Bike ran fine, now it barely runs. Help!

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leadfarmer

New Member
Sep 30, 2011
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VA
The facts:I have a Dax 66cc china doll. It is apx 200 miles old. I have been riding it all day. Earlier I gapped my spark plug to .030. The spark plug boot broke. I got an NGK boot. All is well. I ride bike a few more miles.

I run out of gas, I fill tank up with 32:1, up from 20:1.I am trying to tidy up my cables so I zip tie throttle front brake and clutch to handle bar. I kick start the bike it doesn't want to idle. Throttle cable doesn't like the zip tie, fine, I take it off. Bike still won't run right.
It is BACKFIRING(it has NEVER done that before) and will not run at low RPM's, if I peddle for half a block, it will run roughly and seems to run better at higher RPM's. HELP!
CDI? or 32:1 fuel problem? Help me Norm.
 

leadfarmer

New Member
Sep 30, 2011
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VA
I checked the carb to be sure it is seated on it's gasket. I tried moving the clip on the jet from 2nd position, to first, to third. Now motor no longer will start.
 

nightcruiser

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Mar 25, 2011
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I checked the carb to be sure it is seated on it's gasket. I tried moving the clip on the jet from 2nd position, to first, to third. Now motor no longer will start.
check that you havn't flooded it with all that fiddling. I would go back and check things that have changed since the motor used to run well, maybe you moved somthing or pulled something loose when you were strapping the cables down? Check your electric connections to the cdi, disconnect the kill switch temporarily until you have her running (they are reputed to be tempermental). Maybe your new wire/boot isn't connecting well? Maybe the new boot needs the spark plug cap to be installed (instead of the threaded connection)? Verify you have fuel flowing.... Just a few things that come to mind....
 

leadfarmer

New Member
Sep 30, 2011
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VA
I finally had time to mess with my engine again. My woodfruff key is fine, but I have no spark. I ordered an new magneto from Dax, hopefully that fixes it.
It sucks because the weather is nice here in Virginia right now, any day winter will set in. I wish I was riding my MB, instead of checking the mailbox.
 

nightcruiser

New Member
Mar 25, 2011
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USA
Reading back, it seems the last thing you did to your bike before it died was replace the spark plug boot. You reported it ran on the new boot a while then died. Are you SURE the boot isn't the source of your no spark problem?
 

2door

Moderator
Staff member
Sep 15, 2008
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Littleton, Colorado
Also check the spark plug wire connection at the CDI. You've moved or changed something. Go back and check your electrical connections. Get ride of the plug-in connectors that came with the kit. Solder those connections and protect with heat shrink tubing.
I suspect the high voltage lead (spark plug wire) either at the plug boot or the CDI. If you're not using a metallic core wire make sure the conductor is making good contact with the metal part in the boot and the CDI. Let us know what you discover.
The kit boot will not work on a standard plug unless you remove the top cap. Also an aftermarket boot will not work on the kit plug if the top cap has been removed.
Tom
 

dakota47l1

New Member
Oct 2, 2011
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st louis mo.
i just wanna add...pull off the float bowl and see if the jet hasn't worked its way loose...that happend to me and it ran as you described...but it sounds like you have no spark also?


.xx.
 

Bicycle Motor Fun

New Member
Sep 17, 2011
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Warren, Michigan
My new 66cc engine would not run at all until I set the spark plug gap to about 0.015 ~ 0.020"; then the engine fired right up. Since then, I replaced the spark plug boot/cap with one from a old lawnmower engine since the original one was falling apart. Try resetting the spark plug gap, I think that my (these) CDI spark systems are just to weak. BMF
 

leadfarmer

New Member
Sep 30, 2011
149
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VA
I got a new magneto, and it runs again!! Thanks for the replies, I learned even more about my China Doll.