strange random metal tap at idle that almost kills the bike

[th3funkyfresh]

it runs perfect the whole time driving and idle fine when randomly there is a metal ting noise and it almost dies then continues running fine usually for a long time to then will randomly do it again only ever noticeably does it at idle

 

[Fire-medic]

Too-low of an octane of gas will cause detonation, very-harmful to an engine. It can sound like a quick metallic, repeated noise, like ball bearings being dumped onto an anvil.

https://help.summitracing.com/app/answers/detail/a_id/5007/~/engine-detonation

 

[th3funkyfresh]

Too-low of an octane of gas will cause detonation, very-harmful to an engine. It can sound like a quick metallic, repeated noise, like ball bearings being dumped onto an anvil.

https://help.summitracing.com/app/answers/detail/a_id/5007/~/engine-detonation

I will try that but it’s not a bunch tings at once it’s always just one ting noise that does it

 

[Radioguylogs]

The sound may be cause or it may be the effect.

I had one blocked pilot that caused the bike to trip and stumble occasionally on idle. The parts in the engine make unsettling noises when it happens.

JAT in case it helps.

 

[Fire-medic]

The sound may be cause or it may be the effect.

I had one blocked pilot that caused the bike to trip and stumble occasionally on idle. The parts in the engine make unsettling noises when it happens.

JAT in case it helps.

My experience with obstructed pilot jets is that the idle is irregular, exhaust header pipes run much-cooler because the fuel/air mix isn't igniting, since it's off-of what it should be (use an infra-red gun, or put a spritz of water on the pipe) and that as revs rise to mid-range the obstructed cylinder(s) will fire normally, since it's above the pilot jet range of operation. The bike smooths-out, and makes more-power. Let the bike return to idle, and it begins missing once-again.

I thought of something-else. With a properly-carbureted bike, the cam chain is under constant tension. When the bike is having irregular carbureton events, the cam chain is not under constant tension, and it can slap-back, which causes a noise as the slack happens and then is taken-up. A worn cam chain would exacerbate this sound, along with a poorly-carbureting engine.

 

[Wirenut]

Does it sound like a knock? Does it speed up when the rpms increase? I’m having the same issue and am hoping it’s not the piston rings. It started immediately after I filled up at the gas station. I’m running flat slides and plan on taking those apart sometime this week.

 

[th3funkyfresh]

well guys mine has not done it since switching to 93 octane fuel so i think that was my issue but i will report back if it does it again

 

[Wirenut]

Hmmmm. So crappy gas could be an issue. I’ll be messing with it this weekend.

 

[Fire-medic]

Look inside your faux tank cover for a recommended gas type. I use regular from a name brand station. But if it works for you OK. The lowest octane which does not allow detonation is adequate.