Motorcycle General Discussion

[Michael GilliganParticipant @michaelgilligan61133]

Nice one, Ian

MichaelG.

[HopperParticipant @hopper]

Mmm. That looks crusty. You might have a bit of a project by the look of things. Have you worked on Airheads before? They are quite nice to work on but do need a few special tools, which can all be made up if you have a lathe and a welder.

[FulmenParticipant @fulmen]

How hard is it to true a spoked wheel? My front wheel is feeling a bit lumpy…

Is this something I can figure out myself with some patience and a dial indicator or is it more of a black art involving incantations and blood sacrifice?

[DiogenesParticipant @diogenes]

You can do it yourself.

If you look at the pattern of the spokes at the hub, you can see which way they will ‘pull’ the rim – it’s not very different from truing work in a four jaw – slacken the opposite side to the one you want to tension.

Must be info on the ‘net, I’d guess.

[HopperParticipant @hopper]

Don’t use a dial indicator. It will scratch the rim and you absolutely don;t need that level of precision. Most factory workshop manuals specify a maximum allowable runout of 2mm. (And that includes my Honda VFR800 sportbike with a 240kmh top speed.) YOu can see that by eye with a simple pointer.

I use a homemade truing stand made from two planks of wood stood upright on a base, with a V notch cut into top of each plank to hold the axle. Then a piece of wire or scriber or old spoke is held to one of the uprights with a wodge of blue tack to provide a reading on “truth” by observing the gap as wheel is slowly rotated.

It takes a bit of practice and a lot of patience to true a wheel. You need to true it in both directions, side to side “wobble” and concentric runout. The latter is best measured on the inner shoulder of the rim where the tyre bead actually seats, as the outer flange can get distorted by tyre levers and bumps etc over the years.

I always take the tyre off so I can b e sure not to puncture the tube with rotating nipples. And use a proper spoke wrench to avoid rounding off the flats.

Not a dark art. Just takes time and a methodical approach. As Diogenes says, plenty of videos on YouTube etc worth watching.

And before you start, spin the wheel in the bike to make sure it is actually out of true and not just out of balance, which can cause lumpy feeling too. And tap the spokes with a screwdriver and listen to the note to find if you have loose spokes that give a dull thunk instead of a twang.

[FulmenParticipant @fulmen]

Thanks for the pointers and encouragement. I’ve looked at a couple of vids, but they all start by lacing the wheel from scratch which I don’t really want to do. Other than tapping the spokes, are there any way of judging spoke tension? I don’t think torque would be very accurate without some disassembly and cleaning.

 

[Fulmen]

On Fulmen Said:

[…]  Other than tapping the spokes, are there any way of judging spoke tension? […]

 

It obviously varies with the state of one’s hearing, but … hopefully you will find it very easy to detect a flat, or excessively sharp, note or two out of perhaps 36 in a wheel.

Just spin it gently and let a spanner drag across them.

MichaelG.

[FulmenParticipant @fulmen]

Finding a couple of bad ones should be doable, I’m just wondering if it’s possible to judge the overall tension of the spokes.

[HopperParticipant @hopper]

MG is right. Go around and tap them all with a screwdriver or spanner and listen to the note. You will soon hear any “dead” ones. ‘Tis the time-honoured method.

Measuring torque is fine in theory but in practice, spoke threads corrode up and get stretched and deformed under load so torque readings on the nipple to spoke interface are meaningless.

And if you spin the wheel still in the bike with a bit of wire attached to the forks or swingarm with some blue tack, you will soon see if you have a wobbly rim. Then sound the spokes and you will find a correlation.

[Hopper]

On Hopper Said:

 

Measuring torque is fine in theory but in practice, spoke threads corrode up and get stretched and deformed under load so torque readings on the nipple to spoke interface are meaningless.

Yeah, that’s my take as well. So basically I will have to assume that the majority of the spokes are good and just tighten the loose ones to the same by ear?

[HopperParticipant @hopper]

Pretty much. Or take the wheel to shop and let a professional do it.

[Michael GilliganParticipant @michaelgilligan61133]

Just to honour the title of this ‘Topic’ … Let me present this [spotted by a friend on his recent visit to Sicily]:

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We are both intrigued by the presence of a life-belt, at least 2km from water … but the bike is a gem, for sure.

MichaelG.

[HopperParticipant @hopper]

^^ Very nice. Cute little 2LS front brake and all.And that dicky seat…

[Hopper]

On Hopper Said:

take the wheel to shop and let a professional do it.

That’s quitter talk 🙂

[Fulmen]

On Fulmen Said:

On Hopper Said:

take the wheel to shop and let a professional do it.

That’s quitter talk 🙂

By all means do it yourself but it takes time particuarly if you have no experience. I have done it once but it was far easier to take it to a local gentleman spent most of his time rebuilding wheels for scramblers and grasstrackers after busy weekends. However my wheels never had any priority. The builder died a few years ago leaving a local void. These people are disappearing and will not be replaced.

So have a go at wheel building. If you are successful advertise your services!

JA

I always fancied a Moto-Guzzi Falcon except for the final model like the one shown. It did take safety a bit far. Doubt if many were hurt by the exposed flywheel.

[FulmenParticipant @fulmen]

Huh. It was the mechanic that put on the new tire that mentioned it first. I wasn’t shocked as I kinda had noticed a slight front end shake in the past. I figured it was just the (really) old tire but now it’s much more noticeable. So I took a quick look-see and I can’t really see anything really wrong. The spokes are a bit uneven to an untrained ear, but no dead ones. And I don’t see any obvious run-out either, at least not enough to judge without an indicator.

It almost feels like a bad balancing job, but this is a reputable shop that I have used for years. Guess I’ll have to break out the dial indicator after all just to make sure I’m not not seeing things.

[Grindstone CowboyParticipant @grindstonecowboy]

There’s a lot of good info in the book “The Vintage Motorcyclist’s Workshop” by Radco. Edit: about wheel-building, etc. – forgot to specify that!

Just found an example here, but looking at the price, I’m glad I bought it when it first came out!

Another edit: seem to be photocopied versions available on Ebay, but not entirely sure of the legality of those.

Rob

Links to https://www.amazon.co.uk/Vintage-Motorcyclists-Workshop-Re-issue-Motorcycling/dp/0854294724

[FulmenParticipant @fulmen]

Thanks, I’ll check it out. You know the saying, a book is worth a thousand youtube videos…

[Michael GilliganParticipant @michaelgilligan61133]

@fulmen

The sort of ‘tensiometer’ device that I think you were pondering IS available, but all the ones I have seen are aimed at affluent cyclists … the design principle is obviously transferable, but I suspect it could end-up a little ‘lumpy’ if scaled-up for motorcycle wheels.

MichaelG.

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This appears to be the silly-end of the scale:

https://www.starbike.com/en/cyclus-tensionaut-tensiometer-for-digital-measurement-of-spoke-tension-with-radonaut/?country=GB&currency=GBP&keep_params

… perhaps it comes in a Lycra bag [?]

[FulmenParticipant @fulmen]

Ooooh, that’s a nice toy for those with more money than sense. I assume they work by applying a bending force to the spoke and measure deflection? Clever, but as you say it would probably be hard to do on a motorcycle. Perhaps something akin to a guitar amplifier reading the pitch would work? Perhaps using an electromagnet to excite the spoke?

[JimmieSParticipant @jimmies]

https://www.sunbeamland.com/wordpress/wp-content/uploads/2019/04/The-Vintage-Motorcyclists-Workshop.pdf

Enjoy the read

Jim

[FulmenParticipant @fulmen]

Wow, thanks. I’ll be sure to study up before doing anything stupid.

[Clive FosterParticipant @clivefoster55965]

The fundamental trick to wheel building is getting it to stay true once it’s built.

Getting it initially true in the first place isn’t intrinsically terribly difficult. Just monumentally tedious the first few times until you get the feel for whats going on.

Ending up with the tensions one the spokes all nicely right and even is where the art comes in. Most especially when the rim isn’t dead true in the first place. As a lot weren’t back in the day. Some of teh pattern ones were horrible.

Clive

[HopperParticipant @hopper]

Yes quite a few rims had a bit of a flat spot at the weld where they were joined together after being rolled from a piece of flat. But tyres seemed to round out the profile regardless. But truing up an old bent out of shape rim can be a challenge for sure.

You should be able to see balance weights if your mechanic balanced the wheel after fitting the new tyre. If not, it is much easier to balance a wheel than true it so I would start there and see how it runs.

[FulmenParticipant @fulmen]

It has fresh weights, about twice as much as before as far as I can remember. I’ll measure the wheel with an indicator first, if it checks out I’ll have a chat with the mechanic. Removing the wheel is such a hassle and I don’t want to give them any undeserved grief.

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