These are some mods that started last fall up to 6-4-10
This is a modification I made several months ago because I was having so much trouble with my scoot I needed easy access to the engine to work on it. It is a simple repositioning of the airhose and zip ties on the airbox. I liked it so much I left it like that for a while after I got it running correctly.
Has anyone "Swiss-cheesed" their air box for better flow? Ive thought about a cone filter or the like, but Ive had good experience with Swiss-cheesing air boxes on cars before as well. Keeps it stock looking but give better flow (only slightly less then CAI) Thoughts?
Post by Scooter Doc on Apr 25, 2010 4:33:46 GMT -6
Very nice link as usual Alleyoop. These boxes are the ones commonly used on newer "racer" type models like the one shown. They sit under the front of the seat connected to the carburetor via a cumbersome hose that usually develops a kink in it. The inlet holes are underneath the box and not visible on these photos. If you drill more holes for air flow it will start to run lean and new upgrade jets would need to be installed to compensate, just like going to a Uni filter. Bashan reports that he hates these boxes and is replacing his with a Uni filter when he redoes this scooter in the near furure. Scooter Doc.
My wife has a scooter exactly like mine, except it still is in it's original form. I took a big zip tie and carefully tightened it around the kink in her air hose to open it up. I didn't tell her and the next time we went out she commented about how much faster it was. Also, the mixture was still good so I didn't have to reset the screw. So my theory is that with typical Sino-engineering, they designed it for that size air hose but didn't factor in the inevitable loss of air flow from the kink in the hose. Maybe all scoots with this design aren't like this, but both of my Bashans were exactly the same. I'm beginning to like the side airbox like what's on my Amore more and more. Rich
This is the next experiment I did with the hated airbox. I simply cut off the hose at the bend and clamped it to the carb. This actually did make a big improvement in performance, it accellerated much quicker and had a higher top end. I understandably had to tweak the A/F screw. The next step is to put on a Uni with rejet. Rich
I finally moved on from to the next phase of engine modification. First I took off the floorboards so I could get to everything easier, took off the cooling system, and installed a chrome intake manifold:
Unfortunately, the manifold proved too long to allow my carb to fit behind the engine mount, DARN! So I went back to the old and proceeded to install a 115 jet to replace the stock 103, a pretty big jump:
After getting the carb back on with the old intake I tried to put the new Uni on. It would NOT fit under the ,yes once again, engine mount. So I took a piece of the stock air hose and cut it down to just the U part without any of the flex rings left. I then used good 'ol black duct tape to attach the Uni to the hose:
Also during all of that I reset the valves which were way off, put in a new NGK plug gapped to .032", I took it out for a ride and it's going to need some adjustment on the needle clip and A/F screw.
Post by jake aka:ventoscoot on May 17, 2010 10:17:08 GMT -6
what solved my problem with that intake was a different hose instead of the rubber one that is not flexible. also a 28mm flatslide carb. the carb is shorter so it fits just barely.
2007 Vento Phantom GT5 150cc(160cc w/59mm kit) Iridium plug, MRP coil and CDI UNI Filter, Custom exhaust with O2 Sensor, 28mm FS carb LED forward assist lighting and ground effects, Tail Mods, removed stock air box and all CARB crap, new head with no EGR valve. And a bunch of other crap!! THE PUNISHER!
Ah, so I wasn't crazy! Thanks guys, I was beginning to think I was doing something wrong, but I tried that puppy every which away I could. I thought this could be used to go under and through the mount:
I finished the next phase of modification with the removal of the CVT cover, addition of a performance coil and CDI, and removed the kickstart mechanism:
It runs very strong with the 115 jet and UNI, I had to set the needle to the leanest setting. Next I plan on painting the cooling shrouds, variator, clutch, and rear fender red. I may try to go back to the chrome manifold at some point with some adaption and then I think I could set the needle richer or go to the 125 jet. But I think I'll just put some miles on it for now. Rich
Bashan my man, If its running strong and not Lean at WOT why are you jumping from a 115 to a 125? Since you already have the Needle set at the Leanest position you will not have any more compensation with the 125. It will probably be sluggish or bogging in the lower RPMS with the needle all leaned out already. If you think it could use a little more fuel put in a 120 or a 118. Alleyoop
I wasn't clear as susual AO, I tried the 125 and it was WAY too rich, I was saying I might try that again if I installed the bigger chrome manifold in the future. I bumped down to the 115 and it was OK at the middle needle notch but still didn't feel right. I put the needle out to it's leanest clip and it ran better in all aspects. I actually think one step lower on the jet would help but it would be a crap shoot...I'm close. What I don't understand is why they recommended I buy 115, 125, and 135 as a package. No way with the 125, and the 135, called "the guzzler", was absurd. I wasn't putting a friggin supercharger on so why sell me something like that? It was only 4 bucks a jet but I blew $25 on that chrome manfold which wouldn't fit without significant mods as Jake pointed out (I'm gonna get that other carb Jake even though I got this one to work, NO AUTOCHOKE!). These damn dealers should know what fits your bike, I talked to the guy in person, it wasn't an internet cart buy. Oh well, enough of my skreed. Rich
Today I finished painting the cooling shroud red and rewiring the bike. I moved the rectifier up under the seat and ran the stator wire directly to it. Here are some pics:
Rectifier on right seat frame, red cooling shroud and fender:
Rectifier moved before final assembly:
Next phase is painting the rear, side panels, variator, and clutch red. I've got some Frankenstein ideas for the carb too. When I paint the variator I might as well change the weights while I have it apart. Rich
Bashan, Quote "What I don't understand is why they recommended I buy 115, 125, and 135 as a package. No way with the 125, and the 135, called "the guzzler", was absurd. I wasn't putting a friggin supercharger on so why sell me something like that?"
Simple my man, most need 115-120 not to many will take 125 and up unless you have it modded engine wise. So they have a crap load of those laying around and cannot get rid of them. So they put them in a package 120 and up, knowing damn well the 120 might even be to big:) my .02 Alleyoop