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Post by godlesscommie on Feb 16, 2013 22:16:40 GMT -5
Hi there, This is my first post, and I promise I will post a proper intro thread as soon as I can. So, please bear with me for now. I have a Merlin. It's a GY6 based, 16" wheel scooter. I am in the process of installing a big bore kit, with the works. I did run into a clearance issue with the new 30mm carb. There is no way it will fit without fabbing a longer manifold. I'm pretty sure I will run into fueling problems with a homemade mani. So, I thought I could install the carb facing forward. Everything clears that way. But, now the carb sits at an angle. You guys are the most experienced bunch I have had the pleasure of reading on the internet. So, could you please give me some ideas about whether or not the carb will work the way I have mocked it up please? Thanks!   Also, I am thinking about using my wideband setup to tune the carb. Good idea, or waste of time? |
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Post by edfr on Feb 16, 2013 22:29:34 GMT -5
No that will not work to much of an angle draw a straight line horizontial line and look at where the fuel level will be in the bowl. You need a manifold with more curve on it like this one Also you need to support the carb by the air filter so it does not bounce up and down: www.dhgate.com/intake-manifold-for-125-150cc-gy6-engine/p-ff8080812cd082c8012cda6c71971df4.htmlOr you can cut that extension and have a nice curved one welded on which will be nice and straight using the bottom of that same manifold. Or you can decide whether to go out to clear the valve cover OR go up before making a curve and not as far out and able to get at valve cover for valve adjustments. Lefty |
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Post by wangchicken on Feb 16, 2013 23:14:53 GMT -5
you can buy an angle clocking flange from here ,http://www.composimo.com/gy6-parts/gy6-angled-clocking-flange.html or you can buy a hose like a radiator hose that has like a 45 degree bend and just cut the part you need, take a look at the intake i made for my scooter its here listed as project sunkist ,
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Post by wangchicken on Feb 16, 2013 23:16:02 GMT -5
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Post by medman1952 on Feb 16, 2013 23:37:45 GMT -5
Or you could consider a Fuel injection conversion.
And just in case everybody is wrong you could give what you have a try and then come back and tell us if it worked or not.
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Post by edfr on Feb 16, 2013 23:45:31 GMT -5
Here it is with the angled flange I still think that is to much of an angle. Lefty  |
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Post by tvnacman on Feb 16, 2013 23:56:43 GMT -5
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Post by godlesscommie on Feb 17, 2013 20:59:53 GMT -5
Thanks for the responses.
I guess I will be manifold hunting at the bike shops on Monday.
My goal is to end up with a manifold that is not too much longer than the stock one.
I may have to get a couple, cut and weld them to do that.
On another note, the idea of a forward facing carb does not sound like such a good idea anymore. I mean, the way the carb is mounted in stock form, it sits right at where the entire engine/suspension assembly pivots, and is therefore prone to less vibration. Moving the carb to the extreme end of that assembly may cause fuel foaming.
Also, I am seriously thinking about installing an O2 sensor bung on the exhaust on the scooter.
That way, I will be able to park it next to my car, install the car's wideband on the scooter, and tune the carb using the gauges in the car and the datalogging feature on my MSIII.
Do you guys think that would be a good idea, or a waste of time?
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Post by tvnacman on Feb 17, 2013 21:11:40 GMT -5
ya know the o2 sensor sends a small signal/voltage to the ecu . Based on the level of the signal the ecu adjusts the mixture . All that about connecting to the car , that might be a bit of a reach .
John
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Post by godlesscommie on Feb 17, 2013 21:20:48 GMT -5
ya know the o2 sensor sends a small signal/voltage to the ecu . Based on the level of the signal the ecu adjusts the mixture . All that about connecting to the car , that might be a bit of a reach . John I'm afraid I have not explained this clearly on this idea. I would only use my wideband for tuning the carb. I would install the wideband sensor on the scooter's exhaust, turn the key on in the car so the gauges will work, warm up the GY6 engine, and adjust the idle mixture on the scooter so that I will see 14.7 AFR on the car's gauge. Then, I would do a steady state check on 2500, 5000 and 7000 rpm levels, and look for appropriate AFR numbers such as 14.7@2500, high 13s in the 5000, and 12s in the 7000 rpm range. Finally, I would do acceleration tests to see enrichment. I mean, nothing reads exhaust gases better than a wideband, which produces a signal in the 0 to 5 Volt range. I already have a cool system running in my car, and the O2 sensor has a 2 meter lead on it. |
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Post by edfr on Feb 17, 2013 21:30:40 GMT -5
Hey give it a shot, if it doesn't pan out just plug up the sensor on the exhaust pipe no biggy.
The hardest will be to weld in the sensor in the pipe.
Lefty
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Post by godlesscommie on Feb 17, 2013 23:14:20 GMT -5
The hardest will be to weld in the sensor in the pipe. Lefty Naah, labor's cheap here.. Maybe 5 bucks to have it drilled and welded on. I have a couple spare bungs, anyway. |
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Post by edfr on Feb 17, 2013 23:23:05 GMT -5
Well then do it
Lefty
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Post by sharks06lly on Feb 18, 2013 9:44:24 GMT -5
if you are gonna go to all that trouble why not get a efi kit with a tunable ecm and call it a day. then you wont have to worry about clearance and it will be better off anyways
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Post by ericrockstar on Feb 18, 2013 12:09:51 GMT -5
I'm surprised everyone jumped straight to the efi conversion....NOT!
But seriously, why not just stick with the regular 24 mm carb and upset to like a 120or whatever it would need with the BBK? Whatever floats I guess.
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Post by godlesscommie on Feb 19, 2013 17:58:32 GMT -5
Well, I exchanged emails with martin at MBE and pulled the trigger on the EFI kit.
I guess this new fork on the road will be the beginning of a new saga. (How's that for dramatic exaggeration...)
Anyway.. The scoot will be running on the carb for a while - I don't want to mess with two things at once. Break-in is a serious procedure.
I will be running the scooter with with a frankenmanifold till then.
Pics to follow.
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Post by motts on Feb 19, 2013 21:58:55 GMT -5
Where do you buy the EFI kits? Will you post a link?
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Post by wangchicken on Feb 20, 2013 3:15:37 GMT -5
in that case welcome to the wonderful world of efi. motts read the post above your last one
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Post by wangchicken on Feb 20, 2013 3:20:01 GMT -5
tvnacman the angle clocking flanges are machined aluminum , the plastic you speak of is the "phenolic like"spacer its an insulator.
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Post by ltdhpp on Feb 21, 2013 12:54:26 GMT -5
The NCY blue teflon intake is much shorter and supposed to work where the chrome ones don't.
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