Evo Mild build confusion!

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Mar 16, 2020 | 09:18 PM

Adam76

Thread Starter

Road Master

Joined: Apr 2017

Posts: 1,050

Likes: 92

From: out there

Evo Mild build confusion!

Hey guys, posting from down under, and it's my first post in a few years.

Looking at buying a 1997 evo fatboy with stock motor and 50K miles on it. Supposedly genuine but who ever knows?

I have done a lot of reading about the best way to get some power it of these old motors without any bottom end work (hopefully!!) and without a big bore kit. Don't want to break the bank.

1. With a cam upgrade - what's more important the increase in compression with boring the cylinder and installing high comp S&S / Wiseco pistons? Or shaving, porting, polishing heads with valve job?

2. Quality Headwork may be an issue due to possible lack of good experienced shops here.

3. What cam, what compression? Shooting for around 85/85 nothing's emphasis on strong midrange. nothing too crazy.

4. Anything else I've missed? Ignition?

I'll probably need using a 2-1 Propipe.

Thanks, appreciate any help.

Also, if you think I'm better off going with a low mile TC88 then advice is welcome. Possibly not from this section though 😆

Mar 16, 2020 | 09:28 PM

BigMike67

Cruiser

Joined: Jul 2019

Posts: 186

Likes: 86

From: Pennsylvania

can't go wrong with an Evo.you could go with an Andrews EV-27 cam and adjustable pushrods and not have to tear into the engine at all but you're looking at mid to upper 70's hp there, but from the stock 60 you might have at this point you'll feel it...
if it's in the budget a 520lift range cam and a mild street port and mill the heads a bit for some compression in to the mid9's:1 will get you into the 80's
i got mine with 50K on it and the next year put an EV-27 cam in it and loved it but rode a buddies similar bike (FLHT) with the 13 and i liked it better.. a bit more bottom end pull for the bigger bike.
good luck!

Mar 16, 2020 | 09:47 PM

Bass Player

Grand HDF Member

Joined: Aug 2018

Posts: 4,126

Likes: 2,117

From: W. MI.

I put an EV27 cam in my 96 springer. S&S oil pump. Valve job and then ported the heads and put in adjustable push rods. Power is excellent. I also vented it to the atmosphere to keep the crap out of the engine. Good luck on your build. Oh, welcome back.

Mar 16, 2020 | 10:55 PM

Adam76

Thread Starter

Road Master

Joined: Apr 2017

Posts: 1,050

Likes: 92

From: out there

Thanks for the replies guys.

I'm seeing that headwork is popular for the evo to support the cam...... That's not really an option for me, so increasing compression will have to be done by high comp pistons. Don't know which ones or how high to go out whether flat top SE or Keith Black domed ?

Cheers

Mar 17, 2020 | 08:10 AM

Bass Player

Grand HDF Member

Joined: Aug 2018

Posts: 4,126

Likes: 2,117

From: W. MI.

Just a suggestion. Your bike do how you want. IF you aren't going to do any head work, don't go nuts with compression. It will need to breath.

Mar 17, 2020 | 09:13 AM

djl

HDF Community Team

Joined: Jun 2006

Posts: 12,779

Likes: 2,609

From: san antonio

Quote:

Originally Posted by Adam76

Where in Aus are you located? I have a retired friend from Aus that knows where all the Harley techs are in Aus and the good, the bad and the ugly. I have emailed him to see what he says about machinists and head porters. I will post again after I have heard back from him.