Mystery rattle from a '90 Revere

[zzzzzzz]

Hello! New around here - glad to find this group. Writing with a question that I'm trying to troubleshoot:

I'm on a '90 Revere with about 72,000 miles on it. Recently (weeks? a month? two? who knows) there's been this rattle from the bike that I can't identify. It sounds like its coming from the front, kind of a metallic, tinny rattle. It reminds me of the type of sound from a decade ago when one of the exhaust pipes on my first bike, an old Yamaha 250, shook loose. (I was, erm, new to bike maintenance.)

Now the rattle only happens while the bike is moving, and only between 4000-5000-ish RPM. Sometimes a little less, sometimes a little more. Most often when I'm accelerating and then let off. The rattle used to come and go but is now a bit more constant, while moving in that RPM range. I've checked for obvious loose things, and all is good there. Cam chain or oil pump chain would make the noise at a standstill too no? 

I'm a bit stumped on what it could be. I realize this diagnosis is probably far over my pay grade, but I want to DIY if I can. Any tips on where I should start checking? Thanks!!!

[Yellow_melos]

Hello there, welcome to the forum.. this is a little slow these days and everyone seems to use the facebook groups but some people still post here.

anyway.. down to your problem.

if this is only happening when you are moving then it will be drive train related.. so could be wheel bearings, drive shaft, gear box or speedo as these only move when you are moving.
if it is only happening at that kind of rev range then it could be input shaft related ( unless it is specific gears ) if you are in neural and and rev the engine to that speed i take it does not make the noise ??

but it could be just something that vibrates to point that you can hear it at the speed. first thing is to check all the bolts that hold engine and and bits on to confirm everything is ok..

they work as a process of enmination.

1. does it do it when in neutral yes/no
2. does it do it in every gear yes/no
3. if you are travelling at high speed and pull in the clutch ( and close the throttle ) can you still hear it yes/no


and so on..could be something starting to wear.. could be something is loose.

[brendan0]

...and does it rattle on full lock, left or right? indicator wires made a funny noise on mine that I struggled to trace (big fairing for wires to slap off!).

I wonder if original downpipes are double-skinned like some 80s Hondas? They never wear out, so at 25+ yrs old, the inside layer may be loose? (I may be talking boll@cks though!)

Good luck

B