Thumper Club Forum
Technical => Project Progress => Topic started by: andy230 on December 01, 2022, 08:20:03 PM
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Hello all, very long time since I have looked in!
Over the last few years, I seem, remarkably, to have got all the projects through the pipeline, and have finally gotten around to (thinking about) a refresh on the Skorpion.
Its quite a good motor, got the ginormous MZ race seat and low bars and hi pegs, but always wanted spoked wheels on it.
The checker website tells me I haven't run it in 7 years... :-X
I will just clean it up and refresh it (I hope!), but have a Bonnie front end which will need surprisingly little work for the skorpion yokes. They wont be great forks (thruxton), but at least as good as the paoli's which I got sick of rebuilding. Probably a Triumph brake, but will see, and a 17" wheel for standard tyre size.
Rear might be tricky, am going to try an XT wheel that a mate has as a potential donor. Skorpion rear sprocket looks very close to the swingarm. However, it is currently under carpets in the shed, and has been for since the shed was built, when it graduated from the garden under a tarp.
So my query here is 2-fold:
1. Anyone put spoked rims on a skorpion you know of? Google gives me nothing, (lots of trick, hipster'd skorpions, all with the grimeca cast wheels, but I surely cannot be the first person in the world to do this!
2. Anyone with a complete rear XT/(in fact all inc XTZ to 98 I think...?) rear hub, cush, sprocket +/- the rim they could either a) measure (easily) and/or b) want rid of?
Thanks all,
Andy
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The alternative would be the other impossibility of an MZ Baghira/ Mastiff hub or wheel, but I cant see many of them coming up on the bay...!!
Cheers,
a
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Hello Andy,
May I suggest that you PM SteveH, as he may be able to assist you? I know Steve did this conversion on an SRX, but there was talk of "moving on"! ;)
Pleased to read that you are still not conforming and hope that the family are all tickety boo. ;)
Duke's Pass is rubbish these days. 6 wheeler coaches full of towerists, tear the surface up, which is then "repaired" with gobs of sprayed in tarmcadam, flattened down with a back of a shovel. Then, all levelled off with a top dressing of emulsion and quarry dust chippings! :( Plus a 40mph speed limit!
The Duke has been getting aired regularly and was out again on Sunday past, only to receive a coating of finest Cheshire salt from two passing gritters. Still a good wash, shampoo, rinse and application of silicone spray and the old bird dosnae look so bad. ;)
Good health, Bill
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Hi Bill,
Shame about the Duke's Pass. Sounds like travesty. Up here just now actually, family stuff.
Have been keeping it British of late- the only vehicles I can drive inside the ulez, bit mad.
Yep, I saw Steve's efforts, fantastic but I think his used a TDR rear hub. Will ping him, good call.
Will see how the xt rear goes in and source bits if it can be made to fit.
And see if I can can post some pics once I get the bike out.
Cheers,
A
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This works I think. Needs only a 5mm spacer on the spindle (and 2x of same for Triumph caliper.
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In principle!
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I have the loan of an xt rear, and will report back. Ebay is nice for very reasonable spacer manufacture, but I don't expect the back to be as straightforward!!
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As dragged out from under the carpets! I feat it will take more than spoked wheels to make it pretty!!
Cheers for now,
Andy
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Aye Andy,
Good to see the old bird dragged out and getting some tlc.
All the best with the spacers and XT rear end fittings. That should keep you distracted for a wee while.
Good health for 2023 to you and yours.
Slainte, Bill
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Hi Andy, it looks a sweet bike in it’s Norton guise. Wouldn’t it have been easier to just “restore” it back to that, maybe with just a few minor mods?
Still... I suppose that would have probably felt a tad boring. Best of luck with the rear end... ooo eerr, more tea vicar
Cheers, Michael
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Well, I always wanted spokes on it, and I hate the OEM forks, so thought if I am going to tidy it up a little, then I didnt want to keep the forks. The Bonnie stuff goes in easily at the front, but will need a spoked rear wheel.
The rest should just clean up ok...
I have a chopped subframe (no pillion pegs, so would have to think about the exhaust mount) which I am tempted to use.
The plastic tail is just so big, and when I see it stripped, its lovely!!
Will probably keep the body work for now... (High level pipe?) Never really finished are they?
Will post up how the XT stuff works (or doesnt)
a
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I for one will keep my eyes 👀 open for your progress. Never tire of seeing what other blokes (and ladies of course) are doing to their steeds. I’ve never had a skorpion, only ever seen about half a dozen over the years, so be good to see how it turns out. Best of luck with the build Andy 👍🤞
Cheers, Michael
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XT fits with Skorpion spindle. Will need sprocket carrier machining to allow sprocket to line up, then re-lace wheel to account for offset
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Must be a a slight relief that the spindle went straight in Andy. Have you got a completion date in mind or are you just doing it when the fancy takes you so to speak? Looking forward to seeing the finished bike👍
Cheers, Michael
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Nice to see another garage nearly as messy as mine!
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Ok, so I found a relatively cheap XT600 rear wheel with sprocket and disk etc, knowing that there was a good chance it could be made to fit.
I knew the sprocket carrier as standard needed a bit of slimming down, so I (got an engineer to) remove 10mm from it.
The XT has a big dust seal, but I figure with a sealed bearing, for all the distance I will do in it, it will be fine.
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The stock XT uses big studs and nuts to hold the sprocket carrier on. These had to go, and were replaced by bolts.
I plan to build the wheel "left to right". By this, I mean, without the chain run being right, its a no-go. The rim can be adjusted to compensate, but the chain run has to be right.
I knew the sprocket face had to be c.10mm from the swingarm. Rough measurement told me that from bearing surface to swingarm needed a 7mm spacer.
A nice man on Ebay made this for me from stainless, and you can just see it winking out from this pic.
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Next, I put the rest of the standard XT wheel on, and shoved it all over to the drive side.
I measured/ calculated that I needed to lose 15mm from the standard XT caliper carrier to fit the swingarm.
The same nice engineer man sorted this for me as per the pic. Which will be meaningless unless you know what the OEM caliper carrier is like...!!
However, key is the fact that metal was removed from the outside of this, meaning that the relationship between the carrier and the wheel is maintained. Meaning that the OEM XT caliper should fit straight on and mate correctly with the disk.
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(I also had to cut a tab from the Skorpion swingarm, used to mount the black plastic hugger. See it in the initial pics with the bodywork. It is most definately not going back on. This is the first thing I have done which is not reversible, but I think needs must now.)
And it appears to fit just about right!! Its a bit of a faff getting the new 7mm spacer in the drive side, but very do-able.
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So in short, for the back wheel:
10mm off the sprocket carrier
15mm off the caliper carrier
(Ditch both XT spacers between the wheel and swingarm)
Procure 7mm deep spacer, 17mm ID (29mm OD)
Re-use Skorpion spindle
And that's about it I think?
Sprocket is in same place as Skorpion, and I have a rear brake coming from Ebay. I am going to give the old chain a going over (a few gubbed links) but will use it for initial test.
Of course, I need to work out the offset for the new rim. It needs to be about 10mm over to the right from where it is now, but I will measure up and get Hagon to build up a new wheel, (with stainless spokes, blast and paint hub) to hopefully match the front rim.
But thats not such a problem. It can absolutely can be done, and if you are daft enough to waste time and money then its far from impossible. Helped hugely I think by the fact that the swingarm is FZR Yamaha, both the MZ and XT (and presumably FZR) are 17mm spindles, and these guys dont change anything across the range that they dont absolutely have to.
Next: rear brake (bolt on and bleed), chain soak, clean, and replace (note to self- how many teeth on rear sprocket?) then start to build up the bits onto the handlebars to get it somewhat rideable.
Wheel build, road tyre.... done?
I am going to re-use the old pipe and bodywork for now, and as soon as I can, see if I can get it tested as being ULEZ compliant... fingers crossed.
Cheers for now, will post a few more pics when its looking a bit more complete
Andy
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Very nicely documented 👏
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Mod/ SteveH?
Can maybe move this to Project Progress if better?
a
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I’ll echo Matt’s comment, very well documented and really enjoying reading/following your progress Andy. Lots of head scratching and messing about no doubt but very satisfying when the end result works out. Looking forward to seeing the finished bike. Best of luck with the rest of the build and look forward to seeing your next few posts.
Cheers. Michael
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Looks great, well done.
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Hi Andy, nice to see you are still active likewise. If you ever need a bit of turning/machining doing, just pm.
Ian
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If you ever need a bit of turning/machining doing, just pm.
Ian
What if one is called Michael... does that count 😉👍
Cheers.....err. Michael
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If you ever need a bit of turning/machining doing, just pm.
Ian
What if one is called Michael... does that count 😉👍
Cheers.....err. Michael
Rhetorical question Michael!!
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After a lot of measurements, I determined the new centreline of the hub to be 1.5mm over towards the sprocket. So got Hagons to build me a wheel offset 1.5mm to the brake
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So once in the swingarm eith the spacers I held my breath and measured up again.
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And from the brake side
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It was out by 0.6mm, too far over to the brake, so only needed 0.9mm, rather than the 1.5mm I specified. I think I'll live with that, as the MZ is likely not perfect anyway, and I'm hardly doing MotoGP with it!
If repeating, 0.9mm isn't much, so you could run the sprocket slightly out and centre the wheel I think?
Anyway, new XT sprocket to retain skorp gearing (15/43), and the old XT disk should clean up.
It's off getting the (old!!) tyres put on, which will do for an MOT till I decide what to do with it longer term...
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Hats off to Hagons who blasted and painted the hub with the wheel build. The colour is similar to the Bonnie front hub I had and the the profile, while not perfect, is a good enough match for the front.
Quite happy, all in. I have never converted a bike to spokes, and It wasn't as hard or as complex as I thought. I got lucky with compatability, but maybe someone else who wants to do it can use the info
And I also took the opportunity to junk the old Bilstein shock. Not great when new, and unimproved by 25 years! You can just see the new one in one of the pics. Remarkably the bottom spherical bearing replaced about 18 years ago was still new. (Sat for 8 years tho!!). I just cleaned and regreased.
So I will start getting it back together and get an MOT. Will post a pic of it when together. After that, I will replace the subframe with a chopped one I have, and maybe move the pipe a bit. It hangs off the existing pillion pegs, but they will go. Supertrapp maybe....?
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Aye Andy, looking good! ;)
Trust all well, wi' you and yours?
Good health, Bill
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All good thanks Bill, plodding on. Hope you are too. Was up the road and did the West Highland Way in April. Fantastic. Very little rain, remarkably.
I hid the Irish supercar (in a disused mine ;) ) at Fort William, and walked up to get it with a pal.
A few days R&R at Castle Sween afterwards to rest the feet before back down to London. About 1400 miles all told, and it was fine.
Wee bit of riding down here, but much more time on the spanners than riding now. I'm OK with that.
Will stick a photo of the bike up when it's done. Will be trying to get a ulez compliance ticket for it, so I can ride it after August!! I know a few folk with XTs who did it, so should be OK. Tho the skorpion is slighy hot with a flowed head, cam and dynojet kit. Let's see...
Cheers for now,
A
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I got it together, and had a little spin in the street.
A few things today, but nothing with the wheels, brakes, or forks! ;D
I am quite pleased with the look. And the spoked wheels are an awful lot lighter than the cast Grimeca ones.
Front brake has a little too much feel, and not quite enough bite. But it may bed in.
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I quite like the supertrapp. Need to make a bracket for that.
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And will see if I can find a front guard. Previously had an SRX one on the skorpion forks, that might be re-usable...
And I think once I have an MOT and ULEZ ticket (hopefully), then I will fit the chopped subframe I have, to ditch the now redundant pillion pegs.
Cheers for now
Andy
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Hi Andy, nice to see you are still active likewise. If you ever need a bit of turning/machining doing, just pm.
Ian
Oh, and thanks Ian, very kind! Must have missed this!
Cheers for now,
Andy