CT125 engine randomly cutting out at high speeds

[joseywales]

Hey everyone,
Was wondering if anyone else has had this problem. When on a highway and traveling at full throttle, my 2021 CT125 (which has about 12k miles) is randomly cutting out like its not getting gas. It does this only for a second then recovers then It will do it again a few seconds later like it's not getting any gas. Once I slow down then its fine. I thought I might have bad fuel but I have filled it up several time and it's still happening. I havent seen any posts about this yet and was wondering if anyone else has had this problem? I think I read there is a gas filter built into the bottom of the tank and wondering if it might be getting clogged up or something maybe wrong with the fuel injector? Anyone have any ideas?

 

[CB Spoolmak]

Hey everyone,
Was wondering if anyone else has had this problem. When on a highway and traveling at full throttle, my 2021 CT125 (which has about 12k miles) is randomly cutting out like its not getting gas. It does this only for a second then recovers then It will do it again a few seconds later like it's not getting any gas. Once I slow down then its fine. I thought I might have bad fuel but I have filled it up several time and it's still happening. I havent seen any posts about this yet and was wondering if anyone else has had this problem? I think I read there is a gas filter built into the bottom of the tank and wondering if it might be getting clogged up or something maybe wrong with the fuel injector? Anyone have any ideas?

I assumed it has a rev limiter. My bike, 4th gear downhill w/a tailwind, throttle twisted to eleven does this. Drops out for a split second, revs/speed drops, cuts back in & then does it again when max velocity is reached again.

 

[dmonkey]

I would recommend checking for Diagnostic Trouble Codes. If there is one it could point you to the culprit and cut out a lot of the process of eliminiation.

Is the issue better or worse with a full tank of fuel? There is a "blockage reminder" design to the fuel pump system where a clogged fuel filter should cause more performance issues on a low fuel tank than a full one. Details on that can be found on page 1-33 in the service manual.
Are there any performance modifications on your CT? Is the air filter clean, snorkel inlet unobstructed, and oil level near the max fill line?

 

[m in sc]

some 1st gen groms would do this and eventually there was a fuel pump recall. also, check spark plug make sure its clean and in good shape.

 

[JPMcGraw]

When i had the Takegawa FI-Con installed it would do this randomly at different speeds so if a future person is getting this and has that installed check there too.

 

[CTExplorer]

I would recommend checking for Diagnostic Trouble Codes. If there is one it could point you to the culprit and cut out a lot of the process of eliminiation.

Is the issue better or worse with a full tank of fuel? There is a "blockage reminder" design to the fuel pump system where a clogged fuel filter should cause more performance issues on a low fuel tank than a full one. Details on that can be found on page 1-33 in the service manual.
Are there any performance modifications on your CT? Is the air filter clean, snorkel inlet unobstructed, and oil level near the max fill line?

You learn something new every day

 

[joseywales]

I assumed it has a rev limiter. My bike, 4th gear downhill w/a tailwind, throttle twisted to eleven does this. Drops out for a split second, revs/speed drops, cuts back in & then does it again when max velocity is reached again.

It may have a Rev Limiter but it never did this before even with 12k miles on it. Will have to do some more research. Thanks for the info!

 

[Kritou]

Apart from the filter inside the tank is there any breather for the tank itself to prevent a vacuum, and hence fuel restriction, forming?

 

[dmonkey]

Yes, that setup might vary by region but the USA models at least have an EVAP canister. Easy way to test for an issue or clog there is to run the bike with the fuel filler cap removed. Or for less risk of spilling fuel, disconnect the hose next to the fuel filler cap so it's temporarily vented, blow compressed air through the tube into the tank to make sure it's not clogged right there, and then run the bike with the hose disconnected. If you do either of these it would be a good idea to pinch the hose to the EVAP canister as you could be creating a vacuum leak to the intake if there isn't a clog.

 

[Kritou]

I wonder if all bikes, regardless of destination build, have the charcoal canister trap? Anyway, as you say, running the bike with that hose disconnected and it’s spigot checked would be an easy first step for the OP to try

 

[Shoot870p]

I can not begin to imagine hitting the rev limiter in 4th gear. Mine will not get close to that!

 

[SneakyDingo]

I can not begin to imagine hitting the rev limiter in 4th gear. Mine will not get close to that!

JTF 273.13 and JTR269.45. 7200 RPM and barely 49 mph wooooooooo.

 

[Shoot870p]

i can not quite get to 72 (gps indicated speed). I feel if I could squeeze a couple thousand more revs out I possible could but not real sure.
any guidance on what I should try?

 

[SneakyDingo]

i can not quite get to 72 (gps indicated speed). I feel if I could squeeze a couple thousand more revs out I possible could but not real sure.
any guidance on what I should try?

JATO Rockets.

 

[Shoot870p]

I actually had not even thought of those!!
to be honest, I can not hit 60. (Speedometer )and I am not near 120 miles per gallon. I’m short on all of the points it seems. My machine just putts along with decent gas mileage but not excellent. And certainly low on power. But I enjoy it for what it is.

 

[SneakyDingo]

As do I. I feel the need for speed occasionally, but only out of a wish to not run the bike at or near maximum speed. But for how I use this bike, that's ok! I use it as a commuter vehicle primarily on non-highway riding. I wouldn't buy another one knowing what I can now (price, wait, other options that weren't available at the time), but I'm so glad that I have this bike right now.

Also if you're not aware of it, the JATO Rocket car is an urban legend (that was tested on mythbusters) hence me saying "JATO rockets"

 

[oldskool]

i can not quite get to 72 (gps indicated speed). I feel if I could squeeze a couple thousand more revs out I possible could but not real sure.
any guidance on what I should try?

A different bike.....

 

[Kev250R]

A different bike.....

Or multiple bikes!

I have four street-licensed bikes and choose whichever one is appropriate for whatever I'm going to be doing. My Trail was in it's element last summer when I was going-on camping trips in the mountains (graded dirt roads, 40MPH or lower speed limits in-town and around the lake) it also makes a handy pit bike for the races I like to go to.

If I could choose only one bike though, I don't think it would be a Trail, but everyone's needs are different.

 

[m in sc]

the ct is a good 8th bike, thats for sure. But, its fun, i ride mine quite a lot more than I thought i would.

 

[m in sc]

but, to the original question: have you tried a new sparkplug? seems stupid simple but sometimes, thats all it is.