AJS & Matchless Owners Club

Hi, just bought my G9 and was surprised that there is no filter on the carb. Does anybody use a venturi gauze like this?

I use one on my 18S but to be honest, it's mainly because I like the look. It will keep out stones (and prying fingers!), but has no effect on the dust that causes 99% of the wear. Andy

Cheers Andy, is it normal to have no filter? This is my first classic bike.

You don't give the year of your bike (it helps to put the year and the model in your Profile) but as an example, for the '56 models it was an optional extra. See pages 13 and 14 of the Spares List here:
http://archives.jampot.dk/book/Spares_l ... G9_G11.pdf

As Andy said, they look a bit cool but with a mesh that size it really isn't going to do much filtering.

SPRIDDLER wrote: ↑Tue Jun 08, 2021 11:10 pm You don't give the year of your bike (it helps to put the year and the model in your Profile) but as an example, for the '56 models it was an optional extra. See pages 13 and 14 of the Spares List here:
http://archives.jampot.dk/book/Spares_l ... G9_G11.pdf

As Andy said, they look a bit cool but with a mesh that size it really isn't going to do much filtering.

It's a 1957 model, cheers.

I recall reading somewhere that the primary purpose of these gauze covers was to prevent fires in the event that the engine "spits" back into the carb. The gauze prevents any flames from going outside the carb area and thus reduces the possibility of a serious fire.

As has already been said, as a filter they are ineffective!

To be able to stop flames the gauze has to be much finer, like in the old miner lamps.

https://en.wikipedia.org/wiki/Davy_lamp

Hi

In my opinion that type of intake is purely cosmetic, by all means fit one if it floats your boat but be aware that it will restrict the air flow and you may need to compensate by adjusting jet sizes or mixture setting.

Regards Mick

GSAX1 wrote: ↑Wed Jun 09, 2021 7:11 am To be able to stop flames the gauze has to be much finer, like in the old miner lamps

Beat me to it gsax, was looking for a pic to demonstrate same thing when yours popped up! (Humphrey D got all the credit and life-long kudos for the Safety Lamp, but I seem to remember reading it wasn't without some argy-bargy with another inventor who'd allegedly beaten him to it.)

Coarse gauze keeps large objects, wildlife, flapping coat tails, stray nuts and bolts (!) etc out, but that's about it I reckon. Pretty to look at though and I have liked them when I've had them on things.

Mick D wrote: ↑Wed Jun 09, 2021 7:40 am Hi

In my opinion that type of intake is purely cosmetic, by all means fit one if it floats your boat but be aware that it will restrict the air flow and you may need to compensate by adjusting jet sizes or mixture setting.

Regards Mick

Thanks, yeah I did wonder if it would restrict airflow enough to need re jetting.