Werks 2058.

ebay auction 180721760017

I'm seeing the same thing Murnan is with this engine. I honestly dunno why they went away from the bore/stroke they had before, which was the same as the old Vspec and Speed. I would have kept with the old short stroke combination and changed some port timing and combustion chamber around... There is a TON of bottom end to be had with the older engine with a modification of course.

But now we work on what is out. Improving this engine isn't a problem but i don't feel like its the all around engine the old JX .21 was "same feelings twards the new speed and Vspec" as i like an engine that makes the bottom and will hold top end as long as possible while still managing to stay smooth and the old Vspec, Speed and JX .21 did this and REALLY shined once changed up a bit in my shop BUT in saying that everyone has their own preference on what they like. Myself i want it all.. top to bottom, smooth, run time, ease of tune with a great carb, longevity etc!

Ditto your JX21 B01A Mod engine is awesome mine is still running strong power is abundant but very smooth one of my best engines in my OS arsenal.

Very glad to hear Bigjay! Love those mills myself!

+1 to that statement. My AB Mods JX21 B01A is one of my favorite
engines in my arsenal too. I can't understand why Mugen went along
with the new generic configuration offered to them. They dumped
the long l.s.n. in the carb and settled for the three port sleeve.
I think if I had to replace my JX B01A engine, I would buy the Arrow
Racing GTR.21 and have it modded.

Does the eb mods head button make a difference on the bo1a?

I cant speak for Ed but I do a modification on the B01A head button that makes a world of a difference. WELL worth it modification that picks up not only the bottom end but throughout the entire RPM range.

yes. the eb button is excellent on all OS based short stroke .21's ie' vspec, JX, original Speed, etc etc..

OK so the os 2060 is not that good on this motor either!? What is the difference in performance between 2060 and 2058?

I have a few 2058 pipes at home but am running mugen so they dont fit properly, is there a different tighter bend header that you can run in the mugen for the 2058 or is it just bend the stock one till it fits?

use the 2060 header with the 2058 i have and have not noticed any change in performance i also run mugen and had that problem with the werks and other brand pipes

Just thought id chime in that comment. I ran an arrow with the ninja carb (arrow carbs arent that good, although i heard it has been improved) and ninja crank installed. I tried a few pipes and still unsure on what to use (probably stick with 2060 or give the RE10 a go) but personally think ill keep using my old ninja parts and running arrows. I dont know if it was all in my head but with the changes i got solid run times and more power. I could tune it finer with the carb and had more power bottom and top than any person needed. Im not running down the new ninaj motor or trying to re invent the wheel, but to out it bluntly if i spend any more money on rc gear my wife will shoot me I tried it and it works for me everyone is different and thats what i love about this sport, but the arrow motor gives guys like me with little cash but a few os/ninja spares a chane to remain in the game.

Well this is probably going to start a war so here goes,

I honestly feel, based on what I've seen out of both my Ninja's (BO1A and BO2), the 3 port is just better. Now I am running the EB Mods backplate on both Ninja's and it does increase the top end on the BO2 as well as smooth out the bottom. The new Ninja tunes the same as any other OS motor just as long as you don't think the same way as the older long needle carbs. I've never counted how many turns out from flush the needles should be, I just look and listen to my engines and tune them to give them what they want. I've never once thought the new short needle carbs were hard to tune. To me, my BO2 tuned in the same way as my BO1A, same result. But compared to my BO1A my BO2 is absolutely better and no, I don't run a werks pipe on it either. I run the same 2042 Ninja on the new mill as I do on the old mill and I still get 12 min runtimes in truggy with it.

Is the front bearing size the same from both B01 and B02 engines?

Yes it is.