ET: Engine (Twin) How to fix crack in ET24 (HRD) Valve Inspection Cap

[Texas John]

One of my Valve Inspection Caps (ET24) has a crack where a DPO took his slip-joint/arc-joint/water-pump pliers to it rather than using the proper tool. Seeking suggestions on how to fix it so it does not leak oil through it. It was previously sealed with white silicone seal (e.g. caulk) which washed when I was cleaning it with gasoline. I do not have a welder. I was thinking of packing JB weld through the crack which the little bit exposed would match the dull gray cap (Stainless?). Other suggestions welcome. Thank you.

 

[Robert Watson]

Just look for a nice used one that matches what you have. Many Owners have a few spares. Post a picture.

Even welded you may need to swap it out for one of the "less accessible" ones where no one can see it!

 

[Monkeypants]

I tried Tig welding one and it disintegrated with very little heat applied. I learned afterward that the original caps are made of a non weldable alloy. There might be later jobber versions that are weldable.

Glen

 

[Whiteshadow15]

Probably have 150 Or so original used ones, as mentioned post a pic and can take a look

 

[greg brillus]

150.......pathetic........I've got a 44 gal drum full of those old pesky things............

 

[Texas John]

Well - could use 1 HRD cap or two if you would like to help me replace one that has the Vincent Scroll (swap or whatever you would like to arrange). I think these are original as I know they have been on the bike at least since I got it in 1974. The fellow I got it from had more than 1 Vincent so that is probably where the Vincent cap is from. Or maybe he wrecked one so bad he had to replace it long ago.

 

[Texas John]

How did you acquire so many? Do you go to Vincent meets and borrow them? ;-)

 

[Bill Thomas]

John , There is that low temp' welding/soldering stuff on the market,
But the alloy has to be so clean, Keep brushing it with a copper brush.

 

[BigEd]

I had four of my HRD logo caps off yesterday to check/adjust the valve clearances. They appear to be original caps and you could see inside that there was some porosity that didn't go all the way through to the outside so the material would be quite thin in places. Welding could be a bit tricky especially as there could be oil ingrained. I would use an epoxy adhesive (Araldite, JB or similar) and maybe swap the caps around to put it in a less prominent position if the epoxy was visible and it bothered you.
If you want a new one the VOC Spares Co have them in stock or alternatively it sounds as if there is a good supply of second-hand caps as a cheaper or maybe even free option.

 

[Bill Thomas]

Just to add to that, I would always put each cap back to where it came off,
Or take the spark plugs out and turn the engine over slow,
I have seen many marks on the inside of the caps, Where the adjusters have dug into the cap,
Mostly when Mk2 cams are used.