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Please help.! This makes no sense.

Posted: 04:59 pm May 06 2017
by nate9521
Got a 93 kdx200 with low end problem. Mid to full throttle is good and strong. On the low end there is hesitation and bogging. Thought it was lean so lowered the clip (raised the needle). Did nothing. I have to twist the throttle very very slowly to get through the low end without it cutting off. Then when i get off it will come down to an intermidiate idle position then after a while it will go back down to the original idle. Ive tried a bigger pilot and it didnt help. Im 90% sure there is no air leak. Sprayed around the engine and carb with starter fluid and no rev up. This is driving me crazy. Please does anyone have any idea what could be causing this horrible low end throttle response?

I have provided a link to a video of the bog


Re: Please help.! This makes no sense.

Posted: 05:15 pm May 06 2017
by KDXGarage
dirty carb is where I would start

Re: Please help.! This makes no sense.

Posted: 05:53 pm May 06 2017
by nate9521
Jason wrote:dirty carb is where I would start
I promise you the carb is clean. I promise

Please help.! This makes no sense.

Posted: 06:07 am May 07 2017
by cornishwrecker220
I would check the float height & pilot jet ....wrong float height? ...clogged pilot jet ?

Also check the air screw , ....should be anywhere between 1 & 2 turns out

Please help.! This makes no sense.

Posted: 04:29 pm May 07 2017
by nate9521
Ive been reading about the jet block gasket. I did soak my carb overnight in cleaner. Could that gasket be causing my problems?

Re: Please help.! This makes no sense.

Posted: 04:49 pm May 07 2017
by KDXGarage
Was it the same before you dipped it?

Re: Please help.! This makes no sense.

Posted: 05:17 pm May 07 2017
by nate9521
Jason wrote:Was it the same before you dipped it?
Dont know. Bought bike after it had been sitting for years. Cleaned carb before i ever cranked it. I just cant think of anything else. All carb parameters are in spec and no air leaks

Re: Please help.! This makes no sense.

Posted: 06:17 pm May 07 2017
by KDXGarage
What did you dip it in?

Re: Please help.! This makes no sense.

Posted: 06:58 pm May 07 2017
by nate9521
Heavy duty carb cleaner. Think it was berryman

Re: Please help.! This makes no sense.

Posted: 07:06 pm May 07 2017
by KDXGarage
Well, honestly, it sounds like it never was running at all and now you have no clue as to why it won't run. It could be many things. Berryman's is a no-no for Keihin PWK carbs. I think we have a post about it once a month on here.

Re: Please help.! This makes no sense.

Posted: 07:11 pm May 07 2017
by nate9521
Jason wrote:Well, honestly, it sounds like it never was running at all and now you have no clue as to why it won't run. It could be many things. Berryman's is a no-no for Keihin PWK carbs. I think we have a post about it once a month on here.
It runs. It will idle and good top end. Just horrible low end

Re: Please help.! This makes no sense.

Posted: 07:13 pm May 07 2017
by G22inSC
I know the jet block gasket and dipping comes up all the time. The issue is a lot of KDXs are bought used and you do t have any idea what a previous owner did or didn't do. Just because you may not have "dipped" the carb doesn't mean it's never been done, unless you bought the bike in question new.

Re: Please help.! This makes no sense.

Posted: 07:19 pm May 07 2017
by nate9521
G22inSC wrote:I know the jet block gasket and dipping comes up all the time. The issue is a lot of KDXs are bought used and you do t have any idea what a previous owner did or didn't do. Just because you may not have "dipped" the carb doesn't mean it's never been done, unless you bought the bike in question new.
So what are the symptoms of a bad jet block gasket? Its so confusing cause at low end the bog sounds lean like its not getting any gas but the plug is black which suggests its rich. Like i said idle and top end are good. Its just bog and die with quick throttle. and hanging idle

Re: Please help.! This makes no sense.

Posted: 08:45 pm May 07 2017
by G22inSC
If I'm not mistaken, bad jet block gasket is a rich problem. A hanging idle or surge is a lean/air leak issue.

Re: Please help.! This makes no sense.

Posted: 09:08 pm May 07 2017
by nate9521
G22inSC wrote:If I'm not mistaken, bad jet block gasket is a rich problem. A hanging idle or surge is a lean/air leak issue.
Thats whats so confusing. There are rich and lean symptoms. The plug is black and oily

Re: Please help.! This makes no sense.

Posted: 09:31 pm May 07 2017
by MaverickAus
nate9521 wrote:It runs. It will idle and good top end. Just horrible low end
Excuse me if this is stupid but isn't that a sign of bad powervalve?

Re: Please help.! This makes no sense.

Posted: 11:47 pm May 07 2017
by KDXGarage
Usually, it is no high RPM power / "won't rev out".

Re: Please help.! This makes no sense.

Posted: 07:34 am May 08 2017
by david
What jets are in it?

Re: Please help.! This makes no sense.

Posted: 09:31 am May 08 2017
by nate9521
david wrote:What jets are in it?
155 and 45

Re: Please help.! This makes no sense.

Posted: 11:14 am May 08 2017
by david
That could be your issue. My bike hated those numbers. Stock is 48/150 and that is what works for me. I'm at about 450' elevation. Mine also had the lean bog off idle.

Also, make sure you are using fresh gas and you might want to replace the spark plug too.