Hi there

Im after some advice on my sons Bantam

It has a D7 Engine, standard Amal carb and standard style Air Filter. Currently it doesnt have electronic Ignition.

We have only had it a few weeks and took to first trial today. Up to now its been tried out in the street with no problem.

First couple of sections if was fine - then started to bog badly when opening the throttle - also a bit of backfire ?

Got to the point it was difficult to ride was boging so badly. Changed the Air filter for a foam one I had in the tool box but the problem was the same.

Got home and after an hour or so on the trailer, fired it up and it ran spot on (albeit only for a few minutes).

I do intend to fit electonic ignition anyway (electrex world probably, I've used them on a few bikes with no problem), however any more advice ??

Many thanks

John

 

 

Edited November 15, 201510 yr by john b

Something causing timing to slip? - backplate moving/loose flywheel/points screw slack?

welcome to the wonderful world of bantams.. they are notorious fickle when it comes to jetting no two are ever the same and you may as i did have to experiment for a significant time before finding the sweet spot but when you do you ll know.. i ve used the electrix world and they fit and work ..

If it has the original wipac round coil in the stator plate, remove the HT lead but leave the low tension side connected to the points. Run a wire from the points to a Japanese 6v ac coil, put that under the tank.  Fully advance the stator plate, set the points gap at 10 thou and bend the points spring a bit to give it more tension. Fit a new condenser.   I used a 6v dc coil and battery  on  the  D7 Bantam I had. It was a lot better with that set up.

Sounds weak and as it warms up it will get worse? Try lifting the needle or a lower cut out slide

Be careful it not overheating, bantams have a tendency to run hot

Thanks for info !

I've ordered electronic ignition anyway, then going to step through carb etc

Cheers

John