KTM450 intermittent bog/sputter

[Ktm300]

Hi all, I have a new build this year, a 2022 450sxf with a riot 3. It’s set up with all the regular snow specific stuff, thermostat, engine blanket, airforce velocity stack, C3 ECU, heatet bars, etc.
For 99.9% of the time it runs so amazing and runs hard, but occasionally it’ll bog/sputter in the most random spots. Acts like it’s running out of fuel or something.
When it happens, if I turn it off it’ll always start right back up. I replaced the in tank and in line filter just for piece of mind, but that didn’t help.
Outside of this scenario described, once it gets over it’s little fit it runs good. I can be climbing something full throttle in 2-3 gear and zero fuel starvation issues.

My only thought is when this happens, I’m usually going slow-ish on a mid-snow trail/transfer, could maybe steam be getting in my intake and causing it to bog occasionally?
What are your thoughts ?

 

[everytime5.9]

Did you reset your tps when you installed the vortex? What map are you running and what are your fuel trim tabs set at?

 

[Excalibur]

Hi all, I have a new build this year, a 2022 450sxf with a riot 3. It’s set up with all the regular snow specific stuff, thermostat, engine blanket, airforce velocity stack, C3 ECU, heatet bars, etc.
For 99.9% of the time it runs so amazing and runs hard, but occasionally it’ll bog/sputter in the most random spots. Acts like it’s running out of fuel or something.
When it happens, if I turn it off it’ll always start right back up. I replaced the in tank and in line filter just for piece of mind, but that didn’t help.
Outside of this scenario described, once it gets over it’s little fit it runs good. I can be climbing something full throttle in 2-3 gear and zero fuel starvation issues.

My only thought is when this happens, I’m usually going slow-ish on a mid-snow trail/transfer, could maybe steam be getting in my intake and causing it to bog occasionally?
What are your thoughts ?

Hey KTM300,

Put your stock ECU in and test. A few of the C3 ECU Vortex boxes have a 4th and 5th gear problem. My bike 22 450 KTM same set up air force intake ETC, had the same symptoms and it would only happen when on the trail, probably 4th or 5th gear. Never on a climb or hard pull. Contact C3 they will warranty it. Stock ECU works well also!

 

[Ktm300]

Did you reset your tps when you installed the vortex? What map are you running and what are your fuel trim tabs set at?

I did the tps reset yes. And I’m running setting 3 I believe, the pump gas Snowbike map with additional RPM. My three fuel trims are all on 5.

 

[Ktm300]

Hey KTM300,

Put your stock ECU in and test. A few of the C3 ECU Vortex boxes have a 4th and 5th gear problem. My bike 22 450 KTM same set up air force intake ETC, had the same symptoms and it would only happen when on the trail, probably 4th or 5th gear. Never on a climb or hard pull. Contact C3 they will warranty it. Stock ECU works well also!

This seems to only happen to me in 2nd and 3rd gear around 1/2 throttle or so. Luckily my 4-5 gear in the trail have been fine.
Then when it gets over it’s fit, I could be climbing in 2-3 gear full throttle and it rocks.
I’ll pop my stock ECU in next ride and see if it still acts up.

 

[everytime5.9]

I have the same issue with a similar setup. Map 3 pump gas and would bog 4-5 times a ride always in the worst spot. Switched the map on the bars to map 1 which is just a dirt map and it went away.

I assume a lean bog on the bottom end so i added 1 notch on the lo adjuster but i haven't been out to test. If you add fuel and it gets worse you know what direction it needs to go. I'm installing my AFR gauge for this weekend to see what its actually doing.

 

[AllHatNoCattle]

I have the same issue with a similar setup. Map 3 pump gas and would bog 4-5 times a ride always in the worst spot. Switched the map on the bars to map 1 which is just a dirt map and it went away.

I assume a lean bog on the bottom end so i added 1 notch on the lo adjuster but i haven't been out to test. If you add fuel and it gets worse you know what direction it needs to go. I'm installing my AFR gauge for this weekend to see what its actually doing.

Do you have the Vortex ECU?

I have a 2020 450FC and I have something similar happen. Usually its after I stop for a bit and then take off. A few times a day it will just sputter and stumble. Like you say, it always happens at the worst time, right when I am trying to climb out of a valley or something.

I might try swapping to Map 1 on the bars and see if that helps. I have the Vortex ECU though, so I am not sure what effect that will have.

 

[Ktm300]

Do you have the Vortex ECU?

I have a 2020 450FC and I have something similar happen. Usually its after I stop for a bit and then take off. A few times a day it will just sputter and stumble. Like you say, it always happens at the worst time, right when I am trying to climb out of a valley or something.

I might try swapping to Map 1 on the bars and see if that helps. I have the Vortex ECU though, so I am not sure what effect that will have.

This is on a Vortex ECU with C3’s Snowbike tunes on it yes.

 

[AllHatNoCattle]

This is on a Vortex ECU with C3’s Snowbike tunes on it yes.

I have the Vortex from PR2, now that I think about it. So maybe switching the maps wont have the same effect.

 

[kempmechanics]

I have heard that its from snow on the intake sensor. I only get a bog on the deep days. Running stock or raze ecu never a problem

 

[AllHatNoCattle]

I flipped my intake so that the intake sensor was on the top. That did help reduce the frequency of sputtering.

I agree, it is on the deep days. I also feel like it only happens when my bike is parked facing downhill for a little while. So it would make some sense that perhaps the snow is melting and running into the intake somehow.

 

[CATSLEDMAN1]

I have had the same issue on several KtM in the past, traced to spark plug cap, If you don't have your engine covered and ride deep powder the drain hole in the spark plug cavity can plug with pine needles etc, then the cavity fills with melt water as you ride. Then goes away as it drain or dries out. long term the water corrodes the inside of the plug cap and gets worse until you replace the cap., and blow some air up the drain hole on occasion. Since everybody in our group now uses real tight fitting engine covers, no problems the last few years. If you replace the cap KTM wants a ton for them, but the cap is common on small race car engines and if hunt a little on the net you can find them for about $10.

 

[everytime5.9]

All good points above to consider.

I've had 4 or 5 rides with the vortex ecu with c3 maps. Each time I would have a random bog throughout the day on map 3 trim 5,5,5. Switched to map 1 and didn't bog the rest of the day. Was able to replicate it every weekend. Last two rides i just stayed in map 1 the entire day and no issues.

 

[Teth-Air]

I simply had old gas in mine and it did that.

 

[Ktm300]

I simply had old gas in mine and it did that.

I definitely have fresh gas in mine.

 

[Ktm300]

All good points above to consider.

I've had 4 or 5 rides with the vortex ecu with c3 maps. Each time I would have a random bog throughout the day on map 3 trim 5,5,5. Switched to map 1 and didn't bog the rest of the day. Was able to replicate it every weekend. Last two rides i just stayed in map 1 the entire day and no issues.

There’s seems to be a noticeable power difference between map 1 and map 3, so I’d hate to leave power on the table by not running map 3. Maybe I should run Map 6 which is the Av-gas map ? ?

 

[Teth-Air]

I definitely have fresh gas in mine.

I simply responded to show how sensitive they are. Is it possible that your fresh gas had water in it from the station? I have seen this a couple times.

 

[Revv Up]

I had the quick release fuel lines one way valve get sideways and partially block fuel flow

 

[Allseasons]

I’d bet it’s a rich bog, not a lean out

 

[AllHatNoCattle]

I rode with the owner of a snowbike shop this weekend and he said that he thinks it is because of the elevation changes.

He said if it starts bogging you should shut the bike off and wait 30 seconds. Then start the bike without touching the throttle for 10 seconds and then it should reset the readings from the MAP sensor.

Something to try I guess, but honestly waiting 40 seconds is a long time when everyone is taking off.