The BSA A7-A10 Forum

Technical (Descriptive Topic Titles - Stay on Topic) => Lucas, Ignition, Charging, Electrical => Topic started by: BSA500 on 24.09. 2025 13:17

Title: Waterproofing the K2F magneto
Post by: BSA500 on 24.09. 2025 13:17
Hiya,
 As in the subject, twice now the A7 has been caught parked in the rain. Started ok but within 5 mins spluttered to a halt. Took the pick ups off and found the gearbox side (lower one) full of water. Top one dry and where the HT leads screw in dry as well. So I assume the rain runs off the magneto body and past the pick up gaskets. What does everyone use to prevent this, sealant or something like vaseline etc. Riding in the rain is ok it just runs off the bike engine as its parked on the side stand(no main stand and no bike shelter at work)
Title: Re: Waterproofing the K2F magneto
Post by: muskrat on 24.09. 2025 20:16
G'day BSA500.
Vaso would be my first choice above any type of silicon sealant.
Cheers
Title: Re: Waterproofing the K2F magneto
Post by: BSA500 on 24.09. 2025 21:08
That's what I thought
Title: Re: Waterproofing the K2F magneto
Post by: sean on 24.09. 2025 21:11
doubt vaseline would stay thick with the engine temps .....maybe a bit of clear silicone or high temp grease  ...wouldnt hurt to spray your HT leads with WD 40 it displaces water .....back in the 60s we used to start the bike at night or a dark place and get a spray bottle  with water and spray the ign system , ht leads cap etc for stray spark leakage 
Title: Re: Waterproofing the K2F magneto
Post by: BSA500 on 24.09. 2025 22:04
I have some hivac silicon grease should be good for higher temps
Title: Re: Waterproofing the K2F magneto
Post by: Billybream on 25.09. 2025 09:21
Always fitted an o ring to the points cover, although to be fair now tend to avoid rain
Title: Re: Waterproofing the K2F magneto
Post by: chaterlea25 on 25.09. 2025 10:55
Hi BSA500,
Are the rubber boots that cover the acorn nuts on the pickups fitted?
If it has manual advance, apply the silicone grease to the cable at the handlebar lever
Also rubber boot over cable going into the mag,
John
Title: Re: Waterproofing the K2F magneto
Post by: BSA500 on 25.09. 2025 12:59
John,
 Yes I have some nice tight fitting boots over the acorns and that part of the pick ups are bone dry. All the water collets in the bottom pick up around the carbon brush bit. So its either getting past the upper pick up gasket and running down or the lower gasket or both. Its an automatic magneto and the points housing is nice and dry.
Title: Re: Waterproofing the K2F magneto
Post by: Triton Thrasher on 25.09. 2025 13:40
There are drain holes in the base of my magneto.
Title: Re: Waterproofing the K2F magneto
Post by: berger on 25.09. 2025 14:38
triton thrasher they are ventilation holes not water drain holes
Title: Re: Waterproofing the K2F magneto
Post by: CheeserBeezer on 25.09. 2025 16:36
The new pickup gaskets available from the usual source (!!!!Grrrrr!!!!) look like fibre but actually are plastic with a red coating. They don't work because they are not soft enough to form a seal between the pickup and the mag body. The originals were cork or cardboard or thick fibre mat. They need replacing every couple of years. I make my own out of cork sheet.
Title: Re: Waterproofing the K2F magneto
Post by: Triton Thrasher on 25.09. 2025 17:01
triton thrasher they are ventilation holes not water drain holes

They’re drain holes when water or oil gets in.
Title: Re: Waterproofing the K2F magneto
Post by: BSA500 on 25.09. 2025 19:59
Problem is they are at an angle and tiny
Title: Re: Waterproofing the K2F magneto
Post by: 8iggles on 26.09. 2025 09:05
Best policy on the open brass screw terminals at the top of telegraph poles was to clean all traces of corrosion and dust, cobwebs even bumblebees occasionally then dry and spray with silicone spray. Really get rid of anything that will absorb moisture and cover with a slippery coating that also acts as a barrier for air too. Don’t really want anything sticky that catches dust then gets damp?
Some of the sprays for repelling moisture we had were really effective and they didn’t have oil in them so evaporated, you could connect your mega and watch the needle, it was like insulation in an aerosol.
Everything gone Idc these days, although connections are grease filled to keep the air and moisture out! ( no open brass screws)
Title: Re: Waterproofing the K2F magneto
Post by: berger on 26.09. 2025 13:34
well as i understand it they were fitted with felt and allowed the mag to breath
Title: Re: Waterproofing the K2F magneto
Post by: Worty on 27.09. 2025 12:33
The new pickup gaskets available from the usual source (!!!!Grrrrr!!!!) look like fibre but actually are plastic with a red coating. They don't work because they are not soft enough to form a seal between the pickup and the mag body. The originals were cork or cardboard or thick fibre mat. They need replacing every couple of years. I make my own out of cork sheet.

Got caught out and bought a box of these - utter s***e for anything other than tiddlywinks. *angry* *angry* *angry*

Have cork sheet now and intend to have a go at my own gaskets as and when I need them.
Title: Re: Waterproofing the K2F magneto
Post by: BSA500 on 29.09. 2025 13:08
Well the gaskets on mine weren't to bad so I smeared some of my high temperature hi pressure vacuum silicon grease on them(perks of working in the chemical industry during my career)