Triton Starting

[hammo]

Hi guys i have a 1971 750 triton , it has a boyer ignition and mikuni flatslides , when it was running it had a good spark and the battery shows a good 12V , however now i cannot get her to start , the plugs are black , could it be a carb problem ? thanks guys .

[R]

First thing to try is new plugs, and see if it starts.
Or clean those plugs, and see if it starts.

If it starts, maybe time to look at the grade of plug - maybe a grade hotter required. Or less pottering around town. ?

Then - does it idle cleanly ?  Adjusted the idle mixture lately - if its chugging black smoke (we can't see your bike running), then definitely a carb problem.

Fuel quality can also affect dirty plugs, burning oil can affect dirty plugs, and weak ignition can affect dirty plugs, so its time to consider those too. Battery voltage still good - measured it as at least 12.3x volts ??
Over to you...

[Revband]

Pretty much as R says, but some Triumph engines are prone to melting the piston if you use hotter plugs, so I would not advise that, also how long is it since the bike was running?, is the petrol stale?.

[R]

While urging caution about going to hotter plugs, if the ones in use are a grade too cold, then what other answer is there ?
Assuming is not fouling from oil...

Stale petrol possibility also needs to be sorted out - these days, if all the lighter fractions evaporate off, whats left doesn't seen to burn !

[Rex]

"Plugs are black" is too subjective to be helpful. Plugs are often black when there's starting problems, but that doesn't mean it's the primary cause of the non-starting problem. Soaking wet would obviously need sorting, but before urging plug grade changing, clean gap and check the plugs are actually firing first.

[Revband]

Hi R

I was referring to not using a hotter grade than Triumph recommended for the engine originally, obviously if the wrong grade (cooler plug) is fitted now then no problem with fitting a correct hotter plug.