loss of power

reignman · May 28th, 2013, 08:16 AM

So I finally got my sisters ninja 250 put back together and running decent. took it around the neighborhood a couple times and everything was fine. Yesterday I decided to take it on a little long ride down the road. I was turning out onto a busy road so I was accelerating somewhat hard. Went up to about 10k rpms, shifted to second then continued to accelerate. That's when I herd a strange noise that I can't quite figure out how to describe. Anyways, then the bike had very little power and I luckily was able to make it the mile or two home down the road. At wide open throttle the bike was going about 40 in third or 4th gear. Anyone have any ideas?

Motofool · May 28th, 2013, 08:38 AM

Did you check that the spark plugs are still bolted to the head?

Lychee · May 28th, 2013, 09:34 AM

Maybe we can help you describe the noise?

Was it:
Surging? Rattling? Popping? Hollow? Tapping? Banging? Loping? Crackling? Hissing? Farting? Like the substitute teacher in peanuts (wah wha wha wah)? Like your in laws on a bad day?

I'd bet it was running on only one cylinder. Test for a difference in temperature between the exhaust pipes. Look for soot on one but not the other. Smell the soot for fuel.

reignman · May 28th, 2013, 10:01 AM

I didn't have time to look at anything before coming to work today but the sound was almost comparable to the sound when you hold the key too long in your car when starting. It road fine the way home no noises or anything just weak power. it does seem like it could have just been running on one cylinder for some reason. I'll look at the plugs and exhaust when I get home today

reignman · May 29th, 2013, 05:22 AM

i looked yesterday. both plugs were in fact still bolted into the head. i checked spark with both. they both spark but one is a purpleish blue and the other is white. they are new plugs the bike has only been run like twice with them in there. one of the plug wires was loose. maybe under my hard acceleration it popped off and wasnt sparking at all or enough. seems to fit the symptoms. i cant get it to stay running now though. maybe thats just some carb adjustment issues

CaptainPlatypus · May 30th, 2013, 06:43 AM

I'm having the same issue described in the thread - sudden loss of power while riding, if I'm very careful I can hit 45mph in third gear wide open, engine won't start without the throttle cranked and nearly dies any time I start from a stop, even with the throttle wide open. It certainly sounds like only one cylinder is working.

It looks like what I should start with is checking the spark plug wires, but I honestly am not sure which wires I should be looking at - is there a way to do this without removing the gas tank?

reignman · May 30th, 2013, 02:18 PM

i think that was part of the problem on my sisters. one of the plug wires is falling apart. yes you can check the wires with the tank on. and they are a think gauge black wire that runs from the coils to the top of the head. you would be best to take the spark plugs out though (which would be hard to do without removing the tank) and check for spark on each side.

n4mwd · June 1st, 2013, 04:04 AM

Did you mess with the valves when you had it apart? If so, read this link.

Some people are just lucky when that happens, but you should not run the bike again until you have determined the cause.

May 28th, 2013, 08:16 AM	#1
reignman ninjette.org member Name: Ray Location: Columbus, Oh Join Date: Mar 2013 Motorcycle(s): 2007 Yamaha Fz1 Posts: 13	loss of power So I finally got my sisters ninja 250 put back together and running decent. took it around the neighborhood a couple times and everything was fine. Yesterday I decided to take it on a little long ride down the road. I was turning out onto a busy road so I was accelerating somewhat hard. Went up to about 10k rpms, shifted to second then continued to accelerate. That's when I herd a strange noise that I can't quite figure out how to describe. Anyways, then the bike had very little power and I luckily was able to make it the mile or two home down the road. At wide open throttle the bike was going about 40 in third or 4th gear. Anyone have any ideas?

May 28th, 2013, 08:38 AM	#2
Motofool Daily Ninjette rider Name: Hernan Location: Florida Join Date: Mar 2011 Motorcycle(s): 2007 Ninja 250 Posts: A lot. MOTY - 2016, MOTM - Dec '12, Jan '14, Jan '15, May '16	Did you check that the spark plugs are still bolted to the head? __________________________________________________ *Motofool* *.................................Never ride faster than your guardian angel can fly* "Mankind is composed of two sorts of men — those who love and create, and those who hate and destroy. Love is the bond between men, the way to teach and the center of the world." - José Martí

May 28th, 2013, 09:34 AM	#3
Lychee sail away Name: Jon Location: San Jose Join Date: Jul 2012 Motorcycle(s): gixxer (sold), ninjette (upgrade!) Posts: 964 Blog Entries: 8	Maybe we can help you describe the noise? Was it: Surging? Rattling? Popping? Hollow? Tapping? Banging? Loping? Crackling? Hissing? Farting? Like the substitute teacher in peanuts (wah wha wha wah)? Like your in laws on a bad day? I'd bet it was running on only one cylinder. Test for a difference in temperature between the exhaust pipes. Look for soot on one but not the other. Smell the soot for fuel. __________________________________________________ Unregistered found this post helpful. Track Day Preparation Checklist 1. Financial 2. Mental 3. Physical 4. Gear / Bike

June 1st, 2013, 04:04 AM	#8
n4mwd ninjette.org certified postwhore Name: D Location: Palm Beach, FL Join Date: Oct 2010 Motorcycle(s): 2006 Ninja 250R, 2007 EFI Ninja 250R Posts: A lot. Blog Entries: 1	Did you mess with the valves when you had it apart? If so, read this link. Some people are just lucky when that happens, but you should not run the bike again until you have determined the cause. __________________________________________________ My Ninja Blog Proud member of ABATE.My NYC Road Rage documentary - CENSORED!

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May 28th, 2013, 10:01 AM	#4
reignman ninjette.org member Name: Ray Location: Columbus, Oh Join Date: Mar 2013 Motorcycle(s): 2007 Yamaha Fz1 Posts: 13	I didn't have time to look at anything before coming to work today but the sound was almost comparable to the sound when you hold the key too long in your car when starting. It road fine the way home no noises or anything just weak power. it does seem like it could have just been running on one cylinder for some reason. I'll look at the plugs and exhaust when I get home today

May 29th, 2013, 05:22 AM	#5
reignman ninjette.org member Name: Ray Location: Columbus, Oh Join Date: Mar 2013 Motorcycle(s): 2007 Yamaha Fz1 Posts: 13	i looked yesterday. both plugs were in fact still bolted into the head. i checked spark with both. they both spark but one is a purpleish blue and the other is white. they are new plugs the bike has only been run like twice with them in there. one of the plug wires was loose. maybe under my hard acceleration it popped off and wasnt sparking at all or enough. seems to fit the symptoms. i cant get it to stay running now though. maybe thats just some carb adjustment issues

May 30th, 2013, 06:43 AM	#6
CaptainPlatypus ninjette.org member Name: Eric Location: Los Angeles Join Date: Apr 2013 Motorcycle(s): '86 Honda VFR700 Posts: 173	I'm having the same issue described in the thread - sudden loss of power while riding, if I'm very careful I can hit 45mph in third gear wide open, engine won't start without the throttle cranked and nearly dies any time I start from a stop, even with the throttle wide open. It certainly sounds like only one cylinder is working. It looks like what I should start with is checking the spark plug wires, but I honestly am not sure which wires I should be looking at - is there a way to do this without removing the gas tank?

May 30th, 2013, 02:18 PM	#7
reignman ninjette.org member Name: Ray Location: Columbus, Oh Join Date: Mar 2013 Motorcycle(s): 2007 Yamaha Fz1 Posts: 13	i think that was part of the problem on my sisters. one of the plug wires is falling apart. yes you can check the wires with the tank on. and they are a think gauge black wire that runs from the coils to the top of the head. you would be best to take the spark plugs out though (which would be hard to do without removing the tank) and check for spark on each side.