Wildgoose Chase Moto Guzzi

General Category => General Discussion => Topic started by: Chuck in Indiana on January 14, 2015, 07:08:53 AM

Title: UNI pod filter sizing
Post by: Chuck in Indiana on January 14, 2015, 07:08:53 AM
I'm looking for filters (cheap)  ;D for the 36mm pumpers on the aero engine. The carb measures 1.88 diameter. UNI sez they have 1 3/4 and 2 inch diameter. I've never used UNIs before.. which one should I go with? Will the 2 inch tighten down ok?
Oh, and are they flexible?
Title: Re: UNI pod filter sizing
Post by: Antietam Classic Cycle on January 14, 2015, 04:08:40 PM
Uni pods are very flexible, the 2" should squeeze down fine.
Title: Re: UNI pod filter sizing
Post by: Chuck in Indiana on January 14, 2015, 07:06:10 PM
Uni pods are very flexible, the 2" should squeeze down fine.

Thanks, Charlie..
Title: Re: UNI pod filter sizing
Post by: Morizzi on January 14, 2015, 07:21:02 PM
Chuck,

There are a few types. http://www.uniflow.com.au/contents/en-us/d297.html (http://www.uniflow.com.au/contents/en-us/d297.html)

Straight with a metal end (buy singly) or a kit that is all foam but angled.

I have used both types with no issue but I'm guessing this is for the Lario. PHF 36s and small block frame so I can't advise on which one will fit better but the angled ones can be rotated to fit most spaces.

Cheers

Rod
Title: Re: UNI pod filter sizing
Post by: Chuck in Indiana on January 14, 2015, 07:28:38 PM
Chuck,

There are a few types. http://www.uniflow.com.au/contents/en-us/d297.html (http://www.uniflow.com.au/contents/en-us/d297.html)

Straight with a metal end (buy singly) or a kit that is all foam but angled.

I have used both types with no issue but I'm guessing this is for the Lario. PHF 36s and small block frame so I can't advise on which one will fit better but the angled ones can be rotated to fit most spaces.

Cheers

Yeah, I'm looking at the angled one.. I've never even had a UNI in my hands. If it is flexible enough to bend a little, it won't be a problem.

Rod
Title: Re: UNI pod filter sizing
Post by: Morizzi on January 14, 2015, 07:43:37 PM
I actually like them Chuck. They are flexible but the part that hits an obstruction will be pushed in rather than the whole filter bending. It will of course rub and wear. No problem, just seal up with some tough goop like sika flex.

No light shines through them and you use normal products. Turpentine to clean and a 50/50 turps/engine oil to oil.

I do find that as they are actually a filter rather than a gauze/cotton seive they are just slightly more restrictive but nowhere near as much as the trendy little cone shaped seives due to their larger surface area.

I can always find a position of rotation for them to sit freely. I have them on the monza, V65GT but they are of course PHBH carbs so a bit smaller. I have the big ones on a Cali III without issue too.

I've used both the straight/steel cap abnd the angled. The angled give much more surface area but I have put holes in the steel caps to plumb the breather system into.

Cheers

Rod
Title: Re: UNI pod filter sizing
Post by: Antietam Classic Cycle on January 14, 2015, 10:25:14 PM
One thing to keep in mind is that an oiled foam filter can catch fire if the engine backfires. I think this happened to Mark @ Moto Guzzi Classics on a freshly restored Loop a while back and I remember mtiberio relating a similar story.

I've heard that if a piece of wire mesh is placed over the carb inlet prior to fitting the filter, it acts as a spark arrestor and keeps this from happening. My XT500 seems to bear this out - it has a screen built into the forward plate that sandwiches the foam filter element.
Title: Re: UNI pod filter sizing
Post by: Morizzi on January 14, 2015, 10:50:00 PM
One thing to keep in mind is that an oiled foam filter can catch fire if the engine backfires. I think this happened to Mark @ Moto Guzzi Classics on a freshly restored Loop a while back and I remember mtiberio relating a similar story.

I've heard that if a piece of wire mesh is placed over the carb inlet prior to fitting the filter, it acts as a spark arrestor and keeps this from happening. My XT500 seems to bear this out - it has a screen built into the forward plate that sandwiches the foam filter element.

Ive read this too Charlie but the 2 bikes I've known that have burned to the ground were fitted with wire gauze/oiled cotton filters. Once you cover the gauze in a flammable material all the heat diffusion qualities are negated.

The wire gauze is used on air vents to large fuel tanks in the marine industry so it does work to prevent the passage of fire.

The common denominator of the bikes that burned to the ground was they were fitted with a crank fired, wasted spark ignition system. I'll fit foam filters but not one of them.
Title: Re: UNI pod filter sizing
Post by: John A on January 15, 2015, 02:56:08 AM
If a screen is put over the inlet most engines will not run well at WOT. A good rule of thumb is that the screen or the end of the filter should be 2.5 times the diameter of the inlet from the end of the carb.
Title: Re: UNI pod filter sizing
Post by: Chuck in Indiana on January 15, 2015, 06:57:19 PM
Thanks, guys. Got em ordered today.. ;-T