Over revving.

[Granty]

Hi.

 

I've a 2021 Honda CB125R with the following problem. On a cold start the bike sits there at constant revs with no throttle inputs. However there has been a few times when the engine revs increase to about 300/400.

 

After two or three seconds the revs drop off. A couple of times its done it twice before it reacts as normal. I'm using E5 fuel only. It doesn't do it when its warmed up.

 

Anyone out who had the same problem and got it sorted.

 

Regards. 

[Tiggie]

That sounds like the Fuel Injection automatically adjusting the mixture to keep the bike running properly until its warmed up. Older bikes would of had a choke lever you had to do manually

[billy sugger]

My CBF600 does exactly the same on cold mornings. There is a flap in the air box that's connected to a vacuum tube, and this closes off the flow of really cold air into the block

[manxie49]

My Beamer does it when it's cold,  As Tiggie alluded to, I think it's just the bike doing what chokes used to do in the cold weather.

[Granty]

Hi.

Thanks everyone. Because of what I've read I'm not overly worried about it now. 

Cheers.