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Author Topic: Need some machining advice on cutting a dome and shaving an ESR head  (Read 2086 times)

Offline Onski326

I recently upgraded my dome setup on my ESR 310PV cylinder. I had a pump gas dome with a pretty tight squish area and it yield 175psi. I just installed a new race dome in it and it bumped it up to 190psi but I had to add 2 gaskets to the base to get the piston to clear the squish band area. I want to get it upwards of around 205psi. How much would I have to tell the machine shop to shave off of the head to get it to 205? I assume whatever they take off the head/dome, they'll also have to take off the squish band area to keep it able to clear the piston as it does now. I did read a post a while back that suggested 0.015".
\'87 Honda TRX250R #326 Toobz Audio/OPS/KP Racing
\'08 Suzuki RM-Z250
\'05 Honda CRF250R
\'05 Honda TRX450R
Onski Powersports
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Offline udontknowme

Need some machining advice on cutting a dome and shaving an ESR head
« Reply #1 on: September 26, 2015, 12:32:15 AM »
i never understood why so many people insist on having x amount of kicking pressure. likely something they heard on the internet i suppose. if i were you i'd call jerry or arlen and explain to the best of your ability exactly what you have and any modifications the engine may have. im thinking youll probly have to do a solder test and send in both domes for them to look at
to much power is almost enough

Offline Jerry Hall

Need some machining advice on cutting a dome and shaving an ESR head
« Reply #2 on: September 26, 2015, 03:19:00 PM »
Quote from: Onski326;58998
I recently upgraded my dome setup on my ESR 310PV cylinder. I had a pump gas dome with a pretty tight squish area and it yield 175psi. I just installed a new race dome in it and it bumped it up to 190psi but I had to add 2 gaskets to the base to get the piston to clear the squish band area. I want to get it upwards of around 205psi. How much would I have to tell the machine shop to shave off of the head to get it to 205? I assume whatever they take off the head/dome, they'll also have to take off the squish band area to keep it able to clear the piston as it does now. I did read a post a while back that suggested 0.015".


What compression ratio was your engine package designed for?

What effect do you expect raising the compression will have on the shape of your power curve?

Adding extra base gaskets under the cylinder lowers the compression, increases the piston to head clearance and changes the port timings.  Increasing the piston to head clearance will increase the likely hood of detonation even though the cranking pressure is lower.

 

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