My Big Girl 960 Seeley Commando

Chris · Jun 17, 2023

The oil tank neck had come loose & needed welding back in. The welder I took it to said there wasnt room between the Monza cap & the tank to run a fillet around. He tried to pull the filler cap/neck up & the opening cracked like a star burst. Suddenly a whole new ball game! It now needs a whole new top panel & the neck welding in.
So I hunted around for something that would work & lashed up my Mk4 tank. Filled it with oil & a new oil filter. Stripped the timing cover & drive side for new oil seals. Loaded up for Pembrey.
Unfortunately it's gone pop! I have a feeling its oil pressure related, so time for a full strip & rebuild. Time will tell what went wrong & how much damage has been done.

Fast Eddie · Jun 17, 2023

Bad luck Chris.

Hope there’s not too many horrors inside.

Do keep us posted mate.

Craig · Jun 17, 2023

Paul (850 Commando.) · Jun 17, 2023

Probably can't help with any engine bits Chris, but just incase you're going to cut up any old oil tanks, I have a couple you can have a look at next time you're here.

Shelby-Right · Jun 17, 2023

Chris said:
The oil tank neck had come loose & needed welding back in. The welder I took it to said there wasnt room between the Monza cap & the tank to run a fillet around. He tried to pull the filler cap/neck up & the opening cracked like a star burst. Suddenly a whole new ball game! It now needs a whole new top panel & the neck welding in.
So I hunted around for something that would work & lashed up my Mk4 tank. Filled it with oil & a new oil filter. Stripped the timing cover & drive side for new oil seals. Loaded up for Pembrey.
Unfortunately it's gone pop! I have a feeling its oil pressure related, so time for a full strip & rebuild. Time will tell what went wrong & how much damage has been done.View attachment 107674

Have you got room to use alloy brazing rod , or some tanks are a top and bottom , I have done a tank , ground right around the seam , split the tank , done repairs and tig-ed back together .

lcrken · Jun 17, 2023

That's still a slick looking bike, Chris. Hope you can get is sorted without too much pain.

Ken

Chris · Jun 18, 2023

Looking good running rough Ken. I will get whatever needs doing done, as its been my favorite bike for a good while now.
Shelby I have a contact now to sort the tank & as you say, thats how he will approach the job.
Paul thanks I have the tank in a bag in the van lol.

Fast Eddie · Jun 18, 2023

lcrken said:
That's still a slick looking bike, Chris. Hope you can get is sorted without too much pain.

Ken

It looks even better in the metal Ken.

Just needs a fairing now Chris…

worntorn · Jun 18, 2023

Sorry to hear that Chris.
What are the bore and stroke dimensions to get 960? Is this a Maney engine?

Glen

Chris · Jun 18, 2023

Hi Glen
Yes its a Steve Maney engine. Stroked crank & big bore 81 x 93. The only thing original is the head.

Ashphalt Al · Jun 19, 2023

A great shame we could not sort it out on the weekend at Pembrey Chris , fingers crossed that nothing nasty has happened .

Chris · Jun 19, 2023

I think maybe it has but making progress in the garage. I will soon have enough room to look

acotrel · Jun 22, 2023

I suggest you will never regret buying that. With any race bike, you need to re-build the motor before you race it the first time. What gearbox does it have ? I found the biggest improvement to performance came when I fitted a close ratio gear cluster. With the standard Norton box, you lose too many revs on each upchange when racing, and coming down through the gears ia never smooth. My motor stays between 5,500 and 7000 RPM during races. Where it is competitive, it should not be competitive
I do not believe performance im provements to a Commando motor actually achieve much.
Another thing is - measure your fork yoke offset - mine is 53mm. The way my bike can be made to accelerate through corners after braking is really great. It took me a while to realise a Seeley can do that.
A good bike makes a good rider.

acotrel · Jun 22, 2023

With a Seeley, every race becomes safer. A Seeley G50 should out-handle a 500cc Manx.

Chris · Jun 22, 2023

All been detailed before Al.

Fast Eddie · Jun 22, 2023

Had a look yet Chris ?

Chris · Jun 23, 2023

Not yet mate. I would just kill what space I have. Lots going on at the moment, hoping to do Kempton jumble in July as Im just moving things around!

Fast Eddie · Jun 23, 2023

You need a reet good clear out mate !

acotrel · Jun 24, 2023

The main thing with the motor is probably the crank. You need to check the big ends - fit new bearings. Also, if the crank still has the big balancing hole - fill it with a threaded steel plug, securely Loctited in place.

Fast Eddie · Jun 24, 2023

acotrel said:
The main thing with the motor is probably the crank. You need to check the big ends - fit new bearings. Also, if the crank still has the big balancing hole - fill it with a threaded steel plug, securely Loctited in place.

Chris’ bike has a 93mm stroke Maney crank in it Al. No threaded plugs.

My Big Girl 960 Seeley Commando

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