Inlet tract discolouration

Legs

Legs

Hero member
Location
Adelaide Hills
One for the brains trust.
Finally started work on the RGS. When last ridden it started to 'ping' under load going uphill.
Yesterday I took the carbs off and noticed that the centre cylinder inlet tract was slightly discoloured whilst the other two tracts were clean.
Anybody come across this and maybe know the cause.
Thanks in advance.
 
stored too long with petrol tap leaking; centre float valve not sealing and fuel quietly evaporating away in the inlet tract. Root cause: lack of use...
 
Legs ( unfortunate name in context of "walking a lot" not riding, blank look on face here ). All a best guess or assumption(s), outside chance a low quality high impurity/damaging additives fuel, giving rise to incorrect flame front initiation to piston angle.

Perhaps causing an early residue indication, given only one carby then ( not all three ), lucky you may have a carby/fuel system leak as AndyW indicates, with the lack of use missive....naughty Andy, a smile here.

As for pinking, a good quality dial back timing light is a good investment, does a quick check of actual amount of advance ( retard ) even on a basic impulse cam, more accurate is a degree wheel as discussed in prior topics. 120 series 2 motors are prone to untoward pinking for some obscure, to my mind, reason. Compared to 180 motors, broad indication. Happens mostly when you give it gobs of throttle at moderate rpm, mostly cured with correct 32DBTDC maximum timing. Curve shape also a significant factor on RGS type engines. HTH j. **** just checked on dial back timing lights, wow it has changed, real bargains out there now, $100 gets a digital with rpm function, a must have for the workshop, i recommend to all. Innova seem popular.
 
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What? You want me to think of your "dial" every time i strobe a crank shaft??? Have little concern about your impulse advances Cam... there is a waterway barrier there to here..... raining and raining here... was sorting a used air con install, of course it rains... wait for another day... perhaps...j
 
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