61 ES2 Sump plug

Previously allen_hanford wrote:

The threads

The thread is BSP.

Ask Stainless Steve for a sump plug (Where I get mine)

01527 831451

Stevesstainless2@aol.co.uk

These have a shoulder for the washer and fastened with an imperial allen key. I find this better as I can get it tighter as there is not much room for the spanner.

I think it is 3/8 (Without going to the workshop) but measure it to be certain as Steve does three diameters.

His prices are good too.

Good luck.

Hi Allen/Neil,

Just want to send a note of caution here, as I think the post 1947 ES2 has a 3/8" Cycle thread 26 TPI, unless this was changed near the end of production,so double check this as these are a real problem being a fine thread in cast aluminium. If the thread in the crankcase is stripped you will need to re-tap with a larger size or heli-coil it. Either of these will need a top end or timing cover strip so you can flush out any swarf from the crankcase. You could try and bodge it up, but that could be a costly option.

Regards, Richard.

Previously allen_hanford wrote:

I found and purchased a 3/8" diameter 26 tpi drain plug and it's a very loose fit. My whitworth thread gauge showed the best match as 30 tpi but because of the distortion of the threads I'm skeptical of this being right.

Hi again Allen,

The nearest, if you can find one, would be a metric 10mm x 1mm thread pitch which is equivalent to25.4 TPI. With this being half a millimetre bigger diameter it might just do the job, but no guarantee as it depends how worn the crankcase is.

Regards, Richard.

Fair point Richard, BUT:

1) I wouldn't even consider putting a metric thread near that sump, it has to be wrong. (Unless it has been butchered)

2) Allen didn't say what year his engine was? All I will say is that the plug I suggested is perfect for the 59/63 singles.

Best thing to do is to drop Stainless Steve an e mail and he will tell you all you need to know.

Good Luck.

Oh my god,

Earlier this year I fitted I fitted a Michelin inner tube!! I'm feeling so guilty now, but I promise to look for a John Bull as soon as possible. I know I don't deserve it but please-please pray formy soul.

Allen, further to washing out the crankcase you can give it an "enema" by putting a tight fitting tube (5/16" ?) tube up the drain plug hole and filling with about halve a pint of petrol or paraffin. Best to get the piston at TDC first and have a large enough drainingbowl before pulling the pipe out.

P.S. Neil do you still havethe original sizemetric wheel bearings fitted ?

Regards, Richard.

In the parts list for the 1961/62 Models ES2, 50, 88, 99, 650 the part number listed is 13765 Drain Plug for Crankcase as on the page 17 under Crankcase and Timing Cover.

No illustration number is given

Mike

Richard, Your Michelin inner tube will still have a diameter measured in inches, but if you are really bothered about it; I believe Avon are now making inner tubes.

As for metric size bearings, it depends what bike you are talking about.

The point about the metric thread in that sump is that it is obviously not original and therefore won't do the existing thread any good. (If still original)

Don't tell anyone else this but the gearbox inspection / filler cover on my Commando had one of the two screws in the outer cover snapped off when I bought it and I couldn't remove it with tools I had back in 89. I drilled it out (Did both to match) and applied a metric thread. And nobody noticed! Bit like your inner tube...

Hi all,

I feel like I'm flogging a dead horse here, but I'm a glutton for punishment, so here goes!

The thread on UNF, Cycle and Metric are all 60 degree angle, in fact 8mm x 1mm pitch metric nuts and bolts are interchangeable with 5/16"Cycle for class B applications although the spanner size will be different. Looking at the picture Allen posted it looks like the plug has damaged the alloy crankcase which is relatively soft. As I posted earlier this is a fairly common problem as the case thickness at this point is only about 5/16" thick and the thread is too fine. A 7/16" UNF will be O.K. as this is 20 TPI, but the problem will be the lack of clearance for the hexagon head. You can either reduce the hexagon or make the counter bore in the case bigger or use a socket head bolt or use a very thick washer!

I don't think you should worry too much whether the thread is the same, Norton were not bothered and most models used a mixture of Whitworth, Cycle, UNF, BSF, BSPand BA threads all on one bike. Almost all post 1930 Norton wheels with drum brakes used metric wheel bearings ( I don't include Francis Barnet wheels ) and all SOHC Manx engines had metric timing side main bearings and Imperial on the drive side. Your bore size is quoted in a metric size but the oversize is Imperial, how does that work??Anyway, if you can make something better, why not?

Regards, Richard.

I'm going to be a bit pedantic.

Threads based on the Whitworth thread form, which includes cycle, are 55 degrees not 60.

Ian

Previously ian_goodhall wrote:

I'm going to be a bit pedantic.

Threads based on the Whitworth thread form, which includes cycle, are 55 degrees not 60.

Ian

Hi Ian,

No not at all, butif you double check my post I only included the first 3 as this was getting the nearest repair size for the original cycle thread which I thought was 60? Pedantic is another's accuracy.

Regards, Richard.

I stand corrected Richard, cycle thread is indeed 60 degrees.

Humble pie being eaten now.

Ian

My turn at being pedantic, Ian: It is actually umble (Umbles) pie. Over time the H crept in but umbles are the bits of the animal left over, heart, entrails etc the people downstairs (Servants) had to eat. But the general meaning today is as you suggest as being corrected. I always say the traditional Umble...

Allen, I have a spare plug I found. Maybe too late though if you have run the tap?

I thought it was 1/8th bsp which is 28tpi.

American 1/8th npt is close but it needs to be a parallel thread.

Paul

Previously Allen Hanford wrote:

I couldn't find a sump plug in my parts book and the condition of my current one is so poor that can't get a thread reading on it.

Anyone know what the correct size is and/or where I can get the correct part?