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Post by Darthchile on Oct 2, 2006 15:55:07 GMT -5
Does anyone knows what is the most recommended carb for a GY6 150cc, regular street use.
I was thinking on the Mikuni TM24, flat slide. Since I guess that I can use the same intake, my scoot comes with a Mikuni BS24, exactly the same as Keihin or other brands that come in GY6s, 24mm.
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Post by sussexscooterhead on Oct 2, 2006 18:10:37 GMT -5
I don't know if you've read my posts in the Tips and Tricks section under the Cool Carb thread but I'm currently running the TM24 Mikuni.
I can not recommend it to anyone who isn't willing to be rejetting on a continual basis. The carb works well but seems to be very sensitive to weather conditions and in order to have it perform at it's best small tweaks are required often.
A lot depends on what other mods you have in mind for the future as well. At the moment all I have is the carb and air filter but am planning on a pipe, a cam, dial a jet, lighter weights and clutch spring and a few other goodies that will allow the TM to shine through a little better.
For someone looking for better performance and minimal upkeep I'm guessing the 30mm CV is the way to go.
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Post by 90GTVert on Oct 2, 2006 21:02:42 GMT -5
It depends on what you want. The Mikuni is probably a little more powerful, but also more fussy than the CV style carbs. The Keihin 30mm CV will fit the manifold and all of the fitment is virtually the same as stock. The 30mm CV is slightly shorter than the OEM Keihin or Walbro so the air box will most likely have to go (which is a good thing) and be replaced by a foam filter. Rejetting will probably be required on either carb, but you also gain an accellerator pump in the deal as well. Stan Does anyone knows what is the most recommended carb for a GY6 150cc, regular street use. I was thinking on the Mikuni TM24, flat slide. Since I guess that I can use the same intake, my scoot comes with a Mikuni BS24, exactly the same as Keihin or other brands that come in GY6s, 24mm. |
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Post by jackthefuzz on Oct 2, 2006 22:16:07 GMT -5
the keihin 30CVK gets my vote for a scooter. for a GY6 powered ATV I would do the Mikuni or OKO slide carb
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Post by Darthchile on Oct 3, 2006 16:59:28 GMT -5
Thanks Stan, well my airbox is gone! I'm using a UNI Foam Filter, on the original plastic "U" tube that was connected to the Airbox, with a little adaptor I built for the UNI filter. It works fine, after jetting the carb apropiately.
I ended up with a 125 main jet. Acceleration did improve, now I have to work on the gears and variator to add a couple more mph to my top.
But I'm in need of more power (I greedy!!!), so I ordered a big valve head, and as soon as I can install it I'm guessing this 24mm carb is not going to be enough.
The only thing I don't like about the TM carb is the choke, I do like that little electric buddy, but I read somewhere else that TM carbs are way more responsefull than CVs.
How would the accelerator pump help?
I was also thinking on a TM28, but it seems way too big for a 150cc to me. There are differences in the size between TMs and CV style right?
I mean, a TM24 is not the same size as the BS24 that comes in my scoot. the spigot is different, I haven't found the dimensions of the 30mm CV carb.
Eventhought the TM24 is a 24mm carb the spigot is 31mm and 33 for the TM28. My BS24 is quite small.
Also, the TM24 comes with a 130 main jet by default, that is too big for my scoot, well, I have to check how the head would affect my jetting still.
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Post by Admin on Oct 3, 2006 17:07:35 GMT -5
The CVK 30mm can be a beech to get it to fit but once in, it's a good carb. Get a performance exhaust on there too and you'll see 5-10 mph top end improvement. I'm not familiar with the other carb but if Stan says it's fussy.....it's fussy.
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Post by sussexscooterhead on Oct 3, 2006 17:43:00 GMT -5
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Post by sussexscooterhead on Oct 4, 2006 10:13:27 GMT -5
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Post by Darthchile on Oct 4, 2006 10:21:26 GMT -5
The TM33 seems like a hot option, but tgetting that 40mm spigot to fit is going to be a nightmare!
Do you think that fits in the 30mm intake?
And, what is the difference between having or not an acceleration pump.
Well, afterall 30mm vs 33mm is not a huge difference, is it?
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Post by sussexscooterhead on Oct 4, 2006 10:35:14 GMT -5
I'm no expert but I don't think the venturi on the 30mm CV carb is actually 30mm - I thought I read somewhere that it was closer to 26. If that's true, then it would be quite a jump to the 33mm Mikuni.
I think that the larger bore has the potential to hurt performance most in the bottom end range but I think the accelerator pump might compensate for this.
A properly set-up accelerator pump will give you pretty much instantaneous throttle response. It squirts fuel directly into the venturi as you open the throttle so there is no waiting for fuel to be sucked through the jet passages.
As for fitting a larger carb to the intake manifold, I'm pretty sure a 40mm spigot would not fit in the rubber that comes with the aluminum intake but autoparts stores sell radiator hoses with various inlet and outlet sizes and I don't doubt you could find one to suit your needs. This is what I used to attach my air filter to the carb.
I would love for you to try the TM33 on your scoot but I really have no idea if it would work or not. Definitley talk to someone with more experience first.
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Post by Jacine on Oct 4, 2006 10:41:30 GMT -5
Depending on the make, a 30 Keihin is 30mm at the venturi. There is a 26 mm Keihin that is being substituted in some of the V3 and V5s, probably because of a shortage of the 30s. There has been a big push for Keihin Carbs since they are popular on the racing circuit. It seems that 4 mm does make a big difference of about 10mph if the engine can handle it.
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Post by sussexscooterhead on Oct 4, 2006 10:47:09 GMT -5
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Post by sussexscooterhead on Oct 4, 2006 11:09:40 GMT -5
Just to confirm I wasn't imagining things: "The CV series carburetors equivalent size is smaller than the venturi area . A 30 mm CV carb probably has the same venturi size as a 26 mm round slide mikuni." Taken from: www3.telus.net/dougsimpson/CVcarb.html....in the paragraph beside the Horsepower to Carb Size chart. Unfortunately, he doesn't go on to explain the comment. A worthwhile read, though. |
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Post by Darthchile on Oct 4, 2006 11:21:38 GMT -5
Found it cheaper at Amazon, less shipping. But thanks! If I getting working I'll let you guys know. |
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Post by daddyeby on Oct 6, 2006 8:13:06 GMT -5
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Post by daddyeby on Oct 6, 2006 8:14:17 GMT -5
Ops see you already had looked at it and posted teach me to just scan the page.
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Post by daddyeby on Oct 6, 2006 8:16:04 GMT -5
All I can say id the cv carbs adjust themself to a piont so are less picky on weather and other factors that effect the mix so I can see how it would be nice to stay with one.
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Post by Darthchile on Oct 6, 2006 13:28:08 GMT -5
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Post by sussexscooterhead on Oct 8, 2006 6:54:09 GMT -5
As far as price goes you'd be hard pressed to find better than that! OKO carbs have a good reputation as a less expensive alternative to Keihin. I think that seller is the one Pdaddy gets his parts from and is on my 'favorite sellers' list for Ebay.
My personal, uneducated feeling is that a 30mm carb without an accelerator pump or something to help with low RPM throttle response is too big.
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Post by Darthchile on Oct 8, 2006 21:56:11 GMT -5
You are correct sussexscooterhead, I get parts from that guy too. Very good price, I'm just not shure if the low price will compensate the lack of the pump.
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Post by Darthchile on Oct 25, 2006 16:44:16 GMT -5
OK, I just got a Mikuni TM28 off ebay for $25!!!
I test it and let you guys know. Thanks for all the help.
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Post by homernukem on Mar 15, 2012 21:03:27 GMT -5
so howd it go?
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Post by dubvortex on Mar 15, 2012 23:58:07 GMT -5
lol, 6 years later...
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Post by beachbum on Mar 16, 2012 0:03:11 GMT -5
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Post by pizzot on Mar 16, 2012 1:04:44 GMT -5
Haha, awesome. Time Capsule Forum
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Post by hollipl on Mar 19, 2012 10:18:06 GMT -5
I guess it didn't work lol  |
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Post by hollipl on Mar 19, 2012 10:20:06 GMT -5
Darthchile hasn't logged in since 2007, there's probably a chance his scooter isn't even working any more. But were never going to find out what happened to that poor scooter that got experimented on  |
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