my brother bought a cbr400RR recently. it runs well and stuff. but there's a weird clicky noise coming from the engine.

double checked with my dad's super 4 and my NC35. our bikes dont have the sound.

we brought it back to the shop for a check but the mechanic says its just a loose screw and they fixed it. however the noise is still there.

anyone knows what the problem could be?

It could be that the valve clearances need doing, as they progressively get less accurate it makes a bit of a tapety noise, at least that's what I've noticed. Then again I may just be nuts.

is it intermittent?
if so its just the fuel pump points you can hear.. nowt to worry about

Is it rev dependent? It could be the start of a hole in the exhaust.

Lets face the reality folks , its a noise at issue here and as good as we may think we are a noise can only be diagnosed by hearing it , not by this format.

True enough but at least we can give him things to look at and check.

ive had my cbr a couple of monthes now and also have heard a clicking noise. seems to be coming from the carbs. only happens when the fuel is low so the fuel pump theory could be true. although i didnt think they had fuel pumps???.

one more thing to try although not exactly a clicking noise, pull the clutch in see if its still there. adz400 the cbrs do have a fuel pump for sure.

If you leave the fuel turned off with the bike running for a couple of minutes and you will hear the fuel pump ticking noise.

I had a CBR4 whuich i changed the engine. That clicked for about 8 months then stopped. I never managed to figure where it was coming from or what caused it.
I changed it as the original one was had it. You could hear a tinkling noise before it let go, though I guess I'd ran it like that for a year or so.