3 1/2 valve timing

wessex_man · March 01, 2016, 08:29:50 PM

That whats it's all about keep em on the road

VicYouel · March 01, 2016, 02:48:06 PM

Just in time for practice Brighton run!!! Thanks for keeping us informed John

Vic

John Cole · March 01, 2016, 01:11:54 PM

Have now got the bike back together; timed with inlet opening at TDC and exhaust closing approximately at 12 degrees after, magneto timed at TDC with full retard. Started and ran 2nd kick, hurrah! The only problem I had was that the timing cover would not seat flush, due to the 'F' type cams being 3mm greater in width. Managed to remove the cam bushes which thankfully are quite wide and machined them down by the appropriate amount, strangely enough they are made of cast iron. Now to have a couple of runs out and hopefully ride it on the Pioneer run at the end of March. Many thanks for everyone's help on this, warm wishes John.

John Cole · February 02, 2016, 03:18:44 PM

Many thanks Gentleman, this explains it all, shall set with inlet opening BTDC and exhaust closes 17 ATDC. Have just been out to garage (cold out there) and set up roughly and looks similar to the photo. I shall set up with degree disc during the weekend, very many thanks again.

phutton · February 01, 2016, 10:13:53 PM

Hi John,

The manuals from 1923 on show a valve timing diagram. Attached is the 1926 one. Given that the bore and stroke of your 3 1/2 is the same as the Light Solo, I think the valve timing should be the same. I hope you can read it!

wessex_man · January 31, 2016, 12:27:25 PM

I don't know if this picture will help you any or at least give you a starting point for their positions so you can mark the timing pinion and cams ?

The timing pinion you should have is the small taper one (first LH one) I am pretty certain the Keyway is uppermost when pistion is TDC.

VicYouel · January 29, 2016, 04:29:13 PM

Usually at TDC (not the firing stroke) you can detect the inlet valve opening just before TDC and the exhaust closing just after TDC on all engines. Rocking them "to and fro" is easy to check.

On sidevalves there is less overlap. than an OHV.... I would go for Models 1/2 and 5/6 timing as used in the twenties of inlet opens at 0 degrees BTDC and closes 60 degrees ABDC. The exhaust opens 60 degrees BBDC and closes 17 dgrees ATDC.

But then I could be wrong..... maybe Tim P could advise?

Cheers John and hope it is ready for the Pioneer.

Vic

John Cole · January 29, 2016, 11:27:21 AM

After a disaster I have had a new main shaft pinion made and some 'F' type inlet and exhaust cams re modeled to fit my veteran but of course I now have no timing marks. I have tried to find out what the timing should be but have come up with conflicting information. Can anyone help as to what the best set up should be.