RZ/RD 350 & Misc. 2-Stroke Tech BBS

TIG welding to join the cones and MIG in a few spots to join the header tube and muffler flange in the correct position

Thanks MK. More ignition advance will get close to detonation limit. PV is fully open now at 7300 rpm. I will try playing with later full open PV next.
I might get more dyno time testing a set off Jollymoto GPs pipes against stock F2s.
Damn it is a big job building pipes but a fun challange

I made some expansion chamber exhausts to move some power up the rev range to max at 9300rpm and did a dyno run.
Here are the results, the red baseline is with f2 pipes and stock crankshaft. Blue is 4mm crankshaft and custom pipes
Thanks to MK for his pipe building guide

According to Engmod air/fuel ratio is pretty signifacant. Good for 2,6HP on 11afr vs. 12afr

Today I had the RD383 dynoed. Dont know if I picked the wrong date, but temp was 6 deg. celcius and 99,6% humidity. The rented box trailer lock would not open and I had to use my hobby trailer to transport til motorcycle to the dyno shop. When I got back the front disc brake had allready started to ...

Dyno time is not that expensive. The build is now complete and bike has had initial startup, runs fine at idle, and has good 125psi compression on both cylinders. But due to no winter ensurance I cannot ride the bike. Outside temp is now 0 deg. celsius and needs to be at least 7 deg. to do proper dy...

Here are the final EngMod calculations. The rd350 project file I got was apparently for a heavy modded bike. Having measured all the components of my engine and put in that data, here are the final dyno simulations. Current bike: simuated: 31.63 x 2 =63,26 HP in motor /1.11 = 56.99 rwhp real life dy...

Thats what I did too 1,25mm bigger

These are the gains from enlarging the ex port down to match piston top at BDC

I dont know the stock roof angles, but in the RD350 file from engmod (Niels) the roof angles are
A: 0 deg.
B: 15 deg.
C: 60 deg.
I think A is wrong because its seems angled and not straight...
Changing angle A from 0 deg to 20 deg. made a whooping loss of 0,2HP at all rpm

edgefinder you are correct. Keeping the original powerband and lifting it up a notch is what i am after. Its my everyday street bike so I want to maintain a good strong midrange and it needs to be stable at cruise speeds too at small throttle openings :smt033 I have been playing with different setup...

I did not remember correct regarding the ignition timing. Here is the ign. table. You have to divide values by 2, since Microsquirt ECU thinks 180 deg. rotation (2 magnets) is one full cycle. Just did the machining on the cylinder head yesterday to make room for extra stroke and set the desired cham...

Ing. timing is 26 deg up to 6000rpm, then tapers down to 10 deg. at 9000rpm. Powervalve curve is for now 3 step (arduino based controller) . Closed until 5800rpm, then opens 80% ish, fully open at 7300rpm. Gives a nice "kick" at 7300rpm . Exhaust is modified F2 with different silencer.

I selected the wrong fuel for the bigbore setup, "regular" instead of 95 ron which was selected for the baseline. Now the simulated dyno gains look better. Compression, port timing basic setup is the same.. Dyno simulation is for one cylinder. :smt041 BLACK curve is baseline (bike current ...

Bigger exhaust stinger on +4mm crank setup, more power from 6750rpm and up, but less peak