settings for 421b

[miami fanatic]

i have just purchased a421b motor. i heat cycled it for about 8 tanks. ran it one week of racing and it lost the pinch the motor ran at 270-275. i just pinched it again and was wondering if anyone has any suggestions

 

[s14det]

the temp is to high I would think...I ran my Rb ws7 at 230ish and it lasted me 8+ gallons. A friend of mine runs the RB 5 port and he got almost 5 gallons, with temps in the 280ish range. He even had a aftermarket cooling head on it. But yours only lasted not even a gallon, so something is wrong

 

[Nitro_Freak]

maybe there was an airleak somewhere or dirt got into the engine somehow. 270 isn't too high, make sure you're tuning by performance, not temp (unless temps are 300+)

 

[miami fanatic]

There was alittle dirt on top of the carb when i pulled the air cleaner off would that cause the problem

 

[miami fanatic]

i was wondering if anybody else is running this motor i would like to know what your low speed needle and high speed needle is set at?