OS R2104 engine Thread
 

Another new OS motor.

Coming soon from O.S. Engines is the new 3.5cc R2104 competition nitro on-road engine. The 9-port power plant was developed with this year’s IFMAR 1/8th Nitro On-road World Championship in mind with an updated liner and piston increasing overall torque while the DLC-coated crankshaft offers improved transition between low and high RPM. The engine also sports a new combustion camber insert with a silicone O-ring, adapted from O.S. Engine’s off-road engines, preventing dust and dirt contamination. The R2104 is rounded off with a new design cooling head in a 2-tone black and red finish with white laser-engraved graphics. Beside the single engine O.S. also offers a combo package including the T-2080SC muffler and MR02 manifold.

https://cimg8.ibsrv.net/gimg/www.rct...f28a527c32.jpg

OSR2104
 

https://cimg6.ibsrv.net/gimg/www.rct...14f5960bda.png

Damn, sure it will perform the best

I wonder if the choice of 9 port was a commercial thing or realy a performance choice to add some tiny extra perfomance.

Just had the same conversation and question... I trust OS. I think it will help performance.

to some other 7 ports owners, they would like to find out if they can use the sleeve set to their 2103, 2102,...housing

I think its more a top end thing than anything else. Thats really the only place a OS lacks to say a MAX

Is it? I have seen team engines from Kabuto and Maxima going like crazy. I say "team engines" because I have seen the standard customer engines and they are just OS stock with their own designed head but the timings are not that different from the MAX.

Based on having run the standard R2101-R2103 motors, to me as a customer and end user it seems to be more of commercial "Trend" Alternative offering by OS. I am highly satisfied with the current mills, and although the new 9 port may offer some performance increase, it may just be so incremental that as Roelof stated, its full potential or the benefits may only be seen by the Pro's. It may just be a bridge gap and a "Mental Placebo" lol.

I'll stick with my older R series motors, unless perhaps for some reason the replacements parts for this new motor seem cheaper than previous. Yet with Horizon now handling the US distribution, i am sure this will not be the case!

They look more and more like a Novarossi based sleeve to me..

Yes, the new sleeve is also compatible and can fit the the R2101/R2102/R2103

So what has changed on the crank?

I haven't had the crank in my hands. Looks like they increased the size of the counterweights. I will have to check the timing once they have arrived.

Other than part no and size of the counterweight, any timing change in the new crankshaft?

Timing same as the R2102
Shape of the crankshaft counterweight has a slightly different design.

I found the 9 port took a lot longer to break in than the 7 port.

Have others expierienced this too?