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05 450X Running Horribly

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Hey guys.  I recently pulled my 450X out of winter storage to get it ready for the riding season.  I changed the oil and started the bike and everything was running fine.  Upon inspection I noticed the float bowl on the carb was leaking.  When I replaced the seal I pulled the pilot screw out and noticed there was not one but three rubber o-rings on it.  So I pulled the extra two o-rings and reassembled everything.  I knew the pilot screw would need adjusting but never imagined it would create the problems that it has.  I now have problems getting the bike to idle and it has a bad decel backfire.  I tried increasing the slow jet from a 48 jet to a 52 and it didn't seem to help.  I messed with the idle in hopes of at least getting the bike to idle with no success.  I had a similar problem last year and it ended up being the stator.  Is there a possibility that's the problem again or am I just that bad at getting everything adjusted correctly.  Please guys, if you can shed any light on the problem I'd be most grateful.  TIA

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It could be a whole host of things. You can test your stator with a meter to rule that out but it sounds like you carb is all out of wack. Pull it and clean it good, get you jetting back to where it ran good and go from there.

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No mention of airbox or exhaust etc mods? Is the motor stock?

A 52 pilot (Slow jet) seems way too big depending on your setup? A 45 pilot can be plenty enough usually

The "pilot screw" or fuel screw you mention has 3 o-rings? Who knows why? Sounds like the thread may be stuffed, Where exactly is the fuel screw set at now, How many turns out (360 degree is one turn out)

There could be some of the circuits inside the carby blocked up past the pilot jet which is commonly blocked up after sitting

Seems to be a standard common thing with you guys in the USA to store your bike for winter but no matter what the weather is like I would start my bike around once a month so this kind of thing does not happen

 

Edited by CRF450XINOZ

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Pull the  float bowl, and look for corrosion

Most likely have have partial clog above the pilot jet, which you can clear with stiff fishing line compressed cleaner

If so, you will need to clean and polish the float needle and cavity, clear the accelerator pump cavity and passages too. 

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Torch tip cleaners are by far the best tool you can use for manually cleaning the circuits in the carb.

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Having used them for yrs I'd say they work very well, the you understand they come in a variety of sizes, many which are thinner than monofilament fishing line. Not to mention they are designed to clean small orifices. Maybe it's just me, but I like using the right tool for the right job.

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Thanks for the fast replies guys!  I'm running a full Jardine exhaust with a stock air box.  I'm using a crfsonly pilot screw and originally put it at 1 1/4 turns out and have turned out as far as 3 turns out, only because that's where it was set when it was running fine and had 3 o-rings.  I can say that the slow jet and float bowl are clean and clear.  As for above the pilot jet I can't say for sure.  I'll be sure to check that out tomorrow.

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Cant see how it would run right with 3 o-rings? Why was 3 installed in the first place & in what order was the fuel screw washers & spring etc installed?

Not sure why there where 3 installed.  Last year I took it to two different shops trying to figure out what was wrong with it.  I'm assuming when they took the pilot screw out they assumed they lost the o-ring and replaced it not knowing it was still in the carb.  I can't see anyone putting more than one in there intentionally.  As for the order it's spring, washer, then o-ring.

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I recently pulled my 450X out of winter storage

 

  I think you already know the answer; plugged/corroded carb as has been said.

 

  That the float bowl gasket was leaking (meaning it dried out or the carb corroded) is a good sign that the carb is the source of your troubles...

 

Jim.

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Yeah... debris in your pilot jet circuit will cause that.  BTDT!  Clean it out with fishing line or a small guitar string and compressed air like everyone says.  Also, use a good light and look up into the fuel screw threads to make sure you have all the o-rings out of there, then reset to your fuel screw to initial factory setting, and go from there.  But I'd also concur that you probably have corrosion in the carb or a stuck/leaky needle and seat as a result.  If you can't get it figured out on the bike, you'll probably need to yank the carb and take it apart to clean out/replace parts.

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I think what everybody is missing though is after I pulled it out of storage it ran fine.  It wasn't until I replaced the float bowl seal that it started running bad.

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I think what everybody is missing though is after I pulled it out of storage it ran fine.  It wasn't until I replaced the float bowl seal that it started running bad.

Hmm...maybe you dislodged some crud in there.  My FCR once spontaneously crapped it's self... had debris get into the pilot passage, and it ran terrible till I cleaned it back out.

 

Is it possible you knocked a float out of spec or the needle valve isn't seating properly anymore for some reason?

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 Chances are it's something you did when you did the float, but I think I'd first pull the pilot screw out and confirm that you have the spring, washer, and o-ring on in the right sequence (o-ring closest to the tip) and that the o-ring is in good shape.

 

 The second thing  that would come to mind is that with 3 o-rings on it, it never has been jetted correctly in the first place.   Easy enough to check; put the 3 o-rings back on and see if it runs right.

 

  if not, then it's something that happened when you did the bowl gasket.

 

Jim.

Edited by Jim Dettman

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Sorry it took me so long to get everyone updated.  Monday I pulled the carb back apart and removed the pilot screw.  While I was fiddling with the spring I dropped and and couldn't find it to save my life!  So I had to order another pilot screw kit with a new spring, which I picked up today.

Anyways when I pulled the pilot screw out I checked up in the hole and to no surprise there was the remains of a 4th o-ring.  It was split into two pieces.  So I cleaned the hole out and put in the new screw set up today.  So with much pleasure I can now say the bike is running great and I'm ready to rip up the trails of Northern Michigan this coming weekend.  Thanks again everyone here that chimed in.  I hope someday I can do something that will help you all out.

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