I want to discuss something that I did before I assembled the engine.  Anytime you mess around with high lift cams and high compression pistons, you really should check valve-to-piston clearance.  To check the valve-to-piston clearance, you have to temporarily assemble the engine with light valve springs (checking springs).  You place modeling clay on top of the piston and see how much the valves squash the clay when you turn the engine through several rotations.  I failed to discuss that in Part 2 of these reports.

With the Wiseco piston it’s pretty hard to ram a valve into a piston unless you have the cam waaaaay out-of-time.  There’s plenty of room between the valves and piston.

You can see from this picture that there’s a lot of room between the exhaust valves and the piston.

That’s as far as it’s goin before I install it in the frame.  The cylinder head is on.  I am at a point in my life where these old bones can’t handle the complete engine.  Just too darned heavy.  So, to save what’s left of my body, I remove and install the engine with the following items left off:

Clutch, Clutch Cover, Starter, Alternator Rotor, Starter Drive Gear, Starter Override, Drive Pulley, Alternator Cover & Stator.

This is what the engine looks like.  It’s funky but I’m not entering a beauty contest.  It’s all about propulsion.

To prepare for the swap, I remove all the same stuff from the engine currently in the bike.  I also remove the flywheel and starter (not shown in picture).

See how the sleeve fits.  The rotor bolt can’t turn.  All the force will go into popping the rotor off.

I machined the lip off the rotor bolt.  I’m hopin that makes things easier the next time around.  I’ll apply a generous dab of anti-seize to the end of the jack bolt before I start jacking.

I already covered flywheel removal in Part 4.  I like doing that with the engine in the frame.  It’s a lot easier since you don’t have to hang onto the engine.  Once the engine is all stripped down, its out with the old, in with the new.  The old 94mm is on the deck, the 97mm Big Bore is in the bike.

I’ve been running an oil temperature gage and a cylinder head temperature (CHT) gage.  I have roughly 500 miles worth of data from these instruments to use as a measure for the Big Bore’s performance.

The oil temp gage has a pickup that I have installed in the discharge passage for the oil pump.  It measures oil temp directly out of the pump.  The pickup goes here (it's the red thing).

So that’s about it.  The rest of the stuff is routine R&R.  The chain tensioner extension was 9.5mm.  I left the ignition timing retarded 2° like it was on the tight quench engine and the 94mm Wiseco engine.  The valves were adjusted to .004” all around.  I left the 38VM jetting as-is except for the main jet.  To be safe, I increased the main from a 210 to a 220.  Crankcase was filled with 20W-50 Castrol V-Twin dino oil (API SG).  Ready for break-in.

It’s the moment of truth.  Will this Frankenstein engine run good or die instantly?  It has a hobby lathe bore job, Honda valves, Subaru valve springs, factory recall spring retainers, a dirt bike cam & piston, a miniaturized flywheel, an intake port stuffed with epoxy, an exhaust port from hell, a header the size of a smoke stack, and a muffler that looks like a plumber’s apprentice practical exam.  This will be fun.

I hope you found this report informative.  As always, I welcome your questions and comments.  Knowledge is power.

Best regards, Mike