1994 FLHR Road King (57,000 miles). I am having my cylinders bored 0.020 over, new rings and pistons, heads gone through, new 510 Andrews cam and adjustable lifters and S & S carb. What are some suggestions on breaking in the motor after these upgrades?

 

Having similar work done to mine right now gunna have all the specs for machine work soon. Commenting so i can get some sound advice as well and follow this thread. All the best man! I will update when I have specifics on my new top end. Will be in the next couple weeks

 

3 Heat cycles for starters with Dino oil.. First 2 to 150* cylinder temp and 3rd to 250* cylinder temp. After each warm up let motor cool to ambient temperatures. Do not keep idle steady. Vary motor rpm's between 1500 and 2000 RPM.. You will need an IR gun. When taking it out the first time again vary the engine rpm's. Some will say don't got over 3500 rpm's for 500 miles others will say we brake it in on the Dyno tune right up to 6000 rpm But only after heat cycling the motor. If your doing it at home make sure your not running lean and don't be afraid to reach 4000 RPM at times for first 100 miles.. you should be good to go.. change oil at 500 miles..

Or follow your machine shops advice..

One more thing, isn't the Andrews 510 a twin Cam camshaft?

 

don't you think this is a question for the engine builder??

 

Yup! Start with the chap who is doing the job. That way you have it from the horses mouth. Given time, when this subject has been raised in the past, the replies have ranged between the most remarkable extremes and simply create confusion!

 

Great advice. Thanks for the replies.

 

Keep the RPM's under 4000 for the first say 300 to 400 miles. While keeping the rpms under 4K, run it up in the gears, and then run it down in the gears. You want to do a fair amount of engine breaking. Don't be afraid to work it after the first heat cycles like previously mentioned, but again, under 4k for awhile, then under 5k for awhile with a regimen of engine breaking.

You are getting moving parts to "hone or mesh" together. You want to do this at varying RPM's and varying loads. Thats my 2 cents and I agree check with the builder.

Your also going to get varying opinions on how to break an engine in. All I can say is, don't baby it, and don't flog it either. Try to vary the RPM's as much as possible. Change the oil and filter a few times during the process.

Check your tappet screen filter often during break in as well. Put the screen on a white paper towel and reverse flush it with brake clean, check what comes out of it with a magnifying glass. You will get some debris, you will find some fine particles initially, then that should taper off while the break in progresses. YD

 

to me there is a difference between breaking in a new/rebuilt engine and breaking in a new top end. for the top end and engine both, one of the most important things is that you are trying to get the rings to make a great seal. there are lots of opinions on how to get this, but to me with a top end job that is one of the more important things. breaking in a new/rebuilt engine that includes new crank, rod, inner cam bearings and things of that nature includes new surfaces and more attention to break in techniques. before i owned a dyno, i usually went with a conservative rev limit, 3-3.5k rpm with varied loads on the engine, no hard acceleration and no extended idling or heat build up. change the oil at 50 miles and 500, then get on the schedule that you like. also not necessarily down shifting for engine breaking, but letting the engine wind down on it's own to get the rings to flex. I am now trying out some dyno break in techniques, but the jury is still out on that one.
m

 

+ 1 or 2 or whatever it's up to. Most start with heat cycles. Then varying the rpms up to a certain limit for xxx miles. Accelerating and decelerating. Change oil after 500 miles. I Changed mine at 50, 250, and 500.