2007 Honda CRF450R Lean Bog
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    mxbrad57
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    2007 Honda CRF450R Lean Bog

    by mxbrad57 » Wed Jul 29, 2020 7:19 am

    No, this isn't your typical lean bog post. Yes I have read a million posts on this.

    I have a 2007 Honda CRF450R. The bike idles fine, runs fine, goes through all the RPMs fine. But I just started having the dreaded lean bog.

    I have had this issue with my old 2004 250x, the solve was the usual.. Tie the AP mod and change the leak jet. I did that on this carb. I went from a 55 to a 45 leak jet, cleaned all the jets, cleaned the brass squirt nozzle with Honda carb cleaner. I stretched the spring out 15mm longer and let everything soak in carb cleaner.

    I have what seems to be a powerful stream of fuel when I whack the throttle. It does not hit the slide, and it seems to last about a second like it should(maybe just short of a second? That's a hard thing to tell). The bike was working perfectly fine.. So something changed.

    Any other ideas?? Am I left to buy an AP rebuild kit and a JD jetting kit? It seems like the AP works perfectly fine but yet I still have the lean bog!

    Question as well: is the hot start cable suppose to be 'free' moving at the carb fitting? I already replaced that cable a year ago with a motion pro one that doesn't have a plastic fitting, but it's very 'loose' feeling all of the sudden(at the carb fitting) and I'm wondering if thats taking in some air and leaning me out?? As far as I can tell there is no leaks on any seals at the carb.

    I'm out of ideas(and I'm suppose to leave in a week for riding(which I will still do, just have to remember about the bog lol)) .. So I'm looking for other ideas!
    TIA.
    In dirt, we trust. - mxbrad57
  • Back2-2
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    Re: 2007 Honda CRF450R Lean Bog

    by Back2-2 » Wed Jul 29, 2020 11:33 am

    I think you are ready found and know what the problem is. Loose fitting = air leak = leak fuel condition.
    You did not mention that you adjusted the A/F screw. If you want optimum fueling that needs a slight adjustment as air temp and density change throughout the year.
    Neil
    Black Hills of SD
    Life without Motorcycles would just be boring, really boring
    Honda 450X. Yamaha Tracer GT900. HD Fat Boy. Triumph Bonneville. Yamaha Majesty 400. Yamaha Grizzly. Yamaha Wolverine. Yamaha TW200
  • Leardriver
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    Re: 2007 Honda CRF450R Lean Bog

    by Leardriver » Wed Jul 29, 2020 7:15 pm

    If the accel pump squirt is strong and missing the slide, you don't need a rebuild. In 2007, the carb was changed so that you don't need to wire anything. The factory version was great.

    What altitude do you ride, and what is your current jetting? If you didn't change anything, it is unlikely that your jetting is the sole cause of any driveability issues, but maybe it can be improved.

    I have seen rapid deteriorations like you describe because of contaminated fuel. In other words, self solving eventually. Have you run some gas through it?
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    mxbrad57
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    Re: 2007 Honda CRF450R Lean Bog

    by mxbrad57 » Thu Jul 30, 2020 2:16 pm

    Good to know about the accel pump being changed and not needing to be wired. When I first looked at it, it wasnt hitting the slide so I was skeptical of tieing it to begin with but seeing as I had past issues with a different bike, I thought that was the same problem.

    I'm around 600ft according to Google for my area. It has never given me an issue(third season with it). And it wasn't giving me this issue at the beginning of the year.

    I ran a tank through it that day but haven't had time to ride again. Maybe I'll just drain the tank, get some fresh fuel and go for a ride and see what happens. Everything seems to check out, that's what has had me confused.
    In dirt, we trust. - mxbrad57
  • Leardriver
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    Re: 2007 Honda CRF450R Lean Bog

    by Leardriver » Fri Jul 31, 2020 12:12 pm

    Your jetting should be a 165 main, a 45 pilot jet, and the fuel screw about 2 turns out. That is close enough that jetting will be ruled out.
    Last edited by Leardriver on Sat Aug 01, 2020 9:18 am, edited 1 time in total.
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    JimDirt
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    Re: 2007 Honda CRF450R Lean Bog

    by JimDirt » Fri Jul 31, 2020 3:53 pm

    Welcome to the site !! \:D/

    In reference to your Hot Start , at the lever it should "snap" back , and pull easily , if that is happening then most likely the Hot Start is working correctly , you could physically check it at the cable adjuster , if the locknut has moved and there is no threads showing , it could have become mis-adjusted , but you want about the same "slop" as a clutch cable would have , so it is not tight and allows some movement of the lever before engaging , but not excessive , just a slight movement is all that you want .... again , if it does not snap back at the lever , it is possible that the Hot Start Plunger is stuck , possibly open and is causing a lean bog , it should snap back when released because of the spring tension pushing the plunger in

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  • Back2-2
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    Re: 2007 Honda CRF450R Lean Bog

    by Back2-2 » Sat Aug 01, 2020 5:42 am

    He has an air leak at the fitting going into the carb body. The plastic fitting is either broken or come loose.
    Neil
    Black Hills of SD
    Life without Motorcycles would just be boring, really boring
    Honda 450X. Yamaha Tracer GT900. HD Fat Boy. Triumph Bonneville. Yamaha Majesty 400. Yamaha Grizzly. Yamaha Wolverine. Yamaha TW200
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    mxbrad57
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    Re: 2007 Honda CRF450R Lean Bog

    by mxbrad57 » Mon Aug 03, 2020 2:50 pm

    He has an air leak at the fitting going into the carb body. The plastic fitting is either broken or come loose.
    Unfortunately not the case. It is a new Motion Pro cable with the metal fittings.

    I have exhausted all options and no one seems to have this exact problem. I sent the carb off to a local guy who cleaned it again for me but didn't find anything concerning so he is getting the whole bike as a second carb cleaning didn't fix it!

    Ill let you guys know what happens!
    In dirt, we trust. - mxbrad57
  • Back2-2
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    Re: 2007 Honda CRF450R Lean Bog

    by Back2-2 » Tue Aug 04, 2020 5:43 am


    Question as well: is the hot start cable suppose to be 'free' moving at the carb fitting? I already replaced that cable a year ago with a motion pro one that doesn't have a plastic fitting, but it's very 'loose' feeling all of the sudden(at the carb fitting) and I'm wondering if thats taking in some air and leaning me out?? As far as I can tell there is no leaks on any seals at the carb.
    There is your problem. Plastic, metal - whatever. That's the air leak.
    Neil
    Black Hills of SD
    Life without Motorcycles would just be boring, really boring
    Honda 450X. Yamaha Tracer GT900. HD Fat Boy. Triumph Bonneville. Yamaha Majesty 400. Yamaha Grizzly. Yamaha Wolverine. Yamaha TW200
  • Leardriver
    Posts: 462
    Joined: Wed May 05, 2010 10:33 am

    Re: 2007 Honda CRF450R Lean Bog

    by Leardriver » Tue Aug 04, 2020 7:33 pm

    It wouldn't take much to smear some caulk around the top of the fitting and then test to see if the bog is gone.

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