I think the temp readings are a combination of differing factors, but I think the main factor is the head design.

My Ninja MR21- R01A will not run very good until it hits at least 260F+. At 240F it is so fat it would hardly even shift into second gear. 275F- 280F seems to be the sweet spot for me.... performance, safety and fuel mileage wise.

If you have an Exergen DX-501 be careful..... the sensor window will contact the glow plug and damage the temp gun. Put an exhaust gasket arond the nose cone of your temp gun and you'll prevent it from going to deep into the head.

Or just don't measure the temp, but look and listen to your engines performance.......

thanks for all the great input!!!

Hi Mike,,

I know it's been a while since you posted this info.. , but would you recommend this brek-in procedure for the .21 Ninja..??

Thanks in advance bro..

The head is shorter than most other 12's. Plus the opening by the glow plug is wider so you are reading differently than most other motors. I couldn't get my car to shift (still breaking it in) until I got the temp up to 210. I thought that might be a little hot. But, it isn't really. It's kinda like reading about 180 on other motors. Even though people are saying that the motor runs good at 270, it's probably more like 240-250. Just reads higher on this motor. Will take a little while for me to get used to it. Just my 2 cents.

why wont the pipe header clear the belt tentionor?

It's probably more likey the that the "other" engines are actually at 270F as well, and the Ninja head design allows a more accurate reading by allowing the temp gun to reach deeper into the head. Mine runs way too fat at anything under 250F. 270F wakes it up and I feel that temp is safe for me. Actually I barely made the last pit stop in Toledo while pulling out of the pits at exactly 5 minutes to go in the main. I came in bone dry! I may switch to 25% for fuel mileage or lean it a tad more. I still have both extra shims in the engine as well!!

There is currently NO better engine for the money...... or even $100 more.... until the Mario Rossi mod come out

The MRT.12 is out, someone bought it around US400 and US90 for the new FL pipe.

Who ever requires a good price on a brand new BOSS .12 Engine + conical manifold and pipe let me know. Offer starts at $200. You can either PM me or email me on [email protected]

How often is everyone changing the con rods on the .21 Ninja's?

If you have broke a rod, how much fuel did you get through it before it let go?

where for $400?

Hi there

tot of getting one MRT too

any feedback on the engine? or pics?

heard that the whole engine is almost black?

Anyone?

I've worn out a piston and sleeve and kept the rod for the replacement p/s. It all depends on the play in the bushing...any play, replace it. It should be snug.

The 02 rods (come with R01A) last even longer.

Sohlman.... What's good dawg? Ready 4 301?