S&S Cycle New Bolt-On 4″ Big Bore Kits For Harley Twin Cams.

Just available from S&S Cycle, these proven performance kits don’t need any machining, any rebalancing. Just bolt on in pistons and cylinders (4” bore, 4 3/8” stroke) in place of the stock ones. Installation can be done with engine still in the bike!

Kit works well with stock cylinder heads, or let S&S CNC port those heads for even more power. The factory 1999-2006 Twin Cam engines will roll up to 100” and the 2007-later models (except 2017 touring models) will become 110” monsters.

The 10.5:1 compression makes for a very street able and dependable engine that also responds well to performance cams. S&S 4” bore kits are available in color matched silver or wrinkle-black powder coat finish. See your local S&S Dealer or go to S&S Bolt-On 4” Bore Kits.

11 Responses to “S&S Cycle New Bolt-On 4″ Big Bore Kits For Harley Twin Cams.”

  1. 1 Sam Dec 21st, 2016 at 10:04 am

    On this and the winter kit there is not sufficient material for fitting oversize pistons for rebuild. This is not a criticism but for information only.

  2. 2 Zundap Dec 21st, 2016 at 10:51 am

    Good luck.

  3. 3 Steve Carr Dec 21st, 2016 at 1:27 pm

    Why would you be concerned with a re-bore on a brand new set of Cylinders and Pistons, that would be a concern way way way down the road and even then just buy another set at that point.

    Not a criticism, just an observation….

    Steve Carr

  4. 4 Zenaldo Dec 21st, 2016 at 11:09 pm

    anytime you can bolt on cubic inches it’s a win..and these guys get it right every time..

  5. 5 Sam Dec 22nd, 2016 at 9:00 am

    Steve, I’m not concerned. I called S&S about this and was told that due to the thin liner (and yes I know it is plated..that was part of my question) oversize pistons could not be used. I wanted to know. I’m simply sharing information. Rebuilding an engine seems to be outdated.
    Thank you so much for taking your valuable time to provide me with your sarcastic remark.

  6. 6 Red Dog Dec 22nd, 2016 at 10:14 am

    Good one Sam. Right on. Merry Christmas mostly everybody.

  7. 7 Steve Carr Dec 22nd, 2016 at 1:17 pm

    No sarcasm, just an observation.

    The size of the bore and the stock case diameter simply dictates there is no more room for oversized pistons or they would have gone even bigger for even more ci.

    Steve Carr

  8. 8 Geezer Dec 22nd, 2016 at 2:07 pm

    Sam and Steve: Behave yourselves boys or you both go to your rooms without supper!

  9. 9 Sam Dec 22nd, 2016 at 3:02 pm

    First: Merry Christmas Red Dog. Secondly, I appreciate what you are saying Geezer. I understand that Steve Carr is a true gem of motorcycle knowledge, so rather than air this out here, I’ll just iron out this little wrinkle with Steve personally. Sorry I took the bait. I’m a fan of S&S. I stupidly rejoined this elite group and obviously do not belong. I do not like bullies and I detest know it alls.

  10. 10 richards Dec 22nd, 2016 at 3:10 pm

    Sam, I found your original remark informative and useful. Thanks for sharing.

  11. 11 rebel Dec 27th, 2016 at 10:38 am

    Sarcasm, just one more service we offer! they’re nice pistons made by CP, you could shave in the dome finish

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Cyril Huze