Gear driven camshaft

I can't see any point in even trying to do this apart from the satisfaction of fixing a problem which doesn't exist. You would probably get great self pleasure  from an engineering point of view , but it wouldn't be an easy or quick fix. Of all my Commandos no problem arose with the chain drive and even my 961 has the same setup. If you were that way inclined engineering wise, your time might be better spent looking how to change the final drive from chain to shaft.  :-)

I agree with Peter.  It would be an interesting engineering challenge but with doubtful benefits.  Most Modern OHC bikes and many car engines run chains, albeit inverted tooth because they are long lasting and quiet. 

A gear solution would need an intermediate gear to get correct camshaft rotation. Gear driven cams can be noisy, unless they are helical. As a cam closes a valve, the valve spring tries to rotate the cam, reversing gear tooth backlash and making a noise. Listen to an old Triumph with high mileage and you will understand!

It's been done by using a set of double gears but it results in the crank gear self destruction so not worth the effort.

If you want a challenge - how about changing to hydraulic tappets?  That might be fun. 

Incidentally - a stated benefit of having four lobes on the one cam (rather than separate inlet and exhaust camshafts as use by B and by T) was that torque reversals due to valve spring reactions are less severe with Norton twins, hence placing less onerous loads on the camshaft drive.

The Jubliee and Navigator both had Gears inside the Timing Cover to drive their camshafts.  My 500cc Twin has as well. It has to be possible as a modification using Lightwieght Norton or Triumph gears. But not too sure if the Camshaft timing would need altering.  I guess you need to weigh up the gains against the losses.

Yes, the lightweight twins do have gear driven cams ,but they were designed that way as I imagine your 500 twin was Phillip . On the other hand converting a chain driven cam on the Norton twin would be quite a complicated issue ,  plus the additional problem of the cam revolving in the wrong direction thus needing another ider gear . An interesting engineering exercise but little more than that I feel .

hello your engineering time may be better spent in making roller-type camshaft followers as Harleys have done with their engines  this is to give a quieter cam and this helps to reduce wear on the cam face,  many Diesel stationary engine has them  but messing the geared driven cams  dose not make good engineering sense  chain are far better and do give a bit of variable valve timing at high rev speeds   and their harder ware-ing  yours  anna j  

Anna 

I,m intrigued. How does this variable valve timing work in our twin cylinder engines?

Regards

Peter

… that Anna means "variable" as in "random".