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My 4 year old is bummed and I'm out of Ideas

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I can't get his KFX50 to run and we leave early tomorrow for a 4 day desert trip.  It was running like a champ a couple weeks ago when it up and died in the middle of him riding it.  

 

I know it has good spark

brand new spark plug

fresh clean gas

carb has been apart 3 times and cleaned and wire run through every jet and hole I can find.  Any other hole has been sprayed out with cleaner.  

gas getting to the float bowl and into the cylinder.

 

This damn thing is so close to starting, you can hear it really want to but still nothing. I'm baffled.

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I can't get his KFX50 to run and we leave early tomorrow for a 4 day desert trip.  It was running like a champ a couple weeks ago when it up and died in the middle of him riding it.  

 

I know it has good spark

brand new spark plug

fresh clean gas

carb has been apart 3 times and cleaned and wire run through every jet and hole I can find.  Any other hole has been sprayed out with cleaner.  

gas getting to the float bowl and into the cylinder.

 

This damn thing is so close to starting, you can hear it really want to but still nothing. I'm baffled.

 

 

I had a buddy who had a Polaris 50cc quad and wouldnt run, everything was in order. It ended up being a tight exhast valve, typical of new, the valves wear into the seats. This is why they like you to come in for your first check over after buying new. Anyway, I would get a pop from time to time through the carb. I adjustedit, done, rips now. It was a Honda XR/CRF50 motor in this Polaris. Probably a chinese clone, but exact engine. Check it out. Simple to do> I suspect you have the round access caps for valve clearance. Bet its too tight on the exhaust.

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Not sure what the problem may be, but I would take it on the trip in case you have time to fiddle with it.

 

Or heck, who knows, it may start on the first kick when you get there.

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Have you checked that it is getting spark? Being a two stroke it really comes down to spark, fuel, and air.

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It is auto clutch.

Great spark on a new plug. Air filter is off for the moment.

It is baffling me because it has been running great for over a year. Then it just sputtered out while he was riding.

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Compression check time. Is it possible that the oil injection portion was in fact out of oil?

The oil tank is full. Guess it is possible the line or somewhere in the injector is clogged.

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Stop by a shop and pick him up a shiny new 

crf50stock.jpg

You'll be #1 Dad for the rest of your life. Oh, it doesn't have to be "Red".  

 

Plus, the ladies will love him when he grows up with his huge sack instead of a vagaga.... from riding a Keyyyywad.  :lol:  :lol:  :lol:  :lol:  :lol:  :lol:  :lol:  :lol:

Edited by MXOldtimer
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Just tested compression. 60psi is way low. Top end time I guess.

Bummer little guy will have to share in his big brothers pw50.

Thanks guys.

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Oil injection is too quetionable for me! My boss blew up his Evinrude outboard due to a faulty oil injection system and bad warning buzzer. On my little brother's old PW80 my dad ended up leaving the tank empty and mixing the fuel and oil the traditional way.

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Dump the fuel in your current gas can. Drain the fuel tank (and clean it out) and clean out the carb, refill with new, fresh fuel Your symptoms are typical of water in the system. If you like, drain the fuel tank into a glass jar, see the water on the bottom.

 

Nothing wrong with oil injection unless the owner 'thinks they know better' and screw it up.

 

You can probably pull the jug, clean the ring lands and get the machine to run fine again. It is not a race engine and those little 2S are very accomodating to a little cleaning.

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Dump the fuel in your current gas can. Drain the fuel tank (and clean it out) and clean out the carb, refill with new, fresh fuel Your symptoms are typical of water in the system. If you like, drain the fuel tank into a glass jar, see the water on the bottom.

 

Nothing wrong with oil injection unless the owner 'thinks they know better' and screw it up.

 

You can probably pull the jug, clean the ring lands and get the machine to run fine again. It is not a race engine and those little 2S are very accomodating to a little cleaning.

 

Thats what I originally thought and did drain everything, fresh gas straight from the station with the same results.  If I have time tonight after packing everything else I'll pull the jug and see if it can be cleaned up.

 

Thanks again everyone.

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does it actually have spark ? i.e. if you pull the spark plug and hold it next to the motor touching the outside of the plug, will it fire when you kick it over ? these things are pretty bullet proof. anyway, if it doesn't have spark, check the wiring, especially the kill switch and circuit. if it has spark, will it fire up if you spray a little  wd40 in the plug hole, and put the plug back in ? if it does, but then dies, it's probably fuel delivery, i.e. the carb has some dirt or water in it, or one of jets/circuits is gummed up. oh, is the petcock on ? I have had buddies call me to check out their non-starting bike, and they forgot that they shut off the petcock...

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