Z1OwnersClub GB

Hi All,

After a recent rebuild of the carbs on my A1 I’m having trouble getting a good seal on the round brass float bowl drain screws.

I’ve tried standard size o rings, slightly larger o rings with a bigger cross section, I’ve tried silicone rubber seals Punched from a sheet of 3mm thick silicone rubber sheet, I’ve even tried different o ring materials like Viton but I’m still getting an annoying little weep which after a while drips onto the top of the motor staining it brown.

Any thoughts as to why I’m getting this problem and is there a solution I’m missing?

I’ve ordered a piece of PTFE bar and I’m going to turn it to 9mm o/d and part it off just thicker than the depth of the recess in the float bowl and see how that goes.

Any input would be welcome.

Cheers.

Whats the o ring seat face on the bowl like? A scratch, bit of crap or uneven surface there and it'll weep through by the thread.

I’ve checked them out and they look ok. I’ve even superglued a small disc of 240 grit wet an dry onto the end of a piece of 9mm steel bar and tried to dress the face by hand to ensure it’s smooth.

I’m really trying to avoid taking the bowls off again if possible.

Okay, bit of a trick I learned way back when. When you can't get them to seal but you do have some gasket paper. Cut a 12mm washer from gasket paper. Put that on the drain plug first followed by the o ring.
Benefit is twofold. When you tighten the drain plug the thickness of the paper pushes the o ring harder against the bowl face and the papers larger diameter makes a seal against the larger bowl diameter.
Works every time and any excess paper can be trimmed with a sharp knife when the plug is tight.

Thanks very much for that. Not a bad idea. I’ll have a go at that!

I had similar problems. I did have one float bowl that needed replacing but maybe it’s your screws themselves.

New are available here https://www.ebay.co.uk/itm/372816183092