I’ve got a similar issue with a D7 Bantam engine. When I do the cases up tight the gears lock solid. There are two bushes for the layshaft, should I be looking to take a little off both of them or can it all come off one?
TIA

Just buy a Bantam!
No wet-sumping, and some don’t even have an ignition switch!
Happy days!

Hi all,
My Bantam trail bike is edging towards completion. It has C15 forks fitted. Can anyone confirm the quantity of fork oil I should add to each leg? I think it’s 190cl?
Many thanks,
Stu

That museum is in Nicosia and is well worth a couple of hours! A really interesting collection of ‘bikes, when I was there I got chatting to the owner and got some of the back story to the exhibits. Even the wife enjoyed it!

Hi,
Have you seen “Bushman’s Carb Tuning secrets”?  It’s very informative and easy enough to folllow.

http://www.ntnoa.org/carb_secrets.htm

Click on the link to the pdf and print it off for some bedtime reading!

The seals are always worth checking for wear and/or incorrect fitting but that does involve a full engine and gearbox strip.  Before you go down that route it’s worth double checking the ignition especially as you say it doesn’t even cough.

Sparking outside the cylinder does not always equate to inside the cylinder. Ensure the plug cap does not have a resistor in it and swap out the plug for a trusted genuine one. As you say replace the condenser, check the points themselves are working as they should. All normal stuff.

The wiring, especially on D7s is complicated as the switching tries to match generator output to load. The different wiring harnesses look the same but aren’t. It might be worth hot wiring the ignition ie by-passing the ignition switch completely to see if it makes any difference.

Then ..

Is it a “magneto” ignition ie spark direct from the coil on the left side of the engine? If so you could rig up a constant loss external coil and battery to see if the bike will start, if it does then suspect the internal coil or the magnetism in the rotor (can be re-magnetised by Villiers services).

Next ..

On these earlier engines with generator and points on the left the keyed shaft can turn in the crankshaft flywheel as a result of a seizure. If this has happened then the timing will be out. (The rotor will also be out of sync with the magneto coil which will also affect the spark). To add to the confusion the D1/3 crankshaft assembly looks the same as the D5/7 assembly but isn’t as the angle of the woodruff key slot in relation to TDC is different. This can all be checked by removing the left hand side cover and the generator stator plate and measuring the angle of the key BTDC. The central bush in the stator plate is also suspect, if very worn it will allow the crankshaft to whip and affect the timing but this will usually only be an issue at higher revs.

Or ..

If the points are on the right the cam is not keyed to the shaft but is held by a taper.  This means that it’s possible to have the timing 180 degrees out.  Worth checking.  These bikes have an external coil so this can be swapped out to check.  Watch out for the low tension feed to the points as it runs under the engine and is very vulnerable to damage.

Bantams can be (are?) infuriating but do start reliably once set up properly (mines a first or second kick starter).  They seem very simple but things are of course fifty years old, I’m sure a methodical approach will have things running.

Courage!!

Hi Griff

The parts book says WM1 19” front and rear.
regards