How to break in a fresh rebuild

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Take Warning15

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Did some searching and found bits and pieces in several threads, but I'm sure there is more out there. Everyone has there own ways I'm sure, but how do YOU break in a freshly rebuilt engine?
 
I usually run the bike hard right from the start Full throttle to 7000 RPM let off to 4000 a couple of times. Then do 100 miles on the interstate 4500 to 6000 RPM. Then some secondary roads for a total of 300 miles change the oil and torque the head. Break in complete.
 
Well, here's the `70s oldschool method we gave customers after overhaul back then, many items outdated old wives tale by now:

1st 500 miles, ride normally, not aggressively, avoid overheating (if it's hot out, take frequent breaks).
Use straight-weight pennzoil 30wt, grade SE or SF, check level frequently.
Avoid full throttle, try to keep below 1/2 throttle.
Avoid long periods at one speed or rpm, change criuse speeds occasionally.
Drop throttle occasionally during cruise, pulls cooling/lubricating oil up thru rings.

At 500 miles, full tune-up, filter(s) clean, oil change (can now use preferred oil), throw away plugs (micrifine iron on porcelan)
Retorque head bolts/nuts, check for leaks.
Gradually come out of 'babying' stage of riding over next 500 miles.

At 1000 miles, another oil change, filter(s) clean, full tune check, plug clean/inspect, replace optional.
Done...

This was the dealership recommended method, pragmatic, but some thought it's just another way for the dealership to make money, replacing oil and plugs and such. The so-called break-in oil is long gone, so the experienced members here will have to give their recommendations...
 
I used Valolene motorcycle 20-50 . Don't use automotive oil it will cause clutch slipping. No synthetic oils for break in. 30 weight with a SE rating Yamalube ect.. I switch to Mobile 1 V-Twin full synthetic after. Never a Problem with thermal break down or over heating. If traffic jams on a hot day not a problem regular oil will do. I have had a bike over heat a back jug on regular oil running all out all in on a hot day. Jamming not traffic jam. :D
 
As scabber said the run hard at first with a hard acceleration then coast back down. Is very important in the first 25 to 50 miles. This hard acceleration with the coast down seats the rings properly and quickly.
I do this on a long up hill pull. This works even better. Do thus as much as you can in this first few miles. At least a dozen or more. I then change the oil at about the 50 mile mark. You get the greatest amount of crap left in the engine in tis first oil change. You need to get the crap out or it will do excessive wear. Inspect the oil and filters for crap. You will be amazed to see all the stuff in your "clean" engine. Oils cheap, a rebuild not so much.
I then retorque the head after it cools off.
It can take a few heat cycles to get the headbolts to hold torque.
I ride the bike a bit easy up to 200 miles then change the oil . Ride it about normal till the next oil change at 500 miles.
Then It's pretty much broken in. At this point I go to the 1000 oil changes.
A synth oil is fine for break in running. Just be sure it's a good motorcycle oil.
Leo
 
BobbedSled and Leo, you guys run them up to the redline straight away? Briefly, but to the redline?

Scabber, do you prefer the 20 50 or straight 30?

On a slightly less related note, this is my first bike. What are the signs (besides heat) of the bike over heating? Is it something you can just feel? Obviously in liquid cooled engines the coolant will boil, but in air cooled engines...?
 
Run up to second gear redline and compression brske down then again up to third gear and decomp down and continue on to top gear same way. I let it col down then don't again. Done. Always did mx bikes that way too. Definitely notice a difference between hard break in and baby break in. Babying it just polishes the bore. Compresion braking really helps seat the whole deal in.

Lots of opinions on what works. Don't think there's a "wrong" way per say, but on my 4 stroke mx bikes I could definitely tell a difference. Even with my turbo cars I would drive a new engine like it was stolen out of the box. Subsequent duo tuning over 12 month showed motor stronger.

Just pick a method and run with. Don't over think it. You'll be fine.

Good luck.
 
Take Warning15 said:
On a slightly less related note, this is my first bike. What are the signs (besides heat) of the bike over heating? Is it something you can just feel?
Click to expand...
That's a lot more then slightly related! Especially during break-in.
If this is your first motorcycle you may be a bit surprised at just how hot they run, but it's a sure bet that if your pant legs burst into flames, it's too hot :laugh:
Ok, all kidding aside, if when you are riding, you can tell that it is getting hotter and then it starts to ping or knock, that's a sure sign that its getting too hot. If you push it beyond that point and then it feels like its fighting itself to accelerate that's another sure sign and this is a critical sign. It means that the motor may be trying to seize up.
If at all possible, ride in open areas during break-in and avoid traffic jams at all costs. Keep the cooling air flowing over the motor during this period.

Take Warning15 said:
By compression braking, you mean to just use the engine to slow the bike down?
Click to expand...
Yes. When you shut off the throttle, the combustion chamber creates a large vacuum and with a new motor (and an old one) it will pull oil up past the rings. Oil going past the rings during break-in is your friend.

Like what has already been said, try not to over think this too much, let common sense be your guide.
 
Wow, a lot has happened in break-in method over the last 30-40 years. I feel like Rip Van Winkle, waking up to the 'new' method. We would employ the 'hard' break-in for a customer on the rare occasion that it was over-babied, glazing before seating, and lightly smoking. The reasoning we understood for the 'hard' break-in, was that combustion pressure would go behind the top rings (by design), and force the rings to press harder against the cylinder walls, cutting thru the premature glazing, and forcing them to seat. I've read somewhere else that today's top builders also 'hard' break-in, and have dyno proofed the method against old-school baby break-in. Wish now that I could find that.

Bottom line: A lot of improvements have occurred over the years, fine-tuned by professionals who have had a long time to know what works and what doesn't. I would recommend following these newer/proven methods...
 

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