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nothing like not having to clutch and shift after a hard day of work
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Post by scoottech1 on Jun 23, 2013 7:56:19 GMT -5
ok hear me out.... why are our carbs backwards? fuel has to fight its way forward and down against gravity and inertia. however, having your carb clocked 180 degrees (or reversed) it naturally flows into the intake and slides down easier due to the carb being at a slight upward angle. now it does take some tinkering with the float level, too much and you will overflow, not enough and it will run lean or not at all. its pretty easy to get right. ive done this twice now. seems at higher speeds i accelerate faster due to the fuel being pushed back into the intake.   |
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Post by jerseyboy on Jun 23, 2013 9:44:07 GMT -5
I thought something looked funny about your sig pic yesterday,,lol..your carb is still on the normal way you just used an opposite bend intake(or spun it 180) so the air cleaner is out the front,,looks like the bowl is at a pretty significant angle.It does catch your eye when you see it,,I thought you had a longer hose on the filter at first. I'm not sure how much this would help the fuel being sprayed into the engine,,but if you can keep the float full Im sure it wont hurt! Keep up the tinkering,, that's how new things are invented!! Tom BTW-Id get that little rubber grommet off the throttle cable if I where you,,mine got hung up last week and things almost got ugly  |
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Post by lykos23 on Jun 23, 2013 10:11:17 GMT -5
I accidentally put my carb gasket on backwards just once and I noticed a big difference in performance with just turning the gasket around. Unfortunately it was a huge drop in performance. I don't know if everyone's heads are like this, but on mine the carb gasket can only face one way or it blocks off a good quarter of the intake hole.
It's interesting that you got better performance...
Good luck with your inventions and mods!
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Post by jeepsteve92xj on Jun 23, 2013 10:17:06 GMT -5
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Post by oldchopperguy on Jun 23, 2013 21:14:39 GMT -5
Jepsteve92xj,
THANK YOU for testing out one of my pet theories!!!
I have one of those Chinese GY6 150's that ABSOLUTELY WILL NOT RUN RIGHT except with either a UNI "sock" filter, or, NO filter at all. Period. NOT even with a short piece of tubing on the carb mouth... End of story.
Since my scoot is the typical "full-body" crotch-rocket wannabe... LOL... It's not the easiest trick to get that carb facing forward. But... I'm convinced it is probably well-worth the effort! Now that there are "clocking manifolds" available, allowing the carb to be turned left and right, it should not be so difficult to get the carb facing forward. A little hacking, and, with the carb forward, any air-filter can then be experimented with.
A handful of Chinese scoots seem to run fine in "factory" trim, BUT... From my experience, as well as other posters, I believe the truly dismal factory air-intake, AND the undersized exhaust headers on these often combine to make them nearly "un-tunable".
Get a full-sized exhaust, and a short, free-breathing air cleaner on, THEN adjust the carb and roller weights and you may end up a ride that can now be tuned, not "guessed-at".
I think the reversed carb should be high on the list of mods to any scoot, not just the "nekkid" skelly customs! Why should the Ruckus Boyz have all the fun?...
The Chinese got the PRICE and general build right, but it's gonna take good old American hacking to get the PERFORMANCE and reliability right. Reversing the carb on "Lil' Bubba" will likely be my next mod... I'm tired of stuffing a UNI under the cat-back engine mount where it gets flexed and beaten, or, not being able to tune the engine with any extension to place the filter ANYWHERE else...
Thanks again!
Leo in Texas
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Post by jerseyboy on Jun 23, 2013 21:49:35 GMT -5
It would be pretty cool to have the UNI sticking out front between your legs,,Id cut a little hole in my cover for it to come through..good air flow there also  |
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Post by wilds on Jun 24, 2013 0:11:12 GMT -5
When tuning the intake and manifold we are trying to create a smooth line for the fuel mixture to get into the cylinder.
With the intake mounted in the "right direction" it would give "straight" line for the fuel mixture from the carburetor to the intake valve.
Mounting the intake the other way would give a sharp angle (almost a U-turn) for the fuel mixture, and that is not what we want...
Or am I totally off here?
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Post by jerseyboy on Jun 24, 2013 16:05:40 GMT -5
[replyingto=wilds]wilds[/replyingto]Depends if the intake port on the head is at a flat plane or not,,if it was then it wouldn't ,matter which way the mixture came in,,I never had an intake manifold off to see myself.
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Post by tinman7809 on Jul 3, 2013 3:12:29 GMT -5
The only thing other than the obvious angle issue is that 4 strokes run hot and that head being so close to to the bowl may cause the fuel to heat up or even boil. Colder the fuel=more HP. The higher temps in intake and fuel temps may reduce any gains from the more efficient flow into the engine.
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Post by jeepsteve92xj on Jul 3, 2013 6:51:09 GMT -5
In the normal carb position, there is a small rubber duct that direct air from the fan at the carb bowl.
With the carb out front, it would be more in the air already, but a bit of heat shielding would never hurt.
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Post by tinman7809 on Jul 3, 2013 13:12:30 GMT -5
If he is running his plastics,Shrouds the airflow Is minimal. If he is running it without I can see it being better but still with only 1/4" clearence I would try to add either a spacer or extend it away from the valve cover. itistheride.boards.net/index.cgi?board=cbs&action=display&thread=2668I simply used a 1.25@ piece of mild steel tubing .065 wall I think, to extend it away. Cut the end that goes into the intake at a 10 degree cut so I could angle it slightly down to keep carb level. All in all cost 10-15$ |
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Post by kingkaymo on Jul 7, 2013 14:58:09 GMT -5
fighting airflow? gravity??  im sorry but your theory is kinda flawed here, unless you are running a naked scoot with direct ram air pressure on your carb. that would make a small difference, but not much of one. your air charge is not fighting your forward momentum to get into the engine. air is everywhere, and while the engine is sucking it in, the air around it replaces it period, its not having to work against any force except restrictions in your air box and your filter. if you had a naked scoot with an airbox with its intake pointed backwards, then you could have a slight issue but doubtful you could even feel a difference, but with the stock airbox, or even a uni filter with stock plastics, you wont have much of an issue with the airflow going around you sucking your good oxygen away from your engine. let me ask you a question, when you turned it around did you lengthen the intake space between the carb and head any? |
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