Burning rubber smell followed by popping noise

thestew42 · June 2nd, 2015, 08:44 PM

Hey I'm hoping you can help me with another issue I just experienced today. After doing the valve adjustment, spark plugs, and some other regular maintenance a few weeks ago, my bike has been mostly fine. However, I noticed that a couple times when I started it in the morning there was a popping noise when the engine first started running (not when I hit the starter, but right when the engine fires up). Although I'm not entirely sure where the noise came from and it didn't seem loud enough to be a backfire to me, I assumed it was just this issue (https://www.ninjette.org/forums/showthread.php?t=15025). The strange part is that it never did this before I messed with it

Anyway today when I was riding home, I started to smell sort of a burning rubber smell similar to when you leave your car's e-brake on while driving. At first I thought it might be a car in front of me, but after getting ahead of the cars in front of me it was definitely coming from the bike. After smelling this for a few minutes, I heard a pop noise similar to when starting but maybe a bit louder. After that the smell went away and it seemed fine for the rest of the ride home.

If anyone has any ideas of what might be wrong, I'd really appreciate it. Been searching forum posts for a while now and haven't found anything that sounds quite like this. Thanks.

Motofool · June 2nd, 2015, 10:03 PM

Quote:

Originally Posted by thestew42

......... The strange part is that it never did this before I messed with it

It is normal that the cause of a recent problem is the last thing you changed.

Maybe the valves were not properly adjusted and the pop is coming from an intake valve not fully closing via intake box.
It could also be a poor contact regarding one spark plug that induces an explosion out of time.

I don't believe the smell and the noise are related.
Sometimes, plastic or paper bags get wrapped on the exhaust pipes while riding and get burned.

thestew42 · June 2nd, 2015, 10:18 PM

Quote:

Originally Posted by Motofool

Maybe the valves were not properly adjusted and the pop is coming from an intake valve not fully closing via intake box.
It could also be a poor contact regarding one spark plug that induces an explosion out of time.

Thanks for the suggestions. I double checked the clearances after putting the cams back on and all of the valves were near the middle of the range. Of course it was the first time I've ever done this, so its possible I measured incorrectly. Also what do you mean by poor contact with the spark plug? The spark plug cap (not sure if that's the right term for the long black plastic/rubber thing that goes in through the valve cover) might not be seated correctly?

Since this pop has only happened 3 times now in about 500 miles of riding since the service, I don't really know the best way to be sure I've fixed the problem. It would be nice if I knew how to reproduce the conditions that cause the sound. I also don't know how serious the problem is...like if I shouldn't be riding it at high speeds for safety concerns.

thestew42 · June 3rd, 2015, 08:34 AM

Well I tried to get a video of the noise with some cold starts but no luck. I don't have much experience with engines (yet

) so maybe someone else hears or sees something strange in this video:

Link to original page on YouTube.

I disconnected and re-connected the spark plugs, but I don't really have any way of knowing if that fixed it. I'd prefer not to go through the trouble of opening up the valve cover to re-adjust the valves if that isn't the problem, but if it happens again I'll do it this weekend.

June 2nd, 2015, 08:44 PM	#1
thestew42 ninjette.org newbie Name: Stewart Location: San Diego Join Date: May 2015 Motorcycle(s): 2009 Ninja 250R Posts: 6	Burning rubber smell followed by popping noise Hey I'm hoping you can help me with another issue I just experienced today. After doing the valve adjustment, spark plugs, and some other regular maintenance a few weeks ago, my bike has been mostly fine. However, I noticed that a couple times when I started it in the morning there was a popping noise when the engine first started running (not when I hit the starter, but right when the engine fires up). Although I'm not entirely sure where the noise came from and it didn't seem loud enough to be a backfire to me, I assumed it was just this issue (https://www.ninjette.org/forums/showthread.php?t=15025). The strange part is that it never did this before I messed with it Anyway today when I was riding home, I started to smell sort of a burning rubber smell similar to when you leave your car's e-brake on while driving. At first I thought it might be a car in front of me, but after getting ahead of the cars in front of me it was definitely coming from the bike. After smelling this for a few minutes, I heard a pop noise similar to when starting but maybe a bit louder. After that the smell went away and it seemed fine for the rest of the ride home. If anyone has any ideas of what might be wrong, I'd really appreciate it. Been searching forum posts for a while now and haven't found anything that sounds quite like this. Thanks.

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June 3rd, 2015, 08:34 AM	#4
thestew42 ninjette.org newbie Name: Stewart Location: San Diego Join Date: May 2015 Motorcycle(s): 2009 Ninja 250R Posts: 6	Well I tried to get a video of the noise with some cold starts but no luck. I don't have much experience with engines (yet ) so maybe someone else hears or sees something strange in this video: Link to original page on YouTube. I disconnected and re-connected the spark plugs, but I don't really have any way of knowing if that fixed it. I'd prefer not to go through the trouble of opening up the valve cover to re-adjust the valves if that isn't the problem, but if it happens again I'll do it this weekend.