New Project(s)

[cheb]

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.

[Rockburner]

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)

[Count Steer]

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.

[Rockburner]

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.

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)

[mangocrazy]

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.

[Rockburner]

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

[mangocrazy]

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...

[Rockburner]

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).

[mangocrazy]

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

[Rockburner]

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!)

[Screwdriver]

Somebody has been playing with generative design in Fusion. Designing parts to their optimum strength/weight ratio is fantastically complex and best left to a computer these days. Nature has been doing it since forever of course which is why some of these latest design iterations look so "organic". Nature got there first!

But it is all about the design and getting back to the original question, no you can't just pop a hole into a structural member without really knowing what you're doing. I mean yes you can but you won't know what you've done!

[Skub]

Porn.

[Rockburner]

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?

[Taipan]

Would blue hylomar not fix this?

[Screwdriver]

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?

Yes but also no. Epoxy metals like JB Weld will fix the leak but will eventually degrade. Whether that happens to a face sealed by a gasket is a moot point, epoxy is not really a good solution for petrol.

Low temperature weld would be the ideal fix for you. Lumiweld I think one brand is called. Personally, I'd hit it with a genuine aluminium Tig weld but I alrady have the kit (and it nearly works too).

[cheb]

Is the thickness of 1/4mm a typo? Should it read 1/4"? Are spares easily got before you start repairing the old one?

[Rockburner]

Is the thickness of 1/4mm a typo? Should it read 1/4"? Are spares easily got before you start repairing the old one?

Not a typo, it's the wall thickness of the float bowl itself, there is no 'flare' to provide a larger mating surface for the cover. (it might be more like 1/2mm, but it's no more than 3/4mm ).

[cheb]

Have you pictures of the thing?

[Rockburner]

Have you pictures of the thing?

I'll try to take some tonight.

[RiceBurner]

This is the carb float bowl.



This is the nick on the mating face.



This is the "cover". (Its a fancy "big reservoir" version)