R5 vs RD350 power characteristics

[gargantua350]

Hi All:

Back in the late 90s I had an R5; actually an R5 motor in an RD350 rolling chassis.  I had the typical set-up with 1st gen moto Carrera sport chambers and rejetted carbs and Uni filters...

I found an RD350 motor and rebuilt it with new pistons, seals and bearing and such.  I retired the R5 motor as it had at least 15,000 hard miles on it.  I set up and tuned the RD motor to the best of my ability.  Next I put the RD in place of the R5 with the same pipes and carbs(rejetted).  What's weird is that it seems the RD motor lacks mid range and top end power vs the R5 motor(piston port).  I understand that the reed valve motor is an improvement over the piston port for street riding. 

Has anybody had or experienced similar riding/tuning characterizations with the two motors?  Does the piston port motor inherently have more top end potential? 

thx

[Organicjedi]

 

[m in sc]

your rd motor wasn't tuned right.

[Dvsrd]

At least based on the early version of TZ350 vs TZ750, I guess one can say that the piston ported 350 had potential for more hp/displacement than the 750. But less for midrange power. After all, help midrange was what the reed valve is supposed to do.
If your R5 and RD had stock port timing, then it sort of makes sense that the R5 had more midrange, due to a shorter exhaust port duration.
I also believe I read something about the change from DS7/ R5 to RD250/350, where it was said that the RD 250 became a bit torquier than the DS7, while the 350 sort of used the reed valve to more or less maintain the midrange, while allowing a bit more hp on top.
But as Mark wrote, it could well be something off with your RD engine.

[m in sc]

owning both i can say that the r5 def runs out of steam earlier. the power is more linear .. but,  the rd is, when tuned right, just as good as the r5 in the mids and down low, but really rips over 5k where the r5 is 'ok' there.