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wooden Aug 10th 2016 04:01 PM

Sweet popcorn smell from front of Street Triple
 
So my bike has been smelling weirdly sweet, almost identical to microwave popcorn, at the end of my most recent rides. It definitely comes from somewhere around the engine, hard to pinpoint though. Smells just as heavily at the back of the engine as it does near the radiator.

I checked the oil level and it looks fine, maybe it's the coolant? It doesn't smell like the coolant in my car, but it is definitely very sweet smelling. I'll have to consult my manual to see how to check the coolant levels, though it was just in Cascade Moto Classics for a valve check and 12K service a little over 1000 miles ago - I would certainly hope they checked coolant levels.

Is there anything else on a modern Triumph that can burn up and smell particularly sweet? It's been doing this for a couple weeks and I'm starting to worry a bit.

Chrishil54 Aug 10th 2016 04:07 PM

Not sure if there are other things but id sounds like a coolant issue. I'd keep an eye on the levels and check hose connections.

daneloire Aug 10th 2016 04:33 PM

I had almost that exact same problem with a shitty Buick I drove twenty years ago. Smelled like sweet, toasted popcorn or corn chips. It turned out to be coolant leaking into the heater core.

Rusty Nail Aug 10th 2016 04:54 PM

Coolant leak. Only thing that smells like that.

Howdy Wooden! I hope you get her fixed up.

Quixote Aug 10th 2016 05:35 PM

Naw, it's not microwave popcorn; more like burnt cheese I think. About once a month I'll notice that weird smell on my Tiger 800 start up. Drove me nuts.

I checked mine out completely, no coolant leak, no evidence of burnt critters, no fluids hitting anything, no nasty residue in the tail pipe, nothing. Bike runs fine.

My theory is that it may be some derivative of the oxides of nitrogen in the catalytic converter. Lots of chemistry going on in there. They lean the new motors so much to meet EPA regs. I had a Subaru that was a poster child for Beano; when you pressed the horn button, it said "Excuse me..."
:bounce:

daneloire Aug 10th 2016 05:49 PM

Not sure I've ever smelled anything sweet in relation to a catalytic converter, but you're right that some of the lower nitrogen oxides (nitric, nitrous, etc) do smell kinda sweet in volume.

I've never heard of those being produced in significant amounts by anything in the exhaust or at least none of my bikes have ever had sweet smelling exhaust, but you could well be correct!

Rusty Nail Aug 10th 2016 09:32 PM

Quote:

Originally Posted by Quixote (Post 23451)
Naw, it's not microwave popcorn; more like burnt cheese I think. About once a month I'll notice that weird smell on my Tiger 800 start up. Drove me nuts.

I checked mine out completely, no coolant leak, no evidence of burnt critters, no fluids hitting anything, no nasty residue in the tail pipe, nothing. Bike runs fine.

My theory is that it may be some derivative of the oxides of nitrogen in the catalytic converter. Lots of chemistry going on in there. They lean the new motors so much to meet EPA regs. I had a Subaru that was a poster child for Beano; when you pressed the horn button, it said "Excuse me..."
:bounce:

He noticed the smell only recently. If it was the cat then he would have noticed it much sooner. He also said he noticed it near the engine itself, not the exhaust pipe.

tfmktm Aug 11th 2016 07:07 AM

I have the same experience with my Speed Triple that only has just above 1k miles on it. I wrote it off as break-in smells (I thought it smells like pancakes...mmmm....pancakes....). Weird that the smell doesn't seem to go away after miles/years of use?

HalcyonSon Aug 11th 2016 08:30 AM

Probably just coolant moving back and forth from the expansion tank. If it gets hot enough, or if the system is over-full, you'll get a small amount of spillage from the overflow tube on the expansion tank. It can splash inside fairings, around the triple, or down the frame, depending on how the hose is run.

The other most likely culprit is the weep hole on your water pump.

After that, things get progressively more depressing and difficult to find. Small leaks around radiator hose clamps, hoses near the exhaust forming micro-cracks, aging hoses going soft and deforming, head gaskets working out of place (maybe bad placement from the valve check), on and on...

elSueco Aug 11th 2016 09:19 AM

Quote:

Originally Posted by daneloire (Post 23444)
I had almost that exact same problem with a shitty Buick I drove twenty years ago. Smelled like sweet, toasted popcorn or corn chips. It turned out to be coolant leaking into the heater core.

Yeah, I'd take the bike in to the dealer and have them check your heater core. Can't be too safe!

daneloire Aug 11th 2016 09:37 AM

Quote:

Originally Posted by elSueco (Post 23492)
Yeah, I'd take the bike in to the dealer and have them check your heater core. Can't be too safe!

Maybe have 'em rotate the tires and refill the turn signal fluid too while they're at it.

wooden Aug 11th 2016 03:11 PM

Checked coolant level after riding to work this morning - it's hovering on the MAX line. Could indeed be overflowing into the expansion tank.

She hasn't been washed in a while so since I can't make the Thursday night PDX ride after all, I'll do that tonight and look for leaks around coolant lines. Might drain a bit of coolant, too.

If I can't find anything and draining some of the excess coolant doesn't help, I may just have to take it to the dealer... who needs money, anyway?

wooden Aug 11th 2016 03:13 PM

Quote:

Originally Posted by tfmktm (Post 23486)
I have the same experience with my Speed Triple that only has just above 1k miles on it. I wrote it off as break-in smells (I thought it smells like pancakes...mmmm....pancakes....). Weird that the smell doesn't seem to go away after miles/years of use?

The smell is pretty recent. I've had the bike since April of last year and it's over 13K miles now - smell didn't happen until after the 12K service, and even then I don't think it happened for a week or two after it. Hard to remember.


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