Villiers ignoramus seeks advice.

[Tribsa110]

Hi,
I think I've worked out that the comp. engines of late 50s/early 60s are based on either the 9E or 11E crankcases and that the 33A/34A/36A designations come about through the particular mix of barrel/head/gear ratios fitted?.
Is this correct?.
The question is where would I start looking for information on identifying, for example, the differences between 9E and 11E bottom ends and between trials and scrambles barrels/pistons/heads?. As always, on the web I find apparently conflicting information e.g. 33A short rod, 34A long rod, 36A long rod on one site but all listed as 66 bore, 73 stroke on another.
Can anyone point me towards decent written information on these things please?.

[Tribsa110]

Wow, that was quick!.
This looks like the bees knees right enough, thanks a lot for that.
Tribsa110.

[Rob]

The Villiers barrels are reasonably straightforward. The only 250 barrel that will fit a standard 9E is the 31A. This was the first 250 and has a thin base flange and needs an inlet manifold. Villiers then decided the flange was too thin and thickened it up which lead to the conrod being lengthened by 1/4". This 'first of the longer barrels' was fitted to the 32A. Stroke did not change, remaining at 72 mm.

The 34A scrambles barrel has the carb mounted directly to the barrel with no separate inlet manifold.

However! Longer rods got fitted to 9E's and people machined the barrel flanges down to get the longer barrels to fit the shorter rods so there are plenty of traps for the unwary!!

Although it all seems a bit confusing, it makes sense once you read up on it. As you say, there are conflicting stories out there but the above is how it is. Back in the 60's when I rode around on a Scottish, I used to swap between 197 and 250 barrels, pistons and head depending on which bits were the less broken and what I could get my hands on!

If you have a specific question, just post it on the forum and we will do our best to answer it.