H/weight head refit.

itma · Post by **itma** » Wed Nov 21, 2007 7:14 pm

"rev to 20,000 "

that'll be a new crankpin on order then, Sir?

crawsue · Post by **crawsue** » Wed Nov 21, 2007 7:24 pm

Suits you sir !

56G80S · Post by **56G80S** » Fri Nov 23, 2007 10:57 pm

I didn't used to use a torque wrench, but do now. As for re-torquing, I always have, despite it being a pain taking off the rocker box.

If it wasn't necessary, why tell you to do it?

But each to their own.

Johnny B

itma · Post by **itma** » Fri Nov 23, 2007 11:09 pm

No Matchless instructions ever given re torque wrenches as in the days they where in use, outside of perhaps aero engineers, no one had ever heard of them, certainly you would not have found one in the average bike shop of the 1950`s.

bag-o-nails · Post by **bag-o-nails** » Sat Nov 24, 2007 9:43 am

crawsue before you refit your head have you ground in the valve's to the seats?

bag-o-nails · Post by **bag-o-nails** » Sat Nov 24, 2007 9:59 am

hi ya ken how you doin
on an iron head it would be difficult to cause dissdortion by overtightening the need for use of the correct Ib/FT came with the development
and progressive use of aluminium i know some early models had ally heads and i think from
experience better results have developed by the use of the torque rench

oh and let me be the first

SEASONS GREETINGS

REGARDS B-O-N

crawsue · Post by **crawsue** » Sat Nov 24, 2007 1:49 pm

Valves ground in,new seals fitted and new head gasket annealed and fitted.Head gradually tightened up then torqued to 38 lbs/".Allready compression feels stronger at the kick start,so here's hoping,etc.Bye the bye I measured the old head gasket after annealing and compared to the new one (after annealing)old---27 thou,new---38thou.I gave the spiggot a good clean up --probably took off about 2 thou,and cleaned up the 'head recess.Amazing difference to the "feel" of the valve lifter lever (as with the clutch lever)new springs are pricey but I think well worth it.Discovered that the carburetor to 'head spacer was narrower than the 1&5/32 bore of both the port and carburretor so have ordered a new one.It can't have helped gas flow at higher revs,which was one of my complaints.As for the re-torquing issue,I know that it is recommended in the manuals,but I ask again,when these machines were new and going back to the dealer for the 500 mile service,does anyone seriously suggest that it was done.I just can't see it.

itma · Post by **itma** » Sat Nov 24, 2007 1:54 pm

said it before, back in 1956, no one used one.
common sense was the only thing needed.

Biscuit · Post by **Biscuit** » Sat Nov 24, 2007 2:46 pm

The 500 mile free service included tightening all EXTERNAL nuts and bolts. The cylinder bolts on singles are not mentioned, but the nuts on twins are.

The first reference I can find to torque figures is in 1964.

crawsue · Post by **crawsue** » Sat Nov 24, 2007 4:14 pm

So does this give weight to the argument that once the 'head is fitted that further tightening down is NOT required.To re-iterate,I have torqued it down to 38 lbs/ft.To emphasise the point,after refitting the 'head,both push rods had to be slackened off,so 'head must be tighter to the barrel.