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Discussion Starter · #1 ·
I finished converting my filters to foam today. Only took about an hour to do both filters. I used a sheet of 1/2" UNI foam. I found a package of it at Cycle Gear, a large national chain. Cost was $12.00 and there is enough material for 2 sets of filter elements, using double elements in each filter.

I cut the paper element out with a very sharp knife, then using a Dremel sanding drum, I removed the rest of the paper residue from around the edges where it was glued onto the frame. Take care to clean as much as possible off to avoid small paper particles from being ingested into the engine.

After pressing in both elements, there was still about 1/8" of the lip left. To make sure the elements don't move, I drilled 2 small holes in the lip, one on top and one on the bottom about 1-1/2" from each end. I then bent a piece of 3/32" brass brazing rod into the shape of a long allen wrench and placed it thru the holes. It neatly and firmly holds the foam in place, although I would imagine that it would stay in place anyhow, as I cut it slightly oversize to compress slightly when installed.

I did find that the foam was much more permeable to airflow than was the pleated paper. I am surmising that the stock airfilter is a bit restrictive above about 4K RPM. After finishing it up, I tried some performance runs, and found that the torque did increase from about 4k on up, pulling quite strongly. Coupled with the Malossi variator and modified Leo Vince pipe, the scooter really performs nicely. It is hard to imagine much better performance from a heavy 400 cc machine.

I am running the default Power Commander map for the stock Majesty, except that I leaned one bar in the midrange, and one bar in the high rpm range. My measured CO is about 3.5%, but I will probably have it custom mapped by the local DynoJet facility, now that I have completed all of the mods that I intend to do on this machine. My CO meter does not enable me to check under load, as it is only a tailpipe sniffer, so I am sure that a map created on the DynoJet dyno will be much more accurate at various loads and throttle angles.
 

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Ron I've been running on foam filter since May and with this dry weather and sand and clay roads I've found that I have to clean them around 1500 miles. I found using a engine cleaner like Engine Bright works real good at getting all the dirt out. I have my foam in layers so I can get the dirt out, course and 2 fine with a good filter oil. I'm glad to see that I'm not the only one who made this filter mod. Thanks Rob
 

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Discussion Starter · #5 ·
Robert Colley said:
Ron I've been running on foam filter since May and with this dry weather and sand and clay roads I've found that I have to clean them around 1500 miles. I found using a engine cleaner like Engine Bright works real good at getting all the dirt out. I have my foam in layers so I can get the dirt out, course and 2 fine with a good filter oil. I'm glad to see that I'm not the only one who made this filter mod. Thanks Rob
Good info, Rob..I live in an area where there is not much dust and airborne dirt, but my paper filters still got really dirty and needed cleaning about every couple thousand miles. I can't imagine running the entire 12,500 mile interval without cleaning! I will probably check mine at least every oil change, and depending on the condition of the filters, maybe even more frequently.
 

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PCM84 said:
Ron, do you have photos? How many filters are there on a Majesty?

Are there two identical filters?
No, I didn't take any pictures, but removal of the covers over the airfilters only takes a couple of minutes with a long phillips screwdriver. The instructions are in the owners manual.

There are 2 filters, one on each side, with the larger one on the left. They are not interchangeable.
 

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Discussion Starter · #9 ·
Mine look just like Robert's except that I put 2 brass pins thru the front just to make sure that the foam elements stay in place. I feel certain that they would, but "just in case"
 

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I later on added a piece of wire to hold the foam in place because the bumps were so bad on my road the prefilter started to move out of place. I also tried a 1" foam piece but you never could get the dirt out as good as the thinner foam. Rob
 

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If you want a cleaner thats a little easier on your hands try Simple Green. It melts grease and cleans really well. I use it to wash the foam Pre-filters for all my outdoor equipment and it works great.
 

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I tried a similar conversion, but I did not use foam...I bought an oversize K&N filter and cut it down to fit the area where the paper goes...I think the foam would work better...I have noticed no real increase in performance or in fuel economy, so I am ready to try the foam now...I wonder if I can order that over the internet since we dont have a local dealer for itt???? Aanyhow, glad to see that we are all working to address the few weaknesses in the Majesty design.
 

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Hi all,

I was intrigued by the idea of foam elements and decided to make some. I too used the uni foam but made it a two stage filter... 2 pieces each a 1/2" thick, one of the standard density and one of the coarser density foam. I wanted decent filtering but with the lowest reasonable restriction possible. I have to say the experiment worked. The new elements are in place and over the last 5 tanks of fuel, the fuel economy has improved about 2-4 mpg. I was getting 50-53 on average around town and 57-60 on the road...looks like road mileage is 60-62 now and around town 52-55. The colder weather has had a real effect too...what was nearly mid 50's in town is down to about 50 in the cold. I guess I'll be waiting till spring to get more warm weather data. It's still twice as good as the car...and twice the fun!

Cheers!
 

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hotshoetom said:
Hi all,

I was intrigued by the idea of foam elements and decided to make some. I too used the uni foam but made it a two stage filter... 2 pieces each a 1/2" thick, one of the standard density and one of the coarser density foam. I wanted decent filtering but with the lowest reasonable restriction possible. I have to say the experiment worked. The new elements are in place and over the last 5 tanks of fuel, the fuel economy has improved about 2-4 mpg. I was getting 50-53 on average around town and 57-60 on the road...looks like road mileage is 60-62 now and around town 52-55.
Cheers!
I am going to have to find some of this and make me some of these foam filters. I contacted AMSOIL and they did not seem interested in making these even though they do have a great foam filter for many vehicles. I think I will order a set of New filters from Yamaha and then try to make me some foam filters The hardest part will be locating the uni foam I think and keeping it in place in the filter frame as well.
 

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here are the pictures of the ones made by uni filter australia for a friend of mine's wifes majesty.

it's taken me a while to get around to posting the pictures.

they charged $57 AU each for the conversion job, they are dual density foam and apparently he is very happy with them. im thinking about having a set converted for mine soon.

jason.









 

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Hi all,

I think it is interesting that a few of us have taken the bull by the horns and created from readily available materials what can't be bought as an assembly. Those foam filters should save a few hundred dollars over the life of the bike, both in filter costs and fuel used. Now tell me why Yamaha doesn't offer such a filter in their 'speed parts' bin? It would provide them with yet another item they could charge excessive prices for and many folks would pay it...the very idea that two air filters would be around $80 is pretty ridiculous to start with, but if the filter was a foam filter that could be washed and reused...not such a bad deal. I think mine cost me about $100.00 to make and I have enough foam material left to make at least one more set of filters and maybe two more. At any rate, I am pleased that there is a measurable mileage increase and that the bike's performance has not changed for the worse.
 

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some people actually report a gain in the upper end performance.
with the foam filters.

jason
 

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GPSNut,

I have no idea about the upper end performance of the bike...I have had it ONCE to an indicated 90 mph and I ran out of guts...since then probably have touched an indicated 80 a couple of times...most of my riding is 65 mph or less. Not sure if I am high enough on the RPM scale for there to be any improvement at those speeds. You have any thoughts on that????
 

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all i know is that he said that it seemed to have more power at 6000 rpm than before, possibly because it was "breathing" easier through the foam, than the paper ?

he said that it seemed to rev a little harder too.
like you, most of my riding is done at about 65-70 mph (the highest legal speed here im oz is 110 kmh) though i did once want to see just how fast it would go. that was 93mph. had zero left at that speed.

jason
 

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That sounds plausible at least. The foam should breathe better and the fuel injection should compensate for the better airflow without reducing power. More air at the same rpm should equal more HP. I have been pleased with the impact on fuel economy and have yet to see what top speed is...maybe when I do a long cross country run sometime I'll get the chance to really open it up. Who knows...I'd also like to live long enough to tell about it too. :)

Hotshoe TOm
 
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