500 Two-Stroke Tech

Oooops ... almost forgot .

Never buy / read Mr Bells
4 stroke book .

His attitudes toward what he
terms " Internet Tuning " , while
accurate will cause irreplaceable
shrinkage to all participants .

Lucky no one reads this shit .

Purchase A Graham Bells 2nd edition of " 2 Stroke Performance Tuning ". Read it . ( the bit about removing the bottom ring from a 2 ring piston .... Nooo !! ) Apart from that still a good read / investment after all these years . Have you ever heard the expression " Brain surgery by c...

Have both heads skimmed the
minimal amount to remove any
distortion .
Make sure each one is done
in one machining operation .

Do not exceed the recommended
torque setting .

Scarily similar to mine .
When I work out how to
post piccies I shall ..

Where is the exit point from
the engine exactly ?
( sadly I have a spare engine ...
The coolant route I get ; the
exit strategy has me intrigued ) .

Pop your head up when this
is about to happen ... I shall
run through this procedure
in more detail and importantly
the correct order machining
wise .

The quick version .
Machine a plug that drops into
the bore ; it will need a lip / flange
that fits the recess of the step
left left by the head / squish
band machining .
The head can now be bolted
down and dowled .

Read Dale Alexanders paper on " Squishing things till they make power " ( I think ) . Most relevant to water - cooled & answers the smart questions recently posted . Read it twice ... The head / barrel alignment method is a little dated , but it does work . If someone needs a less tedi...

Almost forgot . When I stripped out the MK 1 horror with the Yamaha approved " wobble the head around till it feels centered bullshit " ( Stan Stevens still does this ) what did I find ???? Piston to head contact around one third of the piston ... and wait for it ..... detonation directly ...

Cheap fix if you have figured out how to get the coolant exiting the barrels ... use a lower head & matching head gasket . I don't recommend it , but I've raced with this setup . The cylinder-head stud holes are too large to allow the head ( s ) to be centered accurately over the bores even if p...

How are these one - piece billet heads aligned over the piston /squish-band accurately without access to the individual engine /piston manufacture let alone any obvious method of dowling or pinning these into place ?

Wossner do these .. same dimensions etc .
I had no issues with the Wisecos even at 105 bhp / race only usage; but the Wossner piston in my aircooled 125 cured the dreaded Wisiezeco issues .( 125 dynoed at 27 bhp )
As for compression leakage ???????

Originally Costin used DT125 heads ; not sure of the head gasket arrangement though . The genuine / aftermarket headgaskets are somewhat shit ( big time ) and really f*****g expensive . A better alternative is splitting the originals & O ringing the cylinders . The coolant runs between the front...

Don't stress the wear on the upper pistons .
Needs rebore as you've about to undertake .
Bridge relief is an exhaust port thing .
Goddam ... you have these in Trumpland ??