Have recently replaced the Amal pancake air filter on my Cub with a new foam cylindrical type which I sprayed with Castrol filter spray. Now having ridden the bike I think it is running rich and very badly at lower rpm. I removed the filter which seemed to improve things but need more riding time before I will know properly. Do all foam filters need spraying or have I made a problem by doing so, anyone else had running issues after spraying a foam filter?

I never trusted spray on filter oil it might be applied to little or too much which can cause clogging up

Foamfilter with good filteroil is my personal choice, I also think it is much more frugal too.

 

Surface area of a foam against a pancake is much reduced. Wash the foam out with detergent, petrol seems to attack the adhesive, and try once dry as there will probably still enough oil still in it.

I thoroughly recommend No Toil Filter Oil.  Washes out easily with washing powder in water so can be done in the sink yet works well (you will know the old saying that involves a blanket).

Thanks all for your suggestions and info.

Wouldn't use anything but NoToil,nothing has got through the filter yet.Washes out easily with washing powder,no solvents needed which can damage the filter

I use Castrol Filter Oil Spray. Have done so for at least 10 years. It gets very sticky and will effectively stop dust and particles.

I have found

1 Not to use too much and only at outside of air filter.

2 Let it dry before starting the engine. If wet it can be sucked into small passages in the carb and make problem. I spray the day before I go out with motorcycle. 

I think it is a very good product but takes some care to use.