Please help me understand "thread"

frogbite · May 5th, 2024, 10:02 AM

Hi all. I have a 2010 250R that has been sitting for years. I got it running a while ago but then it sat again but now looking to complete the project.

It was starting with ease but when I would give it gas it would bog down and stall. Pulled the carbs and they were very dirty. What had me confused is when I pulled out the needle in the diaphragm a small plastic washer came out and I am not sure of its purpose. The bike has the stock #98 and #38 main and pilot jets. The air mixture screw plugs had been removed by the previous owner and the air box is stock.

What I have are this washer pictured next to a needle holder and spring:

Wondering if the previous owner was trying to work around or improve an issue. Anyone have an idea?

ducatiman · May 5th, 2024, 11:33 AM

possibly using the washer as a needle shim? Either activly shimming or passively, conveniently storing the washer above the needle, thus enabling quick access if needed?

But just 1 washer, not present on the other slide needle?

frogbite · May 5th, 2024, 01:12 PM

Thanks, there was one with each needle. I was thinking a shim as well as when jetting the needles are adjustable, so maybe the previous owner saw this as a way to improve on the response by allowing gas to flow at a quicker time?

I put the carbs back in the bike using the washers as a shim, will see if there are issues and if so will pull them back out and remove the washer. I would have thought if shimming that there would have been jet changes, hole in the lift made bigger (not sure if it has been drilled out), or a change the air intake like a K&N style filter or individual filters. Also the pipe is stock.

Thanks

ducatiman · May 5th, 2024, 04:10 PM

FYI.....the N9VU needle should be in the LH carb, N9VW in the RH carb....you've verified both are numerically correct and placed in correct locations?

frogbite · May 6th, 2024, 03:20 AM

Yes, found that bizarre but saw that in the service manual.

BoKu · May 7th, 2024, 08:37 AM

Quote:

Originally Posted by ducatiman

FYI.....the N9VU needle should be in the LH carb, N9VW in the RH carb....you've verified both are numerically correct and placed in correct locations?

Just curious, how do you know which needle is which? Are the numbers written on them?

ducatiman · May 7th, 2024, 08:44 AM

yes, side of needle, just under the "head". Very light, may be difficult to read.

May 5th, 2024, 10:02 AM	#1
frogbite ninjette.org newbie Name: Bennett Location: Central Florida Join Date: Jan 2022 Motorcycle(s): 250 Ninja Posts: 3	Please help me understand "thread" Hi all. I have a 2010 250R that has been sitting for years. I got it running a while ago but then it sat again but now looking to complete the project. It was starting with ease but when I would give it gas it would bog down and stall. Pulled the carbs and they were very dirty. What had me confused is when I pulled out the needle in the diaphragm a small plastic washer came out and I am not sure of its purpose. The bike has the stock #98 and #38 main and pilot jets. The air mixture screw plugs had been removed by the previous owner and the air box is stock. What I have are this washer pictured next to a needle holder and spring: Wondering if the previous owner was trying to work around or improve an issue. Anyone have an idea?

May 5th, 2024, 11:33 AM	#2
ducatiman ninjette.org certified postwhore Name: Gordon Location: new york Join Date: Sep 2009 Motorcycle(s): '95 DUCATI 900SS/SP '07 DUCATI SS800 '19 HONDA CBR650R Posts: A lot. MOTM - Nov '18, Mar '17	possibly using the washer as a needle shim? Either activly shimming or passively, conveniently storing the washer above the needle, thus enabling quick access if needed? But just 1 washer, not present on the other slide needle? __________________________________________________ gordon@customcarbservices.com Custom Carb Service www.customcarbservices.com Last futzed with by ducatiman; May 5th, 2024 at 01:01 PM.

May 5th, 2024, 04:10 PM	#4
ducatiman ninjette.org certified postwhore Name: Gordon Location: new york Join Date: Sep 2009 Motorcycle(s): '95 DUCATI 900SS/SP '07 DUCATI SS800 '19 HONDA CBR650R Posts: A lot. MOTM - Nov '18, Mar '17	FYI.....the N9VU needle should be in the LH carb, N9VW in the RH carb....you've verified both are numerically correct and placed in correct locations? __________________________________________________ gordon@customcarbservices.com Custom Carb Service www.customcarbservices.com

May 7th, 2024, 08:44 AM	#7
ducatiman ninjette.org certified postwhore Name: Gordon Location: new york Join Date: Sep 2009 Motorcycle(s): '95 DUCATI 900SS/SP '07 DUCATI SS800 '19 HONDA CBR650R Posts: A lot. MOTM - Nov '18, Mar '17	yes, side of needle, just under the "head". Very light, may be difficult to read. __________________________________________________ gordon@customcarbservices.com Custom Carb Service www.customcarbservices.com

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May 5th, 2024, 01:12 PM	#3
frogbite ninjette.org newbie Name: Bennett Location: Central Florida Join Date: Jan 2022 Motorcycle(s): 250 Ninja Posts: 3	Thanks, there was one with each needle. I was thinking a shim as well as when jetting the needles are adjustable, so maybe the previous owner saw this as a way to improve on the response by allowing gas to flow at a quicker time? I put the carbs back in the bike using the washers as a shim, will see if there are issues and if so will pull them back out and remove the washer. I would have thought if shimming that there would have been jet changes, hole in the lift made bigger (not sure if it has been drilled out), or a change the air intake like a K&N style filter or individual filters. Also the pipe is stock. Thanks

May 6th, 2024, 03:20 AM	#5
frogbite ninjette.org newbie Name: Bennett Location: Central Florida Join Date: Jan 2022 Motorcycle(s): 250 Ninja Posts: 3	Yes, found that bizarre but saw that in the service manual.