Which hw35 seal.

[TonyL]

Thanks for the in depth answer, but I forgot to say that it's already synthetic.
I thought I had fixed the porous breach, but now not sure. I have reassembled and tried it - the results are the same, about 8ftlb.
Tbh, I'm not sure it even had a leaky breach. My plan with this project was not to throw money at it, just do all I can without spending a penny!
I think I'm going to get the new seals and see what happens.

It might need the transfer port sleeving down.

Jim wrote about this in one of his recent, excellent articles. And T20 and Jon Budd will be able to give you the scientific reasonings if they jump in.

New seals are always a good idea.

[clarky]

It might need the transfer port sleeving down.

Jim wrote about this in one of his recent, excellent articles. And T20 and Jon Budd will be able to give you the scientific reasonings if they jump in.

New seals are always a good idea.

This is good advice....the port was too big at 4.0 mm and needs to be sleeved down to a smaller, much argued about diameter of either 3.1mm or 2.8 mm...
The big diameter of air gets out too quick in stock, before peak is achieved....in otherwords a whole load of wasted cylinder dimension for a BSA Meteor performance.
Its further hampered by being too long in length but not much can be done about that.
With a restricted port we can then achieve closer to peak and modern synthetic heads will then act similar to the leather one...
PM if you need info on how to go about it....as power mods prob not allowed on open forum...
Regardless it wont go post 12ftlbs anyway ....11 ftlbs and sweeter if lucky ..