ninjette.org - View Single Post - slow return to idle

bosozoku · August 16th, 2018, 03:42 PM

Hello everyone, new member here that has an erratic running 1997 Ninja 250R with 1000 miles on it (last running 2007). It's exhibiting crazy carburation problems of erratic return to idle, increases to high RPM's (5000) on its own with choke off (verified closed), doesn't come back to idle when throttle is opened and closed, takes forever to do so if it does at all.

The carbs were removed, disassembled and cleaned including the pilot air-screws. Diaphragms, slides and needles looked fine. We replaced the main & pilot jets with new jet. Float valve on one side that looked suspicious was also replaced. Enrichment valve was not disassembled. Fuel flows into carbs normally but petcock vacuum diaphragm seems stuck open. Planning to replace with non-vacuum petcock.

We then cleaned and swapped carbs from another 1996 Ninja 250R (also last running 2007). It is still exhibiting the same slow return to idle. We checked for any vacuum line leaks, everything seems fine.

Do any of you have any suggestions what could be causing this!? My father and I would greatly appreciate your help...Kind regards Jesse

August 16th, 2018, 03:42 PM	#1
bosozoku ninjette.org newbie Name: Jesse Location: Eastern PA Join Date: Aug 2018 Motorcycle(s): Ninja 250 Posts: 4	slow return to idle - really could use some help Hello everyone, new member here that has an erratic running 1997 Ninja 250R with 1000 miles on it (last running 2007). It's exhibiting crazy carburation problems of erratic return to idle, increases to high RPM's (5000) on its own with choke off (verified closed), doesn't come back to idle when throttle is opened and closed, takes forever to do so if it does at all. The carbs were removed, disassembled and cleaned including the pilot air-screws. Diaphragms, slides and needles looked fine. We replaced the main & pilot jets with new jet. Float valve on one side that looked suspicious was also replaced. Enrichment valve was not disassembled. Fuel flows into carbs normally but petcock vacuum diaphragm seems stuck open. Planning to replace with non-vacuum petcock. We then cleaned and swapped carbs from another 1996 Ninja 250R (also last running 2007). It is still exhibiting the same slow return to idle. We checked for any vacuum line leaks, everything seems fine. Do any of you have any suggestions what could be causing this!? My father and I would greatly appreciate your help...Kind regards Jesse