212cc mini chopper

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Tacuff1414

New Member
#1
#1
Hey guys.

I have just about completed my mini chopper build. I put a new 6.5 predator motor on it and took the bulky stuff off of it.
I put a simple air filter cone on the carb, and am using the harley gas tank as the actual gas tank. I also welded my own
exhaust pipe on. It sounds and runs great...when I can get it started. I'm not sure why it is so hard to start most of the time.

I also put a larger jet and 140 emulsion tube and it does run a lot better when it runs with it.

It may be flooding? I have the choke on and the gas feed on, and still nothing. It acts like it wants to crank but doesn't.

Could it be sucking too much air? Not getting enough gas? I'm not sure what all to do or check...
 

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Norcalputput

Norcalputput

Member
#2
#2
Does the motor spin over when you say won't crank my mind says motor is bound if I had to take a stab in the dark you prob bent the float in the fuel bowl shut the fuel off drain the bowl and adjust the float then let us know what you found/did to fix the problem


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Tacuff1414

New Member
#4
#4
Norcalputput said:
Does the motor spin over when you say won't crank my mind says motor is bound if I had to take a stab in the dark you prob bent the float in the fuel bowl shut the fuel off drain the bowl and adjust the float then let us know what you found/did to fix the problem


Sent from my iPhone using Mores code
Click to expand...
I just drained the bowl and everything looks normal to me...I took some more pictures to see if you guys can see anything unormal or
that could be the problem.

I'm sure it would crank every time if I had not put a filter and exhaust on there...but I'm sure there's something easy that will make it
crank and run good.

I ordered the 38 jet and 140 emulsion tube from OldMiniBikes and put that on, and right away I could tell it was running better. But for some
reason now I can hardly get it to start.

If I pull the cord a lot to try to start it, does that make it flood? I also try turning the choke on and off after a few pulls and still nothing...
 

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Tacuff1414

New Member
#7
#7
I just cleaned them out and it still doesn't want to crank.

I did just now find that the cap that goes onto the spark plug is broken. The pressure from the seat must have cracked it.

The spark plug still looks fine and I can still plug the cap on it, but it easily wiggles when capped on the spark plug. Is this
most likely the problem? If the plastic is cracked and broken on the part that plugs onto the spark plug, is there a fix?

I've added a couple of pictures to show what I mean.
 

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trinik7597

trinik7597

Active Member
#8
#8
are you getting fuel into the bowl ? try turning the fuel on the tank and carb on and taking the bowl drain off and see if you have a steady fuel flow . could be as simple as your needle valve stuck shut . the spark should still work ok that is just your insulator . not to be a jerk but your filter adapter looks a little jacked up what is with all the loctite if you got some of that in the carb that could be an issue to
 
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Tacuff1414

New Member
#9
#9
trinik7597 said:
are you getting fuel into the bowl ? try turning the fuel on the tank and carb on and taking the bowl drain off and see if you have a steady fuel flow . could be as simple as your needle valve stuck shut . the spark should still work ok that is just your insulator . not to be a jerk but your filter adapter looks a little jacked up what is with all the loctite if you got some of that in the carb that could be an issue to
Click to expand...
The filter adapter is just a bad weld job. I made my own gasket and cut it out and welded a piece of conduit pipe and then stuck the filter on the end. There isn't anything from that in the carb because I made sure it was clean on the inside before I put it on.

I know I have a steady fuel flow because I took the bowl off with the gas feed off and then turned it to on and it started freely flowing.

I think I've checked everything I know to check so not sure what else to do...probably take it to a local shop that deals with these things.
 
trinik7597

trinik7597

Active Member
#10
#10
you could try one more thing :thumbsup: you say you used a 38 jet .and the 140 e tube . when i opened mine up i used the stock e tube and a 39 jet and it runs perfect . i would take it all apart one more time put the stock e tube back in double check everything one more time and try again :thumbsup: most local shops wont even talk to you unless you know somebody when it comes to these things
 
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Tacuff1414

New Member
#12
#12
trinik7597 said:
one more question you put oil in the motor and made sure the kill switch is in the on position right :shrug:
Click to expand...
Yes the first thing I did when I bought it was put new oil in it and made sure when trying to crank it I had the kill switch on "on".

When I put the choke on, it seems like it wants to try to start better, but barely. For some reason I think something is going on with
the spark plug since the insulator broke. It's like it isn't connected good now or something. Maybe I'm wrong and it's something else but I'm not sure what else it could be if it's definitely getting gas to the carb.
 
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Tacuff1414

New Member
#14
#14
I hate to switch out the 140 e tube since it ran so good right after I put it on...I wouldn't think something like that would all of a sudden keep it from starting. Since these engines usually run pretty good right out of the box, maybe something is going on with the stuff I changed on it...either the air filter or exhaust pipe I welded on. Possibly getting too much air sucking in for the amount of gas flow that causes it not to start.
 
trinik7597

trinik7597

Active Member
#15
#15
the whole purpose of changing the etube and jet is to allow more fuel flow when you open up the air and add a header very basic upgrades should not cause problems like you are having . even with out a larger jet when opened up it should still start and run choked . did you say you welded on a header ? not to the head .
 
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Tacuff1414

New Member
#16
#16
trinik7597 said:
the whole purpose of changing the etube and jet is to allow more fuel flow when you open up the air and add a header very basic upgrades should not cause problems like you are having . even with out a larger jet when opened up it should still start and run choked . did you say you welded on a header ? not to the head .
Click to expand...
The short exhaust pipe (black) that curves up, I cut off almost all the way down to the mount and cut and bent a piece of conduit and welded it as the exhaust pipe to the mount. I did the same thing for the air filter over the carb...cut a piece of conduit a couple of inches long and put a cone filter on the end of it. I sealed up the small cracks around the gasket as best I could.

Is there any way I can check to see if it happens to be the spark plug or the insulator that is the problem?

Does it hurt the motor to keep on and on pulling the cord and trying to crank it so many times in a row?
 
minibikin'

minibikin'

Sho-nuff
#17
#17
Ok, clock that recoil back 1/3 so you can straddle the bike while you start it. Second, replace that broken spark plug insulator. It could be jumping and grounding to the head. Once you do that, report back. If the insulator doesn't fix the starting problem we can go from there. Did this engine run well stock? It may also have a vacuum leak at the carb but we can address that once you fix the other things.


Sent from my Texas Instruments Speak and Spell...[emoji2]
 
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Tacuff1414

New Member
#18
#18
minibikin' said:
Ok, clock that recoil back 1/3 so you can straddle the bike while you start it. Second, replace that broken spark plug insulator. It could be jumping and grounding to the head. Once you do that, report back. If the insulator doesn't fix the starting problem we can go from there. Did this engine run well stock? It may also have a vacuum leak at the carb but we can address that once you fix the other things.

Sent from my Texas Instruments Speak and Spell...[emoji2]
Click to expand...
Explain that first part...in order for me to start it, I have to be standing on the front side of the bike facing the back of it (pulling the cord towards the front of the bike).

The engine ran great stock. Do I need to get the exact same insulator that came with it or would any one from a local shop work?
 
minibikin'

minibikin'

Sho-nuff
#19
#19
If you take the three bolts out of the pull start, you can rotate it counter clockwise 1 bolt hole. That will allow you to stand over the seat, hold the throttle and pull the rope.


Sent from my Texas Instruments Speak and Spell...[emoji2]
 
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Tacuff1414

New Member
#20
#20
minibikin' said:
If you take the three bolts out of the pull start, you can rotate it counter clockwise 1 bolt hole. That will allow you to stand over the seat, hold the throttle and pull the rope.


Sent from my Texas Instruments Speak and Spell...[emoji2]
Click to expand...
Gotcha. That's what I'll do first and see what happens. Should I get the same insulator or is it fine to get any kind?
 
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