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Messages - Calum

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The Star and Garter / Re: UNS thread
« on: 22 April, 2021, 06:46:35 »

probably supplied as an alternative to BSC as the same thread angle 60', same as some suppliers send M5 for 2BA.
I should.hope not! They're close, and often fasteners interchange but they aren't the same diameter or pitch (Or thread angle - 60 vs 47.5)

Using an UN form instead of BSCy isn't too bad, as chaz says they are indeed both 60 degrees with only minor detail differences on the peak and trough radii etc. BS at 55 degrees with the same major diameter and pitch won't necessarily go together with a 60 degree thread, the flank contact will be a little poor but the minor (root) diameter is smaller on a 55 degree thread. This means a 55 degree bolt will go into a 60 degree tapped hole, but a 60 bolt shouldn't go into a 55 degree tapped.hole.

A lot of this is looking onto it too deeply, as for a lot of mass produced fasteners the tolerances are quite large and as such some will go together when strictly speaking they shouldn't... this is helpful for low stress applications as it can get you out of a hole but not ideal!

Singles / Re: Stop light not working
« on: 21 April, 2021, 19:39:39 »
If you're getting 6v at the terminal in the bulb holder with the switch pulled then the wiring up to there should check out... SHOULD.
Multimeters will show a voltage reading when the current is so so very low, so sometimes a dry/broken joint might still show as transmitting power but as soon as you actually load the circuit up (with a bulb or whatever) then sometimes the joint then 'fails' and there's 0v. In many cases a test light is mich better for fault finding (easily made with a bulb holder, some wire and a pair of crocodile clips or similar)

On the other hand I think your issue is probably an earth issue, or the bulb. You said the multimeter was connected to the battery earth. Try the meter across the bulb contact and the base of the lamp unit, or check for continuity between lamp base and battery earth.

Singles / Re: B31 'snatching' in gear
« on: 20 April, 2021, 19:35:32 »
Hi Pete

Email sent. I can see how excess endfloat would cause selection problems, but I would expect this to affect selection of all the gears? I don't have any problem with any of the other gears, just third.

Singles / Re: B31 'snatching' in gear
« on: 20 April, 2021, 18:35:55 »
Hi Pete

It's a plunger (1953), so has the M-series box (unless I am mistaken) with screw in level plug/clutch adjuster cover.
I have a set of service sheets but any info is always welcome!

I've heard of excess layshaft endfloat or that the 'peak' on the selector fork slot (that the selector shaft pin runs in) is worn.. Anyones guess until inspected I suppose.. I'd better get the fettling irons out of hibernation!!  ;D

Yes those were my initial thoughts, but I called the peg and groove a cam. As you say though pure speculation without stripping it down!


Singles / Re: B31 'snatching' in gear
« on: 20 April, 2021, 12:59:31 »
Well I'm glad I'm not alone!

Worn fork and/or dog clutch sounds likely. Sounds as if it is a common problem then? I'm not adverse to taking the box out and sorting it. The bike is new to me (got it last year) so often I find any excuse to take something apart very welcome as it slowly removes any unknowns or hiding horrors which may try and surprise me later on down the line... although I do want to be out riding it whilst the weather is nice!

Singles / B31 'snatching' in gear
« on: 18 April, 2021, 22:08:01 »
Hi all

I've been out today on the B31, bit of a poor start as the nipple pulled off the clutch cable as I pulled out of the filling station! Left the girlfriend with and ice cream and the bike and rode her Ariel home to solder it back on!
Back on the move again I began to notice my B31 'snatching' in third gear (it has done it on previous rides, so not a new phenomenon!). If I keep the gearchange pedal held whilst releasing the clutch this lessens the likelihood of it happening (good practice anyway?) but doesn't rule it out altogether. It's a plunger model, so has an M series box (I think??) with screw filler/clutch rod cover.
Sometimes letting the clutch out I feel a 'kick' as it pulls into mesh, but it kicks/snatches a bit too sometimes, mainly on the overrun.

My suspicion is the cam that moves the dog clutch for third gear is worn on the 'peak' so not letting the dogs engage fully, and the snatching feeling is the resultant dropping out and back in mesh. Should I be able to see if this is indeed the problem through the cover plate at the rear of the gearbox? Looks a bit tight for clear vision so judicious use of a mirror or endoscope might be needed...

Any pointers gratefully received!


The Star and Garter / Re: Attaching photos on mobile
« on: 07 April, 2021, 21:55:05 »
'Lit photo' is the app I use. You can resize, compress, crop etc. Free, so has some adverts, but easy to use.

Singles / Re: M33 noisy tappets, or...
« on: 06 April, 2021, 21:27:12 »
Thinking outside the box slightly... valve lifter definitely clear of the exhaust rocker?

The Star and Garter / Re: Hexagon crimping tool
« on: 01 April, 2021, 12:11:23 »
Agree with the above comments regarding bullet quality. I have one of the simpler two blade brass bullet crimping tools for crimping the usual 'Lucar' connectors. The bullets that came with it work a treat, but I was doing some wiring with said tool on a mate's motor and the brass bullets he had bought split when crimped every time.

Twins / Re: Difference in main roller bearing?
« on: 31 March, 2021, 20:04:37 »
Be very very careful with a bearing without a lipped (flanged) outer race.

Presuming the engine has a bushed timing side earing rather than an SRM type end feed, the lip limits the amount of axial movement. No lip  the movement is not so limited and the crankshaft pinion may even bear against out edge of the main bush and chew it.

When the crank end float is being set it gives just a few thousands clearance between the rollers of the bearing and the outer lip. No outer lip how do you set the float?

Interesting. How is the end float 'set' then? Is there not something to hold the crank in place other than the lipped bearing? Is it just a case of two opposing lipped bearings roughly keeping it in the middle? I've never been in said engine so can't really imagine what's going on.

Twins / Re: Difference in main roller bearing?
« on: 31 March, 2021, 12:42:19 »
There was a discussion similar to this in the pre war section a few months ago. I chimed in as I had a similar experience with a cylindrical roller in an old gearbox - original had a lipped outer race but the new one was parallel and the rollers went right through.

Personally I think it will be fine - if the rollers actually touched the lip in the outer race they'd likely be wrecked in no time. There's not any lateral thrust from the big ends - look at shell or white metal bearings here, they don't touch on the sides. If the rollers are clear of the lip on the old bearing (which they should be) they are in fresh air and so no lip on the new bearing won't make any difference.
Just my thoughts on it.

Singles / Re: Kickstart oil seal removal - help!
« on: 30 March, 2021, 13:42:46 »
Calum, when you say the other way round, you mean the correct way, ie coil to the inside (coil to oil)?

Indeed. Good habit, even though as said above by lightning&starfire in this application it doesn't matter too much

Singles / Re: Kickstart oil seal removal - help!
« on: 30 March, 2021, 12:51:02 »
I've had success removing bearing races from aluminium castings like this by heating them up and using a dead blow hammer to shock it out. If the new seal is inserted the other way around you shouldn't have this problem again.

Bantam / Re: Brake drum skimming
« on: 29 March, 2021, 21:55:52 »
Classic brake services in Chapel en le Frith Derbyshire do this. I plan to use them to rebuild my wheels. I have had one recommendation for them but not used them yet.

Seem hard to find on google and number is tel:07811356619

Let me know how you get on.

Chapel is the home of Ferodo brake and I would imagine this business has been spawned from them.

That's the people I am thinking of. I believe they (or Ferodo) will make linings to any size/shape as well.

Singles / Re: Interesting (non-BSA) bike
« on: 21 March, 2021, 21:49:43 »
Yes I suppose they did. I've never thought about it to be honest! I suppose being shaft drive it was all parallel to the frame of the bike until the bevel drive. Keeps it simple. Transverse flat twin Douglas machines have a more 'conventional' kickstart but then being chain final drive it would be easy to facilitate.

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