Summary of how my carb problems worked out and how the pregen runs now.

Wanderer · October 5th, 2016, 12:35 PM

For anyone that may face the same issue, I bought a 2007 250F with a bad missing problem at cruising speed. No problem starting, idling, or accelerating.

Reference:
https://www.ninjette.org/forums/showthread.php?t=277768

I started by changing the petcock since I found a little gas in the petcock vacuum hose . No change with the missing problem.

I looked for vacuum leaks, I found possible leaks, but no change in the missing problem.

Decided to remove the carbs. First time ever for me. To do this, I removed the back tire, rear fender, battery and then slid the stock air box out the rear to get the carbs out. That sucked!

I decided to never go through that again! I ordered a K&N R-0990 dual pod air filter. I also bought a stand alone crankcase fumes filter.

I also ordered 2ea. Kawasaki 108 Main Jets. And 2ea. new Mixture Screws with steel washer and o-ring. I did NOT order a complete jetting kit. Just 2 new main jets 1 size larger than stock(105). I went to Home Depot and bought 4ea. 3mm stainless steel washers to be added to the carb needles on each carb.

Once I got the carbs off the bike, I begin to remove jets, needles and mixture screws for inspection.

Whoever had taken the carbs apart previously did a TERRIBLE job of it. The Pilot Mixture Screw sealed aluminum covers had been butchered getting them off, but no damage to the screw itself though.

When I removed the Pilot Mixture Screw on one of the carbs, I noticed that the steel washer was missing and the rubber o-ring was cut in two and was lying in the bottom of the mixture screw hole. To compensate for this o-ring being broken, the idiot must have had to screw down the mixture screw almost completely to get the bike to run at all.

The carbs were not that dirty at all. I cleaned all ports, openings and holes with carb cleaner and reassembled the carbs with new 108 jets, mixture screws with new washers and o-rings. The float ports looked like new, so I left them.

I added 2ea. 3mm stainless steel washers to each carb needle also.

I set the Pilot Mixture Screws to 2 1/2 turns out as suggested in many places.

I cut the original plastic air box with a dremel tool to keep the existing battery box. Here is tip for you! I also left the very bottom of the old air box attached to the battery section. This made a great flap to keep any road spray out of the air filter area in case of rain. Turned out great!

I put the carbs back on the bike and installed the crankcase filter and the K&N R-0990 dual pod air filter. I reinstalled the plastic battery box cut off of the old air box. Put the tank back on a refilled the tank with fuel.

Wanderer · October 5th, 2016, 12:41 PM

I tried to start the bike and after the float bowls filled with gas, the bike started right up and idled fine! Yes! I adjusted the idle mixture screw slightly to set the idle to about 1400 RPMs.

I took the bike for a short test ride and it was almost perfect in it's settings. I then took it for a 5 mile trip at cruising speed and no more missing at cruising speeds.

I took a 100 mile trip near my area this week and I then leaned the mixture screw down 1/4 turn to 2 1/4 turns out from bottom.

It now idles fine, cruises great. No sputtering at heavy throttle or back firing when getting off the throttle.

I couldn't be more happy with the results!

Wanderer · October 5th, 2016, 12:52 PM

Results after the 100 mile trip.

You can certainly hear the intake with the K&N R-0990 dual pod air filter. It's LOUD! But, I'm getting used to it. It helps me hear how the bike is running with a lot of wind noise. You can now certainly hear the bike coming on full throttle, but not uncomfortable.

It almost sounds like I have an aftermarket exhaust system on the bike(I don't have one). But, I'm sure it's because the intake is right below my seat.

I just love the flap created by leaving the bottom of the old air box still attached to the battery box. It seals the air box area from any road spray and doesn't get in the way of the new K&N air cleaner or with removing the carbs. I can now remove the carbs and never even take the battery out! I love it!

Would I do it again? Hell yes. If you have any questions or ideas let me know.

Peace,
Wanderer

Triple Jim · October 5th, 2016, 12:52 PM

Good work. Sounds like the only thing left is a MPG report after a couple tanks.

Wanderer · October 5th, 2016, 12:53 PM

Quote:

Originally Posted by Triple Jim

Good work. Sounds like the only thing left is a MPG report after a couple tanks.

I will do that next week I hope.

Wanderer · October 5th, 2016, 01:00 PM

Things I noticed concerning the K&N R-0990 dual pod air filter. The lip on the carbs is not very thick. There are several rows of ridges inside the K&N port where the carbs slide into.

It can be a bitch to get the K&N all the way on the carbs the first time because of these ridges.

Take your time! Keep working the filter on farther until the air filter rubber is all the way to the metal stops on each side of the carbs. Then tighten the hose clamps down tight. No problem with it slipping off so far.

Wanderer · October 5th, 2016, 01:04 PM

I don't know why, but the darn fitting coming out of the engine crankcase for the crankcase fume ventilation is cone shaped! It makes the aftermarket vent filter want to slip off every time you try and clamp the hose clamp it down.

I ended up using the old rubber crankcase rubber "dog leg" hose and then connecting my new crankcase filter to it. That seems to hold well.

Wanderer · October 5th, 2016, 01:05 PM

Quote:

Originally Posted by Wanderer

I will do that next week I hope.

I also need to see how the spark plugs look after a several miles to see if I'm running rich or lean. But, it seems to feel right so far.

Wanderer · October 5th, 2016, 01:20 PM

One last thing I forgot to mention.

The float bowl o-rings that seal the float bowl looked quite old and flat and I should have replaced them, but I wanted to test ride the bike. I suspect that they were the ones that came on the bike when new!

When you push and get impatient, you make mistakes and I did just that.

When I first tried to start the bike, the carb bowls leaked badly. So, I got a chance to remove the new K&N air cleaner and the carbs again! Easy this time with no air box in the way. Took me just a few minutes and the carbs were out again. Easy.

So, replace the float bowl o-rings!!! There are some terrible bowl o-rings on the market. The Kawasaki ones are EXPENSIVE! But, they are perfect fits. You decide.

I put the carbs and K&N air filter back on in about 5 minutes after I put the new o-rings in.

No more carb leaks.

Triple Jim · October 5th, 2016, 01:38 PM

EZ Turn gasoline and oil resistant grease makes a really nice sealer for things like questionable bowl gaskets. You just have to be careful to use a very thin coat, since if a glob breaks off it won't dissolve, and could clog a jet. It's made for lubricating things like the fuel selector valve in the petcock. It never hardens, and dissolves with alcohol.

It's available from Aircraft Spruce.

Wanderer · October 5th, 2016, 01:41 PM

Quote:

Originally Posted by Triple Jim

EZ Turn gasoline and oil resistant grease makes a really nice sealer for things like questionable bowl gaskets. You just have to be careful to use a very thin coat, since if a glob breaks off it won't dissolve, and could clog a jet. It's made for lubricating things like the fuel selector valve in the petcock. It never hardens, and dissolves with alcohol.

It's available from Aircraft Spruce.

Good tip Jim.

The idiot that had hacked the carbs before I bought it has actually put RTV on the o-ring instead of replacing it. It took me a while to get the old o-ring out and to clean all of that crap off.

CaliGrrl · October 5th, 2016, 04:41 PM

Glad you got it running so well!

October 5th, 2016, 12:35 PM	#1
Wanderer ninjette.org member Name: Ruben Location: Arizona Join Date: Sep 2016 Motorcycle(s): 2007 Ninja 250 and 1991 Yamaha Virago XV750 Posts: 228	Summary of how my carb problems worked out and how the pregen runs now. For anyone that may face the same issue, I bought a 2007 250F with a bad missing problem at cruising speed. No problem starting, idling, or accelerating. Reference: https://www.ninjette.org/forums/showthread.php?t=277768 I started by changing the petcock since I found a little gas in the petcock vacuum hose . No change with the missing problem. I looked for vacuum leaks, I found possible leaks, but no change in the missing problem. Decided to remove the carbs. First time ever for me. To do this, I removed the back tire, rear fender, battery and then slid the stock air box out the rear to get the carbs out. That sucked! I decided to never go through that again! I ordered a K&N R-0990 dual pod air filter. I also bought a stand alone crankcase fumes filter. I also ordered 2ea. Kawasaki 108 Main Jets. And 2ea. new Mixture Screws with steel washer and o-ring. I did NOT order a complete jetting kit. Just 2 new main jets 1 size larger than stock(105). I went to Home Depot and bought 4ea. 3mm stainless steel washers to be added to the carb needles on each carb. Once I got the carbs off the bike, I begin to remove jets, needles and mixture screws for inspection. Whoever had taken the carbs apart previously did a TERRIBLE job of it. The Pilot Mixture Screw sealed aluminum covers had been butchered getting them off, but no damage to the screw itself though. When I removed the Pilot Mixture Screw on one of the carbs, I noticed that the steel washer was missing and the rubber o-ring was cut in two and was lying in the bottom of the mixture screw hole. To compensate for this o-ring being broken, the idiot must have had to screw down the mixture screw almost completely to get the bike to run at all. The carbs were not that dirty at all. I cleaned all ports, openings and holes with carb cleaner and reassembled the carbs with new 108 jets, mixture screws with new washers and o-rings. The float ports looked like new, so I left them. I added 2ea. 3mm stainless steel washers to each carb needle also. I set the Pilot Mixture Screws to 2 1/2 turns out as suggested in many places. I cut the original plastic air box with a dremel tool to keep the existing battery box. Here is tip for you! I also left the very bottom of the old air box attached to the battery section. This made a great flap to keep any road spray out of the air filter area in case of rain. Turned out great! I put the carbs back on the bike and installed the crankcase filter and the K&N R-0990 dual pod air filter. I reinstalled the plastic battery box cut off of the old air box. Put the tank back on a refilled the tank with fuel.

October 5th, 2016, 12:41 PM	#2
Wanderer ninjette.org member Name: Ruben Location: Arizona Join Date: Sep 2016 Motorcycle(s): 2007 Ninja 250 and 1991 Yamaha Virago XV750 Posts: 228	I tried to start the bike and after the float bowls filled with gas, the bike started right up and idled fine! Yes! I adjusted the idle mixture screw slightly to set the idle to about 1400 RPMs. I took the bike for a short test ride and it was almost perfect in it's settings. I then took it for a 5 mile trip at cruising speed and no more missing at cruising speeds. I took a 100 mile trip near my area this week and I then leaned the mixture screw down 1/4 turn to 2 1/4 turns out from bottom. It now idles fine, cruises great. No sputtering at heavy throttle or back firing when getting off the throttle. I couldn't be more happy with the results!
	1 out of 1 members found this post helpful.

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October 5th, 2016, 12:52 PM	#3
Wanderer ninjette.org member Name: Ruben Location: Arizona Join Date: Sep 2016 Motorcycle(s): 2007 Ninja 250 and 1991 Yamaha Virago XV750 Posts: 228	Results after the 100 mile trip. You can certainly hear the intake with the K&N R-0990 dual pod air filter. It's LOUD! But, I'm getting used to it. It helps me hear how the bike is running with a lot of wind noise. You can now certainly hear the bike coming on full throttle, but not uncomfortable. It almost sounds like I have an aftermarket exhaust system on the bike(I don't have one). But, I'm sure it's because the intake is right below my seat. I just love the flap created by leaving the bottom of the old air box still attached to the battery box. It seals the air box area from any road spray and doesn't get in the way of the new K&N air cleaner or with removing the carbs. I can now remove the carbs and never even take the battery out! I love it! Would I do it again? Hell yes. If you have any questions or ideas let me know. Peace, Wanderer

October 5th, 2016, 12:52 PM	#4
Triple Jim Guy Who Enjoys Riding Name: Jim Location: North Carolina Join Date: Jul 2016 Motorcycle(s): Ninja 250 Posts: A lot. MOTM - Oct '18, Aug '17, Aug '16	Good work. Sounds like the only thing left is a MPG report after a couple tanks.

October 5th, 2016, 01:00 PM	#6
Wanderer ninjette.org member Name: Ruben Location: Arizona Join Date: Sep 2016 Motorcycle(s): 2007 Ninja 250 and 1991 Yamaha Virago XV750 Posts: 228	Things I noticed concerning the K&N R-0990 dual pod air filter. The lip on the carbs is not very thick. There are several rows of ridges inside the K&N port where the carbs slide into. It can be a bitch to get the K&N all the way on the carbs the first time because of these ridges. Take your time! Keep working the filter on farther until the air filter rubber is all the way to the metal stops on each side of the carbs. Then tighten the hose clamps down tight. No problem with it slipping off so far.

October 5th, 2016, 01:04 PM	#7
Wanderer ninjette.org member Name: Ruben Location: Arizona Join Date: Sep 2016 Motorcycle(s): 2007 Ninja 250 and 1991 Yamaha Virago XV750 Posts: 228	I don't know why, but the darn fitting coming out of the engine crankcase for the crankcase fume ventilation is cone shaped! It makes the aftermarket vent filter want to slip off every time you try and clamp the hose clamp it down. I ended up using the old rubber crankcase rubber "dog leg" hose and then connecting my new crankcase filter to it. That seems to hold well.

October 5th, 2016, 01:20 PM	#9
Wanderer ninjette.org member Name: Ruben Location: Arizona Join Date: Sep 2016 Motorcycle(s): 2007 Ninja 250 and 1991 Yamaha Virago XV750 Posts: 228	One last thing I forgot to mention. The float bowl o-rings that seal the float bowl looked quite old and flat and I should have replaced them, but I wanted to test ride the bike. I suspect that they were the ones that came on the bike when new! When you push and get impatient, you make mistakes and I did just that. When I first tried to start the bike, the carb bowls leaked badly. So, I got a chance to remove the new K&N air cleaner and the carbs again! Easy this time with no air box in the way. Took me just a few minutes and the carbs were out again. Easy. So, replace the float bowl o-rings!!! There are some terrible bowl o-rings on the market. The Kawasaki ones are EXPENSIVE! But, they are perfect fits. You decide. I put the carbs and K&N air filter back on in about 5 minutes after I put the new o-rings in. No more carb leaks.

October 5th, 2016, 01:38 PM	#10
Triple Jim Guy Who Enjoys Riding Name: Jim Location: North Carolina Join Date: Jul 2016 Motorcycle(s): Ninja 250 Posts: A lot. MOTM - Oct '18, Aug '17, Aug '16	EZ Turn gasoline and oil resistant grease makes a really nice sealer for things like questionable bowl gaskets. You just have to be careful to use a very thin coat, since if a glob breaks off it won't dissolve, and could clog a jet. It's made for lubricating things like the fuel selector valve in the petcock. It never hardens, and dissolves with alcohol. It's available from Aircraft Spruce.

October 5th, 2016, 04:41 PM	#12
CaliGrrl ninjette.org certified postwhore Name: Kerry Location: Ventura, CA Join Date: Jan 2016 Motorcycle(s): Ninja650 Posts: A lot. MOTM - Apr '18, Apr '17, Apr '16	Glad you got it running so well!