Just started to break in my rebuilt engine today,I used about 3/4 tank and when that is done,It should be safe to let'er rip.Anyway I Added a 40:1 premix fuel in addition to what the oil injector does.Three questions;(1)Is it normal for the fan to run more often during break in?(2)Is it normal for the engine to sputter during high rpm,I would flick the throttle and it would actually run faster at 3/4 throttle than A wide open "blip"?The engine ran fine before ANd the only thing different is the wiseco piston.Are these things from the extra oil?
98 sport 400

 

I can tell you that I hate engine break in's. They always run terrible until the premix is gone and probably the next tank of fresh as well. Yes, the engine will run hot until the new metal parts losen up. Keep an eye on your coolant level while the air in the system gets purged.

See how the WOT is after the second tank. As it loosens up the WOT should be a whole lot better. The extra oil shouldn't have anything to do with the extra heat right now. Only throttle response and running.

What was the 3rd question?

 

biggin,

I would wait until the break in gas is done before you go about changing or adjusting the carb. Assuming that you are running at a slower speed for break in, it isn't unusual to have the fan come on. If you noticed, the Wiseco piston has bigger fuel holes in the intake side of the piston. It could be causing your motor to run slightly leaner than it did with the stock piston. Like I said before, I'd worry about it when the break in gas is done.

P.S. You shouldn't be running it WFO while breaking in the piston & rings.

 

No,I am not running wide open,just blipping the throttle and it revs quicker with 3/4 blip than full blip.I was just trying to keep from running the same rpms to long.I am running at slow speeds and I would shut down every 20 minutes or so and the fan stay on.

I had no bugs following me around like they usually do,maybe I could ride on the road and tell the cops I'm spraying for mosquitos.




Xcrider,the 3rd was,Are these things from the extra oil?