CBR650F Engine Briefly Cuts Out At High Revs

[SpikedCola]

Hi all,

I have a 2014 CBR650F with 16,xxx km on it. Only engine mod is a CS Racing exhaust (also have a gear indicator). Occasionally the engine has started cutting out at high revs, usually in 1st or 2nd gear around 9-10k, often when I'm merging onto the highway or passing someone. It's hard to explain, I lose power for 1/4 second, and it sounds almost like I'm hitting the rev limiter. If I keep on the throttle, it will power through the "cut out" and keep going up to rev limit. No check engine light or any other indications that something is wrong. It's a little unsettling for sure.

Nothing has changed lately with the bike, I've had the exhast for almost 2 years. This has only started happening recently.

Any ideas?

 

[bishop]

Had engine cut off on my previous bike, it was a Ninja 250R, spark plug was bad.

Also had the same thing on my cbr125, ignition wire was loose, so when I rev the piss out of it, the bike would shake and the wire would come loose.

Check these items.

 

[miweber929]

Hi all,

I have a 2014 CBR650F with 16,xxx km on it. Only engine mod is a CS Racing exhaust (also have a gear indicator). Occasionally the engine has started cutting out at high revs, usually in 1st or 2nd gear around 9-10k, often when I'm merging onto the highway or passing someone. It's hard to explain, I lose power for 1/4 second, and it sounds almost like I'm hitting the rev limiter. If I keep on the throttle, it will power through the "cut out" and keep going up to rev limit. No check engine light or any other indications that something is wrong. It's a little unsettling for sure.

Nothing has changed lately with the bike, I've had the exhast for almost 2 years. This has only started happening recently.

Any ideas?

What maintenance has been done to the bike? Plugs ever been changed or checked?

How about fuel, is it the same rank of gas or have you refilled a few times?

How’s your air filter?

 

[baugustine]

Also, just to baseline the vehicle, unplug the gear indicator to verify that is not related to your problem

 

[kylehondarider]

I seem to be having a similar issue but have not found a solution- here's my thread- https://650f.bike/threads/breaking-up-at-7k-rpm.2823/post-30811

 

[JRinKtown]

To me it sounds like a lean issue at high rpm if you haven't compensated with a fuel controller for the full system exhaust. I know the ECU will compensate somewhat but usually not quite enough, so at high rpm it misses. Weak spark or a vacuum leak are other possibilities.

 

[SpikedCola]

Hey all, sorry for the delay. I tested without the gear indicator, and no difference. After reading the service manual and psyching myself up, I worked my way down to the plugs, taking the fairings off, removing the tank... On the way, I had to take the air filter out, and found it to be a mouse house totally plugged up, even some seeds in there!

On continuing disassembly I noticed the air box snorkel has a large opening at the front, which they must have climbed into. I added some coarse metal screen over it. The plugs were totally fine, ended up replacing them anyway since I was there.

I should have known something was up, the exhaust smelled richer (think "carbeurated") and I had more popping and crackling on decel in the time leading up to this issue. Looking back it seems obvious that the engine couldn't breathe well. My bad. Thanks for everyone's input! The lesson here is definitely - check the obvious first.