Mikuni VM34 - what is best filter?

Johnnymac · May 18, 2013

I put on my Mikuni VM34 today and it works fantastic right out of the box. I didn't even change the jets or move the needle. The only thing that took a little work was shortening the throttle cable sheath. It was too long.

The only problem that I have with this kit is that the Airfilter is huge. Do you guys take off the OEM Norton airfilter backing plate to get it to fit? There is no way it will fit...not enough room. TO be honest, the bike runs so well all the way to 8000 rpm and idles well that I'm wondering if I'll have to re-jet once I fit a filter. Does anyone run their Mikunis with a velocity stack or no filter?

Does anyone know the K&N part number for the shorter filter for the VM34?

1up3down · May 18, 2013

I ran a 34mm Mikuni for 15 years, did not have to take off the back plate of the stock air filter.

Yes, you need an air filter, velocity stack with screen no good, lets in way too much crud.

There are two circular air filters to fit the Mikuni, I used the narrower one, maybe 3/4 inch deep so left plenty of room behind it.

There is also thicker filter, think it was about two inches which would still fit, I did not feel it was needed.

pete.v · May 18, 2013

I am really glad you had success.

Go to the K&N web site and navigate to the Universal section. Look for a flange size of 57mm. I would get the biggest one that will fit in there. I and many others have forsaken the old aircleaner backing plate and related eqiupment.
There are many choices.
http://www.knfilters.com/

Hobot · May 18, 2013

Two guys here have learned the hard almost yearly ring replacing lesion of K/N facts of life if expected to actually filter effectively in dusty conditions so requires us to add second wrap of filter foam layer, which takes up room which sorta of defeats the cutie pie size racer filters. The oval shape k/n that came with with 34 miki carb kit had to be forcefully squished distorted squaty'r to fit with the air box back plate on. Later as facts ground in I was able to foam wrap around that. Factory paper filter is the best there is and would be good to be able to adapt it for miki which was a great carb upgrade to me.

Johnnymac · May 18, 2013

Does anyone know the model number for the K&N Filter that comes with the Mikuni kit offered by Colorado Norton Works. It looks to be narrower. I looked for it in the universal section on K&N's site but can't seem to find it.

http://coloradonortonworks.com/wp-conte ... _67062.jpg

pete.v · May 18, 2013

Johnnymac said:
Does anyone know the model number for the K&N Filter that comes with the Mikuni kit offered by Colorado Norton Works. It looks to be narrower. I looked for it in the universal section on K&N's site but can't seem to find it.

http://coloradonortonworks.com/wp-conte ... _67062.jpg

I don't know but I don't like it. It may offer clearance but not much filter area. Not the trade off I would be looking for.

Snorton74 · May 18, 2013

I couldn't find a model number but it measures 1"x 5". The fit is nice and if Matt puts them on his bikes then that's good enough for me.

Hobot · May 18, 2013

Hehe, it does sorta look like a filter and that how its labeled but with that narrow a band to draw thru it should not have much trouble pulling grit through too, but still better than open funnel. The size might need a jet change d/t richening air restriction but it does look cute and can be to me too.

marinatlas · May 19, 2013

Hi, and some UNI filters ?? they seem to have a good reputation, and a much larger breathing area....

Craig · May 19, 2013

I use a red and black oiled foam UNI filter with VM34 great performance breaths very well,cheap
Craig

geo46er · May 19, 2013

Hi,
I too recommend the Uni filters http://www.unifilter.com/clamp-on/ . They are inexpensive and available in simple foam sock or with formed urethane flanged openings. Nothing beats oiled foam as an air filter, its what all the serious dirt bikes come with from the factory.

GB

Johnnymac · May 19, 2013

Well I got it to fit... I had to remove the intake flange from the intake, add the filter, then slide the entire thing up against airfilter backing plate and in to place. Seem to work just fine since the rubber on the flange side is relatively soft and able to bend to accommodate the tight space. Thanks guys.

nortonman72 · May 4, 2020

Craig said:
I use a red and black oiled foam UNI filter with VM34 great performance breaths very well,cheap
Craig

Gidday mate, do you have the specs on the filter(id diameter, length etc)ches

concours · May 5, 2020

I miss hobot....
In amongst the verbal jenga were pearls of wisdom:

L x W = A = putt putt putt

Craig · May 5, 2020

here you go , the interior spring allows flexibility so you can find space for it , I run without the red sleeve as rarely ride gravel ... hope this helps ....
Craig

Craig · May 5, 2020

here are some photos , the spring that provides shape also allows some flex so you can make it fit ... hope this helps

trident sam · May 5, 2020

there is two K and N filters for the 34mm Mikuni K & N part number.RC 2880 - Chrome band and RU 0650 - rubber band

Luke Turner · May 5, 2020

This is the K&N filter I'm using on my VM36. New & old for my comparison. IIRC it's 2" deep. I've always wondered if it's too much?

Craig · May 5, 2020

I think K&N used to sell a thinner pancake style filter also , maybe 20 yrs ago I think I may have had one, maybe from Brit Cycle .... I do have 2 knockoffs that look similar , never really tried them , they had been included in the kit with the set of VM32’s I did try but used the UNI socks as the pancakes stuck out the sides too far ....

nortonman72 · May 5, 2020

nortonman72 said:
Gidday mate, do you have the specs on the filter(id diameter, length etc)ches

Cheers craig

Mikuni VM34 - what is best filter?

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