09 450x Pilot Circuit problem
  • rschlegel
    Posts: 8
    Joined: Mon Mar 09, 2015 4:38 pm

    09 450x Pilot Circuit problem

    by rschlegel » Sun Jun 05, 2016 7:56 am

    Did not find what I needed in search.
    Spring start up and the bike will not idle or stay running once choke is off.
    It did this last year and I removed the carb and cleaned the jets and worked fine. This last fall I added fuel stabilizer and ran it about 5 minutes. This time I just loosened the carb boots and rotated it to get to the pilot jet. Cleaned the jet but it did not really help. Purchased a new pilot jet and still doing it. Once warm 175 degrees, it still does not start unless I give a few full throttle twists but still will not idle. I can ride it around with no problems unless I slow down and it needs to run on the pilot jet. Valves were checked middle of last season and in spec. What do I check for now?
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    JimDirt
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    by JimDirt » Mon Jun 06, 2016 8:24 am

    Make sure the AP pump is squirting , and that it just misses the slide (you have to remove/lift the subframe to look into the back of the carb to see the squirt) , it is possible that there is a internal blockage , also , if you have one of those fuel cap vent caps (instead of just the regular vent hose) , try removing it and see if it runs at lower RPM then , (if it does run better then just replace the vent cap)

    If replacing the jet does not fix the issue , then its either a Internal Blockage or the AP Pump or the Vent Cap (if installed) And/OR , also make sure your Hot Start is working properly , if the plunger in the carb is stuck it can cause a lean condition , and/or the O-Ring on the Fuel Screw can cause a lean condition as well , those are the area's to check , since you have already confirmed the valves are in spec , and the Pilot Jet is clean/new , though the "middle of last season" is a long time ago , and valves can go out in a few rides and be in spec , then out a ride or 2 later , so don't rule them out unless you "just" checked them , same goes for the pilot

    And Most Important .... ALWAYS put FRESH gas in when trying to start/ride the bike after sitting for more than 1 month (Do This FIRST)

    Your best bet is when the bike is going to sit for more than 1 month , is to drain the gas out of the carb (things like Sta-Bil don't really work in our bikes , in your Lawn Mower , yes , but these bikes require higher octane and FRESH gas to run) , you can drain the gas from your bike that wont start , and put it in your lawn mower or car/truck and it will run just fine , pour it back in the bike and no go , but put FRESH gas in and it will start right up, also, you should be able to find some Non Ethanol gas somewhere , most every state has it (Phillips 66 , and places like that) , i actually run a mixture of 110 Octane Sunoco Race Gas (or sometimes Av gas from the local small airport) , mixed with Non Ethanol Premium (1 gallon of Race/Av Gas mixed with 5 Gallons of Non Ethanol Premium , the bike will run and idle better and run cooler) , it also stopped the clogged jets every spring
    2020 CRF450R
    2006 CRF450X
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    Weiser , Idaho
  • Leardriver
    Posts: 462
    Joined: Wed May 05, 2010 10:33 am

    by Leardriver » Tue Jun 07, 2016 6:33 pm

    Where do you live in Denver?

    On a bike that is being stubborn to idle, I lay it on the right side, rotate the carb, and remove the pilot and the fuel screw, washer, and o-ring.

    Then, reach into those passages with a metal dental pick and lightly scratch the top of the passage where it goes into a tiny hole into the carb bell.
    That seems to be a magic collecting place for gas goblins.
    Blow it out with compressed air, and usually you have cured the problem.
  • rschlegel
    Posts: 8
    Joined: Mon Mar 09, 2015 4:38 pm

    by rschlegel » Fri Jun 17, 2016 8:30 am

    Leardriver wrote:Where do you live in Denver?

    On a bike that is being stubborn to idle, I lay it on the right side, rotate the carb, and remove the pilot and the fuel screw, washer, and o-ring.

    Then, reach into those passages with a metal dental pick and lightly scratch the top of the passage where it goes into a tiny hole into the carb bell.
    That seems to be a magic collecting place for gas goblins.
    Blow it out with compressed air, and usually you have cured the problem.


    I live in Highlands Ranch.
  • rschlegel
    Posts: 8
    Joined: Mon Mar 09, 2015 4:38 pm

    Almost there

    by rschlegel » Fri Jun 17, 2016 8:37 am

    I ended up replacing the pilot jet but it did not help. I removed the carb and float bowl to access things easier. I removed all the jets and cleaned them (thought even the pilot was easy to see light through). I ended up putting the carb cleaner nozzle tube up to the passage in the carb body and sprayed that a few times. I could see that cleaner was getting through so I put everything back together.
    The bike runs and idles now but the rpms hang when you blip the throttle. The rpms also raise when shifting. When I let off the throttle to shift, there is a quick rise in the rpm while the clutch lever is pulled in. What are some probable causes for this?
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    JimDirt
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    by JimDirt » Fri Jun 17, 2016 6:42 pm

    I am assuming you removed the Fuel Screw , if so , i would guess the O-Ring got compromised , or was installed in the wrong order (O-Ring is the closest to the tip of the fuel screw , then the washer then the spring) or is not adjusted correctly , the other culprit could be the Hot Start Cable is binding , holding the hot start plunger out (this could have happened when you twisted the carb sideways) it will lean the mixture making the RPM's rise when there is no load on the engine
    2020 CRF450R
    2006 CRF450X
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    Weiser , Idaho
  • rschlegel
    Posts: 8
    Joined: Mon Mar 09, 2015 4:38 pm

    by rschlegel » Sat Jun 18, 2016 5:55 am

    JimDirt wrote:I am assuming you removed the Fuel Screw , if so , i would guess the O-Ring got compromised , or was installed in the wrong order (O-Ring is the closest to the tip of the fuel screw , then the washer then the spring) or is not adjusted correctly , the other culprit could be the Hot Start Cable is binding , holding the hot start plunger out (this could have happened when you twisted the carb sideways) it will lean the mixture making the RPM's rise when there is no load on the engine


    I did not remove the fuel screw. I know, everyone that know carbs is saying "you took the carb off and did not clean the fuel screw?". I am terrified of working on carbs. For as simple as they are, they are daunting to me. Your comment on the hot start got me thinking though. I was trying to pull the little rubber piece away so that the plastic threaded part would be easier to tighten into the carb body for the hot start and the cable housing end came out of the plastic threaded piece. I am thinking there is a good chance I did not get the cable all the way back into it. That would probably keep the brass end on the hot start slightly away from closing the hot start circuit. Other than the hanging idle it seems to be running well.
    Looks like the seat and tank will be coming off again. Hopefully I can get to the hot start without raising the whole sub frame. If I can't, I guess I will get more practice at it.
    I should have put the hot start back together before putting the carb back in place. I had forgotten about it until the carb was back into the intake boot to the cylinder.
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    JimDirt
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    by JimDirt » Sat Jun 18, 2016 9:02 am

    You can get at it fine with just the seat and tank removal , also loosen up the front carb clamp and twist the carb so the bottom is closer to the outside of the frame , this will give you better access to the Hot Start , what i would do since you said you thought you might have pulled on it , is to get everything situated with the cable itself , then work the Hot Start Lever and make sure you can see that everything is working as it should before putting things back together , at least then , you have eliminated it as a cause then , don't try to start the bike till you have the carb back in position and BOTH clamps tight (front/rear)

    As far as the Fuel Screw goes , it can still be a cause of the idling issue , if your idle goes UP , then it means a lean condition usually , so you need to check the circuits that pertain to the idling circuit , which would be the Fuel Screw , the Hot Start (and Choke) a loose Muffler connection (the Pilot Jet , which you said you replaced , but still could have missed some debris in the passage) , and the Floating Plate Seal on the Slide(this can be a issue especially if you used carb cleaner on the slide area)

    If the idle was going up and down , i would say it would be a worn Needle Jet and/or a worn Needle

    A lean condition means either a fuel starvation issue , or a air leak somewhere in the system (fuel or exhaust system) , again , i would check the adjustment of the Fuel Screw , (turn it in all the way and count the turns *1/4 turn at a time*) , you should be between 1-1/4 to 2-1/2 turns out from "gently" seated , you should end up around 1-1/4 to 1-3/4 if everything is correct (jetting size , etc)

    I am still thinking this is a hanging Hot Start , hopefully checking/adjusting the cable helps the situation .....
    2020 CRF450R
    2006 CRF450X
    Image
    Weiser , Idaho

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