rsrmoto_monster-titanium

Weight Watchers winter project

Bitza

platinum with diamond studs member ;-)
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Jul 27, 2006
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550
Location
Poole
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M900ie
Well I've always kinda fancied some lightweight wheels. But secondhand wheels to fit my 94 frame don't seem to come up very often, plus I use a later front. So the first part of my plan was to adapt a Metamecha (?) swinging arm made for the St type frame, and make it fit my hoop type frame. See pics. I make up the brackets with hand tools and get a friend to weld it together.
I'll keep you informed of progress.
 

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Interesting.
How does that compare weight-wise to the original Monster swinging arm?
Was it easier to do this than to bore a hoop arm out to 25mm?
Now you'll have even more ride height adjustment with the round block adjuster, and some you don't need if you have to adjust the chain a lot!

The Paso used this type of adjustment and I was considering one for a project as I thought the round block adjusters looked cool, but I think the ride height change makes it a bit of a nuisance? I abandoned that idea as the obtainability would have be difficult anyway, but grew to like the idea of snail cams instead. There's a good selection available for moto-crossers.
 
Weightwise not alot between the two.
The differences between the two generations arms, is basically that the later one has the drive side arm further out and timing (cam) side set in.
I'd agree with your reticence re the chain adjustment set up, but it's the compromise. As neither Ducati types lent themselves to this adaption, options were limited.
Have to say I'm not too impressed with the Metmachex unit. First you can't use all the adjustment without the tyre fouling the arm's cross brace, even though the arm is about 2cm longer. Plus the solid spindle weighs a ton.
 
Oh yes I forgot to say. A big yes to snail cam adjusters, as per the original Royal Endfields. I used to have one on my G80cs to adjust the magneto chain too.
 
Plus the solid spindle weighs a ton.

Presumably, it's a specific Metmachex part?

When I was building mine I couldn't find a standard, steel spindle so I had one made out of titanium and drilled through so nice and light...
 
I assume the spindle is Metmachex, but don't know. I'm planning on adapting the Ti spindle I used with the original swinging arm.
Have fitted the new arm today all appears to be going according to plan, big sigh of relief after all the measuring and comparing different components.
Next it's the new wheels.
 
Metmachex were quite well known years ago,think it was people trying to get their Japanese bikes to handle.

Good luck with the build

Kimbo
 
New wheels it is, originally I was hoping to come across some Dymag three spoke carbon wheels but never saw any for sale and now they are out of production. BST were my next choice but they come with 6.00 rear wheels which I don't want plus the the fact of the cost of new wheels is too high for me. IMG_20250127_090835.webp
Then I came across a pair of BST carbon five spoke advertised in my hometown. They had hardly been used, in perfect condition at a bargain price, only problem was they were made to fit a Triumph 675r. So lots of comparative measuring before buying. The rear is 5.50 wide with the opportunity to reduce the disc down to 220 mm dia.
 
Woo Hoo! Carbon wheels. 👀
You're in an elite club now.
Are you still using a front wheel speedo drive? That could be the trickiest thing to get working. Although the drive dog is very simple.

Wheels look smashing, and looks like you have two good tyres on already, all balanced up and ready to go.
 
I tell you what .... you will really notice the difference that those wheels make.
Lightweight wheels are the best "bang for buck" in my opinion.
I fitted Dymag 5-spokers to my 750 and I was astounded by the difference they made.
The thing turns if you so much as "think" left or right now.
But not only did they transform the handling, an added bonus which I wasn't expecting was that they seemed to make the engine seem more powerful !!!
At first I couldn't figure this but then I realised that the reduced rotational inertia was allowing the wheels to spin up more quickly/easily, effectively giving me greater acceleration.
Prepare to grin like the proverbial cheshire cat.
Oh, and you'll be needing to buy a compressor (if you don't already have one) and a bead-breaker cos there is no way you'll be wanting to trust anyone else to change your tyres from now on.
I can recommend the Abba bead breaker.
And the "cable-tie" method for slipping them on (and off for that matter) ... easy-peasy.
 
I'll put the ABBA bead breaker to the top of my birthday list.
For the benefit of anyone else contemplating adapting some BST wheels, here's a quick run down of the likely issues. First making the wheel fit your spindle dia is the easy bit, simply drift out the spacers in the bearing, and replace with one's of a suitable ID, the thickness needs to be calculated to suit. On the front wheel the only other issue is the disc spacing which can usually be overcome by obtaining a suitable disc "basket". I got mine from PFM, Wal was very helpful and adapted a pair to my spec at no extra cost, they fitted perfectly. However if the brake carriers on the hub are set too far apart there will be little you can do to make it work. The Ali carriers are attached to the the carbon wheel in a specialised bonding process, on a special machine to ensure centrality and security. They cannot be taken off and reaffixed, if you see wheels advertised as not running true steer well clear. IMG_20250128_113124.webpIMG_20250128_113158.webpIMG_20250128_113443.webp
 
Have fitted new front wheel see previous photos. Slightly disappointed with the weight saving, that came in at approx 1.5kgs, mainly due to the comparable weight of the discs. My old ones were EBC probably the lightest on the market, mainly due to being only 4.5mm thick. The new PFM discs maybe bobbinless but the rotors are 6mm thick and it has to be said they are heavy.
Hoping for a substantial weight saving on the rear.
 
Am on with getting the rear wheel to fit. When it struck me, the difference between two designs of cush drive pins. Ducati have six huge pins while BST use five extended screw heads. Surely somebody got their calculations wrong? IMG_20250131_090929.webp
 
All looking rather sexy Mike! (The bike, not you.)
Going back to your comment about not much you can do if the disc mounting faces are too far apart, or wide; It might be possible to mount the disc(s) inside out with the offset the hub side to kind of make negative offset?
There would have to be enough room for the spokes to miss the calliper of course.

I'm assuming your discs are non-floating, unless they float without bobbins somehow? Rigid front discs are rather unusual these days?

I take it that you simply used a Triumph sprocket carrier? I hope you can line the chain up okay and the tyre too.

I was looking at my six heavy steel drive pins just the other day and thinking how much weight I could chop off with Ti replacements.
Every time I have the wheel out I look at the pins and bushes and put off replacement till another time.
The bushes and pins are quite expensive, I've looked into Polyurethane bushes which would be far superior, but have never found any, they are available for other models though. Poly bushes and Ti pins would be the dream if I had deeper pockets.
 
I've often wondered why someone has not produced a nicer looking, perhaps CNC sprocket carrier for the older Monsters as the stock one looks awful and like you say weighs a tonne.
 
Just to tidy up a few points, the PFM discs are floating the rotors are pushed into the basket from the side and secured in place by a large circlip. If it became an Olympic event then you could expect that with the wheel out both rotors could be changed in under 60 seconds.
The sprocket carrier is BST.
Getting replacement drive pins made up in Ti isn't easy, first you have to find an engineer willing to work Ti, then there is the left hand thread, the hexagon socket end etc. Unfortunately the person who made mine retired because leaning over a lathe for forty odd years totally did for his back. However I do know of someone who had them made in Ali 7075 be it for racing purposes.IMG_20250131_164354.webp
 
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Ah! I think I see how your discs work now. Looks a bit like a Commando clutch circlip.

I didn't realise that there was a LH thread on the pins. Reading between the lines I sounds like you have a set of Ti pins that might be spare if the carbon wheel works out. I can't believe I've been so cheeky. 😜 I probably can't afford them anyway.
 
Well no harm in asking, but will wait till I've checked out new set up before getting rid.
Re:- fitting rear wheel, have sorted centering the wheel /aligning the chain. Another issue was the triggering of the speedo sensor, originally off the six brake disc bolts. The triumph set up uses four bolts. My understanding is that the triggers have to be ferrous, so my solution was to make a studded ring, two of the securing bolts are steel, with four more steel studs set at equal distances, with the remaining securing bolts in Ti.
Next is making a new floating caliper/sensor bracket for the smaller 220mm dia disc. IMG_20241223_094716.webp
 
Obviously make sure that the new set up works first, but please remember me if you do decide to get rid of your pins.

I'd ditch the floating brake and save half a kilo. It's only really of any use to help fight rear wheel hop if you're one for heavily trail braking fast and deep into corners.
A Ti torque pin and bolt will save even more grams.
I reckon it would be easier for the shock to control any hop with all that weight shed.
It's my understanding that Ducati gave up on floating rear brakes on their race bikes after experimenting with them, I'm not fully up to date with what they use now though, probably computer controlled rear suspension?
 
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