when starting my Brumby in the cold weather lately I have noticed an exhaust noise or engine noise, not sure which but its a sort of 'rattle'? or ''knock'? (sounds like grrrrr) which occurs at about 1800-2000rpm under load and then goes when over those revs

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After driving for about 3 minutes or so the noise has gone - or I can't hear it!.

 

Any ideas.?

Edited July 9, 20178 yr by KiwiBrumby

NOBODY got any theories?

I'm not familiar with the specific year / model / engine.

 

But it sounds to me like you are describing loose heat shields on the exhaust system.

 

Buzzing that happens at specific RPM ranges and comes and goes depending on temperature.

I'm not familiar with the specific year / model / engine.

 

But it sounds to me like you are describing loose heat shields on the exhaust system.

 

Buzzing that happens at specific RPM ranges and comes and goes depending on temperature.

 

+1

I'm not familiar with the specific year / model / engine.

 

But it sounds to me like you are describing loose heat shields on the exhaust system.

 

Buzzing that happens at specific RPM ranges and comes and goes depending on temperature.

It's a 1984 Brumby (BRAT in the US) with an EA81 and four-speed, i.e. stock.

Assuming it is a 4 cylinder boxer, if the timing belt slips a couple of gears on one side, the engine will make a louder noise than normal, and have a little vibration.

Assuming it is a 4 cylinder boxer, if the timing belt slips a couple of gears on one side, the engine will make a louder noise than normal, and have a little vibration.

It's a pushrod motor, no timing belt.

My 87 Brumby (Brat) with 206K km (130K miles) has a big end bearing clatter on cold start up but goes away once oil pressure builds up  after a few seconds  - engine a little tired - uses a litre of oil /1000km - apart from that still run fine.

And agree ea81s have gear driven cam plus pushrods / OHV

Edited July 16, 20178 yr by subnz