power loss - mid to high rpms/bike newb

sparmek · December 1st, 2011, 04:30 PM

Hi all I'm having problems with my 250ex and cant find the symptoms anywhere else, hoping someone here can help. Now I'm a complete newbie to motorcycles so please speak idiot to me.

First off I just bought the bike in mid Aug from a private seller,its a 93 ninja 250ex completely stock 13xxx mi or so, and it ran great for a month or so. Two weird things happened the first month but i had just chocked it up to it being an old cranky bike. First after the bike was warm it's idle would range between 1500rpms to 5000rpms (I know now that's not good, but like I said I'm a newb). Second riding to work on the freeway (70-75mph) in the rain and cold, also the first time i had taken it in the rain, the rpms started going down just like if i had run out of fuel I got to the side of the road and it died, i knew it wasn't empty so i tried turning it over a couple times and after about 10-15 sec it started back up and was fine, no problem the rest of the day.

Now the real issue I'm having happened 2 days after the freeway dying episode, i started it up and started driving towards home and noticed it had no power at the mid to high rpm range and had slightly less in the lower range. Now this was such a loss that i couldn't go over 35 mph if i pulled back on the throttle quickly it seemed to "bog down" and start to die if i did it gradually it surged and vary slowly got to 40 mph and that was it. after a bout 20 miles of this all the sudden i had almost all the power back, but i could feel it not accelerate as fast as it did before. The next morning i tried again and it was back to the no mid to high range power and that's where I'm at now. the weird thing is that in neutral i can pull back on the throttle and it revs just fine all the way to red line with no hesitation. I first though it was carbs and took it to a local shop and had them clean them out. when i got it back it did the same thing and supposedly they went through the carbs twice. I'm stuck I've tried simple stuff at home like emptying the gas out and putting in a different brand and octane, oil change, staring at the bike for hours, nothing helps. Any help would be appreciated, and again talk to me like I'm an idiot please it maybe something extremely simple, thank you again.

alex.s · December 1st, 2011, 04:40 PM

is your choke on?

choneofakind · December 1st, 2011, 04:45 PM

Do you have a history of its' maintenance? When was a valve adjustment last done on it?

Did all the vacuum hoses get properly re-attached when you had them cleaned? That about the choke cable? the intake boots? check for leaks. Were the carbs synced after being cleaned?

check that the diaphragms in your carbs didn't get torn.

check the operation of the petcock to ensure that it isn't starving the engine of fuel

helpful link here

another helpful link

service schedule here

hope this give you some help on this. it's at least something to start on...

Skippii · December 1st, 2011, 04:46 PM

Carbs's venturis tend to ice up in cold wet environments at certain throttle positions, which can cause very strange symptoms.
Is it like that first thing in the morning, or only after you ride it a while?

sparmek · December 1st, 2011, 06:59 PM

no the chokes not on ( of course after its warmed up) i don't know what kind of service has been done the seller didn't have any thing for me, though it seems to be well maintained. i would guess the carbs were synched but ill double check it. one of the air box- carb rubber boots is missing and that was there before i took it to the shop. the intake boots are good though(i think). petcock is messed up but its not starving for fuel. it has a messed up gasket that lets fuel through no matter what setting you have it on(on,off,res). as far as the ice goes i don.t think that's it its cold out here but i would think the bike would run fine when its 50f out also the symptoms are worse during warm up after that its the same as i described. thank you for the ideas! please if any one has anything else to add, do it.

choneofakind · December 1st, 2011, 10:26 PM

Quote:

Originally Posted by sparmek

one of the air box- carb rubber boots is missing and that was there before i took it to the shop. t

Well that would explain the power loss if that means what I think it means. Would you mind taking a picture of it for us? if there's a carb boot missing, thats going to let in tons of air and make the mix really lean and lose power, but I just want to make sure we're talking about the same part.

Skippii · December 1st, 2011, 11:55 PM

A missing boot from the airbox to the carb will not only cause the problems you've listed, but will also destroy the engine by getting dirt into the cylinders. Not immediately, of course, but much faster than you want. Air intake with no filters is a very bad idea.

sparmek · December 2nd, 2011, 09:54 PM

Thanks for the fast response guys! now that your saying something about that rubber boot I'm smacking my head on the desk going "duh why didn't i think of that?" anyways ordered the part at the dealer and it should be here in a week, then I'll post pics and results. Thanks again!!

sparmek · December 16th, 2011, 03:34 PM

Awsome that Carb boot was the problem! Got the new one in there and it drives like a champ. Thanks again for all the help!
Posted via Mobile Device

Alex · December 16th, 2011, 08:02 PM

December 1st, 2011, 04:30 PM	#1
sparmek ninjette.org newbie Name: jeff Location: seattle, wa Join Date: Dec 2011 Motorcycle(s): '93 ninja 250ex Posts: 5	power loss - mid to high rpms/bike newb Hi all I'm having problems with my 250ex and cant find the symptoms anywhere else, hoping someone here can help. Now I'm a complete newbie to motorcycles so please speak idiot to me. First off I just bought the bike in mid Aug from a private seller,its a 93 ninja 250ex completely stock 13xxx mi or so, and it ran great for a month or so. Two weird things happened the first month but i had just chocked it up to it being an old cranky bike. First after the bike was warm it's idle would range between 1500rpms to 5000rpms (I know now that's not good, but like I said I'm a newb). Second riding to work on the freeway (70-75mph) in the rain and cold, also the first time i had taken it in the rain, the rpms started going down just like if i had run out of fuel I got to the side of the road and it died, i knew it wasn't empty so i tried turning it over a couple times and after about 10-15 sec it started back up and was fine, no problem the rest of the day. Now the real issue I'm having happened 2 days after the freeway dying episode, i started it up and started driving towards home and noticed it had no power at the mid to high rpm range and had slightly less in the lower range. Now this was such a loss that i couldn't go over 35 mph if i pulled back on the throttle quickly it seemed to "bog down" and start to die if i did it gradually it surged and vary slowly got to 40 mph and that was it. after a bout 20 miles of this all the sudden i had almost all the power back, but i could feel it not accelerate as fast as it did before. The next morning i tried again and it was back to the no mid to high range power and that's where I'm at now. the weird thing is that in neutral i can pull back on the throttle and it revs just fine all the way to red line with no hesitation. I first though it was carbs and took it to a local shop and had them clean them out. when i got it back it did the same thing and supposedly they went through the carbs twice. I'm stuck I've tried simple stuff at home like emptying the gas out and putting in a different brand and octane, oil change, staring at the bike for hours, nothing helps. Any help would be appreciated, and again talk to me like I'm an idiot please it maybe something extremely simple, thank you again.

December 1st, 2011, 04:40 PM	#2
alex.s wat Name: wat Location: tustin/long beach Join Date: Sep 2009 Motorcycle(s): wat Posts: Too much. Blog Entries: 5 MOTM - Oct '12, Feb '14	is your choke on? __________________________________________________

December 1st, 2011, 04:46 PM	#4
Skippii Milkshake Drinker Name: Skippii Location: Richmond, Va Join Date: Aug 2011 Motorcycle(s): 2007 Orange DRZ400-S, 2005 Ninja 250 & Custom Thundercunt Dirt Chopper Posts: A lot.	Carbs's venturis tend to ice up in cold wet environments at certain throttle positions, which can cause very strange symptoms. Is it like that first thing in the morning, or only after you ride it a while? __________________________________________________ "What a sweetheart."- ninja_sleeper to me

December 1st, 2011, 11:55 PM	#7
Skippii Milkshake Drinker Name: Skippii Location: Richmond, Va Join Date: Aug 2011 Motorcycle(s): 2007 Orange DRZ400-S, 2005 Ninja 250 & Custom Thundercunt Dirt Chopper Posts: A lot.	A missing boot from the airbox to the carb will not only cause the problems you've listed, but will also destroy the engine by getting dirt into the cylinders. Not immediately, of course, but much faster than you want. Air intake with no filters is a very bad idea. __________________________________________________ "What a sweetheart."- ninja_sleeper to me

December 16th, 2011, 08:02 PM	#10
Alex ninjette.org dude Name: 1 guess :-) Location: SF Bay Area Join Date: Jun 2008 Motorcycle(s): '13 Ninja 300 (white, the fastest color!), '13 R1200RT, '14 CRF250L, '12 TT-R125LE Posts: Too much. Blog Entries: 7	__________________________________________________ Montgomery Street Motorcycle Club / cal24.com / crf250l.org / ninjette.org ninjette.org Terms of Service Shopping for motorcycle parts or equipment? Come here first. The friendliest Ninja 250R/300/400 forum on the internet! (especially Unregistered)

December 1st, 2011, 04:45 PM	#3
choneofakind ninjette.org certified postwhore Name: . Location: . Join Date: Feb 2011 Motorcycle(s): . Posts: Too much. MOTM - Feb '13, Feb '14	Do you have a history of its' maintenance? When was a valve adjustment last done on it? Did all the vacuum hoses get properly re-attached when you had them cleaned? That about the choke cable? the intake boots? check for leaks. Were the carbs synced after being cleaned? check that the diaphragms in your carbs didn't get torn. check the operation of the petcock to ensure that it isn't starving the engine of fuel helpful link here another helpful link service schedule here hope this give you some help on this. it's at least something to start on...

December 1st, 2011, 06:59 PM	#5
sparmek ninjette.org newbie Name: jeff Location: seattle, wa Join Date: Dec 2011 Motorcycle(s): '93 ninja 250ex Posts: 5	no the chokes not on ( of course after its warmed up) i don't know what kind of service has been done the seller didn't have any thing for me, though it seems to be well maintained. i would guess the carbs were synched but ill double check it. one of the air box- carb rubber boots is missing and that was there before i took it to the shop. the intake boots are good though(i think). petcock is messed up but its not starving for fuel. it has a messed up gasket that lets fuel through no matter what setting you have it on(on,off,res). as far as the ice goes i don.t think that's it its cold out here but i would think the bike would run fine when its 50f out also the symptoms are worse during warm up after that its the same as i described. thank you for the ideas! please if any one has anything else to add, do it.

December 2nd, 2011, 09:54 PM	#8
sparmek ninjette.org newbie Name: jeff Location: seattle, wa Join Date: Dec 2011 Motorcycle(s): '93 ninja 250ex Posts: 5	Thanks for the fast response guys! now that your saying something about that rubber boot I'm smacking my head on the desk going "duh why didn't i think of that?" anyways ordered the part at the dealer and it should be here in a week, then I'll post pics and results. Thanks again!!

December 16th, 2011, 03:34 PM	#9
sparmek ninjette.org newbie Name: jeff Location: seattle, wa Join Date: Dec 2011 Motorcycle(s): '93 ninja 250ex Posts: 5	Awsome that Carb boot was the problem! Got the new one in there and it drives like a champ. Thanks again for all the help! Posted via Mobile Device

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