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Camshaft Capers

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Camshaft Capers

Posted by John Pullen-Appleby at April 15. 2017

Hello All,

I put my crankcases back together today--I used the gasket from a set i bought.  I nearly put the cams in the wrong holes.  I looked at the manual and it identifies the exhaust as being the forward shaft.

 

I could not get the crank to go into the drive side main ball-race without easing it with emery.  I had to heat the drive side case to get the rollers to enter in the outer ring in the crankcase.

 

I had a nagging felling about the cams--on my Triumphs the forward cam is the exhaust but--a look at my engine showed the points driven by the rear shaft.  I managed to get the cases back to bits without ruining the joint (welseal) and changed them over--is the rear camshaft the exhaust one-- or is the manual just wrong?  As eased the cases apart the cam retracted from the ball race--weird--the roller race rotates smoothly bt--it is probably the orginal one and seems fine--I am used to the the drive sided case coming off first leaving the crank in the timing side one.

 

Also the manual advised building the gearbox before fitting the cases together--eh?  I have not--as I was able  to take to bits with the cases together  (I have got those bits ready yet)

Re: Camshaft Capers

Posted by patrick_mullen at April 15. 2017

What manual are you using?  The original Norton maintenance manual & Instruction Book gives very little info about refitting the camshafts and it's years since I last put a Jubilee engine together so my memory could be at fault.

Surely the points are driven from the inlet cam so it follows that the front cam is the exhaust cam. Don't forget to fit the oil seal into the hole through which the inlet camshaft extension protrudes otherwise oil can get unto the points.

Also I have never even considered building the gearbox before putting the cases together- !!.  It is easy to assemble even when the engine is back in the frame.  I can't remember exactly what shim I used to cure jumping out of first gear.  Something like 10 or 20 thou.

On the subject of gearbox shims someone who used to work at Norton 60 years ago told me that they regularly inserted shims into gearboxes on the factory assembly line to cure faulty gear engagement when new.  No shims at all are shown in the parts list.

Patrick

Re: Camshaft Capers

Posted by andy_sochanik at Tuesday 00:16

Exhaust cam is at the front of the engine & has no facility to drive the points.

The Inlet cam is at the rear of the engine & drives the points.

To identify the cams, look at the far end of the Cam

I7 = Inlet Jubilee; E7 = Exhaust Jubilee

I5N = Inlet Navi & Electra; E5N = Exhaust Navi & Electra

See my other answer about main bearings..

Cheers

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