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Old 08-01-2013, 08:59 AM
FtKnoxJim FtKnoxJim is offline
Motorized Bicycle Newbie
Join Date: Aug 2013
Location: Brandenburg, KY
Posts: 1
Default New to the group

Just got by bike and the 66cc kit, put it all together last week, got running ok.

Noticed exhaust was full of oily black stuff so I placed carb pin from 2 slot to 1 slot. reduced the fowling but caused the bike to run too lean and I blew a hole through the top of the cylindar about the size of the quarter...


Any one else learn from the school of hard knocks?
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Old 08-01-2013, 09:02 AM
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xseler xseler is offline
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Join Date: Apr 2013
Location: OKC, OK
Posts: 2,425
Default Re: New to the group

Howdy & welcome!

The 16:1 break-in oil recommendation is too much oil in the fuel. A better alternative is a 24:1 or a 32:1 mix. Does just fine without all the issues.

Good luck on get'n your machine up and running again!
You're never lost until you run outa gas.
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Old 08-02-2013, 12:02 AM
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maniac57 maniac57 is offline
Old, Fat, and still faster than you
Join Date: Oct 2011
Location: memphis Tn
Posts: 4,486
Default Re: New to the group

Moving the needle should not cause a failure like that, no matter how far you move it.I'm guessing something else caused it to break.
I run 40:1 and don't have much gunk build-up in the exhaust.
If more is better, then too much is just enough.
If you can't afford it, build it yourself.
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Old 08-02-2013, 10:48 AM
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Huffydavidson Huffydavidson is offline
Join Date: Jan 2012
Location: st.louis,mo.
Posts: 1,078
Default Re: New to the group

welcome to the forum ,that's a shame I know the feeling my first kit blew up too.yeah all train your feelings should not cause catastrophic failure like that .hopefully you got a warranty send it back
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Old 08-03-2013, 10:16 AM
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2door 2door is offline
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Join Date: Sep 2008
Location: Littleton, Colorado
Posts: 16,219
Default Re: New to the group

Not quite sure what you mean by "blew a hole through the top of the cylinder".

Do you mean the piston? A hole in the cylinder could be a manufacturing flaw like a poor casting.
If the piston burned through that would be the result of a massive air leak or running the engine too long at WOT with no exhaust pipe/muffler. Carburetor clip position would not give you a lean condition sever enough to damage anything.

Oil content or fuel to oil ratio is important. As was stated, the kit recommended 16:1 is too much oil. The odd fact is that the more oil you use in the mix the leaner the fuel to air ratio becomes. Less oil alows more fuel so a 24 or 32:1 ratio actually enrichens the fuel to air mix.

Age and Treachery Will Always Triumph
Over Youth and Skill & "Charlie Don't Ride"
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Old 08-03-2013, 11:51 PM
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chainmaker chainmaker is offline
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Join Date: Jan 2010
Location: Ma USA
Posts: 2,597
Default Re: New to the group

Welcome to the forum Jim. I'm betting the failure had more to do with the motor being one of the ones that were doomed right out of the happens. Post a pic if it's the head you can most likely get a nice machined replacement that won't fail. I spent some time in your neck of the woods in the 80s at Ft. Knox besides the mud and clay it is beautiful.
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