Reversing the carb?

[oldchopperguy]

OK Rebs & Rebettes...

While my scoot runs great with a UNI-sock air-filter (and absolutely NO other air-cleaner setup) I'm tired of the "catback" frame member tearing up the filter. The filter tends to crack on the bottom where you can't see it, and let in raw air. I'm about ready to try reversing the intake manifold and carb, making the carb face forward.

Has anybody out there done that on a scooter with stock plastic body panels? I see it often on Ruckus types and "naked" customs, but have not seen it done on a full-body type. Obviously, the body must be cut away to allow the carb to protrude, but I'm wondering about the actual frame members getting in the way... Also, wondering about the linkages, etc. You can see in my avatar that my scoot is the typical Chinese generic type... A Xingyue Eagle 150... Just like Tank, Sunl and others.

Just checking to see if any riders out in Reb Land have done this conversion, and can pass on any tips. I always like to get advice before making any changes if possible. Even if you've done this conversion on a scoot wih no body panels, I'd appreciate any suggestions that might be pertinent... Particularly about frame-member clearance with the carb facing forward.

The stock carb placement, combined with the interfering catback frame member to me, are THE number-one BAD design flaw in these scooters. That combination of frustrating features totally prevents mounting ANY air-filter except the "sock" directly to the carb mouth.

Seems like having the carb face forward would be a MAJOR improvement, allowing unlimited experimentation with different filters mounted directly to the carburetor-mouth. I can live with the carb poking out of the body easier than living with the MISERABLE stock setup that prevents mounting any standard filter directly to the carb.

Many thanks in advance!

Leo in Texas

[Rebel]

I really don't think it will give you a problem Leo. The only thing in the way should be plastic body panels.

Flip it around before you cut anything and see how it fits.

[jmkjr72]

2 strokers do it so i dont see why you cant do it

normally we have to make new engine mounts for a rear facing intake

you may have to trim your rear under body and make sure you have some sort of fender to make sure the wheel doesnt throw water up to the carb if its wet out

[oldchopperguy]

Feb 11, 2013 3:21:25 GMT -5 Rebel said:

I really don't think it will give you a problem Leo. The only thing in the way should be plastic body panels.

Flip it around before you cut anything and see how it fits.

That's sorta what I figured, but always best to see if anyone else has done it... Since the manifold angles the carb a little, it looks like it's POSSIBLE that the carb might hit the left frame member under the seat. I did some research on GY-6 intake mods, and notice that some riders actually make up all sorts of extensions between the manifold and the carb. These range from just an inch or so, to LONG "U-turn" doodads that reverse the carb and place it light-years away from the manifold... Hmmm...

With all these VASTLY differing setups, all being successfully street-driven, I imagne that should any non-plastic parts get in the way, I could make up a short curved extension to angle the carb a few degrees "cock-eyed" as needed. Looks like so long as the float-bowl is level, these will run OK with the carb anywhere in the same county as the engine...

When I get a chance, I'll see about it.

In the mean time, I finally installed the Prodigy variator! Can't yet report as to the performance as the engine peters out right at the "sweet-spot" around 7,000 rpm. This is due either to my using a different air filter since the UNI broke, OR, because the rollers are too heavy. I have a new UNI sock filter coming. Should be here before the weather warms up again... LOL! That will tell whether my problem is the rollers, or the carb.

My one-and-only test ride before the weather got cold was encouraging! Better acceleration than the stock variator, AND just "loafing along" at 45 mph at only 4,500 rpm. Unfortunately, WOT running only produced the same top speed as before (52 mph) but at 6,800 rpm, NOT the 9,000 rpm with the stock variator. Doggone that stupid air filter!

If the little 150 with a proven air-filter setup will run through her sweet-spot pulling the current rollers, I'm looking at a nice 60+ mph top speed at maybe 8,500 rpm! THAT would make me a happy camper! (12, 13 and 14 gram rollers came with the variator, and I put in the 13 grams to start.) The running is SMOOTH, positive, and MUCH lower rpm at any given speed than with the stocker.

I'll update as soon as weather permits riding/tweaking.

Ride safe!

Leo in Texas

[Deleted]

HEY oldchopperguy

one of the very first post i ever read in response to my questions was from a guy whos 150 went crazy when he put a uni on it.

in a very long post he noted that some of his bikes took to them well and no matter how he moded it it worked well, but most bikes got cranky with them.

He swore it was the lainth of the tube to the carb back air intake.

Another thing is a front faceing uni as you wish to accomplish, takes in cooler air in most apps, a warm intake helps vaporize gas, you can note this when your engine is warm but intake is not yet warmed in winter, and engine sputts till it warms.

Ii know one thing for sure, my engine loves dry air, watch what you do as to how rain may effect it.

[oldchopperguy]

Hey Terra Nuvo,

I know what you mean! I got my carb-jets to experiment with, FREE from the local Honda B&M dealership! NICE guys who don't trash Chinese scoots! They told me even the original Honda GY-6's sometimes acted like mine, and even HONDA couldn't figure out why... Their fix? Add a UNI-sock... LOL!

When it rains, I try to find a nice, dry bridge to hide under... Or, a local watering hole to wait out the "liquid sunshine". And if you go fast enough, that under-seat area barely gets wet anyway... HeHeHe...

I may just keep the old Mikuni where it is, and replace the UNI every season as it gets beat up from the frame. THAT would surely be the easiest fix... But, if it's not too hard, I'd like to try the reverse-carb conversion. Or buy a Kimco... Those "LIKE" 200's are pretty sweet. Look like a vintage Lambretta, VERY classy, and ride nice. They're actually only 160+ cc, NOT 200... They run strong though. Hauled my 235 lb butt to 64 mph in short order! But... 3-grand is still a little rich for this old geezer on Social Security. $20 for a UNI sock is MUCH more agreeable to my tight budget.

Ride safe, stay warm!

Leo

[Deleted]

YOURS -

Or buy a Kimco... Those "LIKE" 200's are pretty sweet. Look like a vintage Lambretta, VERY classy, and ride nice. They're actually only 160+ cc, NOT 200... They run strong though. Hauled my 235 lb butt to 64 mph in short order! But... 3-grand is still a little rich


I THOUGHT I READ HERE KYMCO IS SUNSETIING ITS SCOOTS.

SYM has a program where they test a local mechanic and let him carry out your warranty work.

and this time of year you can still find syms and kyms cheap.

I will not do a china bike again, I got a lemon motor this past purchase and have sworn them off.

Nice thing about syms is you pick the mechanic, as mechanics very like night and day.

[oldchopperguy]

Hmmm... INTERESTING!

I really can't begin to afford a different scooter any time soon. I just got a "Jones" to see what's out there. I'm a sucker for the old-school rides, and the Kimco Italian-style is sorta nice! And fairly fast. Moxie Scooters (the store near me) has a great many-year rep., and says these Kimco scoots rarely give trouble.

Right now however, I'm forced to stay with my Chinese ride. For the most part, it's not been bad. Just the usual never-ending little things...

We'll see if I can get it "better"... LOL!

Leo