2 year old Baja Mini Engine Problems

#1
My bike has sat all summer because the pull start was broken. Well I finally fixed it and when I went to crank it up, I cannot get it to start for the life of me. My friend was messing with it last year when all these issues happened and after he came back from a ride one day, the bike was going way faster than ever before and we had the chain fall off from jumping speed bumps. I'm not sure what he did to it, but I also remember the clutch engaging from being dirty. I have since cleaned the clutch and carb, but I still cannot get it to start. It will try and turn over, but then something just causes it to bog down. I have a link to a video of the noise it makes when I try and start it.

https://youtu.be/AEMAdcUDXJA

Any advice would be really appreciated.
 
#2
Hey doc...I would pull the spark plug out ,then connect it back to the spark plug wire...lay the plug on top of the head so it can ground it self...now pull the rope and see if the spark plug tip sparks. If it does put 8 or 10 drops of gas in the spark plug hole, screw the plug in finger tight and see if the engine tries to hit or pop.
 
#4
Looks and sounds like its yanking the pull rope back.that clunk at the end...maybe bad recoil lockingup engine or sheared flywheel key..... If squirting gas in or spark plug not work
 
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#5
Looks and sounds like its yanking the pull rope back.that clunk at the end...maybe bad recoil lockingup engine or sheared flywheel key..... If squirting gas in or spark plug not work
The clunk at the end is what I think is causing the problem. I'm not sure what it is though. How would I go about fixing the recoil or flywheel key??
 
#6
You have to take off recoil/pull rope piece and see if looks broken.look at flywheel to see if key is sheared and slipped out of position so that your timing is off making valves opening at wrong time..if it is not in the slot then you need to get a new key to line it back up IMG_20161009_085254.jpg
 
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#7
Thanks for the advice. I took the spark plug out this morning and replaced with a new one. I also dropped in some gas like you said and the engine fired right up, but it will stall out after starting up. Do I need to take the carb apart and clean it now? It did sit with gas in it for over a year.
 
#8
Hey doc...I would pull the spark plug out ,then connect it back to the spark plug wire...lay the plug on top of the head so it can ground it self...now pull the rope and see if the spark plug tip sparks. If it does put 8 or 10 drops of gas in the spark plug hole, screw the plug in finger tight and see if the engine tries to hit or pop.
I have cleaned the carb out with carb cleaner as best I could. Drained all of the old gas and dropped a few drops of gas under the spark plug. The bike is starting, revs super hard, and then dies out.

Do I need to put the chain back on for the engine to keep running??
 
#10
yeah..I bought a bike that sat and I took off the gas line ..was full of gunk from rubber breaking down....you will probably need a new line from tank and a carb...and clean the tank..
 
#11
Yea doc it sounds like you carb is junked up pretty bad..ethanol fuel.....its probably the low side jet thats stopped up. If you think you can take it apart and clean it good with spray carb cleaner that would probably fix it .. or you could buy a new carb off Ebay for like $15.00.
 
#13
yeah..I bought a bike that sat and I took off the gas line ..was full of gunk from rubber breaking down....you will probably need a new line from tank and a carb...and clean the tank..
I finally got it going this afternoon! I'm pretty sure it was because of bad gas. I also serviced the clutch by sanding down the gunk on the inside with a piece of sand paper and then oiling the bearing. The chain was really rusty too, so I gave it an oil bath and then tightened the slack by adjusting the motor mount.

Is it normal for the engine to die while idling? It seems to mainly happen when the engine is cold, but it also happens sometimes after coming off of full throttle, going top speed.
 
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#14
The bike I spoke about before with rubber breaking down on fuel line ..i cleaed carb..replaced fuel line..was able to run OK if you kept bliping the throttle constantly to keep running on ldle or coasting off throttle .. I rode with that 2 months..these carbs have no rebuild kits or seal kits..they are basically disposable..got 2 off eBay $17 and change each...what a difference..starts right away.. fast warm-up..good power..didn't have to adjust it just slaped it on...done
 
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