DIY - New air intake for my Buddy Black Jack 150cc

Roofaloof · Post by **Roofaloof** » Thu Jun 27, 2013 6:18 pm

My used Black Jack came to me with a Prima pipe, stock everything else, and a pathetic 92 main jet. I wanted to put an open element filter on, but didn't want to lose the vacuum system functionality of the stock intake. A trip to Home Depot was in order.

I ended up building the intake in the below picture from parts from Home Depot, AutoZone, and Buggy Parts NW. After some tuning work, the engine seems to be running (and sounding) much better than it was before.

Parts:
- 1.5" opening UNI air filter (http://www.buggypartsnw.com/home?page=s ... duct_id=33)
- Strainer tailpiece (http://www.homedepot.com/p/DBHL-1-1-2-i ... cxyj3d-hF8)
- 1/4" Dual Sided hose barbs (http://www.homedepot.com/p/Watts-1-4-in ... cxyzHd-hF8)
- 1.75" Dayco Flex Hose (http://www.autozone.com/autozone/parts/ ... ier=883728)
- 2" hose clamps
- JB Weld Stick
- 3/16" vacuum hose

Remove stock airbox and crankcase vent hose. Leave gas evap hose in place.

Cut about 3" of the tailpiece off and drill two holes in it for the two barbs.

Cut one side of the barbs off and solder them on the holes. After soldering, apply an 1/8" thick ring of JB stick weld onto the end of the tailpiece. This takes up the difference in diameter between the tailpiece and the coupler (flex hose)

Cut off one of the non-ribbed parts of the flex hose. This will couple the tailpiece to the carb.

Clamp hose to carb intake with 2" hose clamp. Clamp tailpiece to other end of hose with 2" hose clamp. Clamp air filter to other end of tailpiece.

Plug in stock gas evap hose. Cut 3/16" vacuum hose to length to replace stock crankcase vent hose. Put in pace on crankcase vent and barb on intake. Zip tie gas evap hose and gas supply hose in place to secure

After all this, the scoot seems happy with a 120 main jet at 0-500' altitude. It also makes some great noises at WOT.

Tocsik · Post by **Tocsik** » Thu Jun 27, 2013 7:09 pm

Excellent engineering and thanks for the write-up. It was especially helpful to provide links to some of the parts you used.

Could you load up a video of how it sounds? Even just running on the center stand? I'm interested to hear how noisy the intake is.

Folks, don't try this at home if you're not a "tuner"!

Roofaloof · Post by **Roofaloof** » Thu Jun 27, 2013 8:26 pm

Thanks! It was a fun project.

I can do that. I'll update here with a link.

Probably good advice. It's critical to do a good job with the solder and JB weld. You don't want your intake falling apart on the road

Tocsik · Post by **Tocsik** » Fri Jun 28, 2013 12:45 am

Hey, also let us know what kind of mpg's you're getting after a while with a 120 jet and all that air! I know mpg isn't very important to a lot of folks but I'm still curious.

And, of course, acceleration and top speed stats!

Roofaloof · Post by **Roofaloof** » Fri Jun 28, 2013 5:04 pm

A first try at recording the engine sounds. It sounds pretty similar until I start opening the throttle. The first rev is to about 1/4 throttle. The second and third are both to WOT. Also during the second and third the sound doesn't seem as accurate.

http://youtu.be/fLq0IbT51GY

My past two fill ups were 65 and 62 mpg. During both of these I spent a good amount of time tuning the carb. That definitely lowered my mpg.

I hit a (GPS) top speed of 71 yesterday doing some high speed tuning. I'm pretty impressed the little scoot can go so fast!

rick71454 · Post by **rick71454** » Fri Jun 28, 2013 8:06 pm

Hello Roofaloof:BuddyLand:

I am glad and impressed you can get 71AMPH on your Buddy. You can passed up a lot vehicles on the Interstate.

Instead of making a successful custom air intake assembly as yours, what are your thoughts about keeping the stock assembly and simply custom making a rectangular paper like or rubber foam filter piece to replace the stock one?

I was thinking of furnace filter material or foam that would allow more air through it but, still keep the dirt out.

Thanks
Rick71454

Roofaloof · Post by **Roofaloof** » Fri Jun 28, 2013 9:39 pm

Hi Rick,

You could definitely modify the stock airbox for better flow.

Don't use furnace filter. It's too coarse and will let damaging particles into your engine.

You could use something like this that's made to filter air going into an engine: http://www.amazon.com/Uni-Filter-65-PPI ... s=uni+foam

Make sure you don't have any air leaks after you're finished. This will cause your engine to run lean (too hot) and also let damaging stuff in.

rick71454 · Post by **rick71454** » Fri Jun 28, 2013 9:56 pm

Hello Roofaloof:

Thank you for providing me a connection to good filter grade foam material.
What do you think of using ordinary rubber foam?
If it is not fine enough.......... use thicker pieces will do?

Kind of looking for a quick fix until I might do what you did.

Thanks
Rick

Roofaloof · Post by **Roofaloof** » Sat Jun 29, 2013 2:42 am

Hi Rick,

I'm not sure what kind of foam you're talking about.

While it's possible that some foam you have on hand would work, it will most likely have one of these two issues:
-too dense. This will restrict the engine from breathing properly. This job the opposite of what you're looking for
-not dense enough. This will let in too much damaging stuff

If the foam isn't fine enough, using a double thickness wouldn't solve the problem. You're still going to have holes large enough for particles to get through.