Yamaha Neos 50cc build

aha that makes more sense... hmm I sense a potential shenanigan. Fire, molten metal, you def got my attention now

What could possibly go wrong?

Wondering what you use as a crucible to melt the metal in?

 

we used a thick wall steel can to melt down alloy , but over time they will leak.
some used a bean can ( steel ones not alloy lol ).

we did try to forge some rebar but we were younguns and couldnt swing a hammer propper lol , we did flatten it out mosting to just testosterone fuels anger lol, but being young you dont pay attention to metal work teachers in school and end up underheating the bar ie cherry red bar when you want it a lot more hotter like sun orange white.

 

ah right I was thinking of casting steel/iron somehow - in which case a steel container might not have been much use. It could work pretty well for casting ali though I suppose

 

Don't get water any where near molten metal for god's sake.
It explodes like a bomb and throws itself out in a shower.
I used to make the casting dies in an aluminium and iron foundry years ago; there was a pocket of water trapped in the ali ingot and even pre-heating it didn't remove the water in the pocket.
When the ingot was slid into the crucible, the pocket opened, and the crucibles entire 250kg of molten aluminium in there exploded upwards and outwards, hit the foundry roof, came back down into the pot, splashed up again, and hit poor desmond square in between his shoulder blades as he was running away from the blast.
It killed him.

 

ok so maybe I'll just stick to welding & lathing

 

yep must say dont mess with it unless you know what your doing, over the years of trying things out i found the knack, but its not simple you really have to be on guard , pre-heat cast mouldings over fire to make sure they are bone dry , DO NOT be using builders sand-sharpe sand wet its just gonna explode you need propper casting sand but its not cheap. being the oldest of the group i was the one doing the pouring and smelting the buddys just stood back and watched or helped charge the forge up with coals. but the rest was down to me. my first pour i shat myself and i will not lie i did nearly poop myself.

forging metal bar is a bit more forgiving but still you gotta be on guard , forging is a starter point then once you know how metals act when hot you can start to branch to smelting. try something like making a blade first an old chunk of railway track makes for a sweet anvil , then just get the biggest lump hammer you got and really belt that hot bar , no tinkerbel tapping you gotta beat it like your life depends on it lol

 

{puts the builders' sand back in the shed}

 

Just had an interesting reply from the "Steady Garage" guys - I emailed them about the hub adaptor i posted a link to, and re whether it would fit my neos, which it' won't (only bws/zuma) but they replied saying they have just added a new hub adaptor to their line-up which *may* work since it does fit the neos drive axle:

https://goo.gl/YOkGZb



The adapter doesn't have the hole spacing I need for my mini-classic rim but if my attempt #2 fails too (which I sincerely hope it doesn't), it may be easier to drill holes for the mini-classic wheel studs/nuts than machining the whole thing as per my current plan.

It would also solve the braking surface issues too - so whilst it's still quite an expensive option ($235), if attempt #2 fails, at least there *is* actually a way forward and if I don't feel I could drill the holes accurately enough myself I guess I could always get them drilled by my local machine shop. Obvs I would prefer to do it myself if possible, though concentricity is king and I'll swallow my DIY pride if need be

 

You'll need to get the Zeus book out for spacing the holes properly of course..................
Mines right tatty now after years of use, but still good to use.
I would think you should be able to get the holes right with the miller and turntable?

 

I've been doing a lot of head scratching about this overall...but re drilling the holes actually the guys at steady-garage came up with a pretty neat solution to that issue - namely, use the lathe to mark a circle of the right diameter for the holes to sit on, then make up a centering spacer for the rim (so that the rim sits perfectly centred on the hub adapter, then use the actual rim as a template for where the holes should go on that circle...drill holes on the drill press and we should be in business. I don't have a milling attachment or a circle table yet so neither of those are really an option atm.

I was actually all set to buy the steady-garage adapter earlier today but somehow I thought it was steel and it turns out it's aluminium. Whilst I'm sure it's plenty strong enough for it's intended usage (regular scooter with lightweight rim mounted on the outside ring), I dunno if tapping holes into the face of the adapter is going to really be strong enough for my usage (heavier rim, more offset, potentially heavier bike, potentially abusive rider), plus they'll be pretty close to the edge of the adapter so again, not ideal....however, that gave me an idea....

If tapping directly into ali is "ok" then why not take the replacement neos rim (which turned up today) chop the outer wheel part off so I'm just left with the brake drum and centre bit...then machine that flat and drill holes and mount the rim directly onto that using the same technique as above for locating the rim/holes. Essentially it would be little different from the steady-garage hub adapter apart from a lot cheaper and probably nowhere near as pretty.

When I was cutting up the last neos rim to extract the splined steel core I was repeatedly impressed/frustrated with just how damn sturdy it was (it bent my 12-ton pipe bender/"ghetto-press") - and if tapping holes into an ali unit is gonna be strong enough, then why not do so on the original wheel/hub unit which only cost £15 vs £300 and which I already have. That also has a steel splined core which the £300-one doesn't seem to have (I'm waiting to hear back re the splined core on the SG adapter).



I measured on the wheel I'd previously cut up and the bit ali where the bolts would go through is at least 6mm thick, and where there's fins/tangs it's considerably thicker...so with strategic drilling I should either be able to drill holes and drop the original mini wheel studs through from the back, or (preferably) just tap 12mm holes so it takes proper metric wheel bolts but where there's enough thread engagement to make it plenty strong enough. I could potentially even add some aluminium to the bits where I'm drilling/tapping holes though I suspect I'd do more harm than good there re messing up any heat-treatment etc (though people do use a welder to repair kerb-rash on alloys so I guess it's possible)

I've checked and regular 12mm tapered wheel bolts fit through the holes on the mini rim without modification and seat very nicely too. I could even do both options sequentially on the same wheel centre if I'm not happy with how one goes.

That should also save me having to muck about with welding on a braking surface since it'll already be there from the neos wheel.

And if neither approach works or the end result doesn't look convincing enough, then I can still hack it up and extract the steel splined core and revert to plan A, but build & machine it all in situ on an axle mounted in the lathe...so one way or another I think this particular "cat" is getting skinned

 

So I've heard back from Steady-Garage again and apparently the splined bit IS ali but they've been using the same technique on tuned bikes for years now without any issues so apparently that's not a problem, as long as the wheel nut is tight..which makes sense.

I think I'm still gonna work with what I've got for now but it looks like if neither of my approaches produce a satisfactory result at least there actually is another option which, whilst pricey, should work out of the box. I guess if i was starting over I'd have gone that route from the outset but then the product didn't exist at that point so I guess it is what it is.

I would imagine for any future fatty neos/yamaha conversions it would be easier to start off with one of the SG hubs and then get a rim to match....and then you'd only have to worry about the stretch bit.

Their support has been *excellent* though which is awesome to see and would give me every confidence in buying from them

 

progress so far on attempt #2...


red dots for where I'd aim to tap holes for studs screwing into the adapter (from the other side)...blue dots for where I'd drop studs through from the back. It'll depend a little on where the mini PCD/radius lands I guess.


on the drive axle in the lathe and ready to start turning. I'm just waiting for a revolving centre for the lathe so I can keep everything bang-on centred.

 

so I got the wheel turned down on the lathe and made a centre lip so the rim sits more or less centred. Thee was a little bit of play but not much.

With the rim on I eyeballed the line for the bolt radius and got it within 0.1mm which seemed pretty good going...probably closer than the OEM mini parts haha.



then again eyeballed the holes with a sharpie and the rim in situ...



and much to my surprise they all came out pretty much bang on. One is everso slightly off but I'm not sure it'll be enough to be a problem, and in the worst case I'll weld it up and re-drill it.



By the time I'd faced the hub flat there wasn't quite as much thickness to drill through as I'd hoped but I'm not worrying about that for the moment. If it all lines up, and the rim mounts and spins smoothly I can back-fill around the bolt holes with weld and then re-drill/tap so it should be plenty sturdy enough.

Whilst there was still a tiny bit of variance in the new axle in the lathe it was only about 0.1mm and the finished adapter seemed to run smooth/true, tested at up to 800rpm.. I've not been able to work out what speed that would equate to on the scooter but it seemed pretty fast and a lot better than attempt #1.

As it turns out I don't have a 12mm drill bit so am waiting on one of those before I can tap the holes and mount it up and see whether practice lives up to theory.

 

decent progress today - I *think* it's working \o/

hub drilled and threaded and mounted on the scoot..the ridge in the middle means the rim gets centred automatically.


decent thread depth - much more than I expected..will probably still fill-in the back side with weld though to be sure.


This hub adapter has a little more offset than the first one I built so I had to trim a little off the exhaust mount so the tyre clears..


but it's on, and whilst the alignment/rotation isn't *perfect* it's near as dammit and seems to be more about tightening the wheel bolts in the right order than whether the adapter is straight or not (which to the best of my knowledge it is). There's more deviation now in the tyre itself than the rim so I think that's probably close enough.

I think it's certainly good enough to continue with the rest of the project. I might still get the hub adapter from Steady-Garage in the end but I don't have the funds available for it at this moment and I'd rather get on with the rest of the project than end up "stuck" on this till I have the funds since I'm sure there'll be a learning curve with the stretch kit too. I reckon I'll try and make the stretch kit in such a way that there's scope to adjust the offset slightly so I can use different wheel adapters, which probably isn't a bad idea anyway.

Wheel is now mounted using M12 wheel bolts from a VW Golf, so no more silly imperial nut sizes either like on the mini hub. Pretty pleased with how it's looking and it feels really nice and solid. *chuffed*






next up - the streeeeeetch..

 

hmm - just found this:

https://goo.gl/yrFvNC





Looks like it might do a similar job to the Steady-Garage adapter, looks to have a steel spindle/core and is only £70 instead of $230 (+drilling+import duty). I'd have to drill the holes I need myself but it might still be a reasonable option and today I figured a way of potentially doing that more accurately than I have so far...

Only potential issue looks like it's more "slimline" than the current adapter (and the SG one) so I'd have to be careful about wheel bolt lengths but still..could be an option. On the upside, less offset so less lateral load on the wheel bearing/axle.

{ponders}

 

bought the ebay adapter...not sure it'll be entirely suitable but I think it's worth checking out, esp if it reduces the offset which it looks like it might, by about 10mm - which would be good from a wheel bearings/lateral load pov.

Am stretching the frame on the Jog today as a trial run since I'm sure there's a learning curve and that's more in bits so easier to tinker with. Have ended up doing about a 12" stretch which should let it get really low too. No wide wheel on the back of this one (yet haha) but it still looks badass as is. pics to follow..

 

did a dry run of the stretch frame/kit - turned out pretty good as it happens... I started a project build thread for that bike since I guess it might be a Thing now. Details here:

https://www.scootershack.co.uk/threads/yamaha-jog-50cc-stripped-stretched.37932/

 

ok so now I'm confused....

This is the wheel adapter I got off ebay, made by "Carenzi":



Looks very nice and pretty, also looks very solid. It's got a steel splined core and the rest appears to be cast, potentially with a machined contact face for the wheel to attach to.

So having learnt from my past mistakes the first thing I did was stick it on the lathe on the brand new Jasil axle I got from Pedparts.co.uk ( https://goo.gl/yQPvby ). Much to my surprise the lateral deflection was *really* bad...wobbling like a mofo bad .

I put a dial gauge on it and recorded over 0.5mm deflection at ~50mm radius. Even the first adapter I built was closer than that...surely that can't be right. I wondered whether an explanation might be with the Jasil axle being new, perhaps there is a "bedding in" period needed for the spline and any wheel which lives on it - which might account for the poor fitment. I'm sure by the time you've ridden round the block a couple of times the axle spline and wheel spline will have become very good friends and being fresh out of the box the axle on my lathe won't have had that...but still. Not particularly impressed so far.

So I stuck it on the bike since that has had lots of bedding in, and I know the yamaha wheels run true on it...it was better but still showing quite a lot of deflection: ~0.3mm @ 50mm radius, which would equate to about 0.9mm at the edge of the rim. I know from the previous adapter I built and the most recent one that 1mm deflection at the rim edge makes for quite a wobble, and doesn't seem like an acceptable tolerance to me.

I didn't really even get into the concentricity/centring of the Carenzi adapter either but I could tell from trying it on the lathe and the bike it also wasn't centred that way either...which means drilling holes to mount a rim on it isn't really gonna work too well imho.

Am I being overly perfectionist or does this adapter strike anyone else as unsafe? At this point the last one I made runs truer than this bought one which really isn't what I expected as an outcome, and I'm leaning towards sending it back and recommending nobody else use it either.

I'm also thinking I probably can't really trust the Jasil axle either. I might see if i can find a used yamaha one to use as a base for building/turning future adapters on.

I made a quick video to show the process I went through - see what you think...am I missing something?

 

i would send it back with a link to your video showing its outta whack

i mean on the motor a yam wheel has less than the adaptor when put on the same spline so yeah its 100% not right , you know the wheel is and it shows very little deflection thats acceptable , but that adaptor os just way out and thats not even gotta wheel added and rubber i bet it would be even more once loaded up.

 

thanks Tamiya, that's more or less what I thought, but wasn't sure if i was being over-cautious. I hope this one is a one-off though and they're not all skew-wiff like that. Fun as the posting-things-back-and-forth-across-the-pond game is I dunno if I'd actually want a replacement if there's a chance it'll be wonky too - may stick with the adapter I made since I got it to run right..I just thought this one would be a better bet. #denied