Hi Bryan,

The bike is a B40
The old valves were very carbonised, lots of wear(so possibly 'riding high'into
valve seats?)
I stripped top-end and sent off to SRM.They lapped new valves (+ exhaust had new
valve seat)
I then put valves back in.(Could this have brought valve height 'down'?)
Only one head gasket!
I will check rod lengths.
Thanks all for taking the time to think this through with me.
Andy


--- In bsa@yahoogroups.com, "beezabryan" <beezabryan@...> wrote:
>
> 4mm?? Unless you used 3 or 4 head gaskets something is badly wrong.
>
> Did you strip the engine?
> Was the valve gear intact when you did the strip?
> If so have SRM sent back to you a different head ie someone elses head??
> Have the correct valves been fitted?
> What engine is it? Gives the experts here more of a chance to help.
>
>
> --- In bsa@yahoogroups.com, "bsa242" <bsa242@> wrote:
> >
> > hi all,
> > have just had a rebore and rebuilt top-end. Reassembled, and to my horror,
cannot reduce tappet clearance enough. SRM Engineering put two new valves in my
head. Is it likely that they were shorter than my original ones?
> > Any ideas would be most welcome on how to rectify this-can you get extended
tappet screws? (I need about 4 more mm. Sorry, not so good on old English)
> > This was my first ever big mechanical job and I'm a bit gutted to say the
least.
> > Looking forward to any ideas, Andy
> >
>