Cold Air Intake? By gmon (Read 8,045 times)

[gmon]

Hi all,
I fitted my Chinese 50cc scooter with a homemade cold air intake (ram air?). I wanted to get your guys opinion. Basically I drilled a large hole behind the front tire in to the plastic shield. Then a ran a pipe from the front opening directly to the air box. I noticed a change of the engine sound in mid speed range. For now I will run the scooter like this, but when my new larger carb jets arrive, I will up-jet and remove the air box completely.  

[Bashan]

Welcome to the forum. Alley has been using a different pic service that seems to work nice...here is his tutorial:

HERE IS HOW TO POST PICTURES USING THIS HOST. IT IS EASY AND FREE:

1. Click on this link:
tinypic.com/index.php

2. Click on Browse, that will link to your computer.
3. Find what you want to load.
3. Click on the name of the picture
4. Click on OPEN
5. Click on UPLOAD
6. Click on the LINK that starts with IMG.
7. RIGHT CLICK and CLICK on COPY
8. THEN Come here to your THREAD ON DOC.
9. RIGHT CLICK and CLICK ON PASTE.
Alleyoop 

You know how to get your pix in a folder on your computer right? Rich 

[gmon]

Thank You Rich, it is working now.
My homemade intake looks like this:


Installed for testing:


To the air box. I don't know what the small hose going from the air-box to somewhere is for. For now I will keep it

[jvino]

That's rocking cool mod man. I like it that's pretty creative. Does it run any difrent?

[gmon]

It does sound different in the mid range. I finished it yesterday and I didn't have time to fully test it. I will make a video soon

[beebo]

www.hotrod.com/techarticles/engine/hrdp_9907_ram_tuning_guide/viewall.html
en.wikipedia.org/wiki/Velocity_stack

Links to some interesting reads that might help you with your intake tuning.

I like what you've done' especially the clear tubing. Looks like it will be easy to re-route to the carb when you pull the air box. You need a free-flowing exhaust, too, to make it all work right! Good Luck!

[Bashan]

Yeah, that's very clever....nice. The small hose is probably your crankcase breather.

[jct842]

It is likely you will kill your engine with that intake. I have a majesty and in some ways the factory did the same. You need a good air cleaner for one thing. Where you have said the air comes from "behind the front wheel means as the wheel goes over dust dirt etc. it will kick up the dirt right into your air intake.

I had to do a top end overhaul, bore and piston/rings in my 400cc majesty. Yamaha has a factory defect in that it too gets its air from what the front wheel kicks up. The previous owner neglected the expensive filters probably because of the price. When the 2007 was new the 3 filters it required cost around $92 at a dealer and the plug up quickly if ridden in a dusty area. I did the overhaul myself and at a dealer it would have run about $1000.

Do what ever you want but you have been warned.

[gmon]

Thank you guys!
So the crankcase breather hose I can just leave it hanging without plugging it when I get rid of the air box?
jct842 I am not worried of debris going up my intake. I put a fine metal window screen at the tip. When I get rid of my air box, I will also put a cut out of vent filters on at least few of the joints. My first set up of the intake was with two vent filters on two of the joints, but I took them out since I am still running it through the air box. The hole for the intake is not directly behind the tire, but more to the left.
I have been riding my scooter for almost a week since this mode and so far no debris in the intake pipe or the air box filter. I get 3 mph more top speed and now down hill accelerates a lot faster into red line. Yesterday I did 9800 rpm couple of times for several seconds with no problem(down hill). I have stock cdi and everything else is stock, except iridium spark plug. I ordered performance cdi and ignition cable and larger jets. Will see then...
Intake opening behind to the right:

The filter I will be using between the joints:

[Bashan]

You will need to elevate the crankcase breather end ABOVE the point of attachment to the engine. Otherwise it will spew oil all over what is below the end of it. Also put a filter on it like an old gas filter to keep crud out. The vacuum on it is a pollution thing to pull vapors off of the engine. As far as protecting the engine or helping performance, the attachment to the intake does nothing. Rich

[gmon]

The package of the filters I'm going to use. I think with 2 of this on 2 of the upper joints and I will be golden. The stock foam filter is not better filter in my opinion. I don't want to over do it with filters on more than 2 joints, because it may reduce air flow and that is the reason I am doing it. I am hopping for ram air effect at top speed and maybe create a 1 psi pressure? Currently according to my speedometer down hill I go with 53 mph. Before intake max was 50 mph.

[gmon]

Thank You Rich, good to know

[jvino]

Gmon that is pretty creative object you got going for you with your air filter. Is that filter right behind the mess you put in the ram air system you created? I was thinking it might get a little dusty in there also from behind the front wheel but your air filter should catch it. Is your air filter getting dirtier faster than stock. It sounds like you've got some great results.

I wish my 125 was faster also I rode with a guy this week who just bought a roteka scooter for 45 dollars. It was real sluggish on the start but once it got rolling on the flat it would do 35 40 mph. I was surprised. But when it comes to the hills it's very sluggish 15 20 mph holding up traffic. Small scooters are slow in my opionion and hold cars and trucks up but who knows could save some ones life.

Gmon I think your mod rocks and have fun riding and be safe.

[gmon]

Thanks jvino. Right now I don't have installed any of the vent filters because I still run through the air box(foam filter). When I go directly to the carburetor, I will install the filters between the two white plastic joints(last photo from the 3rd post), because is almost vertical there and hopefully will prevent clogging. There will be no other filters except the mesh. I am almost ready to go. This afternoon I cleaned my carb for first time and i fitted larger jets - #85 and #38. I watched a video on youtube on how to do it. I also replaced the cdi and coil cable with "racing".
Anyone knows what are those two hoses for? They are hanging from the carburetor and are not connected to anything. The short one is making my carb dirty on the outside

[Deleted]

May 28, 2014 19:47:23 GMT -6 gmon said:

Thanks jvino. Right now I don't have installed any of the vent filters because I still run through the air box(foam filter). When I go directly to the carburetor, I will install the filters between the two white plastic joints(last photo from the 3rd post), because is almost vertical there and hopefully will prevent clogging. There will be no other filters except the mesh. I am almost ready to go. This afternoon I cleaned my carb for first time and i fitted larger jets - #85 and #38. I watched a video on youtube on how to do it. I also replaced the cdi and coil cable with "racing".
Anyone knows what are those two hoses for? They are hanging from the carburetor and are not connected to anything. The short one is making my carb dirty on the outside

those are a bowl vent and a bowl drain. supposed to be disconnected.

as for the vent filters being your only ones, they are made to trap household dust. they wont handle the sand, grit and who knows what else that comes from the road. things will get past it. at least make a small airbox out of tupperware and rout your intake to it and put a uni filter in the box on the carb or something.