Raising compression?
Thread Starter
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Cruiser
Joined: Mar 2010
Posts: 237
Likes: 12
Raising compression?
I'm replacing base gaskets soon, and want to bump compression while I have it apart? What compression ratio(s) work well with EV27? I've heard 9.5:1, but for some reason my mind tells me to go bigger.
I'll also have the jugs punched out .020 over, and the heads gone though as well while it's apart.
I'll also have the jugs punched out .020 over, and the heads gone though as well while it's apart.
Cruiser
Joined: May 2011
Posts: 205
Likes: 1
From: Always moving
I'm replacing base gaskets soon, and want to bump compression while I have it apart? What compression ratio(s) work well with EV27? I've heard 9.5:1, but for some reason my mind tells me to go bigger.
I'll also have the jugs punched out .020 over, and the heads gone though as well while it's apart.
I'll also have the jugs punched out .020 over, and the heads gone though as well while it's apart.
Thread Starter
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Cruiser
Joined: Mar 2010
Posts: 237
Likes: 12
I got cometic. Can't do the Hayden oil fix with these?
Road Captain
Joined: Aug 2012
Posts: 625
Likes: 102
From: New Albany, Ms.
9.5:1
This is what Andrew's say's,
I e-mailed Andrew's about compression ratio's you can use with the EV13 & the EV27 & this was the response I got. And I quote:
I wouldn't go more, but that's me. Looking at doing the same mod's this winter. Ride Safe,
Harold
I e-mailed Andrew's about compression ratio's you can use with the EV13 & the EV27 & this was the response I got. And I quote:
I recommend 9.25:1 (stock is 8.5:1) for the EV13 cam and 9.5:1 for the EV27 cam.
Thank you,
Gary Wallace
Technical Support
Technical Support
Andrews Products, Inc
431 Kingston Court
Mount Prospect, IL 60056
847-759-0190
847-759-0848 Fax
gwallace@andrewsproducts.com
www.andrewsproducts.com
431 Kingston Court
Mount Prospect, IL 60056
847-759-0190
847-759-0848 Fax
gwallace@andrewsproducts.com
www.andrewsproducts.com
I wouldn't go more, but that's me. Looking at doing the same mod's this winter. Ride Safe,
Harold
Road Warrior
Joined: Nov 2007
Posts: 1,641
Likes: 4
From: south of Boston
it's not so much that you don't need it with the cometic, it's that they won't work with them .... the hole in the gasket where the oil passage is, is too small
also, i had the cometic base gaskets on mine...and after about 500 miles the oil began to seep through....so got the 'hayden oil fix' and used stock harley gaskets
i've put about 800 miles since the fix and it's dry as a bone down there
also, i had the cometic base gaskets on mine...and after about 500 miles the oil began to seep through....so got the 'hayden oil fix' and used stock harley gaskets
i've put about 800 miles since the fix and it's dry as a bone down there
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Outstanding HDF Member
Joined: Aug 2010
Posts: 3,486
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From: Union,Ms
I've put 10,000 mi. on a set of Cometic base gaskets and no seepage at all. I guess everyone has different results though.
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Road Warrior
Joined: Nov 2007
Posts: 1,641
Likes: 4
From: south of Boston
the only thing i concluded was that i MIGHT have been getting false torque head readings because the cylinder studs were in the factory position and may have loosened slightly, thus jarring things
....so before i replaced the gasket with the hayden fix i flipped the cylinder studs...and so i bet if i reused cometics i'd have been fine, but just didn't want to take another chance
Cruiser
Joined: Nov 2006
Posts: 206
Likes: 5
I rebuilt my top end 8,000 miles ago, with the ev27 I used wisego 10.1 pistons. Runs awesome, like a striped *** ape.
I always use 93 octane and stay away from ethanol, or if I do use a less high octane, I put in a boost. Plugs look great, and bike runs super.
I always use 93 octane and stay away from ethanol, or if I do use a less high octane, I put in a boost. Plugs look great, and bike runs super.