Is that true for Maney barrels?
Hi Klaus,Hello,
I have to interfer here. Yes, I am the cylindeder head man. What I notice here is, that the mixture graph as well as the power graph are both 500 nearly exact 500 RPM offset to the 820cc graphs. Just take the 920 graphs and draw it exactly at the same starting point as the 850 graphs and the picture looks a lot friendlier.
There is some other point I want to make:
If you touch a Fullauto head you handle it with greatest respect, which means that these people know exactly what they are doing. If you take material of somewhere you cannot put it back to where it was. So, Yves and I both agreed to leave the port- shape standard as near as possible. For me there was only a bit of blending- work to do. I'm curious to read what Yves found out on the flow bench. Only thing is: has Yves a comparison how a standard Fullauto head will flow?
Yves, again the question: Can you send me the power graph per E-Mail?
Best Regards
Klaus Monning
My intake is only 3mm largerHere is the FA port floor moved over for a 5mm larger intake valve (red line), It also needs a little larger diameter at the sides of the bowl.
I don't have the barrels close by hand, but if I remember well it must be 2mm
Is that true for Maney barrels?
Liners in Maney 920 (81 mm) cylinders are nominally 1.5 mm (.060"). I've measured several, and got measurements between .060" - .063". The difference is probably due whether they were original or had been honed for more clearance.
Ken
Yes I know but the dyno man is in Spain for a week, testing some racing bikes, so I can not ask him sonething before mondayYves, a few of us did point out that the graphs looked ‘out’ by 500rpm or so. Let’s hope that’s all it is!
Hi Glen,This is a good argument for finding a dyno hill.
Approach bottom at some specific speed, then run full throttle up the hill and record speed at top with GPS speedo mounted (any common GPS unit)
You can do this in top gear as well as one down on a steep hill.
Make changes and repeat test.
I've found that my local hill works well with 30- 60 HP vintage MCs, not so much with high horsepower moderns,as the speed at top is too great.
The GPS does not lie. Sometimes dynos do.
Glen
Thanks for the encoraging info'sYves I have a Full Auto head that has 1.5 mm larger intake Vvs and so far on the flow bench I am seeing the HP potential of 75 + HP using a 34mm smoothbore carb for testing. I tested against a new 34 mm Mk2 Amal and there was a 2hp potential loss compared to the smoothbore. This is at 0.400 " of lift on the intake Vv
Is your flow man using different stubs and manifolds and carbs to see if there is any change in results?
My head guy is going to play with some plasticine moulding in the exhaust port , then back to the flow man to see if there are any changes.
Your FA head should be good for at least 70+ without any big changes.
Regards Mike