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Post by oldchopperguy on Feb 12, 2013 2:38:08 GMT -6
Has anyone reversed the intake manifold/carburetor on a GY-6 150 to make it face forward? I see it done on Ruckus and "naked" customs, but I'd like to do it on my Xingyue Eagle 150 (same type as most similar Chinese like Tank, Sunl, etc.).
Obviously, the plastic below the seat must be cut to allow the carb/air-filter to protrude, but I'd like advice from anyone who's done it, concerning frame-tubing clearance, linkages, etc.
I always like to get advice from someone who's done it before doing it myself... LOL!
Many thanks,
Leo in Texas
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Post by alleyoop on Feb 12, 2013 14:14:06 GMT -6
Just curious as to WHY you would want to do that and go through all the trouble and work just to have it faceing forward.
Alleyoop
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Post by oldchopperguy on Feb 12, 2013 22:21:02 GMT -6
Just curious as to WHY you would want to do that and go through all the trouble and work just to have it faceing forward. Alleyoop My particular scoot will NOT run right with ANY extension between the carb and an air-filter. Trust me, I've spent literally WEEKS experimenting. It won't even run right with a short extension on the carb with NO air filter. It runs perfectly with no filter at all, or a UNI "sock" filter mounted directly on the carb-mouth. The "cat-back" engine-mount behind the carb won't allow anyting to be "properly" attached to the carb, not even a piece of tubing. The UNI sock WILL go on the carb, but it rubs hard on the cat-back mount. This causes it to wear fast, and it tends to crack on the underside where you don't notice it. This allows unfiltered air in, and is just a pain in general. Here's a picture of the UNI... You can see it fits (sorta) but must flex constantly as the engine-mount depresses it while riding.  With the carb reversed, it will protrude through the under-seat plastic, and ANY type of filter can then be mounted directly to the carb mouth. THAT'S the reason... Just sick and tired of that doggone cat-back engine-mount interfering with the only air filter that seems to work.I see the reverse-carb often on open-frame customs, and I can REALLY see why they do it... If the scoot suffers from the same drivability problems as mine, it would be a MAJOR improvement in carburetion/filtration. Like I say: I can live with the appearance of the carb sticking out beneath the seat easier than I can live with the never-ending interference of that dang engine-mount blocking all efforts to use a filter that works... LOL! Well, maybe NOT so L... HeHeHe... I think the carb WILL fit OK "backwards", and I've even found a "clocking" carb-plate that allows the intake manifold to be rotated 40 degrees left and right! NEAT item. My only real concern now is the float, since the carb will be "tilted" upward compared to stock position. Still, I see them all the time, with the carb aiming slightly "up". Must be workable. My drivability problems are echoed by numerous other riders. Scooter runs great up to about 3/4 throttle, and suddenly around 45 mph it just "peters out" like it's starving. You can re-jet and tweak until you want to send the thing back to China... But nothing really solves the problem... UNTIL you run it with NO air-filter at all (definitely NOT recommended...) or, mount the sock-filter with NO extension between it and the carb. And THAT runs fine, but conflicts with the engine mount. Yup... Front-facing carb fixes everything but the appearance! And they look fine on a bare-bones scoot. I'm not sure about how it will look on mine... But I can live with it.Ride safe! Leo in Texas |
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Post by alleyoop on Feb 12, 2013 23:56:22 GMT -6
Well from what you say that it runs fine with no filter or a really free flow that points to one thing your running awfully rich. So as soon as you add a tube or whatever your making it even worse richer still. What jets have you got in the carb right now?
Alleyoop
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Post by oldchopperguy on Feb 13, 2013 10:55:21 GMT -6
Well from what you say that it runs fine with no filter or a really free flow that points to one thing your running awfully rich. So as soon as you add a tube or whatever your making it even worse richer still. What jets have you got in the carb right now? Alleyoop Alleyoop, That's exactly what I thought too, but I spent an entire spring and summer experimenting to no avail. I've been running now for 4 years with the same jet, and I honestly can't remember what finally worked best. I think it's about a 112. The low-speed jet has never been a problem. I progressively tried every jet from the leanest to "slobbering-rich" and all would run "OK" with no air-filter. The very leanest would starve a little at WOT and the richest would bog just slightly, but ALL would totally peter out as soon as I'd add any kind of extension on the carb. Putting a standard, OR Uni filter on the extension made no difference. The shortest extension that passes under the engine mount is about 4". Just THAT little extension kills the performance even with no air-filter. Remove the extension and the engine runs anywhere from "decent" to downright great with ANY old jet... My plug shows a "perfect" rich/lean condition with the current jet, and the engine runs strong so long as there's nothing on the carb but a Uni. In desperation, first year, I even replaced the stock carb with a new Mikuni. It DID respond SLIGHTLY better to tuning, but only slightly. The engine simply will NOT run WOT with ANYTHING on the carb-mouth. I can't explain it, but I'm not the only one with the same problem. There is SOME glitch in the intake/valve/head design that absolutely defies runnung with a "normal" air-filter system. The original long, curved rubber "tuba" air intake, with paper filter under the seat was the WORST! The scoot would only go to 35 mph before the power would die. It would take an expert in flow-dynamics and lots of research to determine just why some of these scooters do this, but so long as it can be cured with a simple sock filter I'll live with it... LOL! The forward-facing carb has to be the simplest answer... There MUST be a reason it shows up on so many hot-rod scoots. I have a new UNI sock coming. I know it will run fine, so I'm OK for at least a full season with the carb in the stock position, but I'd really like to see about reversing it when I have some free time. That pretty well sums it up. It's not running rich, although it feels like it. I've tried every common jet size and ONLY removing any extension on the carb allows WOT running. Some aspects of Chinese scooters simply defy logic... LOLOL! Ride safe, and stay warm! Leo |
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Post by alleyoop on Feb 13, 2013 15:10:16 GMT -6
Well here is the thing if it's a 24mm carb they usually come with a 103-105 main jet and a #35 Pilot jet. If you just add a free flow filter then you should only go up 1-2 sizes on the main jet.
So if that is all you did and you slapped in a 112 that is why it runs rich with anything on it.
It is air and fuel amount that is the problem, no filter lots of air and right now with the 112 it matchs the amount of fuel that is being sucked out. Add anything to it and now it runs rich as heck because now you took away some air flow.
If you put in a 107-110 you would be able to put on a tube to get it away from the frame mount
Alleyoop
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Post by oldchopperguy on Feb 14, 2013 14:10:03 GMT -6
Well here is the thing if it's a 24mm carb they usually come with a 103-105 main jet and a #35 Pilot jet. If you just add a free flow filter then you should only go up 1-2 sizes on the main jet. So if that is all you did and you slapped in a 112 that is why it runs rich with anything on it. It is air and fuel amount that is the problem, no filter lots of air and right now with the 112 it matchs the amount of fuel that is being sucked out. Add anything to it and now it runs rich as heck because now you took away some air flow. Trust me, I've tried it all. Tested every main jet from a 97 to a 120, with and without the extension on the carb. Same problem regardless of jet size.I've also gone over the entire intake to be sure no air leaks or other problems. I could be wrong about the current jet size (it's been in there for 4 years) and these days I have trouble remembering to eat breakfast... LOL! At any rate, it's somewhere between a 102 and a 112. I found ALL those jets to run well with no signs of too-rich or too-lean, and whichever is in there now is the one that ran best overall. There's just somethng unexplainable about SOME of these GY-6's. Mine isn't unusual. They either run OK with an extension or they don't. Should be explainable, but it's beyond my capability... I got my jets from a local Honda dealer (he GAVE 'em to me to experiment with!). He told me even the original Honda GY-6's sometimes acted like this, and his service people couldn't cure it, except with a UNI-sock... LOL! My Wife's scooter-loving doctor says "Get a Vespa, like his pretty red one"... RIGHT... $7,000. If I could afford a Vespa, I'd have a better car too. Besides, I don't like 10 and 11-inch wheels all that well... The local B&M dealer says: "Get a Kimco"... Better... $3,000. Rode one. They're NICE. But I say: "Get a UNI..." $20... It's worked great for 4 years! I'd just like it "up front" and free from interference from the motor-mount... LOL! Probably I'd be happier just leaving the old Mikuni in its current home, and replacing the sock every year or two. I'm lazy, but still open to a fix so long as it doesn't take rocket-science. I'll keep you posted as to what happens. Ride safe! Leo |
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Post by medman1952 on Feb 16, 2013 0:20:39 GMT -6
Yeah, Leo has posted about this and what he has done on my forum, he has bee running it with the uni filter for a few years it seems.
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Post by oldchopperguy on Feb 17, 2013 23:07:27 GMT -6
Yeah, Leo has posted about this and what he has done on my forum, he has bee running it with the uni filter for a few years it seems. It's been nearly 5 great riding seasons with "Lil' Bubba" just SCREAMING from idle-to-9,500+ rpm WOT! All the time, breathing that dusty 100-degree Texas air... With the UNI-sock, it runs just like it does with no filter at all: In other words, GREAT! It's such an EASY fix for such a FRUSTRATING problem... I'd just like the doggone thing "up-front" where I can get at it without interference. Gotta have all the top-end power I can get with the new Prodigy variator. If the engine will run up through the "sweet-spot" like it used to, I'm expecting a nice increase in top-speed, at lower rpm. Stay warm, ride safe! Leo |
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Post by alleyoop on Feb 17, 2013 23:35:26 GMT -6
Have fun and ride safe..LOL
Alleyoop
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Post by oldchopperguy on Feb 18, 2013 23:45:09 GMT -6
Have fun and ride safe..LOL Alleyoop Thanks Alleyoop! Will do. And as soon as I get the new variator sorted out, I'll do a post. Stay warm! Leo |
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..BAD TO THE BONE..
