Something funny is going on here!

Ok I searched and didn't really see any information I didn't already have..The thing is 2006 crf450r will not start or even try to start...fuel is fresh. carb is clean, has what appears to be good spark, all timing marks align, valves are within spec, no broken valve springs exc, I can get about 75-80PSI compression while kicking over bike has sat for 6-8 months but i'm overlooking something here any suggestions would be great thanks in advance!

Edited by 450duke

Ok I searched and didn't really see any information I didn't already have..The thing is 2006 crf450r will not start or even try to start...fuel is fresh. carb is clean, has what appears to be good spark, all timing marks align, valves are within spec, no broken valve springs exc, I can get about 75-80PSI compression while kicking over bike has sat for 6-8 months but i'm overlooking something here any suggestions would be great thanks in advance!

Sure carbs clean? The ethanol in the fuel makes it gum up and put a coat after a few months... Just a thought. Make sure you can barely see through your pilot. Try pull cranking it? It's a pain in the ass and supposedly not good for the bike but worth a shot

is the plug wet after giving it a few good throttle twist prims and a few kicks?  If it was me I would put in a new plug and tow it a ways in 3rd or 4th and see what happens, but that's just me.  If the plug is dry I would be making sure fuel is getting from the tank to the card for sure, when you open the carb drain does is run fuel out?

Yeah , make Sure the pilot jet and circuit is spotless .

Replace the pilot jet with a new one

Turn the idle screw in 1/2 turn

Edited by Krannie

The plug is new and after some kicking it has some fuel on it. not soaked by any means. with air cleaner off when I twist the throttle I can see the carb priming and it shoots a jet of fuel straight into the head...would think that would be enough to atleast make it fire a few time! Thanks for the input ill try towing it and see if that does anything

do you have striped the carb?

if yes check the dark grey plate on the carbslide.

it can be mounted 180° turned.

Yes card bas been apart and cleaned everything is assembled correctly...took it apart and checked again still no luck with this dang thing!

Is the air cleaner dry? makes the bike real lean,won't start.Like above post new pilot,pull fuel screw make sure its clear . Should start if it started before, carb needs to be right(clean) good luck it's something simple.

Edited by galligar

I had the exact same problem. Carb was gummed up and I replaced jets. The idle screw ( not the mix screw on the bottom) also got screwed up and stuck somehow. Turn it all the way in and then I think it's two turns out for stock setting.

I found the cdi was cracked and exposed the board inside so I replaced..bike ran for few minutes with nee cdi then started running very bad. died and now same problem...traced all wires cant find any bad connections or broken wires

I found the cdi was cracked and exposed the board inside so I replaced..bike ran for few minutes with nee cdi then started running very bad. died and now same problem...traced all wires cant find any bad connections or broken wires

Thats bizarre. Im wondering if the alternator is damaged somehow and is cooking the regulator in the CDI unit causing the first one to crack because of excess heat. Anything aftermarket on the stator, flywheel etc?

Nope bike is all stock but the weird thing is im getting good strong spark that will arc about 1/4 to 1/2 inch gap..i had real high resistance through plug boot so I replaced it new boot had less resistance but still no fix!

Edited by 450duke

I see no real signs of heat or melting on the cdi seems as though maybe it was cracked from an accident some time so no telling if that was the main problem now

You said the carb is clean...Did you clean it? or are you assuming its clean? The issue is with the current gasoline. It'll plug that pilot jet solid in a month, let alone six. 

 

And if it was run, shut off and then the jets became plugged with the shit gas, the pilot circuit in the carb can get plugged up with that shit too. 

 

Are you pulling the choke out to start it? That enricher circuit can allow it to fire and run, but as soon as you close it, it'll probably die. If its throwing a huge spark, and its got compression, the only thing that can be wrong is no fuel. 

 

Unless something bizarre happened like the keyway on the flywheel got sheared off and the ignition timing is off. 

yes I have cleaned carb 2 times and gas is new and fresh same gas im running my other bikes off of..im sure it sounds like it but im not a noob to this stuff im mech for a living and have been working on my own bikes for years..i have a feeling fuel isn't the issue since the plug is wet with fuel when removed so I should atleast be getting a pop. Is there a way im losing spark when under compression I know cresting spark in free air is easier than when under compression..And I have already checked keyway on flywheel all is intact and lined up..thanks a lot for your input on this its clear something weird is going on im just running out of things to check! and am trying to avoid throwint any/more parts at it!

yes I have cleaned carb 2 times and gas is new and fresh same gas im running my other bikes off of..im sure it sounds like it but im not a noob to this stuff im mech for a living and have been working on my own bikes for years..i have a feeling fuel isn't the issue since the plug is wet with fuel when removed so I should atleast be getting a pop. Is there a way im losing spark when under compression I know cresting spark in free air is easier than when under compression..And I have already checked keyway on flywheel all is intact and lined up..thanks a lot for your input on this its clear something weird is going on im just running out of things to check! and am trying to avoid throwint any/more parts at it!

 

 

Step away from the "Partzooka"...  :lol:

 

I doubt you're loosing spark under compression if you can throw a 1/2 spark. That's a solid 15K at the plug (it takes 30K to jump an inch) Close that gap to .028 and it jump through the fuel air with out a problem. 

 

the 06 doesn't have an adjustment on the decompressor so that shouldn't be it. You didn't get the vacuum release plate in the carb upside down did you? Its easy to do...

I would say not but i guess ill pull it apart and check though! At this point ill try anything sadly! haha

It still makes me wonder though if it was a fuel/carb problem wouldn't I still be able to get some sort of fire with having a little prime of carb cleaner or anything?

if the plate in the carb is upside down, the air valve isnt working. The cut away in the plate focuses the air past the pilot circuit when the throttle is closed. If its upside down, the pointy side blocks the air entirely and there's not enough air pulled past the slide when the enricher is open to still allow it to run. 

 

You've got something basic incorrect. These things will run with lots of weird problems. Sometimes they'll run with the slide upside down, sometimes not. 

 

Start at the front of the horse. Check the valve clearances again, the timing marks (use the left side,not the right side of the engine). Having fuel in the cylinder pretty much rules out the carb unless you changed something, cleaned it, or the float is stuck open. 

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