New air cleaner concept, question on design

[Proformance1]

I just bought a set of old 44mm blaster air cleaners and it got me thinking. We really dont have a great design or an alternative to old parts or buying OEM old designed parts.

If you run the 4 bolt topped mikunis your only option are the older OEM intakes. I hate the air horns on carbs, because you have to run race filters or the only good part avail for those are Brian's adapters,from Thrust Innovations. Great choice but what about with the 44mm or 46 mm carbs with the bolt tops.

The great thing about the air horns is they help with air flow into the carbs.

What I'm looking into, and currently designing is the 38mm carbs stock intake top with a new bottom plate that bolts to the top of the 4 bolt carbs. I will incorporate the air horns into the new bottom plate so it just bolts to the top of the carbs, like the normal 38's. Then the stock top bolts to it. Currently I'm designing around the Boyesen 44mm + sized manifold, shown below.

My question is, is the in line intake plastic box too restrictive for an application like this? The intake area is much larger than the single old blaster style.

It would also work with the new Wamiltons intake cover, or stocker

 

[kevbo]

The stock dual carb cover is fine. Stock screens may offer some choking on big carbs but thats not always a bad thing.

 

[Proformance1]

Here is a rough 3d version of the prototype. Again it will use the stock 38mm intake plastic top. Questions or comments??

 

[Dustin Mustangs]

Of course you could measure and compare the cross sectional area of the intake opening and that in the venturi part of the carb, but I think your best bet would be to look at real world setups. Have you ever heard of anyone ditching the 62t airbox because it's too restrictive? I haven't and people run them and the double 61x box on the biggest motors around. Speaking of which, is the opening twice as big as the 61x?

Something else worth considering is that your design seems to lack provisions for the stock airbox screens. Those are there for good reason and it's not to act like a filter.

 

[Proformance1]

Good points! I've been debating the flame arrestor also. It could be added exactly where the stocker goes, but the air horns would have to be removed or altered somehow. The point of the air horns is that they add HP, the 61X air intakes don't. Also maybe a screen could be added at the inlet behind the rubber hose. More later

 

[Dustin Mustangs]

There's more going on there than just arresting flames.

Freeze flame!

 

[Frosty]

two thoughts:

1 - I'm running twin 44's (oem) with a stock yamaha bottom plate and stock air box with a single screen (from the 760 motor). However, I also run an R&D intake mani with a Riva spacer. This set up raises the overall carb location enough to rub on my lowered WDK hood. So, watch the base plate thickness... don't make it too thick bro.

2 - you'll need to show some real HP gains in the set up because the oem parts are relative cheap. Most freeriders go with stock because they work well keeping water out and are cheap. The racers are the guys who spend more on their carb toppers...

 

[Crab]

two thoughts:

1 - I'm running twin 44's (oem) with a stock yamaha bottom plate and stock air box with a single screen (from the 760 motor). However, I also run and R&D intake mani with a Riva spacer. This set up raises the overall carb location enough to rub on my lowered WDK hood. So, watch the base plate thickness... don't make it too thick bro.

2 - you'll need to show some real HP gains in the set up because the oem parts are relative cheap. Most freeriders go with stock because they work well keeping water out and are cheap. The racers are the guys who spend more on their carb toppers...

FYI, I have had better luck with water injestion and much snappier performance with adapters and ProK's with my WDK hood, the tubes on the hood drop down right in front of the stock airbox and trouble...........I think Jeff designed it with a/m tops in mind.

 

[Frosty]

FYI, I have had better luck with water injestion and much snappier performance with adapters and ProK's with my WDK hood, the tubes on the hood drop down right in front of the stock airbox and trouble...........I think Jeff designed it with a/m tops in mind.

yeah, mine drop right in front of the motor... haven't had any water ingestion issues. I did run AM Red Top carbs with Proks with outterwears, and had all kinds of issues which is why I went back to OEM.

 

[Proformance1]

Currently the design, which is not tested yet, is 1/2" shorter than stock height, so I don't see height being an issue. May be too low and hit something, I'll have to bolt it on and see.

As far as the flame arrestors, yes something that needs to be addressed.

I for one hate carb water injestion, and everyone that we ride with that has them has had issues, to the point that anyone that has them is removing them. Most with aftermarket carbs are running Brians set up, or with regular Mikunis running the dual single box air intakes.

I dont have a price yet as the design is just a prototype, but I assume it will be about 100 bucks. Which is why I was doing it in the first place. It took me months to find the dual single air boxes and from Greater Yamaha they are almost 80 bucks each new, and used they are going for 40 each if you can find em. This is just another alternative, at about the same cost or cheaper, and MAY possibly add HP, if I run the air horns. Without them the price drops quite a bit. Then this is much cheaper and easier than any other option avail now. But again only for Mikuni, Xscream, Full spec carbs with the 4 bolt flange on top.

But again this is just a prototype, and not a for sale item! It only will work with the Boyesen manifold kit. I'm still assuming that other manifolds have different center to center spacing.

Keep the comments comming!

 

[DangerBoy]

careful making it shorter
We built one that was shorter than stock and it killed performance.
you need a good amount of space between the top of the venturi and the lid for the air to make the turn

 

[SJBrit]

I love the idea of being able to use the stock flame arrestor from my dual 38's when I upgrade carbs. I'm running dual 46's now, and have spent money on two single stock arrestors for the 46's whereas a base plate adapter would have been an excellent option.

Here's what I would like to see:

• Simple adapter to run the stock flame arrestor from dual 38's on the larger Mikuni carbs
• I'm not fussed about improving the intake - I just want to keep water out
• The adapter needs to accommodate a single stock screen for each carb
• Height is important - it needs to clear both a lowered hood and an aftermarket girdled head
• The price has to be less than I can pick up a couple of 46mm arrestors for, so I would say you need to be shooting for $75 or less

If you build it, I will buy...!

 

[Proformance1]

SJBrit, that is easy. It's the adding of the HP that i'm looking for also. Here is what you are talking about. The factory flame arrestors would fit right in, and it would use the stock SJ air intake. I have to measure surface area of the entrance, but there are less turns than the single boxes and we already know it keeps the water out great. It appears the opening is larger than two single boxes, so.... I'm still thinking, keep it coming!!!!

Dangerboy, Thanks for the input bro. That is very true. I'm going to try and use the stock 38 plastic intake and it's very tall, but not tall enough to hit my aftermarket hood. Sharp turns or reducing volume of the air kills power.when I was talking shorter I was just speaking of the base plate not the cover. The stock 38 base plate is 1" tall, mine as shown is 1/2" I will have to make sure it soesn't contact the head. If it does, it will have to be raised, which will effect cost. More material=more money. right now it's just for me so no biggie

 

[SJBrit]

SJBrit, that is easy. It's the adding of the HP that i'm looking for also. Here is what you are talking about. The factory flame arrestors would fit right in, and it would use the stock SJ air intake. I have to measure surface area of the entrance, but there are less turns than the single boxes and we already know it keeps the water out great. It appears the opening is larger than two single boxes, so.... I'm still thinking, keep it coming!!!!

I would keep the HP addition as a separate model. I have a feeling there will be much discussion about the benefits of that, but a straight up adapter at the right price will be very interesting to anyone upgrading carbs from stock. Aftermarket flame arrestors can get a bit spendy, as can sourcing a couple of 46 stockers especially if you also have to get a couple of XMetal spacers to make them miss the head.

 

[Proformance1]

Word, from my 4 stroke background I can vouch for the air horns adding power. I'm sure most agree. If someone would make a real tunable injection system for my 701 all this would be a moot point, LOL I just measured Frosty loaner single air box at 47.5mm ID, Yamaha must have designed for 44 or 46 carbs then. I thought I was going to have to bore this on the Bridgeport to run my 46mm, but I guess not. Forgot about the risers required also. I may end up running my prototype first instead of the single boxes I just bought.

 

[Frosty]

I'm going to try and use the stock 38 plastic intake and it's very tall, but not tall enough to hit my aftermarket hood.

you need to check mine out... mine is rubbing on the hood liner bad with the OEM air box (with riva reed spacer) and the WDK hood.

 

[Mark44]

i

I made this to adapt my 44's.

 

[Crab]

you need to check mine out... mine is rubbing on the hood liner bad with the OEM air box (with riva reed spacer) and the WDK hood.

Mine hit without a spacer and started to rub through the rubber in front, i'm much happier now with the adapers, proks, and fly outerwears than the oem box and the ski deffinatly rips harder with no water injestion issues lake or surf. I think its key to have a good hood seal and silicone the tubes to the hood liner as well.