Air Filter caught fire

[Racer270]

Hi guys,

On Friday I took my bike to Cyclespot Euro for a service. I have a KTM 450 SXF (2019) with 60 hours on it and it is in perfect condition. I have had no problems since I bought it new.

Cyclespot Euro did the service and they checked the valve clearance and charged me $330.

On Sunday I was at the woodhill 2-man race. I took the bike off the truck, started it, and rode to the start of the race. I was in row 8 so I was waiting for our row to start. The bike died and I tried to restart it, it did not want to start and after about 30 seconds smoke came out of the airbox. When I removed the cover the air filter was on fire. We put the fire out and put the bike back on the truck. The airfilter cage and air filter is damaged beyond repair. I tried to start it again at home but it did not want to start.

I took it back to Cyclespot Euro and apparently the bike started no problem (or so said the service manager). Then the mechanic phoned me and said actually, the bike didn't want to start and he had to use the cold start (which I have never used since I bought the bike) but when he manually disengages the cold start the bike dies. Also, the cold start does not deactivate automatically as it should. He then turned the idle screw in 1 revolution and the bike started and ran fine from there on in. They don't know why the air filter caught fire and of right now they are not taking any responsiblity for it. I am waiting to hear back from the service manager.

What could have gone wrong here?

Thanks guys.

[ellipsis]

...heat, I'd say...

[dangerous]

"cold start" do you mean they used etha to start it? if so residue left on the filter may have smoldered into life, sounds like there is a fuelling issue...

[Racer270]

Cold start as in the choke on the fuel injection.

[dangerous]

Cold start as in the choke on the fuel injection.

the engine is cold... so the ecu richens the fuel mix and ulters the timing.... that would be normal for any cold engine start... shoudnt be an issue...

[husaberg]

They could have used a high flash point solvent IE petrol to clean the filter then never fully oiled it? but any high flash solvent would have dissipated prior to this.
although i have never heard of this happening and i have done it myself 100's of times with zero il effects, there is a reason not to use Petrol other than ruining the glue.
Seems unlikely

[Racer270]

Thanks DD, but what would have caused the bike to die and then when I tried to restart it, the air filter caught fire?

[Racer270]

Yeah I asked them what they used to clean the filter and they said the same stuff they have been using for 9 years, and they washed the filter with water and soap after that. Would and oiled air filter catch a light immediately if you put a lighter to it?

[Bonez]

Yeah I asked them what they used to clean the filter and they said the same stuff they have been using for 9 years, and they washed the filter with water and soap after that. Would and oiled air filter catch a light immediately if you put a lighter to it?Why would you even do that? Foam burns.

Sounds like fuel issue as stated above.

[pete376403]

The foam could be soaked in any volatile solvent but it would still require some source of ignition before it started burning. Used to be a thing on old bikes with manual advance and retard magnetos that trying to kick start with over advanced timing would cause a good backfire and burning in the carb (in the days of carbs and no air filters). Was the bike running normally prior to the event, no backfires?

[Racer270]

pete376403 Yeah the bike was running fine, no backfire from the truck to the start line.

[pete376403]

" what would have caused the bike to die and then when I tried to restart it, the air filter caught fire?" - does the bike have anysort of diagnostic associated with the EFI ? I would guess that the ignition fired at the wrong time = inlet valves still open and the flame gets back up the port to the airbox. If there is any way of reading the efi computer you might be able to see a fault code that identifies the event

[F5 Dave]

I always clean my filters with petrol.

But I leave them overnight to dry.

I sprayed some engine start down the guts of a reluctant foulstroke and the backfire set the airbox on fire, just the residue ether. I'd removed the filter if course. Smothered it. Started thereafter just fine. Flammable mixture on the inlet is perhaps a cause.