy chain last a loooong time. Some guys are getting 50k(!!!) out of a chain since it's enclosed no grit gets to it and it's bathed in expensive lithium grease. Neato huh? Well...yeah if they just hadn't made the entire assembly out of cast iron's fatter cousin. Really it's aluminum, pot metal and plastic bit it's also over 20lbs! I'll wax my chain now&then and run a simple aluminum chain guard and be a happy camper. Plus it looks stupid as hell....GONE>

3)Rear fender assembly.
Huggers are pretty common these days and they do a good job of keeping the worst of the crud from blasting off the tire and onto the back of the engine. Gods bless'm but Yamaha in the 80's got 'thiiiiiiiis close' to doing it right......but they failed. Vincent had lovely alloy fender(the light kind) hung from the swingarm and it looked great...this just looks bad, and...it's apparently pretty chubby for what it is. Gone. I'll likely run something in it's place though at the moment I haven't decided. There's a substantial frame element and some other stuff between the tire and the engine and nothing of note under the seat so I may do nothing more than a small aluminum splash shield.

4) Aluminum swing arm in place of the stocker
(see below)

5) Gauges, idiot lights, turn signals, factory controls, mirrors and other annoying heavy things.
The gauges are very much like those on my other favorite Yamaha from the 80's the XS750/850 triple. In a word....HEAVY. And not just heavy but bulky and ugly. Add in big (loose) levers, a chunky mastercylinder, goofy looking mirrors that show me my shoulders, some big 'ol lollipop turn signals and another 10 pounds of pot metal and crap plastic in the form of the aforementioned idiot lights, trim pieces, bracketry, reflectors, various flappy bits and one large wasp nest.....you may note that there's room for improvement.
In this case though the tach is electronic so I may keep that bit and run a smaller, lighter speedo......or just ditch the works and run a Vapor computer. A small LED panel for the idiot lights (what's an idiot to do without his lights after all?) and that should drop some weight as well as clean up the looks up top.
I'm a little bit stalled in my plan for the turn signals though. I like the old BMW style bar end signals a lot

6) No more Veg-a-matics!
The swirly 'Veg-a-matic' wheels are rightly hated by anyone who's a) tried to lug one around to change the tire or b) trying to go fast efficiently. In short, the laws of physics all conspired together (bastards) to make these wheels not only uglier than Rosanne Barr in a saran-wrap thong but heavier than a similar amount of raw fucking lead. Did I mention the ugly? For the immediate future this bike will wear spoked wheels from a CB500...because I have them, they are the right size and they have really nice Dunlops. Even stock, the cb500 wheels weigh substantially less. I'll do a weight comparison just for giggles as soon as I bring my highly accurate bathroom scale in. My calibrated 'Lift-o-matic 2000' (left arm)says that the front is at least 5lb lighter and the rear is closer to 10! Doesn't sound like much but excessive unsprung weight and especially unsprung rotating weight is a handling killer.

These relatively minor changes *should* be good for 55-60lbs depending on what things ACTUALLY weight. The rear shock is heavy as well but that'll be addressed in phase 2.
Keep in mind that this is just the beginning of the chub-shaving. Those BOTT guys....to hear it told they were running right at 300lbs. I have my work cut out for me...

Phase two: Improved handling
I think the weightloss will help a lot and this bike already feels pretty agile just for it's very low center of gravity but like a lot of bikes built in the 80's the suspension is pretty marginal. Braking (wussy as it is) pretty much bottoms out the front end and it's freshly rebuilt to factory specs. The back is just as squishy and my large self does little to help the situation. The frame itself is regarded as pretty stout and looking at the headstock it does appear to be pretty beefy so I'll be concentrating on suspension and setup this go-round.

Forks:
The OE forks are marginal for a bike weighing 100lb less at best and 30 years of progress have illustrated just how lame they really are. Heavy, dangerously under damped, fairly under sprung, too small and very flexible.
What I do have is the complete front end from a 91 BMW K75. These 41mm Showas are also what came equip'd on early CBRs though certainly set up differently. These forks are 4mm larger in diameter and an inch shorter (I'd be dropping the front an inch anyway) and come with a nice factory brace. The stem will fit with some tapered conversion bearings and the BMW sourced triples are Teutonic enough to look 'Engineered' once you strip off all the crap and give'm a good polishing. This pair happens to come with racetech .90kg-mm springs (for the Kay)and gold valve emulators already installed. My phase 1 target weight is 60-ish pounds less than the BMW so the springs should be a good starting point though I will likely have some made to suit eventually.

Rear shock and swingarm:
Yamaha chose to build the swingarm out of steel (alloyed with lead I think) and it's a hefty beast. Really heavy. I've got an Olhins shock that was slated for my old 955i but that bike went away before I installed it, the clevis end threads on and I'll machine something to suit this bike and yield an adjustable amount of lift out back to derake the front a wee bit. As I understand it, on this bike +1" = -1.35deg, so for every inch of lift out back the bike loses one and a third degree of rake. Good stuff. I'll likely start it at an inch of static lift(over stock) with the ability to add more later. Coupled with the 1" shorter front end will yield quicker steering on an already quick steering bike. I'll be adding a gsxr steering damper (it's on the shelf.....thanks Mike D!) as well.
As for the swingarm, I'm looking really close at an 80-ish yz400 piece as that's been spoken of for this bike a few times. I had that particularly evil dirtbike and it is a fairly lightweight piece and quite strong...I tested mine a lot....and it looks like it'll all but swap directly, I've got one coming so we'll see. Otherwise I'll likely need to make something to suit.

Other things that'll be changed out during this period are the horrible seat and the way too heavy/restrictive exhaust.
The OEM seat for the TR1/920r is a nice looking piece and firm enough to make some pussies whine, but then I'd rather my seat be a bit on the firm side. This one feels like someone took the stock foam out and added the thick spongy stuff from grandma's couch and slung a semi-generic ebay-tastic seat cover on it. It looks remotely similar but is just uncomfortable. I'll be carting it off to a local shop for a rebuild. I'd thought to go to Corbin as I've had their seats on a couple other bikes, but I almost swallowed my tongue when I got the quote. For $500 based on my seat pan and foam(!!!) with vinyl...umm.....no. I looked at Sargent and a couple others but none could give me what I wanted for a fair price. Locally though there's a well respected joint that had made some really nice looking seats and as soon as I get some info back I'll be passing it along. Truth be told, even if her costs come close to Corbin or Sargent's I'll still go local...because it's local. Nothing wacky, just that tasty TR1 profile with the pilots seat blended in the thigh area a bit more and the rear edges rounded/softened. This will all get covered with camel leather with red stitching with a diamond quilted pattern on the seating surface. Looks like I have my choice for foam density and will likely add a gel pad under the front part.

The stock exhaust actually sounds ok but lacks authority and is REALLY HEAVY and fairly restrictive if the cross section I found online is accurate. I will likely end up with some one-off pipes once the engine building happens....oh yes, I WILL be building a beast for this bike. Any engine I spend any time at all with ends up way overboard and it's safe to assume this one will too in time. That all being said, likely I'll nab a cheap-o MAC or some other 2-1 exhaust header and I'll sling some kind of muffler on it temporarily...dunno yet but one of my 'parts' 920s has one in ok shape so I may use it.

According to various owners groups and a few articles I've read there's a good 10-13hp laying around waiting to be let loose in this without ever cracking the block. The OE exhaust is pretty but a decent (the MAC was cited) 2-1, a dynojet kit in the carbs and pod filters will do the trick. I know that the stock backbone/airbox setup is restrictive due mainly to packaging so this should help.

Pods on CV carbs!!??? I must have lost my nut huh? Apparently it works just fine in this case because the ol' girl's big lungs (even with the low factory compression) give a good strong vacuum signal and the dynojet kit allows for drilling out the slide ports so it should still yield decent throttle response I hope. Worst cast I'll jet up this pair of VM40s I have on the shelf....but we'll give this a shot first.


Imagine this one with smaller turn signals, less obtrusive clocks and you get the idea of what I want at first. If I can get this thing to ~400lbs, 75hp and good handling I'll be happy with Phase 1.

The future....well.....that may lead to something like this:

trellis frame, 100hp torque beast, under 350lb......yum!
 

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Discussion Starter #2
Provided to me by my pal TJ over in Saxony....
 

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Looks like you have got some good ideas. Will the Ohlins need to be revalved since it is a direct actuation instead of using a linkage like the 955?

Ken
 

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Discussion Starter #4
I'm certain of it, along with a new spring. It's equipped with a 930lb spring and right now anyway it looks like something closer to 570 would be more suitable.
 

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Rawr!!!11

Looking forward to seeing the progress on this, Lee.
 

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Hey Mr. Swagger,

Your idea sounds just like the one I had this spring:D Bought a TR1, chopped the stuff you just mentioned and drove it through summer. Meanwhile bought a spare engine and started to build a new frame for the engine:)

This is CAD of the frame in current state:


Hope to finish the frame this winter and be happy driving next summer.

Good luck with your project! I'll be following!!

Best regards,

Loek
 

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Discussion Starter #8
mlinder: Me too Mark(progress), me too. Hey did you get that email about Mr.Martini?

Tanshanomi: Yeah it is, thanks.

Loek: Hello again, you're popping up everywhere! This is an interesting joint, your work will be appreciated here.

I actually got a few minutes and started yanking crap off the bike that won't be going back on:
>Cast grab rail = 9lb 7oz
>Teeny tiny luggage rack, rear turnsignals/tail light and rear "storage" box = 6lb 11.4oz
>Rear fender/hugger abomination = 3lb 13.1oz
Total removed last night: 18lb

>1) cheapo temporary cateye tail light/plate bracket - add 14oz
>4) similarly cheapass cat eye turnsignals - add 8oz (w/aluminum tabs)
-8" aluminum fender stub and 3 bolt/washer/nylock combo - add 1lb 1oz
Total weight reinstalled (when done) ~2lb 7oz
 

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Nice bike. When I started my XV920R project 3 years ago (I know, I know) I thought I was in uncharted territory. Now, literally dozens of these bikes have popped up with modern suspension, etc. totally blowing past me.

Since I have the parts at hand, thought I would share some weights, so you can plan accordingly.
The chain enclosure, tubes and brackets, minus sprocket (which you need in any case) weighs in at 6 lbs


The 920R rear wheel and tire, with complete brake assembly, weighs in at 34 lbs:


compared to a CBR900RR wheel, tire and brake rotor (no caliper or bracket) at 29 lbs (of course, a LOT more rubber)


So, 10lbs off the rear by ditching the stock wheel and enclosure... like 10,000 lawyers at the bottom of the sea - a good start.
 

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Discussion Starter #10
Hey that's good info, I can see that some of what I have on file is incorrect ie; chaincase weight.
Also somewhat disappointed as I was hoping for a more dramatic weightloss before getting to the heavy fab portion of the project.
I've not weighed an 18" spoked alloy rim, wonder how that'd compare?
 

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Discussion Starter #11
So......perhaps a more accurate bathroom scale is called for Turbodog?
I have seen some references for the weight of the chaincase anywhere from 20lb for the assembly down to yours as the lightest. So much variation! I have a 250lb commercial shipping scale on the way from a buddy and it was calibrated in June so I'll get some accurate measurements.

In the meantime I nabbed a Progressive rear spring or $10 off CL locally that was still in the packaging.
I don't plan to keep this shock as it's heavy and not all that impressive overall but for the short term this and some mechanical preload and 15psi in the forks have firmed things up to the point that I wouldn't feel too bad riding around a few corners. Plus it doesn't look lowered anymore.

I didn't realize that the OE tach is electronic until I pulled the gauges off. It's light too so I may keep it and run a small digital speedo instead of a complete swap to an Acewell or Vapor. Maybe....

I attempted to put some dragbars on but ran into switchgear clearance issues with the tank so for the time being it's got superbike bars. They're ok but with the peg location the grip really need to be down a minimum 2" from where they are now. To do so will require some tank rework. Luckily these bikes are kind of unloved(foolish mortals) and a 'local' wrecker has three of these tanks in nice shape for cheap so I'll grab one to hack up for the front end/clip-on setup. I may try some Norman Hyde M-bars though too.


>41mm Showa front end preloaded with emulators and racetech springs.
>CB500 wheels in good nic with nice tires will do for the time being.
>CBR900 discs, will need the bolt hold opened up just a touch.
>Tokiko 6-piston calipers, had'm on the shelf for a while. Too much for the 110 tire's contact patch I'm sure but they'll end up on the final version so might was well run'm now. If they prove unridable with this relatively skinny tire I'll swap on some less aggressive 4 piston Nissins I swapped off something else (can't remember what they came from)
In the back:
>92/3/4-ish Concours barkolounger: Comfy for two, needs carbs
>96 Triumph SupoerIII: Going back to a trackday toy. It's just too wacky for street use.
>Dirty Bitch! my 02 WR426
>05 1050 Sprint: almost comfy for two, quite comfy for one who wants to tour at speed


Can't wait!
 

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Hey Mr. Swagger,

Nice pile of parts you've got there!! My hubs are almost the same... but i'll be using standard CB750 disks at the front.



What are you planning chain wise? it's hard to find a suitable sprocket at the back that goes with the 630 TR1 chain. And a different sprocket at the engine side to change chain size is quite expensive (has to be made custom). I'm not sure yet what's best...

Best regards,

Loek
 

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Loek,

Nice work there. You may like to reconsider the disk choice though. The difference in weight and braking performance between old disks and modern light disks is considerable. You could save 4 or 5 kilos off unsprung weight there.
 

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Hi there,

I think you're absolutely right there... but because i'm building a "new" bike it has to be approved for registration and insurance. And that means I have to pay tax for all the parts ($$$$) i put into the build.... After the registration all the changes are tax free.

The rule book for this kind of DIY bike is almost 80 pages[V]

It's a lot of paper work to get a registration on a DIY bike, but when finished it gets a single registration with a brandname that I can make up:).

So there are already some plans for when it's road legal:D

Best regards,

Loek
 

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I'll double check with another scale... just as soon as my wife goes to bed, so she doesn't see me carrying it out to the garage :)
I agree, nice pile 'o parts. If you switch to a 530 chain. all the XS650 and TX 500/TX750 sprockets work... you just have to drill 2 holes in the countersprocket. Fortunately I was able to buy one pre-drilled from a guy on Tr1.de.
 

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OK, weights with good scale:
enclosure, tubes, brackets, no sprocket = 9.4 lbs
enclosure with tubes, brackets, sprocket and grease = 10.6
XVR rear wheel = 36.0
CBR rear wheel = 30.4

The higher weights you got might include the chain, but I doubt it weighs 10 lbs. I sold mine and haven't replaced it, so don't know.

Just for reference, my shaft drive 920 weighs 340lbs with a full tank (5 gal) of fuel (admittedly on the questionable scale).

 

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Hey Lee, no I didn't.
Use mlinder (at) hondatwins dot com.
I don't check the one you have.

Gimme a call.
 

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Discussion Starter #18
Working backward...

Mark: will do and I'll shoot that pic out to the new email

turbodog: Wow, nice weight loss on the shafty! Must make a big difference even with a stock motor. I see you're running with the frame cut down, did you do anything unusual around the S/A pivot? Perhaps box that portion of the frame stub? I'm thinking really hard about running mine the same way and simply fabricating S/A pivot portion from scratch. At that point I have lots of swingarm options. I've heard from Herr Koch who races the pants of a few of these that there's no issue with flexing the top end and it really opens up the center and will drop some weight. My concern is the S/A portion and how solid it will be on it's own down there.
What battery are you running? I've GOT to do something about the damned car battery slung on the side of this beastie..it's friggin' HUGE!

loekm: I'll run a front sprocket from an XS650 and I'll pick the appropriate rear to suit the rim. I'll probably swap to a 530 chain and possibly even a 520 but it'll depend on what I can get the weight down to.
 

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Discussion Starter #20
Worth thinking about for certain and I want to shed a lot of weight so maybe. The SuperIII has the same brakes(branded) and I've never ridden a better stopping bike.
 
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