Early Knuckle Air Snoot Filter

[40 Nuck]

The only filter I have ever seen offered for the early Knukcle "snoot" air covers is the copper mesh. The mesh, however, has several issues ... doesn't catch really small stuff, has been known to blow out the air intake hole if the bike backfired, and the last time I used one, some of the copper strands actually came loose and looked like they may have been sucked into the carb. My guess is that others have addressed this issue on the forum before, but I couldn't find any earlier threads on the topic.

I did, however, come up with a solution to share. Briggs and Stratton makes a large foam filter element part #270843S for their larger applications (8-11 hp engines). Cost is about $6. This filter is a little larger in places than the snoot - two sides match perfectly, and is easily cut down to match the shape of the snoot on the other two sides so that it fits snugly inside. Air flow to the engine seems to be normal, with no issues noticed. A mesh screen (cut from a new generic air filter) was added to fit against the snoot backing plate, and held in place by the backing plate to carb bolts. This screen would prevent the foam from being sucked into the carb. The only down side is that the green filter element can be seen from the back of the bike. I've thought about blacking it out somehow, but haven't done that yet. Additionally, it looks like I may add a thin foam "shim" to the filter to keep it tightly against the carb hole, as the deeper into the snoot, the deeper the profile, and it looks like there is potential for a very small gap (maybe 1/16th of an inch) to develop between the filter and backing plate ... a little extra material would solve that easily. Anyway ... thought I would share, and also ask anyone if they've done something similar and experienced any issues or would have concerns with this application (aspiration, performance, foam element breaking down, etc.). Link follows ...

http://www.google.com/products/catal...0749293818046#

Thanks,
Vic

[Rubone]

I guarantee that no foam filter will work without hampering performance up here. 7000 ft and going up! I tried various foam filters from K&N, and others and found all of them strangled an engine with the snoot. So thanks for the info, it may help some. But be forewarned at high altitude!
Robbie

[Steve Slocombe]

I didn't think the 1936 EL air intake had a filter. It looks like a mirror image of the 1935 VL one. Steve White at Vintage Motorcycles Northwest has some good repros on 253.846.2775.

[len dowe]

the lightweight filters is what i use for my air snout. nice and round and compact. they won't get blown out or sucked into the carb. I'm same elevation as robbie and it doesn't hinder the performance at all.

[ricmoran]

the lightweight filters is what i use for my air snout. nice and round and compact. they won't get blown out or sucked into the carb. I'm same elevation as robbie and it doesn't hinder the performance at all.

Len, what type of filter is this? Part number by chance?

I was trying to do this last year but ended up with a crappy running engine from what I used which was a filter from a dirt bike with a spring inside of it. The filter compressed ended up beign the reason the bike was starved for air. I went to a 6" repop but would prefer to go back to the air horn if it is possible.

Thanks for any advice.

[40 Nuck]

Thanks for the altitude warning info, Rub. Len, I would also be interested in getting some specifics on the filter solution you mention.

[len dowe]

The element, new part #27805-47. It list it as the complete unit & in my parts books & does not give a picture or a seperate # just for the element(i have several lightweight projects). the filter element is steel, not copper. I believe they used this element up to 1952. Then they changed the filter #2906-53 to a round design with 2 screens on each side(same as 47) from 53-?(maybe till sprints) I have seen them on ebay but not very often. Maybe Jim & Mary Godwin might have them. The elements work perfect for the early snouts. Hope this helps and will try to get a # & pic just for the element. Len
Note: I tried the copper mesh and it WILL NOT work. It breaks down and gets sucked into the intake manifold. Not unlike the steel ones and i have been running mine for yrs. Normal maintainence as any other filter. Oil and drain.

[Chris Haynes]

I have one of those I use to scrub pots and pans with. The Mo Co never had any kind of filtering in the 1937-1950's scoop. The Air Cleaner was a totally different part.

[len dowe]

Had it in front of you all these yrs Chris and you never knew it. I know that they didn't have a filter element for the ealy snouts. I use this(as thread was intended) to keep the dirt out and it is a lightweight element

[Steve Little]

I have just had my 37 EL engine re built by Kyle Oanes. He did a meticulous job on rebuilding the engine. Even against my effort of buying every piece of original junk that was posted on eBay ....ooooh another 4 fin cylinder. must have that.

Kyle did a great job of tossing it out the door...Not using that crap..it's 060" too short. I ended up shipping home 2 extra cylinders, and a box of parts that would break you'r back.
My reason for posting is that I have an original "hair dryer" snout air cleaner and also a aftermarket 6" round J slot which isn't correct for my 37 (1935-1937 6" round air cleaners had screws holding the cover to the backing plate)

After all the effort that went into this engine, I wasn,t going to let any air into it that had not been blessed.
The woven pot cleaners are a great idea.
Even though they are a coarser weave than the copper packs of the round filter, I think 3 wired together along the snout and soaked in the correct oil, would end up sticking any dust particle to the oil soaked pot srubber.

[Steve Little]

I have just had my 37 EL engine re built by Kyle Oanes. He did a meticulous job on rebuilding the engine. Even against my effort of buying every piece of original junk that was posted on eBay ....ooooh another 4 fin cylinder. must have that.

Kyle did a great job of tossing it out the door...Not using that crap..it's 060" too short. I ended up shipping home 2 extra cylinders, and a box of parts that would break you'r back.
My reason for posting is that I have an original "hair dryer" snout air cleaner and also a aftermarket 6" round J slot which isn't correct for my 37 (1935-1937 6" round air cleaners had screws holding the cover to the backing plate)

After all the effort that went into this engine, I wasn,t going to let any air into it that had not been blessed.
The woven pot cleaners are a great idea.
Even though they are a coarser weave than the copper packs of the round filter, I think 3 wired together along the snout and soaked in the correct oil, would end up sticking any dust particle to the oil soaked pot srubber.

[ricmoran]

Len, thanks for your update and that is a geat idea. Then as Steve pointed out the element could be built up. Wonder if somethign a little finer, like steel wool on the air intake side would be any benefit.

[Chris Haynes]

If soaking in oil use a heavy weight. Minimum of 50. Anything lees will just get sucked into the engine.

[Steve Little]

I think an important note is that the type to use is the woven pot scrubber that is pictured. Here in Australia we have some different types of pot scrubbers at the supermarket. I have pinched some from the kitchen for different applications in the work shop, and the other type looks like stainless swarf off a lathe. That swarf type has ends that could suck into the throttle body and cause havoc.

[len dowe]

The lightweight filter elements are the same size weave as the copper one's are. Steve, some builders i know recomend an external pan style oil filtration system on any motor. Not pleasing to the eye on early knuckles or BT's, but it does protect your motor and keeps the oil clean which is a huge +.