Modern Buddy

I installed a RAM foam air filter on my Stella 150 4T this yesterday morning, and when I started it up, I was a bit startled by the increased noise. The sound heard when higher revs is definitely the expected sound of air rushing in, but the sound at idle is kind of freaking me out: It sounds like an asthmatic gurgle. at about 15 seconds you can hear what I am talking about:

https://www.youtube.com/watch?v=xyef4VF ... e=youtu.be

It makes the same sound when there is no filter on, and it is definately coming from the carb. Is this normal?

The scoot starts right up, and idles well. I have not taken it out yet due to the sound.

I spent some quality time this afternoon with the scooter. I have an appointment for the annual New York State vehicle safety inspection tomorrow, and my local motorcycle shop will be doing the inspection while I wait so I needed to solve this quickly.

First I removed the RAM air filter and started the scoot: The noise was louder, and definitely coming from the carb mouth. Next I removed the bowl to see if anything was obviously amiss. Nope. The bowl was still clean, the jets were tight and the float was working properly. So I re-installed the old air hose back to the air box and reconnected everything. When I start up the scooter, there is no gurgling noise to be heard. On Friday I will remove the air box hose to see if the gurgling is there, but the air box is simply nullifying it. I may just have to live with it. If here is no problem, the GPR exhaust note should over write the gurgling, but I want to be sure before masking any symptoms. So far, the scooter is running fine.

has anyone else run their 150 4T without the air hose?

video does not exist.

without hearing it, I suspect your gurgle is normal. just make sure it isn't lean. Manufacturers go to all kinds of trouble to nullify noises and "stuff".

Let's try that again...

https://www.youtube.com/watch?v=xyef4VFrOo4

Yes, I agree it may be normal and something that is simply covered up by the stock air box, but I just want to be sure before I mask the sound with my GPR exhaust. I plan on adjusting the valves tomorrow morning, and as long as that goes well, the air filter and exhaust will follow as time allows this week.

What size Ram Air did you get? Also, what did you do with the crankcase vent hose that went to the air box? I'm really interested in getting rid of all that crap in there.

The ram air is a 40mm end to fit on the carb.

http://www.ebay.com/itm/Ramair-Air-Filt ... ee&vxp=mtr

I think I left the breather on... You need something there, even if it simply drains behind the wheel.

A Uni 2 1/4" filter will fit on the end of the hose elbow if you remove the air box and take the hose out. Later, I trimmed the flange at the end of the hose down so it could fit into a 2" to 1 1/2" ABS pipe bushing and I formed the bushing into a velocity stack shape. The 2 1/4" filter fits over the bushing.


Otherwise a Uni 1 1/2" filter fits over the carb mouth, but you might need an angled filter to fit it in with the rear shock and ignition coil. Or you can flip the coil bracket around and give yourself more room.

For the breather hose, I stuck a Uni 1/2" push in crankcase breather filter into it and zip tied it up. You do NOT want unfiltered air being sucked into your crankcase, especially since the vent is right next to the rear wheel.

http://www.amazon.com/Uni-Filter-UP-123 ... B000OO2Q2W

slotrod65 wrote:The ram air is a 40mm end to fit on the carb.

http://www.ebay.com/itm/Ramair-Air-Filt ... ee&vxp=mtr

I think I left the breather on... You need something there, even if it simply drains behind the wheel.

Is that a wet filter? Does it have to be kept oiled?