Air filter help

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Bulah

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Apr 15, 2018
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74 850 setup with twin amal mk2s 2932. Bike came to me with no air filter. I have seen previous threads about turning down the od of the air intake adapters to fit k and d R-0990. Before i go this somewhat extreme rout i was wondering what the options are for dual conical filters. Any helpful insight would be much appreciated.

Scott
 
I also use that K&N R-0990. Works fine, no scratched frame paint, easy on and off.
 
Is K&N's oil flammable? I had a foam K&N many years ago that caught fire when the bike backfired while starting it. Scared me away from K&N filters for good. Dunno if that's still a problem or not.
 
Been using the K&N for years now with no complaints, though they do seem to pass a bit of grit.

Recently purchased a pair of UNI foam filters. I had to raise the needle and float positions, but so far they seem to work well. My sense is that they will be a bit easier to clean than the gauze K&N.

http://4into1.com/uni-foam-pod-filter-set-pk-82-50mm-52mm/
 
Surprising K&N still business with all of the negative reports just on our little forum .... wonder what is said ‘bout them on other sites ..... I also use Uni 2 layer filter on Commando , seems to do the job have found no grit etc. , must be 6 or 7 years now .... K&N on my others
 
I am also working on a 72 Interstate that came with two Amal Mk2 2932 carbs. I have the same issue as Bulah with fitting an air filter to the adapters. Height of filter is an issue, too. There only is about 3 inches of space behind the adapters. Even less if standard air filter back plate is installed, which I planned to use just for attaching the ignition switch.

1) What air filters are available that fit these carbs with the 55.5mm adapters.

2) Any ideas on how to mount ignition switch without air filter back plate installed?
 
Bulah said:
74 850 setup with twin amal mk2s 2932. Bike came to me with no air filter. I have seen previous threads about turning down the od of the air intake adapters to fit k and d R-0990. Before i go this somewhat extreme rout i was wondering what the options are for dual conical filters. Any helpful insight would be much appreciated.

Scott
Click to expand...
I am working on a 72 Interstate that came with two Amal Mk2 2932 carbs. I have the same issue you had with fitting an air filter to the adapters. Height of filter is an issue, too. There only is about 3 inches of space behind the adapters. Even less if standard air filter back plate is installed, which I planned to use just for attaching the ignition switch. What solution did you go with?
 
NickZ said:
2) Any ideas on how to mount ignition switch without air filter back plate installed?
Click to expand...

Mine fits facing out the left side.

Air filter help


But there are multiple places around the battery tray to choose from.
 
Last edited:
The stock key location facing forward is best. This way the rain is forced right into the key assembly.
One does wonder what they were thinking!
 
gortnipper said:
This is also 54mm

https://www.knfilters.com/rd-0500-universal-clamp-on-air-filter

Not sure what the Mk2 centre to centre distance is, and whether the OD of the filter might be a problem or not.
Click to expand...

Thanks for the suggestion. I see that K&N have a few options. The closest fit seems to be RC-2380. But there is the question of fitting a 54mm flange over the adaptor, which I am now measuring to be more like 57mm wide. The website mentions that the flange can stretch 1.5mm, but it looks like it would need to stretch about 3mm. The only option I found that has flange ID of 57mm (RD-4400) is 62mm center to center and I need 75mm. Also, height greater than 75mm would interfere with oil tank.

Even if it fits, will the smaller volume of the RC-2380 have an effect on performance? I estimate it is less than 1/3 the volume of the std commando air filter and roughly 60% of the popular R-0990 from K&N.

I am noticing other issues with Amal Mk2s applied to the Commando. I may start a separate thread on the subject.
 
NickZ said:
Thanks for the suggestion. I see that K&N have a few options. The closest fit seems to be RC-2380. But there is the question of fitting a 54mm flange over the adaptor, which I am now measuring to be more like 57mm wide. The website mentions that the flange can stretch 1.5mm, but it looks like it would need to stretch about 3mm. The only option I found that has flange ID of 57mm (RD-4400) is 62mm center to center and I need 75mm. Also, height greater than 75mm would interfere with oil tank.

Even if it fits, will the smaller volume of the RC-2380 have an effect on performance? I estimate it is less than 1/3 the volume of the std commando air filter and roughly 60% of the popular R-0990 from K&N.

I am noticing other issues with Amal Mk2s applied to the Commando. I may start a separate thread on the subject.
Click to expand...

Some testing that comnoz did I consolidated some of the comments here - https://www.accessnorton.com/NortonCommando/best-air-filters.22665/#post-337121

They make 57mm versions of the singles - https://www.knfilters.com/search/universal/round-straight-universal-air-filter/


I think KN will custom make you what you want if you specify it to them. Just order a few and put them on the shelf.
 
NickZ said:
I agree, but I was hoping I wouldn't have to fabricate anything.
Click to expand...

Actually it was dead simple. I had the broken off bracket and I think I had to drill one hole, maybe two. I think there was an existing hole in the battery tray. If you look you can see the bulge in the backplate, that's where the nut sits. It's like it was meant to be.

Of course you don't have concentric so you won't have the back plate.
 
swooshdave said:
Actually it was dead simple. I had the broken off bracket and I think I had to drill one hole, maybe two. I think there was an existing hole in the battery tray. .
Click to expand...

I did the same. Easy. Mount the bracket on the inside of.the battery tray and it supports the lock more than just one bolt would.
 
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