Rattle noise at high speed.

Did a short highway run with a freind.At around 110mpf to 120 when i cracked the throttle wide open i could hear allmost a sray can rattle type noise.Now to mention lately when i take of my clutch chatters skipping.I tam pretty sure that what i am hearing when i am excellerating hard.
Any have similar probs?

I just read my post and i am not drunk!I have no excuses for my spelling.

ricerocket wrote:

Did a short highway run with a freind.At around 110mpf to 120 when i cracked the throttle wide open i could hear allmost a sray can rattle type noise.Now to mention lately when i take of my clutch chatters skipping.I tam pretty sure that what i am hearing when i am excellerating hard.
Any have similar probs?

Spray can rattle sound might be pre-ignition, so would check ignition timing with a strobe type timing light, including proper operation of advancer unit.

Would also adjust clutch pushrod (through the access plate on the sprocket cover.)

Have no comment about your spelling, because I never make misteaks.

Good Luck!

Well you called it right on the pre ignition!I pulled the number 2 sparkplug and it was pretty much melted away all other were running rich black dry sooty.
Could the pre ignition be caused by out of sync carb?

ricerocket wrote:

Well you called it right on the pre ignition!I pulled the number 2 sparkplug and it was pretty much melted away all other were running rich black dry sooty.
Could the pre ignition be caused by out of sync carb?

Could the pre ignition be caused by out of sync carb? IMO, no, because sync has minimal effect at wide open throttle when the slides are topped out and intake is mainly a function of the bore and main jet, but this is generic advice as I am unfamiliar with 28 flat slides.

Interesting that all other cylinders were running rich black dry sooty, which points to the one particular carb mixture as being suspicuously ultra-lean.

The usual suspects for ultra lean in only one cylinder of four cylinders are:

Spark plug dirty, damaged or maladjusted;

Incorrect spark plug heat range (??new NGKB8ES??);

Main jet clogged;

Wrong size main jet in that particular carb -- possible, but unlikely;

Fuel level too low in the carb feeding the ultra-lean cylinder;


Carb holder loose in the carb feeding the ultra-lean cylinder.

There are off-the-wall ideas, and others may likely have better advice.

Good Luck with the repairs and the speeling.

I forgot something :blush: when mentioning possibility of carb holder loose in the carb feeding the ultra-lean cylinder.

Even if "tight," the carb holder might be cracked or otherwise defective and allowing intrusion of outside air into the fuel mixture being drawn into the the ultra-lean burning cylinder.

But, what the heck -- one time I had a drink.

Post edited by: Patton, at: 2007/10/09 20:51

Patton pretty much covered it. The only thing I would add would be a valve out of adjustment and not closing all the way, especially an exhaust valve.
Or if that cylinder started out way rich a valve could be carboned up and leaking.
Or a burned valve if it was always way lean.
A simple compression check would verify that one, but a leak down test would be even better.
Ride safe.

Post edited by: The Milkman, at: 2007/10/09 20:53