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Post by bluelightning on Jun 27, 2011 13:57:21 GMT -5
Can anyone tell me how many turns I need on the air/fuel ratio screw for a 150cc engine with a uni filter on it, running on 125 jets. This bike used to go about 60, but now it is only running around 45 and I cannot figure out the ratio for the life of me. If you think it may be something else, please let me know as well.
Thankyou in advance.
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Post by sprocket on Jun 27, 2011 14:17:14 GMT -5
Turn the air/fuel screw all the way in GENTLY and then turn it out 2-1/2. Then run the scooter for 5 minutes until it is warm and start to adjust the screw in 1/4 turns, wait for a 10 count and then listed to see if the idle is up or down... keep doing that until the idle is the fastest. Then adjust the throttle screw until the back wheel just starts to turn... then turn it back 1/4- 1/2 turn...
A 125 jet is WAY too big .. you want to be around a 110-112
You go up two jet sizes over stock for a foam filter
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Post by dyoung1167 on Jun 27, 2011 14:21:21 GMT -5
the fuel ratio screw is, for the most part just low speed, and you are getting way too much air, so you probably need a bigger jet to accommodate.
but to adjust it correctly, start by turning it all the way cw to stop (do not tighten), then ccw about 2 -2 1/2 turns. you need to have the bike at running temp. take it for a 5 min. ride or so. make sure it idles, if not adjust the idle screw until it does. then in 1/8th to 1/4 increments turn it ccw and wait a little (between increments) to see if there is any change. at some point your rpm's will increase to a point were it starts to drop again. when you notice it dropping turn cw back to the highest rpm. that is the correct setting, now readjust your idle screw so it idles at about 1500 rpm or so, or where ever you are comfy with it.
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Post by dyoung1167 on Jun 27, 2011 14:23:17 GMT -5
ha, musta been answering at the same time
can't say ireally know about the jets, but it sounded like when i tried to run it with the air filter cover off. started out ok, but didn't get sh!t after about 25 - 30 mph. ran like doodoo.
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Post by bluelightning on Jun 27, 2011 14:38:19 GMT -5
Thankyou both! I do have a quick question though, do I need to wait until I buy a the smaller jet before I even bother with it, or should I go ahead and try it with the 125 in there? I don't remember what the stock size was, but I am sure it was somewhere around 110, so I will try to pick up a 112 and see how well that works.
I will keep this thread updated
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Post by edfr on Jun 27, 2011 14:59:33 GMT -5
You can adjust it now your problem is more with the Main Jet, with the 120 your looseing a lot of power running to fat. If the Pilot Jet is around 2 1/2 turns out you do have the correct Pilot Jet in and that then only needs to be adjusted with Extreme temp changes.
HOT weather you need to Lean it out probably about 1/2 turn. COLD weather you need to Richen it up about the same 1/2 turn.
Lefty
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Post by sprocket on Jun 27, 2011 15:09:10 GMT -5
You can try dropping the throttle needle in the top of the carb. Move the C-clip to the butt end 1 notch. This will help to compensate for a too large main jet...
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Post by bluelightning on Jun 27, 2011 15:16:34 GMT -5
People elsewhere are still telling me to get 120 jets and stuff, but considering it was these same recommendations that put me in this situation i'm going to go out and pick up a 112 today if I can find a place that sells them.
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Post by sprocket on Jun 27, 2011 15:22:38 GMT -5
You can buy a set of jets for under $12. Get a range from a 108 to 118 or something...that way you can play around and see what works best for you...
People somewhere else ..why?... the best information is on this forum ;D
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Post by bluelightning on Jul 1, 2011 0:20:58 GMT -5
So, I went to the local motorcycle store and things went terribly. I told him I needed a 112 jet for a gy6 engine carb. The guy acted like I had just ruined his day, and gone on to me about how that was not enough information. Long story short, I'm going to have to order online for a set of jets.
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Post by Scoot-Hacker on Jul 1, 2011 16:02:02 GMT -5
You asked for a specific size main jet!
How is that not enough information??
He obviously knows nothing about carbs or 2 wheel transport.
Perfect managment material. lol
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Post by sprocket on Jul 1, 2011 16:34:17 GMT -5
Why are you stuck on a 125 jet? They probably work great on an engine with a 62mm BBK and a free flow exhaust.. but not in your situation...
A UNI filter requires no jet change on many engines OR you can go up 2 sizes if you go from a paper filter to a foam UNI...
You oil that filter? You better .. or you engine won't last 2000 miles...
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Post by bluelightning on Jul 4, 2011 17:41:42 GMT -5
Sorry, I meant to say 112 size, I edited my post. I sort of typed it in a rush, I was frustrated. I'm also sorry for the slow reply, as I was out of town spending 4th of July weekend with my girlfriend.
I still haven't gotten the jets though, it's been hard to find a place to get them.
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Post by sprocket on Jul 4, 2011 18:07:11 GMT -5
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Post by tour96se on Jul 4, 2011 21:24:09 GMT -5
i needed to run a 115 mj and dropped down one notch on the needle to get a decent a/f with just a uni filter. my stock was 105
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Post by bluelightning on Jul 5, 2011 11:04:31 GMT -5
Ordering the 112.5 air jet from the site. I can't remember if the stock was 108 or 110, but I'm sure it wont be as terrible as the one I have either way.
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Post by car6car on Jul 6, 2011 12:01:13 GMT -5
So, I went to the local motorcycle store and things went terribly. I told him I needed a 112 jet for a gy6 engine carb. The guy acted like I had just ruined his day, and gone on to me about how that was not enough information. Long story short, I'm going to have to order online for a set of jets. He expected: Mikuni model 123, main jet 110. Different model jets have different shapes. Do all 150 cc Chinese scooters use the same carbs? Same models motorcycles of different years can use carbs from different manufacturers |
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