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2009 CRF150F Bogging
Posted: Mon May 06, 2019 7:51 am
by airbur
Howdy. I've done a bunch of searching and can't find answers. Recently rebuilt the carb and now the bike will stall if I engage the throttle quickly. If I engage slowly it's fine until it reaches higher RPMs and then starts to bog way down and loses power. The bike idles fine.
2009 CRF150F
Newly rebuilt carb.
New air filter.
New plug.
New Oil.
I added 87 octane fuel by mistake so used some booster.
T-handle pilot screw (adjusted to Honda specs with Tach).
I am thinking an issue with Jetting? Any help is appreciated. Thanks.
Re: 2009 CRF150F Bogging
Posted: Mon May 06, 2019 4:19 pm
by Aussiecrf230
Was it running ok before the carb rebuild?
What is your jetting?
What is your height above sea level?
Have you tried opening up the pilot screw to allow extra fuel to be available when first opening the throttle. It maybe the idle jet is to small. There is no accelerator pump on these carbs to cover the bog off idle.
Re: 2009 CRF150F Bogging
Posted: Sun May 12, 2019 10:57 am
by airbur
Was it running ok before the carb rebuild?
What is your jetting?
What is your height above sea level?
Have you tried opening up the pilot screw to allow extra fuel to be available when first opening the throttle. It maybe the idle jet is to small. There is no accelerator pump on these carbs to cover the bog off idle.
Unfortunately, I'm not 100% sure it was running good before the carb rebuild.
Jets are original. I first replaced them with the new jets from the kit, but then reverted to the original ones afterwards. I don't remember off-hand the size. I also adjusted the Jet Needle back to factory setting (the Honda service manual doesn't show different setting for high alt.)
The bike was sold in CO (I'm in CO. also) and had been ridden here only.
6000' above sea level.
I have adjusted the pilot screw from the setting obtained with the tach. That seemed to help idle but not the bogging at higher RPMs.
I also drained the fuel tank and reserve and filled with premium.
Thanks.
Re: 2009 CRF150F Bogging
Posted: Sun May 12, 2019 3:01 pm
by Aussiecrf230
Really need to know what jetting including needle code you currently are using to be able to offer advice. What jets and needle were in the kit you have.
The jetting you currently have may have been changed by the previous owner and we don't know if they got it right.
When you say "adjusted jet needle back to standard" do you mean you moved the clip. If so where was the clip originally and where did you move it to?
I assume you have a clean air filter and it is not over oiled.
Remember a 6000 feet you would run a leaner mixture than at sea level so the standard jetting
Re: 2009 CRF150F Bogging
Posted: Sun May 12, 2019 5:10 pm
by airbur
Really need to know what jetting including needle code you currently are using to be able to offer advice. What jets and needle were in the kit you have.
The jetting you currently have may have been changed by the previous owner and we don't know if they got it right.
When you say "adjusted jet needle back to standard" do you mean you moved the clip. If so where was the clip originally and where did you move it to?
I assume you have a clean air filter and it is not over oiled.
Remember a 6000 feet you would run a leaner mixture than at sea level so the standard jetting
I meant I put the previous jets back in it. Regardless...neither the new, or old jets resolve the issue.
In the kit I have:
Slow Jet: 40S
Main Jet: 90
Main Jet 95
In the carb:
Main Jet: 90
Slow Jet: No visible number.
Attached is the mod I did for altitude to the jet needle.
Re: 2009 CRF150F Bogging
Posted: Tue May 14, 2019 9:40 am
by airbur
Guys...any suggestions? Thanks.
Re: 2009 CRF150F Bogging
Posted: Tue May 14, 2019 2:52 pm
by Aussiecrf230
Hi airbur,
Have you had this bike all along or is it new to you?
Has it ever run ok in the past for you?
What does the plug look like at the moment?
Has the airbox been cut to let more air in and is the exhaust standard still?
Sorry for all the questions just trying to get a picture in my head to where your bike is at.
Have you tried the 95 main jet? I thought standard was 98 and when airbox was done others have upped the main to 115. These people are at sea level though.
Did moving the clip on the needle make any difference?
Have you tried opening the fuel screw say a quarter of a turn at a time to see if that helps get rid of some of the bog when first opening the throttle. The carb has no accelerator pump so will bog if opened quickly.
Re: 2009 CRF150F Bogging
Posted: Tue May 14, 2019 3:37 pm
by airbur
Hi airbur,
Have you had this bike all along or is it new to you?
Has it ever run ok in the past for you?
What does the plug look like at the moment?
Has the airbox been cut to let more air in and is the exhaust standard still?
Sorry for all the questions just trying to get a picture in my head to where your bike is at.
Have you tried the 95 main jet? I thought standard was 98 and when airbox was done others have upped the main to 115. These people are at sea level though.
Did moving the clip on the needle make any difference?
Have you tried opening the fuel screw say a quarter of a turn at a time to see if that helps get rid of some of the bog when first opening the throttle. The carb has no accelerator pump so will bog if opened quickly.
Bike is new to me as of a few months ago so not sure how it ran.
The plug was ok....I've replaced it since.
Airbox has not been cut (I'm not familiar with that).
Moving the clip didn't make much difference if any.
I have not tried a larger jet.....since I'm at 6000' I didn't think that was a good idea.
Exhaust is OEM.
I've tried multiple positions of the fuel screw. It seems to make the idle smoother but that's it. Still bogs quote a bit at higher RPMs.
Re: 2009 CRF150F Bogging
Posted: Wed May 15, 2019 1:22 am
by Aussiecrf230
If it bogs say from 3/4 to 7/8 to full throttle then the main jet will be the culprit. You just need to work out if it is too lean or too rich.
The standard main jet is too small at sea level and is probable still under size at your elevation.
You can pull the main jet completely out and run it and you will definitely know when the carb transitions from running on the needle to being on the main.
It will give you a rich bog