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Re: 1967 P11 rebuild - Dynamite on wheels

Posted: Mon Aug 17, 2020 5:31 pm
by g80csp11
could it be main bearings , my superblends have started to mark and give a hammering under load .
now im gong for new superblends and a BE regrind
perhaps you are sill on the old ball and roller bearings

Likewise , this quick rebuild is going to take weeks

it only started out as a re-ring to reduce oil consumption
but by the time the head and barrel were off i thought i should check mains and BE . one thing so easily leads to another

Re: 1967 P11 rebuild - Dynamite on wheels

Posted: Mon Aug 17, 2020 5:43 pm
by ajscomboman
Don't believe so as under load and running it's lovely and quiet, absolutely no noise whatever after 20 secs and I cannot make it repeat the noise at all, only if I left it cool and start it. Then it's the same again 20 secs approx and totally silent.

Re: 1967 P11 rebuild - Dynamite on wheels

Posted: Mon Aug 17, 2020 5:48 pm
by ajscomboman
Only thing I'd be leaning towards is piston slap.

Re: 1967 P11 rebuild - Dynamite on wheels

Posted: Mon Aug 17, 2020 5:58 pm
by G15 Roy
Or your knees knocking. :lol: :lol:

Re: 1967 P11 rebuild - Dynamite on wheels

Posted: Wed Aug 19, 2020 8:38 pm
by g80csp11
drive side superblend.jpg
This limited rebuild cost are starting to add up :(
Drive side main bearing has very much reduced interference , essentially now the Superblend bearing will just go in at room temperature rather than the 1.5 thou interference
rather than use loctite ive found oversize +1.5 thou superblend available for only the cost of a 'arm and leg'
BE regrind under way

spare parts on order , should be ready to rebuild the engine starting end of next week

tomorrow ill clean down the frame for tify up before engine is ready to go in and after that swinging arm rubbers to replace as the back end is a bit twitchy and i didnt replace then at the original rebuild

Re: 1967 P11 rebuild - Dynamite on wheels

Posted: Thu Aug 20, 2020 2:24 pm
by mdt-son
Be sure to magnaflux your crankshaft before you invest in engineering work. These cranks are infamous for developing internal cracks.

If I were you, I'd also junk the cast iron flywheel, which is prone to exploding at high revs. The way to go is having a billet steel flywheel made up, and the assembly tied together by 3/8" ARP high tensile bolts, as was used on the Commando Mk3.
I was lucky to have this conversion performed by Steve Maney some years ago. He is out of business now. Dominator Engineering in Germany also used to offer this service - he may still do. Jim Comstock in the USA will probably help out also.

-Knut

Re: 1967 P11 rebuild - Dynamite on wheels

Posted: Thu Aug 20, 2020 3:54 pm
by g80csp11
not sure i can go that far , but will crack test rods and cranks , plus fit new crankshaft fixing studs/nuts /tab washers + con-rod bolts and nuts
certainly if you look at the video clip of the P11 they do have a tendency of loosing rods
like all engines after 55+ years its not used like a new bike and only went around Mallory Park on one weekend !

All British bike were stretched beyond their original design and dogged by unreliability in the end

Re: 1967 P11 rebuild - Dynamite on wheels

Posted: Fri Sep 04, 2020 7:16 pm
by g80csp11
How many ways are there to install the spacers on the P11 ? , when i was younger i took it apart and then 6 months later just fitted them in the correct position. now a few years older i took it apart then only 3 weeks later put them back in a different order
Good job i checked the engine sprocket to clutch alignment before doing any more or else it would have to come apart again
is this the first sign of getting old(er)?

just waiting for some new studs to arrive before continuing

Re: 1967 P11 rebuild - Dynamite on wheels

Posted: Fri Sep 04, 2020 7:33 pm
by Mick D
Hi

Nowadays I consider a digital camera to be an essential tool :oops:

Regards Mick

Re: 1967 P11 rebuild - Dynamite on wheels

Posted: Wed Sep 16, 2020 1:52 pm
by mdt-son
I believe there is a recipe at Access Norton of which spacer goes where.

-Knut