[Krieger]

Hey all, I was just wondering how you can diagnose if the engine is running lean or rich and how much does it deviate from ideal A/F ratio. Asking because I´ve been thinking about getting a Rapidbike Easy. Thanks in advance

 

[atinc]

Well well,if your running rich you should see black marks around exhaust tip,also blackened spark plugs,
Your running lean,car or bike wont accelarate like old times.accelaratiion might be flat.
İf you are wondering about duke 390.have checked the ecu.ktm dealers should have a computer to check that.
Back in old times when engines were carburated,you had to adjust from time to time.
Nowadays ecu handles that

How to Diagnose Rich and Lean Conditions - TJ Brutal Customs Support

When tuning a bike for the first time, it may be difficult to figure out if your bike is running too rich or too lean. Both conditions can be very harmful to yo

support.shoptjbc.com

 

[duke of Ca]

Hey all, I was just wondering how you can diagnose if the engine is running lean or rich and how much does it deviate from ideal A/F ratio. Asking because I´ve been thinking about getting a Rapidbike Easy. Thanks in advance

Did you do something to bike already to make it run rich? As far as I know the bikes are all lean running stock thats why we get the fuelx/rapidbike modules.

With that said Im intriqued with "atinc" response. I have. and have always had black specks on my exhaust. Bike ran stock, I added fuelx, the bike runs much better the specks remain the same, no more and no less specks. bike runs great "as is" so no reason to mess with it. but I will eventually check the spark plug at next oil change to see what it looks like.

However, my opinion on the lean or rich is.. its running lean if stock unless it was remapped, than I agree check spark plug.

 

[KTMasean]

The 390 engines run a little lean in the O2/lambda controlled phase (longer for the 2nd Gen) but slightly rich in the open loop phase.