Exhaust glowing red

[ChasF]

My R100GS is running badly (like the carbs are seriously out of balance) and I noticed when I parked it up in the barn without lights on that the left exhaust is cherry red. I assume this indicates a knackered exhaust valve??. Tappet rattle is about the same both sides as near as you can tell, I'll check tomorrow but I guess the damage is done.

 

[Steptoe]

the damage is done.

As that great philosopher of airheads Neil Young once sang.

 

[ChasF]

Right, I've checked the valve clearances. The plug colour is about right and the same both sides but the exhaust is still glowing. Anyone any ideas? Bike runs well enough - just a bit uneven just above tickover, I will sort the carb balance when I have time.

 

[Womble]

Are all the throttle cables seated properly? Make sure that you check both ends as well.

 

[Kenny]

I think you'll find that the exhaust glows red on tickover or low throttle settings...so check the pilot mixture screw and the sealing washer around it...sounds like a weak mixture on low throttle!

Back to my Becks now

 

[Beemerboff]

Retarded timing will do that too , but just why it would be retarded on one side only I have no suggestions.

I remember tuning a mates transit van - we turned the distributor one way until the manifold glowed red, then turned it back the other way until the engine ticked over fastest , just a smidgen back from the point it started to slow down - he claimed it had never gone better though I wouldn't try it on anything I owned.