FCR carburetor clearance

jseng1 · Saturday at 11:28 AM

Plenty of room with the small body 33mm FCRs in a Commando. Everything clears no problem.

Schwany · Monday at 6:34 PM

Are you selling the fuel filters shown in the pics?

jseng1 · Tuesday at 8:21 AM

jseng1 said:
Plenty of room with the small body 33mm FCRs in a Commando. Everything clears no problem.

I still provide a single filter and a T

Schwany · Tuesday at 8:59 AM

jseng1 said:
I still provide a single filter and a T

Is the 90 degree filter what you are referring to?

I would like to find those filters shown in the pics. I searched last night with no luck at all. I like the size. I use the clear plastic sintered filters for 5/16 hose, but the I/O holes in the filters is much smaller than 5/16ths. Fuel starvation can be a problem on sustained WOT. I used to run with nothing more than the filters on the fuel petcocks inside the tank without issues. However more fine particles of something ends up in the bowl drain caps. Anywho, I'm not looking for 33mm FCRs. My 35mm FCRs plus filters have enough clearance under the tank and downtube on a P11.

The 33mm FCRs look good though. Got any reviews from customer that have installed them?

jseng1 · Tuesday at 9:06 AM

Schwany said:
Is the 90 degree filter what you are referring to?

I would like to find those filters shown in the pics. I searched last night with no luck at all. I like the size. I use the clear plastic sintered filters for 5/16 hose, but the I/O holes in the filters is much smaller than 5/16ths. Fuel starvation can be a problem on sustained WOT. I used to run with nothing more than the filters on the fuel petcocks inside the tank without issues. However more fine particles of something ends up in the bowl drain caps. Anywho, I'm not looking for 33mm FCRs. My 35mm FCRs plus filters have enough clearance under the tank and downtube on a P11.

The 33mm FCRs look good though. Got any reviews from customer that have installed them?

Yes that's the 90 deg filter. I'll see if I can find out about the inline filters you're looking for.

Here's a response from one customer. “I took the bike out and gave it a good run. Engine is strong and willing. The carb jetting is really good.” Don K.

Schwany · Tuesday at 9:48 AM

jseng1 said:
Yes that's the 90 deg filter. I'll see if I can find out about the inline filters you're looking for.

Here's a response from one customer. “I took the bike out and gave it a good run. Engine is strong and willing. The carb jetting is really good.” Don K.

Sounds right to me.

Too kind taking any time for my filter request. I thought you knew where they came from already.

jseng1 · Tuesday at 2:07 PM

Schwany said:
Sounds right to me.

Too kind taking any time for my filter request. I thought you knew where they came from already.

Those fuel filters are old stock and probably no longer available.

robs ss · Wednesday at 4:39 AM

My FCR35's have about 10mm clearance from the frame with readily available short adapters. Looks like you've got short adapters on yours too Jim?
I can fit my index finger between the carbs and the frame all around. I don't think you need more than that.
Cheers

jseng1 · Wednesday at 10:55 AM

robs ss said:
My FCR35's have about 10mm clearance from the frame with readily available short adapters. Looks like you've got short adapters on yours too Jim?
I can fit my index finger between the carbs and the frame all around. I don't think you need more than that.
Cheers
View attachment 124545

Yours look OK but some FCR 35 owners have trouble with the bolts rubbing the frame as in the photo below.

What about the ignition switch as shown in the top photo of this thread? And clearance for the DZUS fastener? (I don't have Commando here to check).

More FCR 35 carb clearance info here:
https://www.accessnorton.com/NortonCommando/keihin-35mm-fcr-carb-body-constraints.29501/

BrianK · Wednesday at 3:39 PM

Schwany said:
Is the 90 degree filter what you are referring to?

I would like to find those filters shown in the pics. I searched last night with no luck at all. I like the size. I use the clear plastic sintered filters for 5/16 hose, but the I/O holes in the filters is much smaller than 5/16ths. Fuel starvation can be a problem on sustained WOT. I used to run with nothing more than the filters on the fuel petcocks inside the tank without issues. However more fine particles of something ends up in the bowl drain caps. Anywho, I'm not looking for 33mm FCRs. My 35mm FCRs plus filters have enough clearance under the tank and downtube on a P11.

The 33mm FCRs look good though. Got any reviews from customer that have installed them?

FWIW, I use an inline Pingel on my '73 850 with 35mm FCRs. A bit pricey, but cleanable reusable and yes, it looks a treat.

robs ss · 2026-04-23T00:56:56-0600

They are heavy @BrianK - how do you mount your's.
I have a couple of those but haven't fitted them yet.
Cheers

Fast Eddie · 2026-04-23T02:10:02-0600

robs ss said:
They are heavy - how do you mount your's.
I have a couple of those but haven't fitted them yet.
Cheers

Indeed. They are the best filters available IMO but, they are heavy, causing them to wobble around a lot and potentially put strain on fuel lines and connectors etc.

Schwany · 2026-04-23T17:18:20-0600

BrianK said:
FWIW, I use an inline Pingel on my '73 850 with 35mm FCRs. A bit pricey, but cleanable reusable and yes, it looks a treat.

Nice looking filters.

Might be a bit large. Got pics of your Pingel filter install?

If the 2 in 1 out had opposed 90 degree fittings on the 2 input side I could replace a T with it and possibly make it work. Unfortunately, I don't think I have room for doing it with two filters or using the 2 in 1 out any other way.

FCR carburetor clearance

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