Hi Mark

I think most people run their bikes fully advanced in normal running conditions.

I only retard the ignition to start the bike or if it pinks a bit going up steep hills.

Regards

Pat

email (option): sacombsashtrees@hotmail.com

Retard the ignition only for making adjustments to slow running settings (pilot mixture and tickover), starting the bike, if necessary, or if for example, you are in very slow moving traffic. I tend to just select a low gear and play on the clutch and throttle in that situation though...

At all other times set the lever to fully advanced when running at anything over about 1500 rpm...

Due to the inefficiencies of the side valve design a fair bit of heat is lost from the combustion process and absorbed into the engine castings so you will find they run warmer than a typical OHV engine...

However, running retarded on the lever in conditions other than those mentioned will increase the amount of heat produced, as will a retarded setting of the ignition timing or any air leak or carb setting that will induce a weak mixture...

If you are confident you have set the timing correctly, you are not retarding the ignition inappropriately on the lever and the fuel/air mixture is correct there is nothing to worry about and it's a case of getting used to the extra heat generated by the S.V. engine...Ian

email (option): ian@wright52.plus.com

thanks chaps more confidence next ride

In the 1930s in general and wartime in particular, fuel was of such a low octane that pre-ignition was a real problem under many operating conditions.

I virtually never retard the ignition on the 16H once running. Just occasionally if I'm stuck behind a tractor up a hill or something - and then mostly just out of boredom and to see if it makes a difference.

Do keep an ear open for the sound of pinking if you're thrashing though. A tiny bit back on the lever can help - but certainly not full-retard.

Dear all
I only just got around to taking my bike out for the first time a few days ago and at higher revs the engine was sputtering and a loss of power. After reading this I presume it was due to the fact I was not using the adv retard lever.

Could anyone let me know at what position the lever is at full advance, when the cable is loose or when the cable is pulled

email (option): Deepsea@vol.net

Hi Stuart,
I'm pretty sure the WM20s had a tight advance - the cable should be pulled out when advanced.

email (option): cas.vanderwoude@gmail.com

If the cable enters the mag at the rear on an M20, then it's tight wire advance. Like Rik, I run all mine on full advance once it's running with the occasional retarding if slogging up hills. Ron

email (option): ronpier@talk21.com

It depends on the mag, but is quite easy to work out from first principles. Rather satisfy yourself that you have got it right.

email (option): pvlietstra@gmail.com

Dear All

Many thanks for the advice, I need to take it to a vintage bike show in the morning so ill give it a try, Just been trying to solve all my electrical problems so its road legal before I take it out.

Regards

Stuart

email (option): deepsea@vol.net