is this engine strong enough for my CRT or do i need to get the .28 ninja

I just ran my new JX-21 this past weekend in my MBX5T. It has PLENTY of power for a truggy. The only reason to run the .28 motors is to bash with. They suck more fuel, are heavier and turn slower lap times at the track than the .21 motors.

is the new one better than the old one

depends where you live Tony. 21 in a heavy truggy is a struggle at high altitude.

JLINDS- Where do you live?

central texas

+1 tony i just ran one in the car sat, wow i like it alot. the new ninja is nothing like the old one. the jx motor is made by os with the new 28 block,and the crank is hardcoated.i had both grp ninja's,os vspec,jp mod vspec,p5x and im very happy with the smooth power and top end of this motor.

check out the July issue in RC CAR magazine, they go into detail about this engine and its an AWESOME motor for any truggy! they show detailed pics and went into detail on all the engines internals. excellent review!

Hey tony what pipe did you run in the 5t with this engine? i ran it on my 5r with the fast lock 2053 last saturday and it felt really good but i felt like it could use more top end.

the only pipe i have currently is the j-p3 would that be good or do i need to look for something better

The OS 2060 pipeset is whats recommended from what I have seen.

I actually ran it with the MSR1005 pipe and header. This pipe makes very good mid-top but a little softer on the bottom. I'm going up to EB Mods perhaps next week to throw the JX-21 on the X-dyno to see how she runs with a few pipes. Ed has the 2050, 2060 and his EB Mods pipe. I have the MSR1005 and Novarossi 9853. I'm also going to test it with the Innovative Designs 6mm and 7mm carb inserts.

i ran mine with the new 2042 ninja pipe which looks like a 2060 and the new short header. very smooth power with lots on top. it was killing my buddy's stock vspec with the same setup on a 5r and another's ae also with a vspec.

not sure but i think the new ninja and the os2060 share the same efra number which would suggest they are the same pipe

GOOD!! both mine just got here.

I started with JP 4 on the JX after about 5-6 tanks of break in. Had it tuned to temp right at 198-202. With this set up had lots of top end and my MBX5R was just stupid faast on top.

Then I put the Ninja (efra) 2042, which just seemed to smooth out the entire power band. I had to lean it some more because on the bottom it was 'gurgling' before taking off. Leaned it out and with the 2042, power just seems to be displaced more evenly all over, and my bottom 'gurgle' problem seems to have been solved. Bottom end is now very snappy. I am running the 2042 tonight on a very technical track.

So it seems like on a short technical type of track, go with the 2042.

On a track with more straights JP 4 seems to give more on the top side.