cam chosen... build to start

You are throwing together too many things to even compare.
2 strokes are a whole different kettle of fish.
Factory (road race) engines run faster on lower compressions.
2 strokes are a whole different kettle of fish....

Alcohol only gains a couple of % power - if you slavishly jet it perfectly.
But why would you - its beauty is that it can make hot motors run cool, with big jets and not worry about it.
Your Commando motor needed more than stock (low) compression to take advantage of alcohol.
We start to see you didn't develop it to anything of its potential...

'Running methanol, you don't even NEED plug readings.
Just run it well rich - thats the gorgeous beauty of alcohol.
It can be 50% rich, and it only 'loses' 10% or less power.
No need to worry about melting pistons....'

Shows how much you know - if you want to go slow you can do that. Where did you get the ' 50% rich and it loses 10% or less power' garbage from ? Have you actually measured the power drop or even leaned off an alcohol motor to get acceptable plug readings which show the mixture and plug heat range are 'correct' ?
I'd love to see you guys on a speedway with your Triumph 650 sidecar on alcohol, alongside my brother's 500cc Kawasaki triple two stroke, you would get the fright of your lives.

'Alcohol only gains a couple of % power - if you slavishly jet it perfectly.
But why would you - its beauty is that it can make hot motors run cool, with big jets and not worry about it.'

You keep telling me that however where is your evidence that it only gains a couple of % power - you have never tried it and you are not alone in that. Many before you have believed the bullshit misinterpretation of Phil Irving's comments about methanol. The comment was - ' you can run methanol rich, and it still makes good power' - my comment is - 'but not the most power'.
I will tell you this, many years ago I had a discussion with our top Victorian A grader about jetting for methanol, he always used a petrol needle, and ran it lean right down the needle. The only way you will burn a piston is if the main jet has to be as large as the needle jet, and the mixture meters off the tip of the needle, or the main jet is simply too lean. How often do you use the main jet on a race bike anyway ? The two stroke comment is not irrelevant, the principles are the same however the consequences of getting it wrong can be much more dramatic.
Have a look at the needles in the amal methanol kitted carburetors - they are a waste of space.

Yes - Phil irving had no idea, and you are THE expert.
Look at all the races you won, where you blitzed em.
On stock low-comp pistons ??

Alcohol in a stock motor can only gain a bare few % extra power, at best, no other changes.
Run it rich, keep it cool, fit hi-comp pistons, hammer the opposition.

Speedway Trumpy on high-comp pistons and methanol loved it.
Ran cool as, no melting anything.
Plenty of go...

P.S. My chem book says methanol has half the fuel energy of petrol, so you burn twice as much, roughly.
Not much % potential gain there... ?

tripower said:

... also what would it hurt to run 32mm carb into a 30nn opening ?

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The R-10 head came with tapered manifolds that are 32mm at the carb side and 30mm at the head. I'm not sure how easy it will be to adapt them the mikunis though.

It is not about Phil Irving having no idea, it is the guys who misread the intent in his words who have no idea. It would be interesting to find out whether the top guys who race lay-down Jawa speedway bikes bother to lean them off. Over many years I've almost come to blows with my brother on this topic. These days he rarely loses a race. However he has chickened out with the Kawasaki 750, and runs it a bit richer to be safe . A few years ago it was being run super lean, came on song and jumped into the back of another sidecar. It did a few loops jumping my brother and his passenger, and bent itself up very badly. Please don't hit me with stoichiometry, it is my profession. What you are talking about relies on bomb calorimetry.

acotrel said:

Please don't hit me with stoichiometry, it is my profession. .

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Perhaps you have some explaining to do then.
Like how to get more power with less ingredients ?? !

Perhaps on another thread, since this has nothing to do with cams here.

I have had some training in this field myself.
Which is why your assertions are all the more puzzling.

Meanwhile back at the ranch here's search on cam and compression and compression and cams. If ya 'screw' up on too low a CR for the cam, just end up with doggy engine, if ya have too much compression for the cam it can detonates to death is all. We know 2S cams like 10 even on todays lean burn gasoline and probably could bump up even more. 2S will still work ok below 10 just may have more big cam idle lope and need a few 100 more rpms to responsd to throttle snaps w/o bog, but feeding throttle a bit slower reacts fine, just not as dragster like. As for the lower thermal heat fuels with extra octane, like methanol or propane, you must bump up CR to get most their power benifits w/o losing so much mileage.

https://www.google.com/search?q=cam%20s ... &source=hp

If hes not carefull , he will have to change gears , like on a Triumph . 8)