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UTC

Enthusiast
2001 ET4, 2007 GTS250, 2011 GTS250, 2021 GTS300 Supertech
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Enthusiast
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UTC quote
Started my GTS300HPE today and almost immediately I noticed smoke coming from below the seat. Pulled out the pet carrier and there was quite a bit of smoke coming from the front of the engine bay. I looked for fire but couldn't see anything, and after 90 seconds or so the smoke disappeared. I ran the engine for another couple of minutes but apart from one or two whisps the smoke didn't return. I'm guessing it was likely a fluid leak onto a part of the engine bay that smoked as it heated up?
@steelbytes avatar
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Veni, Vidi, Posti
2019 GTS300 Supertech E3 60,000km
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@steelbytes avatar
2019 GTS300 Supertech E3 60,000km
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UTC quote
What colour smoke?

I'm wondering if it's a coolant leak
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Enthusiast
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UTC quote
Grey. Here's a video

?share=copy

I checked my coolant a couple of months back and it was very low. Topped it up and checked again a couple of weeks later and it was still normal. Ill check it tomorrow.
@znomit avatar
UTC

Veni, Vidi, Posti
LX190 Friday afternoon special, [s]Primavera[/s], S50, too many pushbikes
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@znomit avatar
LX190 Friday afternoon special, [s]Primavera[/s], S50, too many pushbikes
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UTC quote
Sounds like the wiring loom shorting.



GTS 300 wiring harness burnt...again
@srd0060 avatar
UTC

Hooked
2022 HPE 300 tech/ 91 PX 200e/97 PX 200e
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Hooked
@srd0060 avatar
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UTC quote
check all your earth points are grounded properly. it could be oil on the exhaust.
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UTC

Enthusiast
2001 ET4, 2007 GTS250, 2011 GTS250, 2021 GTS300 Supertech
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UTC quote
srd0060 wrote:
check all your earth points are grounded properly. it could be oil on the exhaust.
I have no idea what I'm looking for as far as earth points are concerned
@srd0060 avatar
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Hooked
2022 HPE 300 tech/ 91 PX 200e/97 PX 200e
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@srd0060 avatar
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UTC quote
The wires bolted to the body create an earth back to the battery, the negative off the battery will be bolted to the body as well undo them and clean the surface up with sand paper then bolt the eyelet back on.
Forum member supplied image with no explanatory text
Forum member supplied image with no explanatory text
UTC

Veni, Vidi, Posti
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UTC quote
What did the smoke smell like? If on the sweet side - a coolant leak. If like burnt plastic - a wiring short. If like burning oil, well then it is oil seeping from somewhere. Or it could have been something caught up under the engine from the road after your last ride.
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1980 Vespa P200e (sold), 2002 Vespa ET4 (sold), 1949 Harley-Davidson FL
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@caschnd1 avatar
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UTC quote
Tierney wrote:
What did the smoke smell like? If on the sweet side - a coolant leak. If like burnt plastic - a wiring short. If like burning oil, well then it is oil seeping from somewhere. Or it could have been something caught up under the engine from the road after your last ride.
EXACTLY! They all have a very distinctive and recognizable smell.
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UTC quote
srd0060 wrote:
The wires bolted to the body.
Great, thanks I'll check it out
Tierney wrote:
What did the smoke smell like?
Good question. It definitely didn't smell like burning plastic so I'll rule that out.
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UTC quote
That's good.
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2007 LX150 2015 GTS (on the bench) 2017 BV 350
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@fledermaus avatar
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UTC quote
If the smoke was immediate, wouldn't the engine and exhaust still be cold? Hard to imagine anything liquid hitting it would get warm enough to evaporate.

I'd lean toward electrical....
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UTC quote
The smoke probably started 30-45 seconds or so after I fired up the engine

I definitely have a coolant leak. Checked the level and it's quite low again. The earth points look in good shape.

Due for service next month so I'll book it in and get it checked
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UTC

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GTS300 Super (Heinz) GTS250 Super (Bulger)
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UTC quote
Drip some oil after checking it recently? Oil stick is not easy to reach.
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UTC quote
readyone wrote:
The smoke probably started 30-45 seconds or so after I fired up the engine
That's plenty of time for the header pipe to get hot enough to burn oil. I'd bet you have an oil leak that's dripping on the header pipe.
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UTC

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2009 LX 150, 2024 GTS Super
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UTC quote
After I do a coolant change and start the engine, it takes 30-45 seconds for my drips to start steaming. So it is quite possibly a coolant leak near the thermostat making your "smoke".
@steelbytes avatar
UTC

Veni, Vidi, Posti
2019 GTS300 Supertech E3 60,000km
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@steelbytes avatar
2019 GTS300 Supertech E3 60,000km
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UTC quote
I'm thinking high probability of a lose hose clamp causing dripping coolant onto header. I've sent this before on a couple of gts.

The low coolant level pretty much confirms it's coolant and not oil

Leave it overnight and then inspect the exhaust header and underside of the cylinder and head for dampness. Use paper towel to pat it as the dampness can be hard to see
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UTC quote
caschnd1 wrote:
That's plenty of time for the header pipe to get hot enough to burn oil. I'd bet you have an oil leak that's dripping on the header pipe.
I'd see oil under the bike too though wouldn't I?
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UTC quote
SteelBytes wrote:
Leave it overnight and then inspect the exhaust header and underside of the cylinder and head for dampness. Use paper towel to pat it as the dampness can be hard to see
I had a good look underneath and found a damp spot at the seal here
Forum member supplied image with no explanatory text
@steelbytes avatar
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Veni, Vidi, Posti
2019 GTS300 Supertech E3 60,000km
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@steelbytes avatar
2019 GTS300 Supertech E3 60,000km
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UTC quote
readyone wrote:
I had a good look underneath and found a damp spot at the seal here
Firstly use paper towel to check the colour of the dampness.

Secondly, good chance that's not the origin rather it is likely that it has dribbled down to there. Check further up, all the way to the hose coming out of the thermostat. Wrap the paper towel all around the end of each hose at the clamp to see if it's leaking

Also, it might only leak when the bike is warm, so start it and warm it up for a minute or two then leave it overnight. but i wouldn't recommend riding it for now

Continue to do this checking once a day as it might take a several iterations of letting it slowly leak and then checking to determine the origin
⚠️ Last edited by SteelBytes on UTC; edited 1 time
@steelbytes avatar
UTC

Veni, Vidi, Posti
2019 GTS300 Supertech E3 60,000km
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Location: Batmania aka Melbourne, Australia
 
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@steelbytes avatar
2019 GTS300 Supertech E3 60,000km
Joined: UTC
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UTC quote
Also, don't tighten any hose clamps **yet**. Would be good to try and identify the origin first...
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