Hissing noise — Ninja 250 09 | GTAMotorcycle.com

Hissing noise — Ninja 250 09

mars

Well-known member
Hey peeps,

So on TuesdayI was riding along on the highway when it was raining and the all off sudden the bike starts making this "hissing" sound (best way I can describe it). It makes it wether it's in gear or not and gets louder as I accelerate. I thought maybe it could be a vacuum leak. I removed the fairings and went through it with a propane torch but no change in idle. None of the rubber hoses appear damaged either. The noise doesn't effect performance, she's still running great besides this slight hissing sound. I've done two recordings one outdoors and one inside my garage and uploaded them to SoundCloud; hopefully ya'll can hear it.

https://soundcloud.com/user-672160415/sets/ninja-250-hissing-recording/s-8cEH7

Wondering if anyone has encountered this before and if ya'll think I should get it checked out.

Cheers,

Mars
 
I couldn't hear the noise you described in your sound clip. Anyway if what you are trying to describe is a high pitch squealing coming from the top of the tank area. It's just pressure build up in the tank. Try turning off the bike , open the fuel cap, close the fuel cap and start the bike again and see if the noise went away.
 
Hey @250R-ICE, thanks for the input. Yeah the tank venting sound, I'm familiar with that but no this sounds like it's coming from either the engine or rad. In the clip you can hear the thump thump thump of the engine it's the higher pitch hissing sound in the background almost like when you run water or sand over aluminium. At first I thought maybe it's the coolant running through the rad, but I don't remember it being this loud. Another idea I have is maybe something got caught in the rad's fins and it's vibrating but I didn't see anything.
 
I hear the hissing. Does it do it when it's dry? Sounds like water evaporating against a hot part.
 
Hey @Riceburner, yeah it does it when it's dry too. Unless there's water trapped somewhere… Yeah it's an odd sound isn't it? It doesn't sound catastrophic (like the heads rubbing on something) but it does sound weird. Also forgot to mention the rad isn't leaking (nothing is).
 
I recall on my Ninja I had a slow leak near the thermostat. The hose got loose at the connection. Do you have a normal level in the coolant recovery? Just throwing ideas at you.

You can try asking the members on ninjett.org.
 
Speedo cable or drive ? Does it only make the noise when you're moving ?
Maybe get the front wheel off the ground and give it a spin.
 
@250R-ICE yup coolant level is normal in the recovery tank. Checked all the hose connection and they appear to be solid.

@boyoboy didn't think about the spark plug. I'll check it out and see if it got loose.

@TK4 It makes noise even when it's not moving too. Would it still be the speedo cable or drive then?
 
mars;2488006 @TK4 It makes noise even when it's not moving too. Would it still be the speedo cable or drive then?[/QUOTE said:
Hmmm, when the motor's running but the wheels aren't turning ? That's a weird one.
Does the noise go away when you pull the clutch in ? It might just be clutch basket rattle.
It might also be a water pump bearing, but it seems there are no separate parts available.
Borrow a stethoscope and see if you can narrow down where its coming from.
 
Hmmm, when the motor's running but the wheels aren't turning ? That's a weird one.
Does the noise go away when you pull the clutch in ? It might just be clutch basket rattle.
It might also be a water pump bearing, but it seems there are no separate parts available.
Borrow a stethoscope and see if you can narrow down where its coming from.

or a long handled screwdriver, with a hard plastic handle not one with a rubbery grip, put the pointy end on the part you want to listen too, and your ear on the handle....

old skool, stethoscope....
 
https://www.princessauto.com/en/detail/mechanic-s-stethoscope/A-p2927770e

2927770.jpg
 
@boyoboy checked them out they are both good

@TK4 No the noise is still there even with the clutched pulled. That's interesting about the bearing.

@GateKeeper thanks for the old school method. Will give that a try before buying a stethooscope

@mathew Thanks for the link :D

Bike is out for now until I can get a replacement oil cap (it broke when changing the oil). I'll keep you folks posted after regarding the hissing noise.
 
Hey peeps,

So on TuesdayI was riding along on the highway when it was raining and the all off sudden the bike starts making this "hissing" sound (best way I can describe it). It makes it wether it's in gear or not and gets louder as I accelerate. I thought maybe it could be a vacuum leak. I removed the fairings and went through it with a propane torch but no change in idle. None of the rubber hoses appear damaged either. The noise doesn't effect performance, she's still running great besides this slight hissing sound. I've done two recordings one outdoors and one inside my garage and uploaded them to SoundCloud; hopefully ya'll can hear it.

https://soundcloud.com/user-672160415/sets/ninja-250-hissing-recording/s-8cEH7

Wondering if anyone has encountered this before and if ya'll think I should get it checked out.

Cheers,

Mars

hey mars, did you figure this noise out? curious.
 
lift your tank and check all of the venting hoses
make sure they are on properly and also when you put the tank down look and make sure they are not being pinched
pinched hoses causes tank to have that suction sound when you open the gas cap
pinched hoses = bad
 
lift your tank and check all of the venting hoses
make sure they are on properly and also when you put the tank down look and make sure they are not being pinched
pinched hoses causes tank to have that suction sound when you open the gas cap
pinched hoses = bad

like^ makes good sense (easy zero cost to check)
I think mars .. gone?
 
@boyoboy checked them out they are both good

@TK4 No the noise is still there even with the clutched pulled. That's interesting about the bearing.

@GateKeeper thanks for the old school method. Will give that a try before buying a stethooscope

@mathew Thanks for the link :D

Bike is out for now until I can get a replacement oil cap (it broke when changing the oil). I'll keep you folks posted after regarding the hissing noise.

Is that a custom exhaust? Could it be an exhaust leak?
 
@boyoboy No, I'm starting to think it's regular noise but I've never noticed it. It hasn't gotten worst either so that's good.

@-D- it's not a bad idea just to rule out, but I've had the bike for a year prior and don't remember hearing it. Then again, it could've been there I just never noticed it. It's not a loud noise but it is present. I only get the suction sound if the tank is near empty and it's warmed up (when it's making that screeching sound from the gas vapour escaping).

@mistersouthpaw it is a custom exhaust and I checked it for leaks at the front and we're all good there. Same for the length of the exhaust. Checked for leaks around hoses and carbs, still nada.
 

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