THANKS CRANKY! I know a lot can be done differently because of the desmo valve train [without valve springs], but thought I had gone crazy. So, valve-to-valve at 50 thou'. I only ask about the at-rest figure because it is a good seat-of-the-pants measurement to make before assembly even starts, especially once modifications are made and race cams are planned. My limited experience says there should be around 5.75mm between them or there is potential trouble, more so with long duration cams (NCR, Montjuich and GCM) than with high lift cams (900SS or ST2). I tried a 900SS cam in a stock 650 head, and the valves cleared easily; then I tried a set of ORSP cams and things instantly went crash/bang! My F1b has NCRs and stock-size valves and chambers, and no V-to-V problems, but it was a long time ago that I measured them. Stock 650 heads (small valves) are about 4.5mm apart, and stock 750 heads (bigger valves F1 thru 1990s) about 5.5mm. Thanks again for the quick reply, because I lost sleep over this last night.

My experience with dual plugs and high compression (1,044cc Moto Guzzi) is that is really does help in the lower RPM range, less obvious at the top. The top of those pistons and the combustion chambers were really little different from the Pantah era engines.

PS: Sorry we stole your thread Carlo.

MikeV

Hello Friends, Hello Mike, thou hast not stolen anything, I have read all your posts, and I try to learn and understand so many tests made by you, with different materials.

I understand 50% of the things that you write, unfortunately my translator can not 'give me the nuances of your technical discussions, but I'm okay on the fact that the materials today, allow you to make higher compression and high performance, but do not forget that the crankcase is always the same 30 years ago.

I usto normal valves, from 41-36 and I tried to do an engine block, as they were built dala NCR, namely by lightening and improving the ducts, I have valves that are crossing 0'8mm almost eight tenths of a millimeter For me it is a measure to control the newspapers every now and then, but I think that is fair and within the limits.

My engine had the cams before processing the Ducati F1 road car, I did a launch on the test bench with 54 kW ............... the mechanic who did this to test launch, I was taken for a ride, all week.

Now tomorrow I wanted to start the engine block, and figure out what I increased engine power, making the balancing of the crankshaft, camshaft P, and all the lightening that I did.

As soon as I can I'll do a test launch, although I'm not happy to fi scream my bike on the absurd torture machine.

I do not know if I will launch the test, I believe that brake later and give gas before, definitely my engine will have more power.

I realize that I am a little mechanic in the country, I have to compare with highly qualified and very capable in the calculations extreme, he began to think that perhaps it would be better if I did not see all of these photos, I think you , you have done these things, very much ahead of me, in this kind of mechanical processing.

Thanks for your advice, are important to me

Good timing on this topic, no pun intended!
My heads with the 42, 35 valves are so close together that I have had to go back to stock cams, I sunk the exhaust valve in another 1mm deeeper still the #7s collide.
The valves are about 4mm apart seated
I am sitting at 1mm squish and piston to valve at 1.2.
I will be doing another set of heads for an 82mm bore for #4 Moretti, hopefully the #7 ncr can be used.

Hey, Paul:

45/31 valve combo? I had the JPrecision heads done at 42/35.5 (as per Mr. Weber's set-up) and got acceptable valve to valve clearance with NCR 7s and P cams after trimming a touch off the intake valve OD and sinking the exhaust seat a tiny bit..

The P cam motor is a 790cc with 12:5:1 and has a beautiful power spread - not what I expected at all....

Thanks Steve, I have now corrected the numbers!
Old age!!

Tomorrow morning I try to start it ........

I hope I can hear it from here.

bella collezione di Loctite

A beautiful machine, Carlo! Will we get a video with sound?

I now do gass very strong! You hear the noise?