Hitchcocks Forum

Hi please have a look at this photo of a 'works' trials bike with the oil filter casting removed. the mod was done to save weight and increase ground clearance. Im thinking of doing this on my trials project. Its easy enough to cut the casting off, but Im wondering how to maintain the oil flow when the casting is removed. the colour pic shows the same mod with a remote filter.
any thoughts much appreciated- ta
(the B+W pic is from Don Morley's excellent book: Classic British Trials bikes )

oops! colour pic enc

Mart, the only one I have seen had a plate welded where the filter casing had been cut.
I assmume this left enough space for oil to circulate as per normal.
I don’t think this mod was to save weight, Enfield weren’t known for extensive weight saving.
I believe it was done because the standard oil filter was very vulnerable to damage, just a knock is likely to damage the cap and let all the oil out without the rider knowing.
These days the bash plate would be shaped to cover the oil filter cap.
I suspect they might have thought doing this may effect the cooling of the oil in the sump.
Richard

thanks Richard - I assume they would change the oil after every event as running without a filter is risky.

Hi, my WD/C has a timing cover without a filter. If your model will take the early cover that might be the way to go! Vince.

I'm sure they would change oil frequently, the Trials of the classic era often included considerable road mileage between observed sections so a rider might do 100+ miles on road as well as the competition mileage. Johnny Brittain may have been the originator of the amputated filter housing, he is on record as saying that in his early career he rode in the Scott Trial (a tough long distance event on the Yorkshire moors,) and he hit a rock at speed and tore the filter housing off! More recently some Trials riders have told me they reduce weight by reducing the oil level in the tank by drilling the return hole in the timing chest much lower. This also reduces oil drag on the timing gears or so they say, sometimes these "modifications" are just psychology to unsettle the opposition!

REgards, Mark

or just remove all the oil in the engine, gearbox and forks! every little helps

Most period photos of the works trials bikes show the oil filter retained.

I regularly ride mine on rocky tracks in the Lakedistrict and the filter is not as vulnerable as you may think, although the front corner of the housing has been welded previously, so someone hasn't been so lucky in the past.

If the picture attaches properly you will see the oil-ways in and out of the filter housing, (rear and centre of the housing) you can't just machine it off and fill the holes, you would have to sort some sort of pipe.

https://ibb.co/kZZgGG

Sighs!

lol "or just remove all the oil in the engine, gearbox and forks! every little helps " please dont all the fluids
may this mod more of style and preference :