I was hard on this engine from the get-go... I used the hard break-in procedure from:
http://www.mototuneusa.com/break_in_secrets.htmAt least, as close as one can come with an engine that can't really be pulled hard in a high gear because it's got an automatic transmission. But I opened it up from mile 1, and of course kept varying engine speed.
What I did was to limit idling to a short time, and at stop lights, when the light turned green, I'd nail it until I hit my cruising speed, then vary engine speed after that. I took it on the freeway at night (when there was almost no traffic) for high speed runs, would get it up to speed, then snap the throttle closed and let it coast the engine as it slowed down, then when it was going slow, nail it again up to maximum speed. I changed the engine oil, oil filter and gear oil at 50 miles, 100 miles, 200 miles, 400 miles, 800 miles, and every 600 miles after that, switching to synthetic at 1392.6 miles (the 1400 mile service interval).
Now, the engine's got so much compression I can hit the rev limiter very easily (and it's not even at WOT), and it accelerates like it was launched out of a cannon (despite using heavier than normal weights in the variator). I'm having 7.33:1 rear gears made by Jan Vos from Belgium to replace the OEM 8.48:1 gears, so I can cruise at 65 MPH at 6500 RPM. That should give me a top speed of about 92 MPH. Pretty sure it'll hit that, too... it's got more engine than it's got gears right now.
Not to mention that it burns no oil.
Once I put in the Total Seal gapless rings to decrease ring blowby to ~2%, it'll have a bit more oomph. The ceramic coating (which will be done by Swain Tech Coatings) on the cylinder head, valves and piston face will put more heat toward motive power. The variable coolant temperature (215 F at low speed cruising, 195 F at WOT) that will be made possible by the microcontroller-controlled electric coolant pumps and fans (2 each) will increase fuel efficiency a bit for in-town riding. The Microsquirt ECU will allow me to lean the air:fuel ratio, while also controlling a water injector which will provide just enough water (at a temperature just below its latent heat of vaporization, heated by the exhaust) to increase cylinder pressure and knock down NOx creation. The microwave-frequency corona discharge ignition I'll have built once my electronics guy is done with the coolant pump controller, combined with the increased engine temperature, lean burn and ceramic coatings will allow me to retard timing, which means the engine doesn't have to work against that ~20 degrees BTDC where the mixture is ignited and expanding while the piston is still moving up. The roller lifters I'm having fabricated by Baisley Hi-Performance will allow me to use a cam ground such that it allows faster valve lift, longer open duration, and faster valve close than a flat tappet can do. The custom expansionary exhaust primary will reflect a negative pressure pulse back toward the cylinder just before the exhaust valve closes at the engine's torque peak RPM, while the new cam grind will lock that partial vacuum in the cylinder until the intake valve opens a couple degrees later, which helps the engine to breathe without requiring valve overlap.
I'm also trying to convince a toroidal transmission manufacturer to create a line of their transmissions for retrofit to scooters... 98% efficiency vs. the ~75% efficiency of the OEM CVT, infinitely variable all the way down to "geared neutral" and all the way up to way higher gearing than our engines could ever use unless you wanted to scream down a long hill at 120 MPH.
I also saw an IHI turbocharger specifically designed for 150 to 300 CC engines, and it's only $250... but that might be taking things a bit too far. :)
I'm waiting on a huge parts order I put in today... once that's delivered, then the fun begins.
