8 replies to this topic

[Cyclops63]

Had a look but can't find previous on this. I have a standard '79 850. I have never been a fan aesthetically of the big plastic doughnut air filter box. I'd like to replace it with the older, smaller metal box. I may choose a rocker cover with outlet pipe to attach to it. I'm sure there are a million reasons why I shouldn't do this so thought I'd give everyone their chance to poo-poo the idea 🤣

[mab01uk]

Do you have an 1.25" SU Carb or a 1.5" SU Carb as the early smaller metal filter case was designed to fit the smaller carb?

There was also a plastic version of the smaller filter box fitted to later Mk3 Minis with an 1.25" SU.

 

 

Plastic Air Filter
 

Metal Air Filter
 

Edited by mab01uk, 26 September 2023 - 10:36 PM.

[Cyclops63]

Thanks mab. I should have the HS2 but I'll double check. The metal box is my preferred choice. Much neater and elegant. What I'm wondering is whether the smaller capacity box would have any discernible effect on the mighty engine's running. Perhaps a little rougher when cold? Although, living in tropical Scotland, the cold isn't an issue 🙄🙄

[mab01uk]

The smaller filter should not be a problem on a standard 850 as that was good enough back in the day.....if I remember right you used to have to move the filter inlet pipe by rotating the housing slightly to the winter or summer position. The winter position was pointing at the hot exhaust manifold to draw warm air.

The problem may be if you have the later 1.5" SU I don't think it will fit the old filter set up easily.

Edited by mab01uk, 27 September 2023 - 08:43 AM.

[Cyclops63]

Thanks Mab, yes I recall back in the day moving the inlet from summer to winter position. Round about the same time you'd add antifreeze.

[timmy850]

I used the small metal 850 airbox on my standard 998 and it didn’t seem to cause a restriction

[Cyclops63]

Great Timmy thanks. Would anyone happen to know the thread on the wing nut?

[timmy850]

It's a UNC thread from memory and the part number is 53K2852 if that helps

 

https://www.somerfor....uk/air-filters

[Cyclops63]

I was backing at paying a tenner from Somerford for a single wing nut. I found nos at John Richards Surplus for 50p ex vat. Then they charged me 6 quid for delivery. Bought 4.