So ... after owning CBR F3 and then CBR F4i, i bought a 2001 CBR 929 3 days ago. I noticed that it makes a weird "psst" sound randomly. I mostly ride at the speed limit in the city and I though this sound comes from a car or truck nearby, but no... 2 times now im riding on a random tiny street with around 20kmph (12mph) and i hear this sound again, it sounds like a turbo blow-off valve or even like someone is sneezing, something like a sound from relesing air under pressure, short and fast "psst". Any ideas what th is that?

 

IDK, stay away from the baked beans maybe? LOL, sorry couldn't resist the inner child.

 

Hahahaha ahhh cmon , i was so happy that someone replied so soon hahaha But no, no baked beans were involved hahaha

 

Your tire pressure is staying up ok?

 

That was my first thought, but it happens on nice flat road, no bumps, nothing, it just happens. Idk if it's realted to faulty cooling system, air in the radiator hoses, idk... it happened today twice at around 85-90 degrees celsium , which is normal temperature... no overheating. And in the city i ride for 15-20minutes filtering the traffic.. Never had such noise on my cbr F3 or F4i, weird af

 

Other than what @IDoDirt stated, which I think is probably the proper answer, have you noticed anything coming from the exhaust (the bikes, not yours) when it happens?

 

Not really... the exhaust is behind me, i ride alone most of the time, idk if something comes out of the exhaust. My F4i was modded and it popped out flames ofthen on downshift, but the sound was completely different. I will take a look at the exhaust tip tomorow, but i think the sound comes from the front/right side of the engine, not the back where the exhaust is located. Just in case i will take a look at the exhaust header bolts, you might be right its realted to the exhaust... idk, its weird.

 

I am simply spitballing the exhaust idea. The fact that you think it comes from the front right makes it sound like it might be coming from the radiator area

 

@hamlin6 Hamlin, you brought tears to my eyes, that was so subtle and funny, I couldn't stop laughing. You just slipped that one in there... nice.

 

Have you checked for a loose spark plug?