Throttle bogging

95_ninja · July 19th, 2015, 05:08 PM

I recently purchased a 1995 ninja 250. The bike had 7k miles, and was not running at the time of purchase. After a carb cleaning, the bike ran very well. Now, the bike has recently been bogging when I apply the throttle. Has anyone else had this problem? When I bought the bike it had an aftermarket exhaust pipe. If the bike was not rejected at the time of the upgrade could that cause this problem?

Ghostt · July 19th, 2015, 11:33 PM

After you "cleaned" the carburetors, did you install an inline fuel filter? Did you check to see if there's water in the gas? Petcock working properly? Did you tune the idle mixture screws?

95_ninja · July 20th, 2015, 01:19 AM

No I did not replace the air filter when I cleaned the carbs. I did replace the fuel right away. I did all this in early June, and the bike has ran extraordinarily well up until just recently. When I bought it it would only run with the choke on, and it would die as soon as you moved it off. I thoroughly cleaned the Jets and the the rest of the carb, and that allowed the bike to run beautifully. After the cleaning I did not adjust the idle mixture screws since it ran well. The bogging problem itself comes and goes. It usually begins if the bike goes to a higher rpm during riding.

Ghostt · July 20th, 2015, 01:39 AM

Did you install an inline fuel filter? Without that your leaving yourself open for carburetor trouble. I suggest to get one, any local motorcycle shop should have them

http://faq.ninja250.org/wiki/How_do_...fuel_filter%3F

Also check the petcock for proper operation.

PS I see your fairly close to me, a house call might be in order.

agentbad · July 20th, 2015, 07:07 AM

You could try shimming the needles with a few washers but usually a rejet isn't required for just a slip-on exhaust. If it ran well after the last carb clean then it must be something else. Try checking for vacuum leaks around the carb and make sure those boots are nice and tight and all the hoses are where they should be.

95_ninja · July 20th, 2015, 09:32 AM

Quote:

Originally Posted by Ghostt

Did you install an inline fuel filter? Without that your leaving yourself open for carburetor trouble. I suggest to get one, any local motorcycle shop should have them

http://faq.ninja250.org/wiki/How_do_...fuel_filter%3F

Also check the petcock for proper operation.

PS I see your fairly close to me, a house call might be in order.

No I did not replace the fuel filter. Assuming that the filter is the problem will the carbs need to be cleaned again? Also the petcock is working properly.

Ghostt · July 20th, 2015, 09:41 AM

Quote:

Originally Posted by 95_ninja

No I did not replace the fuel filter. Assuming that the filter is the problem will the carbs need to be cleaned again? Also the petcock is working properly.

Bad news, PreGen Ninjette doesn't have an OEM fuel filter, so unless there is one already in place, then you could have sucked up some crap into carburetors.

If it does have a fuel filter, replace it, and buy a few spares, just in case I carry one in the OEM tool kit.Also pull the carburetors again they might need to be cleaned again if no fuel filter was in place.

Have to adjusted/tuned the idle mixture screws yet?

95_ninja · July 20th, 2015, 09:53 AM

I'm going to replace the fuel filter today. I'm not sure if the one on it now is OEM, it looks like the picture found using this link.

http://faq.ninja250.org/images/thumb..._Filter_6A.JPG

Can I use any inline fuel filter found at like an advanced auto? Like one for a riding mower?

PS I have not adjusted the idle mixture screws.

Ghostt · July 20th, 2015, 10:15 AM

Quote:

Originally Posted by 95_ninja

I'm going to replace the fuel filter today. I'm not sure if the one on it now is OEM, it looks like the picture found using this link.

http://faq.ninja250.org/images/thumb..._Filter_6A.JPG

Can I use any inline fuel filter found at like an advanced auto? Like one for a riding mower?

PS I have not adjusted the idle mixture screws.

Yes a riding mower will do just fine, and that is not on OEM filter, as I stated earlier the PreGen Ninjette doesn't have a fuel filter. See if they carry one similar to the one you already have.

Fuel filter for small engine like a mower works great, as the have a gravity feed fuel system, same as the Ninjette.

When you cleaned the carburetors, what did you set the idle mixture screws to?

Also some other causes might be water in gas tank or tank isn't venting properly.

Testing for vent issues is easy next time it starts to act up, pull over quickly, and open the fuel cap, see if that helps. This is a common problem with an older bike, the two small red diaphragms are not soft and flexible, and have be know to get stuck, thus not allowing the tank to vent, and fuel not to flow properly.

Personally I'd just go ahead now and remove the two red diaphragms, as a preventive measure.

95_ninja · July 20th, 2015, 10:26 AM

I definitely believe there is something wrong in the tank, but I wasn't sure how the two problems would be connected. Pressure builds up in the tank for sure. It whistle out of the cap, and if full sometimes even pushes gas out onto the tanks. Could the two problems be related and if so how?

Ghostt · July 20th, 2015, 10:30 AM

Quote:

Originally Posted by 95_ninja

I definitely believe there is something wrong in the tank, but I wasn't sure how the two problems would be connected. Pressure builds up in the tank for sure. It whistle out of the cap, and if full sometimes even pushes gas out onto the tanks. Could the two problems be related and if so how?

Sounds like it could be a venting issue, no worries it's a free and easy fix,

Quote:

You need you to disassemble the gas cap and remove the two small red diaphragms, assuming this is your only problem.

The diaphragm gets hard and losses it's flexibility and gets stuck, and doesn't allow proper venting.

IMHO this modification should be done regardless to prevent future problems whatsoever.

They are ment to vent the tank, but in the case of an accident not allow gas to leak out, but more often cause problems then they fix.

Here are some pictures to help you.

The plastic piece houses the two small red diaphragm pieces, this one being mine, they are already gone, and you can leave the plastic piece out all together, as I'm going to do now.

Some things to watch out for are, there are 5 small springs under the round collar, and a small round collar as well on the locking mechanism, don't lose any of them.

Good luck.

choneofakind · July 20th, 2015, 02:57 PM

Quote:

Originally Posted by Ghostt

Bad news, PreGen Ninjette doesn't have an OEM fuel filter, so unless there is one already in place, then you could have sucked up some crap into carburetors.

Actually, there's a little fine gold mesh screen on both inlets to the petcock. I've now used 2 petcocks, the original and an OE replacement. Both had the mesh screens. An inline filter is still better.

Ghostt · July 20th, 2015, 03:28 PM

Quote:

Originally Posted by choneofakind

Actually, there's a little fine gold mesh screen on both inlets to the petcock. I've now used 2 petcocks, the original and an OE replacement. Both had the mesh screens. An inline filter is still better.

Excellent point,

The petcock screens are ment to keep out large particulates, which it does, but the smaller sizes make it past and into the carburetors, which causes problems, like float needle valve getting stuck, clogged fuel circuits, etc..........

Below is a picture of my fuel bowls, with 5k miles and a fuel filter, note the lack sediments, I took these as I opened them up. I also make it a habit to run my reserve with each tank full.

A fuel filter is a must have item, for trouble free carburetor operation.

Think of it like this, the engine itself has an oil filter and screen. Would you run the engine with just the screen, and no filter? I think not.

IMHO

choneofakind · July 20th, 2015, 03:48 PM

oh boy.... I'll take a picture of my bowls next time I have them off, they make yours look messy.

Also, I'm currently lacking ANY fuel filtration. I have neither a filter or the mesh, because there's a million other things on my mind and I can have the carbs off the bike in 15 minutes and I have a case of cleaner with straws and easy access to compressed air. A cleaning is nbd, which has supported my laziness

Look at how fine the mesh on the fuel screens is. Comparing that to the oil screen is comparing apples and steak. The oil filtration system is intentionally a two part system. I rode my bike for ~10,000 miles without a fuel filter when I first got it, just the stock gold screens. I didn't know better at the time. No problems whatsoever. IJS.

Yes, best practice says to use a filter. It's a good idea and will certainly not hurt a thing. It can only help. But let's not get crazy here, what good is a spare filter REALLY going to do you roadside???? If your filter has been ground into the pavement and damaged to the point of leaking, you have bigger problems. Leave the spare in a box in the garage.

July 19th, 2015, 05:08 PM	#1
95_ninja ninjette.org newbie Name: Dennis Location: Nashville Join Date: Jul 2015 Motorcycle(s): 1995 Kawasaki Ninja 250 Posts: 5	Throttle bogging I recently purchased a 1995 ninja 250. The bike had 7k miles, and was not running at the time of purchase. After a carb cleaning, the bike ran very well. Now, the bike has recently been bogging when I apply the throttle. Has anyone else had this problem? When I bought the bike it had an aftermarket exhaust pipe. If the bike was not rejected at the time of the upgrade could that cause this problem?

July 19th, 2015, 11:33 PM	#2
Ghostt in your machine Name: Scott Location: Summer Shade, Ky. Join Date: Oct 2014 Motorcycle(s): 98 Ninja 250/F12 aka ZX-2R "SERENITY", 91 Ninja 500/A5 aka ZX-5R "Phoenix", 84 Honda GL1200A "SIREN" Posts: A lot. Blog Entries: 25 MOTM - Jun '17, May '16, Mar '15	After you "cleaned" the carburetors, did you install an inline fuel filter? Did you check to see if there's water in the gas? Petcock working properly? Did you tune the idle mixture screws? __________________________________________________ *violente et ignorantia* ZX-2R BLOG *Twitter and Instagram = Ghostt_Scott* *I'm not here to change your mind, just to inform.*

July 20th, 2015, 01:39 AM	#4
Ghostt in your machine Name: Scott Location: Summer Shade, Ky. Join Date: Oct 2014 Motorcycle(s): 98 Ninja 250/F12 aka ZX-2R "SERENITY", 91 Ninja 500/A5 aka ZX-5R "Phoenix", 84 Honda GL1200A "SIREN" Posts: A lot. Blog Entries: 25 MOTM - Jun '17, May '16, Mar '15	Did you install an inline fuel filter? Without that your leaving yourself open for carburetor trouble. I suggest to get one, any local motorcycle shop should have them http://faq.ninja250.org/wiki/How_do_...fuel_filter%3F Also check the petcock for proper operation. PS I see your fairly close to me, a house call might be in order. __________________________________________________ *violente et ignorantia* ZX-2R BLOG *Twitter and Instagram = Ghostt_Scott* *I'm not here to change your mind, just to inform.* Last futzed with by Ghostt; July 20th, 2015 at 02:57 AM.

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July 20th, 2015, 01:19 AM	#3
95_ninja ninjette.org newbie Name: Dennis Location: Nashville Join Date: Jul 2015 Motorcycle(s): 1995 Kawasaki Ninja 250 Posts: 5	No I did not replace the air filter when I cleaned the carbs. I did replace the fuel right away. I did all this in early June, and the bike has ran extraordinarily well up until just recently. When I bought it it would only run with the choke on, and it would die as soon as you moved it off. I thoroughly cleaned the Jets and the the rest of the carb, and that allowed the bike to run beautifully. After the cleaning I did not adjust the idle mixture screws since it ran well. The bogging problem itself comes and goes. It usually begins if the bike goes to a higher rpm during riding.

July 20th, 2015, 07:07 AM	#5
agentbad ninjette.org sage Name: bob Location: Earf Join Date: Apr 2013 Motorcycle(s): 2005 Ninja 250, 2006 SV650N Posts: 642	You could try shimming the needles with a few washers but usually a rejet isn't required for just a slip-on exhaust. If it ran well after the last carb clean then it must be something else. Try checking for vacuum leaks around the carb and make sure those boots are nice and tight and all the hoses are where they should be.

July 20th, 2015, 09:53 AM	#8
95_ninja ninjette.org newbie Name: Dennis Location: Nashville Join Date: Jul 2015 Motorcycle(s): 1995 Kawasaki Ninja 250 Posts: 5	I'm going to replace the fuel filter today. I'm not sure if the one on it now is OEM, it looks like the picture found using this link. http://faq.ninja250.org/images/thumb..._Filter_6A.JPG Can I use any inline fuel filter found at like an advanced auto? Like one for a riding mower? PS I have not adjusted the idle mixture screws.

July 20th, 2015, 10:26 AM	#10
95_ninja ninjette.org newbie Name: Dennis Location: Nashville Join Date: Jul 2015 Motorcycle(s): 1995 Kawasaki Ninja 250 Posts: 5	I definitely believe there is something wrong in the tank, but I wasn't sure how the two problems would be connected. Pressure builds up in the tank for sure. It whistle out of the cap, and if full sometimes even pushes gas out onto the tanks. Could the two problems be related and if so how?

July 20th, 2015, 03:48 PM	#14
choneofakind ninjette.org certified postwhore Name: . Location: . Join Date: Feb 2011 Motorcycle(s): . Posts: Too much. MOTM - Feb '13, Feb '14	oh boy.... I'll take a picture of my bowls next time I have them off, they make yours look messy. Also, I'm currently lacking ANY fuel filtration. I have neither a filter or the mesh, because there's a million other things on my mind and I can have the carbs off the bike in 15 minutes and I have a case of cleaner with straws and easy access to compressed air. A cleaning is nbd, which has supported my laziness Look at how fine the mesh on the fuel screens is. Comparing that to the oil screen is comparing apples and steak. The oil filtration system is intentionally a two part system. I rode my bike for ~10,000 miles without a fuel filter when I first got it, just the stock gold screens. I didn't know better at the time. No problems whatsoever. IJS. Yes, best practice says to use a filter. It's a good idea and will certainly not hurt a thing. It can only help. But let's not get crazy here, what good is a spare filter REALLY going to do you roadside???? If your filter has been ground into the pavement and damaged to the point of leaking, you have bigger problems. Leave the spare in a box in the garage.