revtothelimit - motorbike forum

When measuring stuff I happily switch between metric and imperial and tend to use whichever is closest (when I'm working in wood). With metal it's metric all the way, except for those rare occasions when I need a hole that's bigger than 6 mm and less than 6.5mm and I play hunt the quarter inch drill bit...

Still think in miles when travelling though, and do the 5/8ths calculations when travelling in France and see the kms counting down...

Quick update:

Last friday I got into the shed for the evening, finally, with a bag of nuts (I bought 3 'grab bags' from Nookies Nuts, Cycle, BSW and BSF.), a Die Nut, and some new threadlock (blue), and tidied up the threads on the loose engine mounting stud, found a suitable nut, and got that little job sorted out.

The new battery I bought a week ago is in, and works fine, also helped me find out that the horn wiring was shorting at full right lock (GAH!). I think that wire will need replacing, but in the meantime I just moved it away from the innocent frame rail it was electrocuting.

Figured I'd start getting other things back together, so the primary chain cover when back on, I adjusted the side-stand a bit (and put some (metric ) locking nuts on the fitting just in case). Tank went back on, seat went back on.... well - sort of, only got 1 nut for it, there's 2 studs at the front which locate into holes in the frame rail, and I tried all 4 thread system I have... nothing fits them. Not metric, not Cycle, not BSW, BSF or any of the random shite I have here. I'm thinking I'll just drill a hole in each stud and use R-clips....

Anyway - moved on from that little clusterfuck and filled the bike with gearbox oil (EP8W90 I had lying around), Engine oil (Miller R30), and Petrol (Esso E5 supreme99) and tried to bleed up the carb... petrol EVERYWHERE!

WTAF?

After some mild panic I figured out that the float didn't seem to be stopping the flow, so I took the bowl end off (with a jug under it) (the Monobloc doesn't have a float bowl 'cover', the outer end IS the 'cover'), and discovered that the float was fine.... but the friggin needle was missing!

.... oh fuck ... says I. I stripped and did the carb over a week ago, and there's been all sorts of crap on the bench in the meantime... I even emptied out my old toolchest full of random crap one evening and redistributed it all... mostly into the bin.....

Looked at the carb diagram to see what the needle looks like.... and fuck me.... I remembered picking the bloody thing up off the work bench while I was going through all the stuff in that toolbox!! I also remembered not being able to think what the hell it was... and throwing it in the bin!

When I had done the toolbox, I also took the bag out of the bin and chucked it into the wheeliebin for friday morning.

Fuckers.

At that point I was pissed off, so I went in and told my better half. Who instantly revealed her gloriousness by saying "But, didn't they do the recycling this morning? That bag might still be there."





Jumped up and checked the bin - yup - the workshop bin bag was still there!

Took it back into the workshop and did my Silent Witness bit... picking through the detritus of a couple of months of rubbish (luckily no food or anything similar in there), looking for a bit of plastic 3mm wide by 6mm long..... and ....









...












....






I ONLY FUCKING FOUND IT!!



Was so chuffed with myself that I carried on and fitted it into the carb, bled it up and it Fired up Second Kick! Running a LOT better than before too, it actually ticks over! (a little haphazardly I'll admit)!


Only small fly in the ointment is that the main-jet fitting is now weeping. My own stupid fault, I should have replaced the fibre-washer, so ordered up a repair kit from AMAL (none of the cheap fibre washers I had in fitted), along with a new needle clip (the old one is tired).

So - just need a bit more carb-fettling and the bike should be back on the road!

Skub wrote: Wed Jan 25, 2023 12:04 pm I've seen similar done before,but,it's certainly not ideal.

This wouldn't actually worry me at all! I've designed loads and loads and loads of structural bits and bobs for various fast vehicles, up to and including F1. That ^ hole is pretty benign.

Without seeing exactly where the hole is RB I couldn't say, but it doesn't immediately scream death to me When you see some of these "stretched chewing gum" 3D printed designs you realise just how much redundant material many parts have. Even F1 is limited by such boring practical limitations as "actually being able to make it"!

Potter wrote: Tue Mar 28, 2023 12:50 pm

Mr. Dazzle wrote: Tue Mar 28, 2023 12:37 pm When you see some of these "stretched chewing gum" 3D printed designs you realise just how much redundant material many parts have. Even F1 is limited by such boring practical limitations as "actually being able to make it"!

Can it have all those holes because it's structurally designed, or is it just a case of remove as much material as you want?
I suspect the former.

I was told that if you remove material then it's fine as long as you put it back, the obvious example is drilling holes into structural steel, then tapping it and putting a bolt in. Dunno if that's actually true.

I'd imagine that depends on whether the drilled hole is in something in tension (probably bad), or compression (probably ok if filled in). Add in torsional stresses which are less obvious to the eye and .... ???

Potter wrote: Tue Mar 28, 2023 12:50 pm Can it have all those holes because it's structurally designed, or is it just a case of remove as much material as you want?
I suspect the former.

I was told that if you remove material then it's fine as long as you put it back, the obvious example is drilling holes into structural steel, then tapping it and putting a bolt in. Dunno if that's actually true.

Second part is definitely not true, most of the time.

The first part - that particular calliper is genitively designed with the aid of a computer. Up until now, virtually all parts like that have been "start with a block of material and keep removing stuff until a) I run out of money or b) it breaks". Pretty much

The other way around is "I want to connect points A and B to transmit load C, add stuff until that works". That's what that calliper is done with. It's what 3D printing really opens up for you.

Goes without saying, that's abridging it quite a lot!

The main things to avoid are stress raisers, sharp corners, grooves, notches or acute changes of section that cause stress concentrations under normal loadings. A circular hole would be lower down the list of potential stress raisers than those mentioned above. And as the hole would be threaded and 'filled' with a bolt, it should be of less concern. On bodyword, if a crack develops, its considered good practice to drill a hole at the farthest point of the crack so it cannot propagate further before filling in or plastic welding the crack.

mangocrazy wrote: Tue Mar 28, 2023 1:15 pm On bodyword, if a crack develops, its considered good practice to drill a hole at the farthest point of the crack so it cannot propagate further before filling in or plastic welding the crack.

Forgot bodywork, they do that on airplane wings

Good news for the carb needle.

Have you got a dial or vernier caliper, a thread gauge and a set of Zeus tables? It'll help you identify unknown threads.

cheb wrote: Tue Mar 28, 2023 1:31 pm Good news for the carb needle.

Have you got a dial or vernier caliper, a thread gauge and a set of Zeus tables? It'll help you identify unknown threads.

No (but I do have a micrometer), yes and yes. I also have a copy of this : http://www.sunbeamland.com/wordpress/wp ... rkshop.pdf which has very easy to read thread tables in the first chapter.

The weird thread on the seat studs is a 26tpi, BUT the correct diameter nuts of both metric AND cycle both go down to about 95% of their width, and then jam.

it COULD be that the thread on the stud is damaged at that point... BUT - the one nut that fits spins down happily on both studs all the way.


I was starting to wonder if it was a BA thread... but the pitch is wrong. (I think... BA is weird)

Rockburner wrote: Tue Mar 28, 2023 1:41 pm
I was starting to wonder if it was a BA thread... but the pitch is wrong. (I think... BA is weird)

Haven't looked at Zeus tables but I'd check BSF or Whitworth.

I reckon a 'quarantine' bin in a workshop is a where things sit a while before going in the 'never to be seen again' bin.

Count Steer wrote: Tue Mar 28, 2023 1:53 pm

Rockburner wrote: Tue Mar 28, 2023 1:41 pm
I was starting to wonder if it was a BA thread... but the pitch is wrong. (I think... BA is weird)

Haven't looked at Zeus tables but I'd check BSF or Whitworth.

Yes - done. neither fit at ALL.

Count Steer wrote: Tue Mar 28, 2023 1:53 pm I reckon a 'quarantine' bin in a workshop is a where things sit a while before going in the 'never to be seen again' bin.

Yup - have now done that. (that's what the old toolbox was)

Rockburner wrote: Tue Mar 28, 2023 1:41 pm The weird thread on the seat studs is a 26tpi, BUT the correct diameter nuts of both metric AND cycle both go down to about 95% of their width, and then jam.

The only 26 TPI thread I can find in my Zeus book is 1/4" BSF.

mangocrazy wrote: Tue Mar 28, 2023 1:57 pm

Rockburner wrote: Tue Mar 28, 2023 1:41 pm The weird thread on the seat studs is a 26tpi, BUT the correct diameter nuts of both metric AND cycle both go down to about 95% of their width, and then jam.

The only 26 TPI thread I can find in my Zeus book is 1/4" BSF.

Several Cycle diameters are 26tpi. Page 7: http://www.sunbeamland.com/wordpress/wp ... rkshop.pdf

Rockburner wrote: Tue Mar 28, 2023 2:00 pm

mangocrazy wrote: Tue Mar 28, 2023 1:57 pm

Rockburner wrote: Tue Mar 28, 2023 1:41 pm The weird thread on the seat studs is a 26tpi, BUT the correct diameter nuts of both metric AND cycle both go down to about 95% of their width, and then jam.

The only 26 TPI thread I can find in my Zeus book is 1/4" BSF.

Several Cycle diameters are 26tpi. Page 7: http://www.sunbeamland.com/wordpress/wp ... rkshop.pdf

Blimey. That's a proper thread pitch rabbit hole to head down. If I'm not back for tea send out a search party...

mangocrazy wrote: Tue Mar 28, 2023 2:03 pm

Rockburner wrote: Tue Mar 28, 2023 2:00 pm

mangocrazy wrote: Tue Mar 28, 2023 1:57 pm

The only 26 TPI thread I can find in my Zeus book is 1/4" BSF.

Several Cycle diameters are 26tpi. Page 7: http://www.sunbeamland.com/wordpress/wp ... rkshop.pdf

Blimey. That's a proper thread pitch rabbit hole to head down. If I'm not back for tea send out a search party...

Somewhat annoyingly - that book talks about metric, but doesn't provide a matching threads table for comparison purposes.

I need to spend some time with the Zeus book.

I'm also considering an imperial tap/die set (or sets) I have plenty of tap-tools and die handles, but no actual imperial taps/dies! (apart from the recently purchased 5/16th Cycle Die nut for the engine mount stud).

Yes, 26 tpi is not that far off 1.0mm. But have you found any metric threads on the bike yet?

mangocrazy wrote: Tue Mar 28, 2023 2:14 pm Yes, 26 tpi is not that far off 1.0mm. But have you found any metric threads on the bike yet?

One or two - side-stand clamps (as mentioned). The front brake is (iirc) a Grimeca 4LS, so that will have metrics.

I went round the bike looking at the allen bolts just to put together a toolkit, and it seems to be about 1/5 - 1/4 metric heads.
(I plan on carrying 2 adjustable spanners for simplicity!)

Mr. Dazzle wrote: Tue Mar 28, 2023 12:37 pm

Porn.

Rockburner wrote: Tue Mar 28, 2023 12:17 pm
Only small fly in the ointment is that the main-jet fitting is now weeping. My own stupid fault, I should have replaced the fibre-washer, so ordered up a repair kit from AMAL (none of the cheap fibre washers I had in fitted), along with a new needle clip (the old one is tired).

So - just need a bit more carb-fettling and the bike should be back on the road!

Or not.....


Got the AMAL gasket kit.... fitted the fibre washer for the jet block and .... great - that's not leaking.



But... hang on.


There's still a small amount of fuel coming from somewhere....

trace it back....



the feckin' float-bowl 'cover' is weeping.

Oh, well - no worries - there's a new paper gasket over there in the kit.


2 minutes later.



"dribble dribble dribble"


WTAF? the NEW gasket is worse than the old one!

Took a much closer look at the mating faces, and there's a sodding nick in the 1/4mm thick ally body of the float bowl, at about 5-o-clock.

I can only assume that the old paper gasket was 'just about' holding a seal before I stripped the carb down, and now, that 'just about' capability has gone. The new gasket is presumably too stiff to mold around the nick.


My first thought was to strip the carb off the bike, and try to 'grind' the mating face down using wet-n-dry on a flat surface: given my hamfistedness that would work better than trying to file it flat in situ!

Then someone suggested a metal epoxy to build up the face, then file it flat. Could that work? given that it's only a very thin bit of ally and in a petrol bath?

Would blue hylomar not fix this?