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Joined: May 20, 2016 16:26:12 GMT -5
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Post by blazejin on May 20, 2016 17:02:43 GMT -5
New here. I have a 50cc Beta that I upgraded to 100cc when I start it will idle and jump from low to middle rev. It gets from 0-30 rather fast. when I get up to 40mph it starts to cut out like a hiccup or bogging every 25 to 30 ft. hesitations. I have 9g rollers, stock carb with  jet, performance coil and racing cdi box to get rig of the rev limit thing . all else is stock. I have my intake valve set at .003 and exhaust at .004 I checked all vacuum lines, gas lines, intake boot, Changed gas filter, The gas is good not bad, no water in it carb air/fuel screw is at 2 1/2 turns, new plug. Not sure what to do next. I do have a performance Variator with 6g rollers and rear bell with 2000rpm torque spring on its way. This scooter thing is new to me, only been at it for 6 months and learn something new every day.. So please people teach me  What is wrong with this thing. |
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Post by JerryScript on May 20, 2016 18:54:43 GMT -5
You probably need a larger main jet. Before switching jets, try raising your carb's needle. If you raise it all the way and it still bogs, that most likely means you need to up-jet.
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New Rider
Currently Offline
Posts: 37
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Joined: May 20, 2016 16:26:12 GMT -5
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Post by blazejin on May 22, 2016 7:19:30 GMT -5
Ok I open up the carb. cause I found some jets I had put up. They are out of just old carbs I had. I put one in and it started the hiccup thing at 30 to 35 mph. so I put different jet and it started at 40 to 45 mph the jets I have are not numbered, there blank so I ordered a main jet set. the I had in it would start hiccup at 35 to 40 mph so I am thinking I need a  jet. when I find the right jet will I need to match it also with a idle jet as well? how will I know witch idle jet to match with? my idle is bad. It wanders all over the place, hard to start as well. I am thinking it may be my starter that is 50cc small and has not got the torque. I can kick it and it will crank right up. maybe the valves still need adjusting more. on the bbk what would be the best place to start on the adjustment, as of now my intake is 003 and ex is 004. |
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New Rider
Currently Offline
Posts: 37
Likes: 1
Joined: May 20, 2016 16:26:12 GMT -5
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Post by blazejin on May 22, 2016 7:19:50 GMT -5
Ok I open up the carb. cause I found some jets I had put up. They are out of just old carbs I had. I put one in and it started the hiccup thing at 30 to 35 mph. so I put different jet and it started at 40 to 45 mph the jets I have are not numbered, there blank so I ordered a main jet set. the I had in it would start hiccup at 35 to 40 mph so I am thinking I need a jet. when I find the right jet will I need to match it also with a idle jet as well? how will I know witch idle jet to match with? my idle is bad. It wanders all over the place, hard to start as well. I am thinking it may be my starter that is 50cc small and has not got the torque. I can kick it and it will crank right up. maybe the valves still need adjusting more. on the bbk what would be the best place to start on the adjustment, as of now my intake is 003 and ex is 004. |
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Post by JerryScript on May 22, 2016 13:41:47 GMT -5
That's perfect for the valves. Most BBK installations do not need a bigger idle jet, but a BBK with a non-restrictive air intake may need a larger idle jet. Check for leaks around all parts first by spraying carb cleaner on them while idling, if rpms change as a result of the spray, you have a leak. If you have to turn the a/f mixture screw out more than 3 turns to keep an idle, you probably need a larger idle jet.
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Post by rcq92130 on May 22, 2016 13:52:37 GMT -5
Wandering idle sounds like a vacuum leak. Hard to tune the carb until all vac leaks are corrected.
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Post by lain on May 22, 2016 16:47:34 GMT -5
It kind of sounds like you are doing guessing like with the carb jet, those you cannot guess with and the wrong guess can end up with you needing a new engine down the road. Speed has no indication of how the engine is doing, pull the plug and take a look when the engine has cooled. It sounds like you are running lean, also check your carb for dirt, in fact I just clean mine every single time I take mine off because hey it's off why not just clean it real quick instead of going back later lol... The tiniest almost unseeable piece of dirt is enough to throw everything off.
Also just curious, you did the BBK yourself? What brand is the kit? Did you follow the guide on how to install the kit to the dot and did not skip or substitute anything? Did you make sure to install your rings on the piston perfectly? Did you make sure to install NEW gaskets on well... everything? Old gaskets on a new BBK can cause SERIOUS leaks, I've actually put an engine into the ground messing around with one I had used old gaskets on, even home made gaskets made of household items like folders are better than using old gaskets, though they don't last a fraction of how long real gaskets will. Most kits actually come with bad quality gaskets though too, the lower priced kits are 100% sure to have bad quality gaskets... I buy the low priced kits and make my own gaskets using gasket material meant for crank cases for CARS, which have a lot more pressure, and the gaskets end up lasting forever in a scooter. The ONLY gasket a consumer is unable to make at home with a box cutter and some time, is the head gasket which is usually made of aluminum and shaped specifically to form a tight seal when it is broken in around the combustion chamber, never ever ever use paper gasket for this part or use any substitutes.
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jet, performance coil and racing cdi box to get rig of the rev limit thing . all else is stock. I have my intake valve set at .003 and exhaust at .004 I checked all vacuum lines, gas lines, intake boot, Changed gas filter, The gas is good not bad, no water in it carb air/fuel screw is at 2 1/2 turns, new plug. Not sure what to do next. I do have a performance Variator with 6g rollers and rear bell with 2000rpm torque spring on its way. This scooter thing is new to me, only been at it for 6 months and learn something new every day.. So please people teach me 
jet. when I find the right jet will I need to match it also with a idle jet as well? how will I know witch idle jet to match with? my idle is bad. It wanders all over the place, hard to start as well. I am thinking it may be my starter that is 50cc small and has not got the torque. I can kick it and it will crank right up. maybe the valves still need adjusting more. on the bbk what would be the best place to start on the adjustment, as of now my intake is 003 and ex is 004.
