|
|
Post by whatheheck on Jan 21, 2008 20:05:54 GMT -5
Just had a bb installed by honda in seattle. 35-88 and idle mixture adjusted. They said it wasn't running well, I paid big $$$ and picked it up. Definately running very rich. I installed a lawnmower type airfilter. No change at all. Dan Durston advised opening the stock airbox. I check the threads, and the holes the guys cut are really big. I drill a single 5/8" hole adjacent to the airbox intake snorkel. Dramatically better performance. I enlarge the hole slightly, and it seems to run even better. Back at the honda shop, they all eyeball my mod, shaking there heads, they testride it. It runs great. They check the plug, perfect. the scooter pulls out fast and is smooth from top to bottom. My point is, does anyone else notice that the stock airbox, (the one we all think is ugly) appears to be designed to encourage a "venturi effect" Basically, when air moves rapidly (when we ride) across a hole, a vacuum is created. I know this sounds counter-intuitive, consider this. Honda didn't accidently create this effect. Perhaps I am wrong, but I suspect there is something to this. Maybe a vacuum effect at speed buffers turbulance. Maybe our engines benefit from "sucking" air in at high speeds as opposed to just being provided with air. I don't know the answer. What do you guys think of my theory?
|
|
|
|
Post by jedisabre7 on Jan 21, 2008 21:41:05 GMT -5
I can't believe you're running a stock air box with the BB. I haven't given much thought to your question, but I do appreciate you voicing your educated guess and am hoping to hear some good responses.
|
|
|
|
Post by whatheheck on Jan 21, 2008 22:11:22 GMT -5
2007 ruckus, 4000 mi. Honda installs Chanito big bore kit. Leave the slow jet alone. Put in 88 main jet. No needle mod. Adjust idle mixture. Install cheap filter. Drill hole in stock airbox (adjacient to airbox snorkel) Runs great. More power throughout. Better topspeed, 40 mph. Powers up hills. Smooth. I'm wondering about the stock airbox design, affecting my engine. Has anyone else tried bb with stock airbox?
|
|
|
|
Post by chanito on Jan 22, 2008 9:41:17 GMT -5
 Thanks on installing a Chanito product ;D ;D I agree the stock intake is a great set up, the air box is a great intake, and flows OK, it has been restricted with a small air intake in the bottom of the cover, but provided with a huge fresh air chamber (the area behind the filter before the intake duct) so under normal circumstances it still provide a lot of air for the huge stock carburetor, so as long as you keep the air velocity intact (do not mess with the exhaust) it should do great, derestricting it by enlarging the snorkel (air intake at the bottom of cover) allows a lot more air in. But you will need to change the main jet and adjust the idle mixture screw. In my opinion changing the slow jet is a waste of money unless you do major surgery to the head, but most people do it instead of messing with the idle mixture  The beginning of the duct have a bell shaped intake which works wonders to increase air flow by reducing turbulence, i did away with it in search of maximum flow at high speed, but probably should modify my homemade intake to adapt a velocity stack in the filter end, to have better response at mid range
|
|
|
|
Post by whatheheck on Jan 23, 2008 23:47:24 GMT -5
I"ve ordered a new airbox cover to experiment with. Only $16. I'm going to run some simple tests on it. I'm trying to discover how the pressure changes at different speeds. I'm thinking maybe the "angle of attack" might change the airbox dramatically. I will post an update if I get any results.
|
|
|
|
Post by whatheheck on Jan 24, 2008 22:13:36 GMT -5
Picked up my replacement airbox cover today. I temporarily sealed off the inside of the airbox, routed a length of clear tubing (where the filter would be) and checked to make sure all was sealed airtight (except for the intake). I taped the airbox to the side of my truck at the appropiate angle. I ran the tubing in through the window and made a loop. I put a small amount of coffee (easy to see in the tube) in the loop and marked the levels with tape. If there were pressure changes (in or out) I would be able to see it. The results: no noticeable changes in pressure from 0-30 mph. The one verifiable result I saw was a slight vacuum (air being sucked out) at 35 mph. Very small but consistent vacuum at full ruckus speed ( the coffee rose in the tube toward the airbox about 1/8 inch). I tried slightly different angles with the intake nozzel (relative to the "wind" we create while riding) no change. What this suggests? I don't know, but there you have it.
|
|
|
|
Post by I Heard A Rukus on Feb 4, 2008 17:09:30 GMT -5
I've never gotten a Ruckus (big bore or stock) to run right with a hacked up box. My suggestion is to either get an intake system, or jet it right.
In the big bores I've built I've seen good luck with a 35/78 and the stock 06 box, all the way to a 42/88 with an intake.
Just drilling holes in the box is good for a quick fix, but I don't condone it for the long run.
|
|
|
|
Post by Dandy Dan on Feb 7, 2008 17:03:16 GMT -5
35/78 does sound about right for an untouched airbox....I have had good luck tuning them with a modified stock box though. My friend Donny has been riding his for a year now at 43-45 mph (which is great for a 2005) with 35/88 jetting.....well it was doing great until it ran out of oil and seized  |
|
