Can't is a four letter dirty word
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Why thank you! Bandera loves compliments!I see that Rick M is still selling those one way clutch sockets. The drive nut in that example happens to be the same thread as the extractor/puller, so that it threads into the ignition rotor. I had qa starter nut on an ex kart TZ motor that fitted over the crank nut and sat in teh rotor recess and was located with 2 off 6mm socket head screws. that's enough to start a simple little two stroke.
That top end is starting to look really sexy. And is that Bill B firing up the H2?
Thank you. Just got off the phone with micro blue Craig. If we micro blue the cylinder and piston we will need to retard the timing even more according to a Craig. I did return all the standard bearings today and ordered the micro blue https://www.microbluebearings.com/ I am going to wait to micro blue the cylinder until we dyno this configuration and get a baseline. He claims significant gains with micro bluing the cylinder and piston. We will see. Well if we beat Zeke I can say I did it with my small transfers and micro blues.That's a pretty flat timing curve......
I'd start at 19 degrees and add more at lower revs where it's off the pipe up to almost 30 degrees and past peak drop it back fairly fast - just as a place to start testing. Too little advance is always safer than too much - within reason.
Ralph's work is amazing though.
On Yamaha twins, Mototplat and Hitachi rotors both had a large hex cast in, but Femsa didn't.
The Magee pipe was designed for 203 on the exhaust duration on our dyno run for the Stock Bultaco M51 was 185.Nice video but peak power at 6500 may have been because that's where the pipe resonated or what the exhaust timing or area or other ports restricted it to. Ask BB what exhaust duration that pipe was designed to work with and from there you can work out whether the pipe or exhaust duration is the issue and if they match the restriction is elsewhere.
If you plug your numbers into teh GW basic version of Bimotion's port-time area target app it will quickly show you which ports are the issue. Or use their graphic port and pipe tools which will show you the target T-A for transfers at a given RPM and output target. The tools are there. Then use MOTA for the simulations.
If you want a hand PM me off line.
On those bearings, they are basically claiming such a significant reduction in friction that you need to retard ignition lead because the pressure rise after ignition would be such that it will get to peak pressure before it would with average old bearings. That sounds bogus.
The largest source of friction loss is between the piston and bore. The largest pumping loss is compressing gas, so the difference in friction may be measurable, the overall effect is likely to be small to immeasurable. Dyno is the only way to get timing right and BB can lead you in that direction. He knows what he's doing there.
We we just messing around and put the Magee pipe.203 is 3 more than a TZ and 185 is quite modest but that's what keeps the revs constrained. I suspect that the exhaust pulses are way out of time with that pipe. But was the pipe just a loaner from BB or is that the one you intend to run on the bike?