weird bottom end problem? please help!

Got questions? We got answers....
Post Reply
nate9521
Member
Posts: 43
Joined: 08:42 pm Feb 13 2017
Country: usa

weird bottom end problem? please help!

Post by nate9521 »

Got a 93 kdx200. just got it running today but something weird is happening. if i go from idle to full throttle really quick, the bike will bog and if i dont get off the throttle it will cut off. but if i work the throttle up in small increments there is no bog. the bottom end response just isnt right. half to full throttle it runs great. I have no idea why this is happening. carb has stock jetting. have messed with the mixture and idle screw but cant find a solution. Anyone have an idea?
User avatar
KDXGarage
KDXRider.net
KDXRider.net
Posts: 14047
Joined: 06:45 am Nov 01 2004
Country: United States of America
Location: AL, USA
Contact:

Re: weird bottom end problem? please help!

Post by KDXGarage »

Did you clean the carburetor?
Thank you for participating on kdxrider.net. :bravo:
To post pictures from a device: viewtopic.php?f=88&t=24128
User avatar
bufftester
Platinum Member
Platinum Member
Posts: 3455
Joined: 06:03 pm Oct 31 2012
Country: USA
Location: University Place, WA

Re: weird bottom end problem? please help!

Post by bufftester »

You have a partially blocked passage somewhere in the carb or a blockage in your fuel delivery (tank valve/line). Take it apart, clean it thoroughly. When you think you have it clean, clean it again. Then set the float height and go through the jetting process. (Of course, it should go without saying that before all that you need to make sure that everything else is in sound condition...no air leaks, cracked boots, clean filter, new plug, etc)
nate9521
Member
Posts: 43
Joined: 08:42 pm Feb 13 2017
Country: usa

weird bottom end problem? please help!

Post by nate9521 »

carb is spotless. did have an exhaust leak but replaced those gaskets. float height is good. specs call for 15-17 mm and its at 16. the mixture screw is suppose to be 1.5 turns out but the bog gets worse the more i turn the screw out. right now its at a quarter turn out and the bog isnt that bad but it still isnt right.
User avatar
doakley
Gold Member
Gold Member
Posts: 1241
Joined: 02:58 pm Mar 10 2016
Country:

Re: weird bottom end problem? please help!

Post by doakley »

Clean it.....again.
User avatar
KDXGarage
KDXRider.net
KDXRider.net
Posts: 14047
Joined: 06:45 am Nov 01 2004
Country: United States of America
Location: AL, USA
Contact:

Re: weird bottom end problem? please help!

Post by KDXGarage »

Quarter turn means buy a new pilot jet
Thank you for participating on kdxrider.net. :bravo:
To post pictures from a device: viewtopic.php?f=88&t=24128
User avatar
bufftester
Platinum Member
Platinum Member
Posts: 3455
Joined: 06:03 pm Oct 31 2012
Country: USA
Location: University Place, WA

Re: weird bottom end problem? please help!

Post by bufftester »

That's why we always say follow the jetting guide to the letter, points out things like wrong size jets (assuming everything is clean and serviceable). Keep in mind stock jetting is overly rich to start with.
Willbilly
Member
Posts: 169
Joined: 09:02 am Jun 17 2016
Country:

Re: weird bottom end problem? please help!

Post by Willbilly »

bufftester wrote:That's why we always say follow the jetting guide to the letter, points out things like wrong size jets (assuming everything is clean and serviceable). Keep in mind stock jetting is overly rich to start with.
What jet guide?
User avatar
bufftester
Platinum Member
Platinum Member
Posts: 3455
Joined: 06:03 pm Oct 31 2012
Country: USA
Location: University Place, WA

Re: weird bottom end problem? please help!

Post by bufftester »

link in my signature or HERE
nate9521
Member
Posts: 43
Joined: 08:42 pm Feb 13 2017
Country: usa

Re: weird bottom end problem? please help!

Post by nate9521 »

bufftester wrote:That's why we always say follow the jetting guide to the letter, points out things like wrong size jets (assuming everything is clean and serviceable). Keep in mind stock jetting is overly rich to start with.
I thought the bog would be because its too lean? i have a 150 main and a 48 pilot. Are you saying I should go down on the pilot?
pumpguy
Gold Member
Gold Member
Posts: 821
Joined: 10:00 am May 29 2012
Country:
Location: Spring Grove, Illinois

weird bottom end problem? please help!

Post by pumpguy »

Jetting is a step - by - step process. You have to complete step 1 before going on to step 2. Read and follow the jetting guide, completing each step before moving on to the next step.

Changing jets, or air screw or needle position without doing in proper order will usually result in frustration. Patience and perseverance along with a good understanding of the before and after results is the key to success.
Willbilly
Member
Posts: 169
Joined: 09:02 am Jun 17 2016
Country:

Re: weird bottom end problem? please help!

Post by Willbilly »

bufftester wrote:link in my signature or HERE
Thank you! I did not realize it was there and am happy you pointed the guide out as I am rejetting now. A guide to follow always makes it easier.
Post Reply