MoCo Factory Evo 96" Kit

[JamesButler]

Anyone know if the MoCo ever offered a factory 96" - Upgrade Kit for those tired 80"-Evos?  If so, what did it entail?

[Ohio HD]

Don't think so.

[wfolarry]

MOCO never.
S&S bore the cases for 3 5/8 cylinders & 4 5/8 stroke flywheels

https://www.sscycle.com/products/complete-96-inch-big-bore/stroker-hot-set-up-kit-for-1984-92-big-twins/

[JamesButler]

MOCO never.
S&S bore the cases for 3 5/8 cylinders & 4 5/8 stroke flywheels

https://www.sscycle.com/products/complete-96-inch-big-bore/stroker-hot-set-up-kit-for-1984-92-big-twins/

You could use the stock cylinders instead of the S&S cylinders?

[xlfan]

Not for a 96" setup

[SP33DY]

You could use the stock cylinders instead of the S&S cylinders?
[/quote]

Only if you use 5" stroke flywheels

[xlfan]

You could use the stock cylinders instead of the S&S cylinders?

Only if you use 5" stroke flywheels
[/quote]

With stroker plates and longer sylinder studs?

[Burnout]

5" stroke doesn't that run into piston speed issues and it tearing open the big end of the rod?

[SP33DY]

5" strokers are not for amateur builders. He asked:

You could use the stock cylinders instead of the S&S cylinders?

The simple answer is yes, with 5" stroker flywheels.

The actual answer is yes, but you better know what you're doing. Ideally with tall deck cases, custom pistons, custom length manifold, etc.

I have played in that playground, years ago I was doing some fuel drag bike work @ 5.250 stroke.

I probably should have let it go and not responded the first time.

[turboprop]

Anyone know if the MoCo ever offered a factory 96" - Upgrade Kit for those tired 80"-Evos?  If so, what did it entail?

No. Harley never offered any larger bore or larger flywheels for for the evolution engine. Period.

[Hillside Motorcycle]

5" arm engines are not for folks that do not know how to operate them.
That said, they are VERY powerful engines, with instant delivery, and can have good longevity, IF IF IF, used correctly.
Not something I google searched.....

[JW113]

Depending on the year, you might get away with boring the cases for bigger cylinders, many do. My cases cracked with just the stock bore. Blow on the dice, give 'em a toss, and take your chances.


These days, if it were my dinero and I wanted a big Evo engine, seems just buying one (like a Ultima 113) is the way to go.

-JW

[jsachs1]

Back in the 90's, I built 8 - 92" Evo engines on stock cases. Everyone made over 100 H.P. Worst 104 hp. -  best 109 hp.
3/4" stroke S&S flywheels, 1200 Wiseco Sportster Piston kit, Big Twin 1340 stock Evo cylinders,.060" head gaskets. My 1.900" Evo heads
Modify oil scraper in the crank case for smaller diameter flywheels, check for normal stroker clearance issues, if any. Check piston to head clearance. Set breather timing (window mod).
Engines are major sleepers, looking bone stock.
John

[JW113]

Yes, that some good numbers. 1200 XL pistons means 3.5" bore, i.e. stock, right? I guess you saying you don't need to bore the cases to get good HP numbers, and clearly you did, that's awesome. I stroked my '91 to 4-5/8 (89cid), don't remember the HP but not over 100. And it didn't look stock, with Screamin' Eagle stamped on the heads! But it ran good enough for me, anyway.


I had wanted to go the 96" route, but my machine shop dude said no way he'd do it, seen too many of them fail after boring the cases. Replace the cases, or find somebody else to do it. I took his advice, no bore. Ya don't argue with an experienced engine builder!

-JW