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lost top speed


Discussion at Motorized Bicycle Engine Kit Forum in the Motorized Bicycle General Discussion forum. Hi I have lost top speed ever since I have got a new carby. It very strong and takes off ...
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Old 10-04-2008, 12:48 AM
4wdingman's Avatar
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Default lost top speed

Hi
I have lost top speed ever since I have got a new carby. It very strong and takes off great but it seems like it doesn't hit top speed. Once it hits top speed it feels like the clutch is on. The clutch is not covering the air hole and the trottle does not cover it too.
So can you thing of a reason why it has lost top speed???
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Old 10-04-2008, 01:20 AM
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Default Re: lost top speed

Quote:
Originally Posted by 4wdingman View Post
Hi
I have lost top speed ever since I have got a new carby. It very strong and takes off great but it seems like it doesn't hit top speed. Once it hits top speed it feels like the clutch is on. The clutch is not covering the air hole and the trottle does not cover it too.
So can you thing of a reason why it has lost top speed???
Check to see if the screen in the Tank petcock valve is dirty.


cheers

Bob
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Old 10-04-2008, 02:09 AM
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Default Re: lost top speed

If your float level is too low it could cause this. When you stop your using less gas so you would have enough to start out good, but you could be,in affect running out of gas at higher rpms.
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Old 10-04-2008, 05:54 AM
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Default Re: lost top speed

Check your plug first....see what color it is. Shouldn't be white or light grey. Should be tan to chocolate brown or a slightly oily black. If you are running too lean it will seem weak and get hot quick, too rich and it will have a good pull, but when you hit cruise or WOT it could "4 cycle".

Now, what do you mean "The clutch is not covering the air hole and the throttle does not cover it too."?
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Old 10-04-2008, 08:45 PM
4wdingman's Avatar
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Default Re: lost top speed

sorry i meant the choke any way i will check my plug and check the float
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Old 10-04-2008, 09:28 PM
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Default Re: lost top speed

Hi
My mb has great start too (clean sounding engine)
But when sustaining mid rpms kind of 4cycles
And when flooring it pulls slow
Mb has a 'vibration' speed limiter...
Plug is dark brown
Should I lean the mixture?
Thanks in advance
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Old 10-04-2008, 11:00 PM
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Default Re: lost top speed

Jose, Check your carb for torque against the manifold. They come loose and make an air leak sometimes. No we need more info like mix ratio, plug type, ect.
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Old 10-04-2008, 11:16 PM
velardejose's Avatar
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Default Re: lost top speed

Hi
I sealed the carb-intake tube joint with grey silicon
Mix is 30:1
Plug is ngk b6hs
Needle clip is in the second notch from top
Tire press is 40 psi (jk)
Thanks in advance
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Old 10-05-2008, 07:10 PM
4wdingman's Avatar
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Default Re: lost top speed

thanks everyone
I switched the jet and the float leveler from my old carby to my new one and it works great i can get top speed...


thanks everyone
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