Inconsequential ramblings of an Old Git

[Count Steer]

Yeah, I know what you mean about those bars. I'm a fan of function over form but...

Look forward to the next iteration.

PS The amazing thing about David Byrne's Big Suit is that it DID fit! It didn't flop about or anything. A miracle of engineering.

Have you seen the announcement of Stop Making Sense 2023? I've pre-ordered the double vinyl already...

https://www.rollingstone.com/music/musi ... 234697972/

Hadn't seen that. Ta.

Unfortunately I have no vinyl or the means to play it any more. I curse myself that my AR deck went in a skip but, on the plus side, I gave the vinyl of any value to a charity along with a list of likely prices on eBay. I miss quite a bit of it though, the CD transcriptions of some Shriekback stuff is pants and I can't find some of the Cabaret Voltaire oeuvre in any format, never mind the 12" singles mixes. Sigh.

[Bustaspoke]

The answer was right in front of me - a pair of much more aesthetically pleasing bar risers. So by the power of eBay I now have a spare Falco top yoke and a pair of MT-09 SP bar risers:

In your position I'd be looking at a bar & risers combo,not the bars that you had fabbed up.Not sure which bars & risers though...

[mangocrazy]

The answer was right in front of me - a pair of much more aesthetically pleasing bar risers. So by the power of eBay I now have a spare Falco top yoke and a pair of MT-09 SP bar risers:

In your position I'd be looking at a bar & risers combo,not the bars that you had fabbed up.Not sure which bars & risers though...

I have been looking at bar/riser combos from Tuonos and Falco streetfighters, but they're not really what I want. Those bars won't have any part in Plan B - I'll be using a similar set of bars to the ones I had fabbed up for my KTM Duke - something like these:

DSC_4484.JPG (694.02 KiB) Viewed 443 times

I think a combination of the MT-09 SP risers and the above bars should look a lot better than Plan A. But I will keep looking to see if I can find a Tuono top yoke. That might be a better option.

[mangocrazy]

Since I last posted I've mainly been waiting for my local tame engineering shop to make up some parts for me and turn down some tube to the required o.d. Some excuse about the bloke who does this stuff having nearly severed all his fingers or somesuch...

Anyway the bloke came back (with all his fingers) and got to work making these for me. This is part of the drawing I supplied for the bits:

Falco_yoke_wedges_detail.jpg (322.96 KiB) Viewed 416 times

Basically they are 15 degree wedges to level up the top deck of the Falco top yoke so I can mount the risers on a flat base. To fix them to the yoke I first sanded off the paint/anodising on the sloping surfaces, applied goodly amounts of JB Weld epoxy and then carefully placed the wedges on top of the epoxy, ensuring that the top face of the wedges were level with the central portion of the yoke. I'd rejected the idea of getting the pieces welded on, as there was a big risk of heat deformation. Once the JB Weld was firm to the touch I plonked the whole assembly on a radiator to speed up the cure.

After 24 hours it was ready for the next step, which was to drill 10mm holes for the risers. I only had one shot at this and it had to be right first time, so I fretted and fussed until I had A Plan. The underside of the yoke had been lightly milled to remove raised casting marks (part numbers, date of manufacture etc.) and provide a flat surface for the lock nuts to sit on. I eventually settled on a point for the first pilot hole and gingerly drilled from the underside with the work clamped down and a 4mm drill bit in the pillar drill. With the yoke unclamped, I was greatly relieved to find that the hole was nicely central and just where I wanted it. Result.

The next thing was to make sure the other hole lined up with the first one. For that reason I left the first hole at 4mm as it's much easier to judge where the other drilling centre should be. For the other hole I was drilling from the top side and eventually settled on a point, centre-punched it, clamped the yoke down and nervously started drilling, initially with a 4mm bit. I then moved through the sizes, finishing off with a 10mm bit. I suspect it's more through luck than judgement, but the holes look pretty well lined up to me. You be the judge...

DSCF3581.JPG (904.8 KiB) Viewed 416 times

And here's a shot of the underside of the yoke. As you can see, the webbing on the underside seriously limits where you can mount the risers, but there was just enough space, courtesy of some careful milling. Next step is to drill out the initial hole to 10mm and see how (and if) the risers fit to the top yoke. Wish me luck...

DSCF3584.JPG (821.33 KiB) Viewed 416 times

[mangocrazy]

Well when you're on a roll, keep the momentum going... Emboldened by my earlier successes, I drilled out the second hole in the top yoke to 10mm, inserted the risers and tightened up the nuts. Then I realised that I needed the bars in place before I tightened the risers up, as they need to be exactly parallel to each other. The MT09 SP has a 'fat bar' (1 1/8" at the centre, tapering down to 7/8" at the grips/controls) and as luck would have it I had the OE bars from my KTM in my spares stash. That was hauled blinking into the light and clamped up in the risers, and only then were the riser nuts tightened up fully. I dunno about you, but I'm calling this a result...

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DSCF3590.JPG (571.29 KiB) Viewed 404 times

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[Demannu]

Not wishing to urinate on your fragaria, but back in the day when I was modding my fazer, there were a spate of brake, break moments with the drilled out R1 yokes. In the end we filled the void with weld, never had an issue after that.
What with my experience of Aprilia alloys, I'd make a new yoke from billet!

[mangocrazy]

Not wishing to urinate on your fragaria, but back in the day when I was modding my fazer, there were a spate of brake, break moments with the drilled out R1 yokes. In the end we filled the void with weld, never had an issue after that.
What with my experience of Aprilia alloys, I'd make a new yoke from billet!

Take your point - I have weakened the structure by drilling 2 x 10mm holes in it, but then I've also strengthened it by bonding 2 ali plates on top. Also the risers generate a clamping force through the top yoke and the ali wedges. With the riser nuts fully tightened there are just 2 threads showing out of the lock nuts, which means that the depth of my modified top yoke is at least as great as the MT-09 SP top yoke, and I presume Yamaha have done their stress calcs.

So I dunno... You don't really want me to go back to Plan A, do you?

I'd be interested to see a pic of the R1 top yoke that failed. Did you drill it out or did it come from the factory that way?

[mangocrazy]

That is unbelievably dangerous. Those handlebars will snap off the moment you hit the brakes hard. The increased leverage you have created with high risers and the thin shitty cast alloy being asked to do something it was never designed for is a recipe for disaster.

I am not kidding when I suggest that when you find this out, it will be at precisely the worst possible moment.

Sort it out ffs! Seriously, that is fucking dangerous.

Hmmm - so why is it OK when it's on an MT-09 but fucking dangerous on a different bike?

[mangocrazy]

These are the parts I've used and this is how they fit to the MT-09 SP. I've used genuine Yamaha risers but mated them to a Falco/RSV top yoke with reinforcement. I've used these parts in exactly the same way as Yamaha have done. How is this dangerous?

MT-09 SP risers.JPG (66.48 KiB) Viewed 688 times

Clearly I have no desire to meet a horrible death as a result of modifying my bike, but I'm at a loss to understand how what I've done is exponentially more dangerous than OE Yamaha.

[mangocrazy]

The depth of my yoke and the depth of the Yamaha one must be very similar, simply due to the length of the riser stud. That is 25mm long and the accompanying nut (also OE Yamaha) is 11mm deep. There is 2mm of thread protruding from the nut, so that gives a yoke depth of 12mm, and this will also be the case for the MT-09 yoke. The length of the stud (25mm) guarantees this. I inspected the Yamaha risers/top yoke closely before going ahead with this and I could see nothing special in the way of rubberised spacers and steel liners. Yamaha are not, as far as I can see, doing anything differently or I would have copied that. There also appeared nothing particularly special in the design or construction of the Yamaha top yoke. It certainly didn't appear any heavier duty than my yoke from a visual inspection.

I wasn't trying to push new ground with this; the whole point was that I wanted to copy and reproduce a known working design, and that is what I have done to the best of my ability. I'm aware of stress risers and how they work and unfortunately the need to mill out a section of the bottom yoke was unavoidable. Without that I wouldn't have had room for the fixing nut and clearance for a socket to tighten it. That is the only section of the design that I freely admit is inferior to Yamaha OE.

Had the studs attached to the risers been longer I would have been very happy to add extra material and avoid milling, but Yamaha only gave me 25mm stud length to play with. Personally I would have preferred a stud length of at least 30mm but I could only work with what Yamaha gave me. I also suggest that the aluminium I've added to the top yoke is of a notably superior quality to the cast ali of either the Aprilia or Yamaha yoke, so this should have a positive effect.

[Mr. Dazzle]

Your gluing is shit though.

This isn't a criticism of you BTW. Most gluing is shit. I hate glue . Plus you can't buy good glue as a lowly member of the public.

Seriously, i wouldn't "take any credit" for the reinforcement of them stuck on plates.

No comment on the rest of it, too tired to get my head around it

Dunno why people have such a downer on castings BTW. The grade and quality are what matters, I'll take a good casting over shit machining any day.

[mangocrazy]

Seriously, i wouldn't "take any credit" for the reinforcement of them stuck on plates.

The sole reason for having them was to provide a flat top deck on which to mount the risers. How else would you have fixed them to the top yoke, other than welding (which I dismissed, for reasons given earlier)? Any such fixing method would need to be available to the great unwashed, of course.

No comment on the rest of it, too tired to get my head around it

Probably best not to post when 'tired and emotional', then...

[mangocrazy]

Your gluing is shit though.

This isn't a criticism of you BTW. Most gluing is shit. I hate glue . Plus you can't buy good glue as a lowly member of the public.

You really gotta ask yourself what the 'glue' needs to do. Obviously don't ask yourself now, as you're in no state to provide a sensible answer. The glue needs to hold the two pieces in sufficient shear strength to allow allow drilling of the two bonded (sorry, glued) pieces without separating and to remain effectively one unit subsequently. Once the two pieces are clamped together using a bolt/stud and nut through a hole drilled to tight tolerances, then as long as the bond is maintained then it's job done.

FWIW I'm not a great fan of glue. I much prefer mechanical fixings, such as welding and bolting. But glueing/bonding has its place and this was one of them.

[Mr. Dazzle]

, then as long as the bond is maintained then it's job done.

This is the problem in a nutshell.

"So long as".

Without wanting to write pages and pages it's incredibly hard to make a good bonded joint, even in an industrial application. I've glued alot of structural parts in my career (not personally doing the actual sticking of course). Whenever there's a problem with a part failing i can pretty much guarantee you it's because the bonding was done incorrectly.

I dunno what prep you did, but for example in industry that ^^^ sort of joint would have been grit blasted or similar on both sides, chemically decreased, held in a fixture for bonding and then baked during the actual gluing. And I'd still look at it through narrowed eyes

I don't think your glue is gonna kill you, but as I as said i wouldn't be making any claims that its making your holes any better either, not in a way id want to depend on anyway. It's neutral at best IMO.

[Demannu]

The Yamaha yoke has turrets where the risers bolt through, yours is flat-ish.
All I know is with risers half that length, several people had some serious squeaky bum moments.

[Skub]

Only one way to settle this.

Meet up for a track day and everyone takes turns trying to brake/break it.

[Le_Fromage_Grande]

Get a role yoke made, your life is worth more than £200, if you need help finding someone to make a yoke I know if two people that will do it, neither will be quick. Also check out moto cnc on eBay, he may already make something that will do the job.

[Mr. Dazzle]

In fairness to ya man, it does appear that the MT09 risers drop straight into a similar 'simple hole'. I half expected the MT09 ones to have a bunch of ribs or whatever on the underside.

I never did work out how to post a pic from an eBay ad....

https://www.ebay.co.uk/itm/165954154009 ... media=COPY

But...and this is the biggy....the MT09 yoke has those raised sections where the risers bolt in. So even if the argument is "the MT09 risers penetrate through the same thickness of Ali", I would have the assume Yamaha put those raised 'hills' in for a good reason, probably to redistribute stress.

Plus, as above, they're using one piece of metal not two bits semi-stuck together. In terms of getting loads "out" of the risers and into the rest of the yoke those stuck on plates will do little even if they're done perfectly. As you may have gathered, I have serious doubts they're done perfectly

[mangocrazy]

In fairness to ya man, it does appear that the MT09 risers drop straight into a similar 'simple hole'. I half expected the MT09 ones to have a bunch of ribs or whatever on the underside.

I never did work out how to post a pic from an eBay ad....

https://www.ebay.co.uk/itm/165954154009

I was just about to do a search on that and post it up, so thanks. I don't see anything very special about that top yoke.

But...and this is the biggy....the MT09 yoke has those raised sections where the risers bolt in. So even if the argument is "the MT09 risers penetrate through the same thickness of Ali", I would have the assume Yamaha put those raised 'hills' in for a good reason, probably to redistribute stress.

Plus, as above, they're using one piece of metal not two bits semi-stuck together.

Yeah, I get what you're saying, but those 'hills' are the only part of the yoke that is 12mm thick. The rest of it is a lot less - 5-6mm at a guess from the photos. The 'Priller yoke is actually more substantial, with deeper webbing and I've bonded a bunch of metal on top. I'll bet that in its unmodified form the 'Priller yoke weighs more than the Yam. Now I'm fully aware that gluing/bonding metal is never as strong as having a single piece of the same size, but those two substrates are also clamped together by the riser bolts, so are effectively 'almost' as strong. We can argue about 'almost' for days of course.

The Yamaha part looks like something that has had some serious FEA, but whether the engineers were concerned about strength or using the minimum amount of aluminium/reducing weight to a safe minimum is moot.

I dunno what prep you did, but for example in industry that ^^^ sort of joint would have been grit blasted or similar on both sides, chemically decreased, held in a fixture for bonding and then baked during the actual gluing.

Both surfaces were sanded, then degreased using brake cleaner, then clamped while bonding and stuck on a radiator for 24 hours.

[mangocrazy]

This is the top yoke off an MT-09 SP, underside view and top view. No steel sleeve or rubber mounting. That was probably done on the MT07 to damp out vibration through the bars.

MT-09 SP top yoke top front.JPG (197.41 KiB) Viewed 549 times

MT-09 SP top yoke underside.JPG (218.02 KiB) Viewed 549 times

For comparison, this is the underside of my top yoke:

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