Crf50 Won't Start , Won't Run?

[unit_mx]

Bought a crf50 last week , Haven't really had a chance to start it let alone ride it really. The guy I bought it off started the bike when I picked it up and I started it and went for a lap around the yard when I got home. Today I started it and started 2nd kick but wouldnt warm up , I didnt like it when I wacked the choke off. Obviously to lean with the choke off. Anyway I let it warm up for a bit and it went ok , very boggy in first without the choke. put it on its stand let it cool off and then went to start it again. It started but cut out with the choke on after about 10 seconds , so started it again kept the choke on and just had the throttle turned a wee bit to increase revs , took the choke off and gave it a few revs. Sounded ok but once returned to idle it would begin to cut out so gave it a few more revs. Then it wouldnt rev and simply just cut out and die.
So I pulled the carby off , noticing the rubber spacer/washer/flange between the carby and the manifold was upside down from the previous owner. I pulled the carb off and took it apart and cleaned it , cleaned out all the jets , needle , bowl , manifold and bottom manifold insulator. un screwed the centre bit of the mainjet , pulled out the pilot jet and ran a bit of copper wire through them.
Stuck it all back together again in the right order. No problems. Cleaned the ****** mesh gauze kitaco air filter in fuel as I didnt look like it had been washed for some time. Bolted it all back on. Stated it. Exact same thing , still cutting out with the choke on after about 10 seconds and killing itself after a few revs with the choke off.
Pulled the plug off to find it extremely black and covered in carbon. Couldn't see why the bike ran better with the choke on but the plug was black = too rich. I cleaned the plug , still the same problem.
I then changed the plug as I had a spare plug of the same laying around ( NGK CR7HSA) and still the same problem.
I pulled the plug out again to see if it had spark. No worries had plenty of spark. Tried my stock rev box , still the same problem
So I left it for a while....

Now the problem is the friggin bike wont even start , nothing. Doesn't even sound like it wants to start , still plenty of compression. But nothing.
It still has spark. So I tried playing with the idle screw but that didnt do ****. Tried the different rev box again , nothing. Pulled my broken killswitch off - nothing. Tried with the filter and filter off. Nothing. Checked for any leaks in the carb and manifold there wasnt any.

The only sound of a leak is comming from the spark plug , cant rember if this is normal or not. but the plug is wound in correctly , not sure about the clearance but never has been an issue.

So would anyone know whats going on here. I've checked the wiring loom out , every thing seems to be in the right spot and connected besides the killswitch connections , which I disconnected.

The bike seems to be spitting out fuel through the air intake.

So in brief:

Problem: Bike didnt run correctly - Died with choke on after 10 sec's , died with choke off when rev'ed a few times. Carbon'ed up plug very quickly. Took carb off cleaned it out , started it and still the same. Tried different rev boxes - still same. Checked spark still has spark. Killswitch has been removed. Left bike for about 10 mins then it wont start at all , still got spark but doesnt seem to be firing the slightest just an umph from the compression.

Checked: spark (YES) , Loom connections ( Seem to be right) , Different rev boxes , Needle positions , idle , checked key ignition , fuel , jets arnt blocked. Cleaned filter.

Also if anyone could please tell me where the little wire needle slot thing ( Not the needle E-clip but the wire the needle sits in) where does this go? The previous owner had the wire slot with the needle beneath it like the clip stayed on the top of the needle above the e-clip rather than the needle slotting through the wire clip and stopping where the e-clip on the needle is.

My carb is a Keihin PE-20mm , the clip position is in the middle. Not sure about the jet size. I tried both a trailbikes rev box and the stock unit.


Some one please help me !!!!!!! Otherwise I'll have to get the shop to have a look at it which will rape my wallet again.

 

[corey58]

we find when there fuel coming out the airfilter it tends to be the flot lever is wrong you could try that...

also u could have water in the fuel(get that all the time)
a easy way to check that is get a clean container and unscrew the bleed bolt on the carby bowl. you will be able to see any water in the fuel because they dont mix...... dosent sound like that because u already clean it but no harm doin it to see takes 2 sec.


also u said u got spark and if the fuel good you could check the valve clearance

 

[Sidney]

check the ground. It is above the engine connected to the frame, it's in a different spot to chinese pitbikes. Mine didnt start once because i forgot to screw the bolt on tight enough. It joins to the top of the airbox.

 

[coolmodee01]

should have kept the mso he lou

oough well we all make mistakes

the carboned up plug tells me she was running way to rich so mixture would be my first bet

probably do valves as jap bike riders become pretty complacent with the service because of the i ride a jap bike aditude

shoulda kept the mso he he he

 

[themountain]

I am with coolmodee...check the valves first...if its a orig. Honda its 0.05mm otherwise 0.08mmm...change the cdi too and check all wires!!

 

[Cactus Jack]

Definitely sounds like lack of valve clearance ...... the inlet valve isn't seating or is bent so reversion pulses are going backwards thru the carb ......... Whenever you get weird problems with a 4 stroke ..... CHECK the valve clearances FIRST .... It'll save you a lot of time in future .......

Incidentally .... reversion pulse waves (momentary reverse intake charge flow) causes bogging .... IF you port heads too big OR fit too big a carb the engine bogs under load because a lot of the charge gets pushed back out of the cylinder due to the lack of intake charge velocity ..... velocity = torque ...... Same thing happens if the inlet valve isn't seating correctly ......

 

[Sidney]

the carboned up plug tells me she was running way to rich so mixture would be my first bet

Not true, if the previous owner just used to bike to ride around his back yard it will be black anyway because he couldnt have been riding very fast.

The faster you go the leaner it gets so isn't that why it could look rich if it was just slow riding?

 

[unit_mx]

Thanks for all the help , I had another crack last night. Still not much is happening so I pulled the entire key igniton unit off all together , I started after around 20 kicks. I think it needs it clearences checked. So for this do I just go and buy a set of 0.05mm and 0.08mm feeler gauges?
Still runs like a dog , Does anyone know a good factory setting for these PE20mm carbs? They come preety standard on most 88 kits. ( Finger points at Minimulisha haha).

 

[mini mullisha]

Sorry to hear bout ya dramas with the new ride,dont worry it cant be too much?
And cant remeber sorry bout my carb settings?I hav two and 18 and 20mill,the 20 mill i just bolted straight on and rode,so not sure ?as would hav to go pull apart to check?see how i go today?might hav look if i got time.
So hav ya checked valve clearance or not yet?

 

[orion125proseries06]

yeah feeler guages are the go, and if i didnt know you id say the fuel was off, but that wouldn't do anything to the plug so thts not rite, what about the killswitch wires, are they all good. or isd it your fuel line, is that clogged or the fuel filter mite be clogged?
im am no expert so im not sure of all of this just i have had expirences with bikes and litlle bits of mechanics

 

[wogtaz ryder]

my shitboss was pretty much doing the exact thing and it turned out 2 wires where touching eachother (cant memba what ones) but after i seperated them started first kick.

 

[unit_mx]

I did what a few of you said and tightend the ground wire up .Got it going. Started first kick today , Conked out for a bit but let it warm up for about 3mins then it went no worries. Preety strange having to let it warm up like that , like there was no way it would go after about 30 secs cold like the old china haha.
I played around with the fuel mixture too , went no worries then put my tb
rev box on and it ran like a dream.

Thanks for the input everyone , much appreciated. Ill get some photos of the new donk soon. Gotta get rid of the ****** kitaco air filter too

 

[andrunious]

i'm having similar issue, can someone post a pic of where the ground is and what it should look like? my 07 crf50 won't start and when it does it dies shortly

 

[Sidney]

the ground wire is mounted to the frame where the airbox is also mounted.

 

[andrunious]

okay, i checked all the connections and everything is fine. i unplugged and replugged them all. drained some gas and found a little trash but refueled and still won't start. ideas?

 

[Flarry]

if it has spark, check your valves and timing and if they're ok try changing the spark plug, on mine everything seemed fine, it had spark but it still wouldnt run, when i changed the spark plug it ran perfectly.

 

[Flarry]

he fixed it ages ago flazz

hows you crf50 cumin along flarry???

any sneak peak pics for me lol

nah I was talking to andrunious, who posted above me.

yeah pretty much done, you'll see pics later.