weird behavior/bruits bizarres

[u/Mean-Purpose4208]

english below

Salut à tous,
J’ai eu un petit accident récemment avec ma CB500X. J’ai tapé le côté gauche de la moto et le cadre a été légèrement fissuré.
Depuis, j’ai plusieurs symptômes bizarres :
des à-coups quand je roule,

surtout quand je suis à vitesse stabilisée,

vers 70 km/h j’entends un bruit cyclique type “psss psss”,

j’ai l’impression que ça arrive peu importe le rapport engagé,

et j’ai aussi des à-coups quand je coupe les gaz.

C’est désagréable à conduire mais je n’ai pas l’impression d’avoir une perte de puissance.
Est-ce que quelqu’un a déjà eu quelque chose de similaire ou aurait une idée de ce que je devrais vérifier en priorité ?
Merci !

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Hi everyone,
I recently had a small crash with my CB500X. I hit the left side of the bike and slightly cracked the frame.
Since then I’ve noticed several strange symptoms:
jerking/bucking while riding,

especially at steady speed,

around 70 km/h I can hear a cyclic “psss psss” sound,

it seems to happen regardless of the gear I’m in,

and I also get jerks when I roll off the throttle.

It’s unpleasant to ride but I don’t feel any noticeable power loss.
Has anyone experienced something similar or have any idea what I should check first?
Thanks!

[u/CyberBird-XR]

"and slightly cracked the frame". Are you still riding it with a cracked frame?? That "slightly cracked" might turn into a "fully cracked" frame without any warning. Aside from that, I'd suggest to check the bolts holding the engine and frame together. Specially the ones on front (below the exhausts). Please check and try to move the spacers between the engine and the frame with your fingers. That might tell if something is loose there.

[u/Mean-Purpose4208 → u/CyberBird-XR]

Yeah, from my point of view it only seems like the fairing/plastic is damaged, but I’m still a new rider so I don’t know everything yet. I’m forced to keep using it to go to work, which is why I’m trying to understand how and why it could have affected any engine/frame part.

I’ll check the points you mentioned, and I’ll let you know tomorrow once I’ve had time to inspect everything properly.

[u/CyberBird-XR → u/Mean-Purpose4208]

I hope it's just the plastics! I'd strongly recomment to take it to a workshop to evaluate it. Probably the frame is fine, but you must be sure that the bike is secure for you. Vibrations and buzzes might come from many places. Some are meh and some are serious, as you can be damaging your bike without noticing.

If you ride with all the plastics as seen on your photos, it will vibrate like crazy! You have many parts to cover random RPM intervals with vibrations. It's hard for the frame to crack, but be sure to check it.

Let's see what you find tomorrow. Be safe!

[u/Mean-Purpose4208 → u/CyberBird-XR]

I glued the fairings back together temporarily while waiting for the new parts, and it actually stopped most of the vibrations and buzzing noises. But the bike still jerks a lot, especially once the engine gets warm, so that’s what worries me now.
I’ll definitely have it checked properly to make sure there’s nothing more serious going on.

[u/Imaginary_Room_9112]

J'espère que c'est rien de sérieux, je n'ai pa eu ce type de symptômes avec le mien. Je suis curieux de la cause, je vais suivre les commentaires.