you shouldn't be worried about the cilinder but the conrod, you should inspect your conrod after every race just to be safe, the crack only starts at the surface & it's always caused by too much tension.
one of the ways to prevent cracks from forming is to polish the surfaces of the conrod, the beam, big end & small end must be polished smooth so rough surfaces are eliminated, i have done this on our 2Fast crank & other conrods for 2takt & 4takt engines.
Saturday ima gonna do a race simulation and if it doesn't do anything weird ill run it at 15,000 and above all the time. Metrakit block seem to be the most reliable to me. Im reving at 15,610 just to be clear and thats not on a real long straight it might peak higher i would love to run it at 16,000 power is nice and its still stock port timing i can imagine wat my ported block will run like at those rpms. Thanks guys ill let u know how it works out and see u saturday Dante bring yah damn leathers so u can ride it u stupid bastard. 15,000 and beyond its so much power with the 28 carb
Hello Rwade
your scoot seems to go well at 15,000 rpm but if you try setting it up to run at 12,000 to 12,600 rpm ,adjust the ignition timing/rollers/pipe length to suit /try running a c16 manifold with the c20 pipe youll see a whole new side to the motor, forget tuning the pro race 2 its already too highly tuned try detuning it by decking the cylinder and adjust the cr and squish to suit if you want more power and huge amounts of torque this is the way forward and a tuning method never considered by most.your set up as it is should produce peak power at between 12,800 and 13,300 but will depend on how youve jetted,set ignition,set cylinder height etc.try finding the heaviest set of rollers it wil pull these revs on for best results and use a brand new torque spring before starting and as often as possible, the spring is most important dont chase lighter roller weights when the power starts to drop off after a few miles of use ,replace the spring first and adjust belt wear with shims to maintain full variation check this by marking pulley with permanent black marker and aligning lower belt width with end of variator centre bush
ive built the same motor myself pr2 and c20 combo and im sharing the experience of over 2 weeks on my dyno developing and track testing and numerous rebuilds and specification changes to C.R./squish/port duration/pipe lengthh/ign timing/fuels ,yes the motor will produce power at 15,000 but its at the tail end of the power curve and well past peak,i regularly find that the transmission has a sweet area that it likes to work in with a specific roller weight and torque spring and thats what youve probably found?is it digital or analogue ignition/digital requires very fine set up when your shifting peak power rpm about ive ran up to 1.5mm different from 1 pipe to another and low comp to hi comp settings,Does Rwade still use the hebo variator,there really bad,i threw mine away.Try sticking it on a dyno and locking out the variator to see where true peak power revs are at then fine tune the transmission to work best with it,it will run a lot more powerful and safer at the lower rpm and at 15,000rpm+ cranks dont last long so if it lets go it will probably take the rest of the motor with it
Rwade,
Hope to see you on saturday. I'll tell you if your bike is running. I'll bring the radar gun set up with me. My theroy is to rev. the motor to what you have your port timmings set at. For example, you can purchase the Gram Bell 2t tuning book which has a guide line that compares rpm with port timmings because nobody has a dyno down here, nor does anybody have the experence to know how to work it properly.
Note: Think you can take the Super Scooter 70cc championship this season?
Speed
just keep fresh gas and good oil in your bike.