1952 ES2 engine sump plug

Ben,

Sounds like your drain plug has been changed from standard. My ES2 engines have a shouldered sump plug with a hexagon head, so you can fit a sealing washer. As this sump plug has a very fine thread, unusual for aluminium, it may have been stripped and a previous owner found something similar to replace it. Sounds worrying that you cannot undo it.

When Mike Pemberton modifies an ES2 engine he drills the hexagon head so that it can be wired in place, as you can't afford to lose this sump plug whilst riding.

I've contemplated enlarging my sump drain to incorporate a modern plug with a magnet, but this means taking the engine out to recut threads and ensure there is no swarf left in the sump.

Philip.

sounds as though its the same type thats fitted on my 19s engine. mine has a hole drilled straight through it. i suppose so it could be wired. i couldn't undo it so i left it in

Barry

Hi Ben,

If you go to the search bar at the top of this page and put in 1961 ES2 Sump plug when the list comes up click on the link at the end of the first entry and it should bring up the whole thread from last August.

Regards, Richard.

Previously ben_tomlin wrote:

Previously richard_cornish wrote:

Hi Ben,

If you go to the search bar at the top of this page and put in 1961 ES2 Sump plug when the list comes up click on the link at the end of the first entry and it should bring up the whole thread from last August.

Regards, Richard.

Thanks Richard, did that and very useful.......I reckon 3/8 cycle thread is probably the most likely bet but on reflection I think I'll leave well alone and live with a little drip until I can find something to fit the current square head plug and can pluck up the courage to try and remove it .......(I don't want to do something I may well regret!)

Hello Ben, thread is 1/8"BSP, (28 TPI)

Regards, BenoÃ?t

Hi Ben/et al,

I'm pretty sure the original thread is 3/8" Cycle thread, but your and Barry's engine looks like they have had 1/8" BSP 28tpi plugs fitted as a repair to help the easily damaged aluminium threads. These are usually tapered and about .010" bigger diameter than the cycle thread size. I don't think any plain steel hexagon bolts are available in 1/8" BSP, although I may be wrong. So on your engine Ben, there will be no going back to 3/8" Cycle unless you heli-coil it.

Regards, Richard.

had another look at my sump plug i managed to removed it and the thread is gone, not much of one there actually. i think the tapered bolt/plug makes its own type of thread not sure. it will fasten up tight though.

mind you it wouldnt be so bad if you could fit something like this

https://www.lawsonproducts.com/lawson/Metric-Self-Tapping-Drain-Plug/59711.l

anyway. thought i would just add its not about my bike. Ben asked the question just thought i would show i had a similar plug problem.

Barry

Use a heatgun to heat up the alloy and the drain plug will be able to be removed. I normally heat and put tension on the bolt at the same time. Just ensure you use a spanner or box socket that fits the head properly.

It's probably a tapered pipe thread (NSPT).