Break in procedure

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Mar 1, 2026 | 04:38 AM

Sammyguy

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1st Gear

Joined: Dec 2020

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From: Matheson ontario Canada

Break in procedure

Hi so I’m currently replacing pistons on my 24 cvo sg. Took it apart and found out the cylinders were pitted from rust of some sort which took out the oil rings. I’m replacing them with the cp carrillos from fuel moto. The cylinders have been honed out and good to go. I’m also swapping to the cr565 vvt cam. Looking for advice from real engine builders here not keyboard mechanics about how to go about breaking it in before getting it dynoed. I already have it booked for May 1st at 905motorsports in Ontario. It’s got the impact ecu kromewerks outlaw 2-1 and se extreme wedge air cleaner. Ben from impact is going to install the map and update everything for me before fire up. Do I start it and rev it till it comes up to temp or let it idle. Revving makes more sense to me but I’d like advice!

Mar 1, 2026 | 08:12 AM

Sullyxlh

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Joined: Oct 2025

Posts: 140

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From: SE Michigan

http://www.mototuneusa.com/break_in_secrets.htm

Mar 1, 2026 | 08:23 AM

Iceman24

Seasoned HDF Member

Joined: Sep 2009

Posts: 25,310

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From: Eastern NE

Quote:

Originally Posted by Sullyxlh

http://www.mototuneusa.com/break_in_secrets.htm

^^^This^^^

Did the MotoTune new engine break-in on new 2009 FLHX & every new bike since.

Mar 1, 2026 | 08:57 AM

2goldens

HDF Community Team

Joined: Mar 2005

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From: The 1980's

Do your dyno people have any suggestions?

Mar 1, 2026 | 10:59 AM

Steve Cole

HD EFI Guru

Joined: Jan 2008

Posts: 4,494

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Quote:

Originally Posted by Sammyguy

There is no good answer to your question on break-in, as much of it depends on how the engine was assembled and with what components. The safest thing to do is have the bike connected to collect real-time data from the ECM so you can keep an eye on things. Now if you used pistons made from 2618 material or 4032 material you want to do different things. How much piston to valve clearance and piston to cylinder wall clearance do you have? Since you cannot prime the oil system, I like to leave the spark plugs out and spin it over on the starter motor a few times or until I see oil coming out around the lifters. This requires you leave one of the pushrod tubes loose. Make sure you get the cooling system bleed and filled correctly! Once the oil is coming out around the lifters put the tube back in place, install the spark plugs and fire the engine up. I leave it run at idle until I feel some heat on the lower fins of the cylinders then shut it off and allow it to cool to room temperature. Do a couple more heat cycles the same way. Check everything over looking for any leaks or funny noises, correct as necessary. Then your ready to give it a test ride, now if you tune is incorrect you can damage the engine so do not go hot rod it until you really know what you've got.

Mar 1, 2026 | 12:34 PM

Sammyguy

Thread Starter

1st Gear

Joined: Dec 2020

Posts: 5

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From: Matheson ontario Canada

I was wondering about heat cycling it I should have been more specific its getting broke in on the dyno for sure I’m just getting it started and ready for dyno