Read this plug

[IDAHOSPUD]

Bike running pretty good. Using a apt billit smart carb. 65 clicks out. Seems like if I go leaner, the bike runs too crisp, bottom kind of lacking but revs out strong. That is at least a year of use on the plug. 45-50 to 1 oil mix.

That plug is showing rich correct?

 

[motopsycho87]

Looks a little rich yes. 2 stroke ratio will have no bearing on the colour of the plug. Air / fuel only, unless you're running 20:1!

 

[AZRickD]

Mine would be a very dark brown after a year.

Do you tend to lug? Not warm up the bike? Not much on the pipe ?

 

[IDAHOSPUD]

Mine would be a very dark brown after a year.

Do you tend to lug? Not warm up the bike? Not much on the pipe ?

Not always but yes on lugging, lots of 1-2nd gear riding, always warm up 1st, sometimes on the pipe, I tend to have to remind myself to get the revs up and clear out the pipe. I'm going to go leaner by one and try it. Thanks for looking.

 

[Jakobi]

I could NEVER get the APT running well across the entire rev range. I have no doubt the bike runs great from 1/4 throttle upwards and pulls a gear high lugging really well. Probably a bit fluffy under which will be skewing your readings.

Also, really its only showing the last state of the engine so if you've been idling after washing it or the likes it will show rich.

My PWK tuned engines show that ideal chocolate/coffee coloured insulator with a small amount of build up around the outer and down a few threads.

 

[IDAHOSPUD]

I could NEVER get the APT running well across the entire rev range. I have no doubt the bike runs great from 1/4 throttle upwards and pulls a gear high lugging really well. Probably a bit fluffy under which will be skewing your readings.

Also, really its only showing the last state of the engine so if you've been idling after washing it or the likes it will show rich.

My PWK tuned engines show that ideal chocolate/coffee coloured insulator with a small amount of build up around the outer and down a few threads.

I am finding that the APT is not perfect, across the whole rpm range also, but i can live with it. I like the overall feel, even if its not perfect. I do think that it runs better than a PWK across the the altitudes that i ride ie 3000-9000 feet (1000-2700 Meters) especially high elevation. Jake, in a given year what is the range of elevation you ride? As always thanks for sharing your thoughts.

 

[Jakobi]

I am finding that the APT is not perfect, across the whole rpm range also, but i can live with it. I like the overall feel, even if its not perfect. I do think that it runs better than a PWK across the the altitudes that i ride ie 3000-9000 feet (1000-2700 Meters) especially high elevation. Jake, in a given year what is the range of elevation you ride? As always thanks for sharing your thoughts.

As long as the rider gels with the overall feel and the engine isn't eating itself alive then that is the main thing to consider (even above a richish plug reading).

We don't really get elevation here on the big island. Mount Kosciuszko is a mountain located in the Snowy Mountains in Kosciuszko National Park, New South Wales. With a height of 2,228 metres (7,310 ft) above sea level, it is the highest mountain on the Australian continent.

For me, home is around 350M and riding areas range from sea level through to around 1000M at most. Temps only vary between about 10-35C across the seasons. Biggest influence here is humidity which varies greatly, even throughout the day.

 

[whtshdwwz]

The more I read about the APT "super carb" the better I am finding my carb. I am sure I will be blasted here by the true believers but I can not see how a single metering carb will ever have the flexability of a nice tuned Keihen.