bugger! I'm still working full time so apologies to how long it took me to reply - plus I'm on the other side of the world. All I can say is "patience" - slow and steady is how it goes with this old stuff.

-Hutch

too late damn damn, I've made a mess now
As soon as I rebuild a new gear I will take pictures of the finished work.
Thanks to everyone for cooperation.

Sandro,

Here are a few pictures of my 2 3/4HP Cork Inset Clutch (from 1915 to 1919). Very similar to 4HP version, but most likely not identical.

You may need to get a suitable deep socket and breaker bar, or maybe ring spanner, on the hex on the sleeve nut to be able to get enough torque to undo it (clockwise as left hand thread). A bit of impact might help as well.

Hope these pictures help you out.

(Unfortunately the sleeve nut I have for my 1915 2 3/4HP project has damage to the thread where the nut that holds the kickstart ratchet and pinion on - another repair job to do for the restoration!  ).

cheers

Hutch

Hello all,

I'm the current custodian of  one of the Bert Thorpe alloy motors.

A friend of mine who is an extremely competent Engineer has split the crank and has expressed his concern that it might be beyond use. It has been skimmed to accept oversize rollers previously in its life. The conrods are home made alloy rods 

It's engine is 68mm stroke and 68mm bore and from its engine number I've been told it's a 1925 TT jobbie.

I'm hoping to fit a new crank and a pair of new rods in this engine, is anyone making new cranks and rods?

Cheers,

Ed

Such a lovely day I took the T6 out for a short twenty mile ride and the more I ride it the more I am falling in love with it, it's so smooth, vibration free and handles like a dream and as I live in Wales there are a lot of hills but the T6 laughs at them so much torque.

 Am hoping next week to get my head around the front brake, I will post results as and when.

Ride safe, Colin

Sandro,

Yes a picture is worth a thousand words as they say! (..or I my case maybe two thousand    ).

I have a similar one but it is for 2 3/4HP not 4 HP. It is loosely attached to a gearbox and I can take some pictures of it disassembled for you tomorrow (as it is the evening here.)

These "old traps" may challange us, but worth the effort I think 

I apologise for taking a long round about way to answer your question but I hope you are close to getting it apart with out resorting to the lathe solution.

Cheers

Hutch

good morning, this is the photo of the half cater with clutch plate still mounted; it is different from the one in your photo and should be a 1916/1917.
In fact, the serial number 4836 is stamped on it.
Today I will try to disassemble the piece again, but tomorrow I will use the lathe to widen the internal hole of the gear to the depth of the bearing and then I will disassemble everything.
I am starting to hate these old traps!!!! 

Sandro,

Patience is often required when dismantling these old machines that have parts that have been together for a very long time ! :-). Good that you are able to re-make the gear if things don't go to plan but I think it should still come apart without being too violent with it!

I am wondering if you have the earlier cork inset clutch type? I don't have any good pictures of the 4HP version but I found this picture of the fitting 642N it uses to attach to the 605N gear. On the 2 3/4HP this is a left hand thread and I assume the 4HP version is the same (I don't have one to check).

(Note that the clutch basket is not fitted on this gearbox). For comparison part 2206N is shown and this is used for 1920 onwards 4HP models. Which do you have?

Because the kick start acts directly on 642N for these earlier clutches via a ratchet, it could be tightening on the 605N gear when the engine is kick started and the bike is not in neutral. This means that it can be very tight on the 605N gear. and hard to undo. It may require a long stiff bar and a quick shock to loosen it (left hand thread)

(The 2 3/4 HP models with 3 speed and flywheel clutch have a similar problem with the kickstarter tightening up the nut that holds on the cush drive to the input gear).

If you get a chance please take a picture of what you have. and best of luck with it on the weekend.

Cheers

Hutch

Thanks for your advice Ron

Good morning and thank you for reply, next Saturday I'll try to look at the whole assembly again.
I tried to unscrew the right or left parts, heating them up to 400 degrees without success.
I tried to separate the two parts with a 12mm (1/2") diameter threaded pin, always heating the hollow stem, but the thread tore.
If I don't succeed at the next attempt, I think I'll completely turn the gear head and then rebuild an identical one.
I have no problems with the gears because I work in this factory:
www.biemmeingranaggi.it.
Thanks for the information, I'll keep you posted