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Post by colonelangis on Jul 26, 2015 5:59:56 GMT -6
So I have a bit of time on my hands & have my 80 cc (72cc) kit. I hate the stock intake manifolds and bought a hoca all steel that elimates the spacer.
I plan to have the head worked on with port matching and valve improvement before it gets installed.
Why the hell is the diameter of the hoca 24 mm? Mainely Scooters replied that it increases the flow.
How would it do this if the 'flow' is running into a ridge and head intake of about 17 mm?
Would using this intake reduce necessary intake pressure a 72cc needs?
Maybe I am missing something here???
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Post by cyborg on Jul 26, 2015 8:27:53 GMT -6
miss matched head / manifold is not a good thing especially if the joint is going into reduction of size,,,this will create waves of turbulance which is not good for flow,,,,put some etchers blue on the manifold and it will leave a pattern on the head,,,,pack the port with a clean tee shirt rag and make it tight dremmel the head to blend the fit together and use a strong vacuum as you pull the rag from the head to pull all chips out ,,,thats my call,,,unless you want to pull the head to do the deed
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Post by usmcdoc on Jul 26, 2015 11:51:37 GMT -6
Why would they say that when.. Bernoulli's principle dictates and has been proven to be true. That being..the larger the diameter of a pipe or tube flowing air at the same volume...the velocity will be decreased. Therefore at 8,000 rpm..the engines vacuum velocity would be drastically decreased. Then to add a smaller orifice at the end would create turbulence and disrupt the flow..
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Post by cyborg on Jul 26, 2015 18:36:49 GMT -6
one of the big reasons some pro "port jobs " actually don't increase performance at all,,,there's a break point when velocity drops and the cylinder doesn't get filled as well as a when a smaller port is used ,, larger than needed ports or carbs are snake oil,,,and even if the larger port/carb make better peak power there's less in the midrange and where most driving occurrs
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Post by colonelangis on Jul 27, 2015 12:36:39 GMT -6
I will just keep it for my 150 trike if needed. So is there anyone out there that can port match a 72cc brand new head to a manifold and spacer? they are just plain awful out of the box. if anyone knows of somebody that can match up a brand new head to a manifold and spacer I would really appreciate it. would like to change the springs out too.
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