56G80S - sleeve or replace barrel

Helpful information and requests for assitance and advice
User avatar
spookefoote1956
Member
Posts: 1836
Joined: Mon May 01, 2017 7:32 pm
Location: Wales Innit

Re: 56G80S - sleeve or replace barrel

Post by spookefoote1956 »

Have you got a piston? I got mine from F W Thornton's. 1956 was a change over year for pistons (so I'm led to believe), so make sure you get the right one. They are expensive though (pistons that is)
Hail Joe Lucas ............ Prince of Darkness!
All my bikes are original........ to me!
"Creativity is your intelligence having fun" Albert Einstein
56G80S
Member
Posts: 3354
Joined: Wed Oct 12, 2005 10:45 pm
Location: N YORKS UK

Re: 56G80S - sleeve or replace barrel

Post by 56G80S »

Spoke to Weir Street and T&L.

In the end packed the barrel tonight and will send to T&L tomorrow. They did a good job on the head and that's what's important. They referred to using a JP piston and I know there's differing views on these but I'll find out.

I'll ask for their opinion on whether boring to +60 will do the trick or not. I have a used but reasonable +20 piston that I took out when the bore got tired. At first, as I am a skinflint, I thought get the sleeve done and bored to +20 but that only really makes sense if the +20 is an original rather than the maligned modern pistons. I have it in a Hepolite box but don't know what the make the +20 is piston is because on the box it says +60! It's so long ago I can't remember the details.

The +40 piston (!), head and exhaust valve are filthy and I'm going to take them for soda blasting tomorrow (chucked my old electric compressor iso can't do it myself). The valve seat is covered in carbon as is the valve - the stem has also blued slightly but it is still a more than reasonable fit in the guide, there's movement but in my opinion not different from when fitted when T&L did the head and that'll be several thousand miles ago. Inlet only needs a gentle lapping.

Also found out why the exhaust pushrod tunnel was leaking oil like fury - for some reason I forgot to put the dished washer back on! I know what I'm doing with these hence the inlet didn't leak a drop but I must've been disturbed when working and thought I'd done it when I hadn't. Quite a lot of oil was running round the head and into the nice new Monobloc which I think may've added to the carbon build up as I hadn't fitted a filter.

I've stacks of pics.

Johnny B
Locked