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Post by lain on Feb 13, 2015 18:49:43 GMT -5
Hey guys. So after installing the new BBK, after a few days of running around in well below freezing temps I have been noticing some very slight bogging on takeoffs from stops. It like hiccups as I apply throttle from idle/stop. Not sure what to look for, I am thinking I may be able to tune the carb to fix it?
Is this a rich or lean condition? Or is it irrelevant? It may also be a tiny grain of sand in the carb somewhere, I plan to clean it out next week if I cannot tune it to fix it.
Haven't pulled the spark plug yet, haven't checked valve clearances (started at 0.005 on both, hoping it hasn't tightened up too much, only been a few days).
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Post by rcq92130 on Feb 13, 2015 18:56:09 GMT -5
Alley has a very good tutorial on how to tune your carb. What you describe is a classic tuning symptom, so before you pull a new carb apart I'd suggest you get your idle mixture set properly and your main jet sized properly.
And --- CONGRATS ON YOUR NEW BBK BEAST!
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Post by geh3333 on Feb 13, 2015 21:16:16 GMT -5
Tuning the carb is usually very simple. The first thing I do is start the smcoot , I usually turn the idle screw up so that the scoot is idling slightly above recommended idle " so somewhere around 1900-2000 rpms" . next I'll turn the air fuel screw to the right until the rpms start to drop off , then I turn the air fuel screw back to the left until the rpms reach their highest point , finally turn the idle screw back down to recomended idle " around 1700 rpms ". do not turn the idle screw up to high before you begin adjusting the air fuel screw , you do not want the scoot taking off on you. At this point you can test for jetting issues and go from there. This is assuming you have no carb issues like vacuum leaks. I've been using this method ever since I bought my scoot.
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Post by alleyoop on Feb 13, 2015 22:06:32 GMT -5
Alley has a very good tutorial on how to tune your carb. What you describe is a classic tuning symptom, so before you pull a new carb apart I'd suggest you get your idle mixture set properly and your main jet sized properly. And --- CONGRATS ON YOUR NEW BBK BEAST! Here is the Step by Step tutorial on how to tune your carb that RCQ92130 is talking about. Even Shop owners have copied it to be used in their shop when working on scoots. Alleyoop itistheride.boards.net/thread/12/4ts-carb-tuning |
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Post by geh3333 on Feb 13, 2015 22:12:08 GMT -5
Alley has a very good tutorial on how to tune your carb. What you describe is a classic tuning symptom, so before you pull a new carb apart I'd suggest you get your idle mixture set properly and your main jet sized properly. And --- CONGRATS ON YOUR NEW BBK BEAST! Here is the Step by Step tutorial on how to tune your carb that RCQ92130 is talking about. Even Shop owners have copied it to be used in their shop when working on scoots. Alleyoop itistheride.boards.net/thread/12/4ts-carb-tuningBasically the same just more to read. Which could be helpful for someone who wants to have a full lesson on how everything works. Your main goal is to hit the highest rpm possible with the air fuel adjustment.if it turns out u need to rejet u will repeat the process. |
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Post by alleyoop on Feb 13, 2015 22:25:46 GMT -5
Have to disagree with your simplified tuning. It is a step by step and what the results should be and if not what to do to correct the situation. You should read it and take some pointers your never to old to learn you know.
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New Rider
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Posts: 24 
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Post by spudsmckinsey on Feb 13, 2015 22:32:57 GMT -5
Lain, I also recently installed the 100cc (50mm, actually 83cc) BBK Did you do other engine mods? Big Valve Head, A9 cam, exhaust ?) I didn't do ANY other mods. I got better launch and hill climbing, but ZERO top end increase. I tried to scan through your posts for the info but gave up after about 5 minutes. My BBK came with a jet and I installed it but it wasn't marked so I have no idea what size it is. Some say it is a #  (standard supplied with 02Starriders kits) IIRC, I didn't get any hesitation like you did. But I did go to a #  main jet. My biggest problem was that the air box proved to be inadequate to supply air for the bigger piston. I also think the "100cc" BBK may desperately need the big valve head. Not sure yet. Just a theory I'm woikin on. |
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Post by geh3333 on Feb 13, 2015 23:18:05 GMT -5
Have to disagree with your simplified tuning. It is a step by step and what the results should be and if not what to do to correct the situation. You should read it and take some pointers your never to old to learn you know. Like I said , mine is for tuning , yours covers more in depth if someone needs to learn the ins and outs , and problems that you may have. U can use mine if you have a carb that is 100% sound no problems such as leaks etc. Since I'm 100% carb inclined I have no need for to take a class on carb tunning. Thanks anyway |
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Post by rcq92130 on Feb 13, 2015 23:38:51 GMT -5
Is the number of "likes" and "bones" a person has related to the value others place in the Comments they leave here?
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Post by alleyoop on Feb 13, 2015 23:49:29 GMT -5
Have to disagree with your simplified tuning. It is a step by step and what the results should be and if not what to do to correct the situation. You should read it and take some pointers your never to old to learn you know. Like I said , mine is for tuning , yours covers more in depth if someone needs to learn the ins and outs , and problems that you may have. U can use mine if you have a carb that is 100% sound no problems such as leaks etc. Since I'm 100% carb inclined I have no need for to take a class on carb tunning. Thanks anyway You ought to give it a rest bud, your jealously is really showing. Alleyoop |
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Post by geh3333 on Feb 13, 2015 23:51:24 GMT -5
I meant nothing by it , sorry if you took it to heart. Being jealous is not in my nature . I don't see anything I could ever be jealous of . I actually think I gave u props in both my posts above for how well and in depth your write up is .
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Post by alleyoop on Feb 14, 2015 0:00:02 GMT -5
I am really a very street smart guy been around the block more than I care to think about. So I will tell you this and chew on it ok, "I may have been born late but not yesterday". Your not as clever as you think you are..LOL But do me a favor before I do you a favor:  |
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Post by geh3333 on Feb 14, 2015 0:04:31 GMT -5
I am really a very street smart guy been around the block more than I care to think about. So I will tell you this and chew on it ok, "I may have been born late but not yesterday". Your not as clever as you think you are..LOL But do me a favor before I do you a favor: He needs a pair of 1911's instead . I like the pic |
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Post by lain on Feb 14, 2015 1:04:21 GMT -5
Lain, I also recently installed the 100cc (50mm, actually 83cc) BBK Did you do other engine mods? Big Valve Head, A9 cam, exhaust ?) I didn't do ANY other mods. I got better launch and hill climbing, but ZERO top end increase. I tried to scan through your posts for the info but gave up after about 5 minutes. My BBK came with a jet and I installed it but it wasn't marked so I have no idea what size it is. Some say it is a # (standard supplied with 02Starriders kits) IIRC, I didn't get any hesitation like you did. But I did go to a # main jet. My biggest problem was that the air box proved to be inadequate to supply air for the bigger piston. I also think the "100cc" BBK may desperately need the big valve head. Not sure yet. Just a theory I'm woikin on. I have a bunch of jets, but found the # to be best for me so far, but I will be experimenting after the blizzard. I've done a lot with my scoot, but even before I installed the BBK I had a higher top speed and pickup than most 50cc stock scoots. The top speed is even higher with the BBK, by I think 30%. Before I installed the BBK I had already installed a performance variator with slider weights which helped a lot with reaching top power faster. I then installed 1.5K RPM clutch pad and torque springs which really helped me with taking off faster and climbing hills. I had also installed a Kevlar drive belt, a decision I made after trying to figure out why I was going through belts at the time I had a delivery job on the scoot and was going through belts each month. After installing the kevlar belts hills gave me a lot less resistance if I had some speed already, though starting from a stop going uphill was always horrible on 50cc. There are many very steep hills in Boston so this was a big plus for me. I stopped breaking belts even when I found my bendix at the time was rubbing the belt as it was running, but those belts are bullet proof! lol I then installed the cone type air filter, you know the ones that look sort of like coffee filters? It didn't really make much of a difference in performance on 50cc, but changed the sound of the scoot. I am guessing it is good with the BBK, but I haven't used my air box in forever. I messed around with slightly lighter and slightly heavier weights, giving me different results being faster pickup or higher top end speeds. Ultimately I moved onto the BBK to get the higher torque to be able to quickly speed up to avoid crazy Boston drivers, and so I could coast at 30-40 instead of redlining to ride there constantly. I get top speed of around 60, and can get to about 30 in 1 second if I really need to from a stop. This is the kit I got: www.ebay.com/itm/100cc-Big-Bore-Performance-Kit-GY6-50cc-139QMB-Chinese-Scooter-Parts-50mm-Bore-/161018154007?pt=Other_Vehicle_Parts&hash=item257d6e0c17&vxp=mtrI used everything from it except the oil pump and gear for it. Mine works, why replace it? lol The only different KEY COMPONENT I used as in this kit it came with thin metal head gaskets, I ended up ordering a thick head gasket because starting up the BBK was really hard with super high compression. the thicker gasket lowers the compression a little bit to allow easier starts. Might also have something to do with my different performance? But we also have different scooters we started with, even though the engine may be the same there may be small seemingly irrelevant differences that may change things so very slightly but in a tiny engine like this even a very slight difference can mean the world. That ebay seller starrider02 is a very good seller. They have great customer service, if you need help they have good advice too. A couple times when I messed up they sent me small replacement parts like piston rings and gaskets for free! The parts they have are good quality too as far as I've seen. I have bought a great starter motor that has little issues pushing the 100cc kit over from them, the BBK kit, twice but only because I messed up the first time, a great KeiHin carburetor, fuel filters, main jet packs, speedo drive gear, fuel pump, intake manifold, stator, stator removal tool, and some other stuff and everything I have bought from them has had no issues except for my own ignorance when I first installed the first BBK the first time a few months ago. |
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Post by JerryScript on Feb 14, 2015 3:12:05 GMT -5
After installing my 50mm BBK with a main, I also had a bit of bog taking off. For me, it was the needle clip needing to be raised. The other adjustment that may help is your accelerator pump, you may need to bend the "C" spring a little bit more to get a bit more pumped sooner. |
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..BAD TO THE BONE..
(standard supplied with 02Starriders kits)
main jet. My biggest problem was that the air box proved to be inadequate to supply air for the bigger piston. I also think the "100cc" BBK may desperately need the big valve head. Not sure yet. Just a theory I'm woikin on. 
