Startup After Top-End Rebuild.

zukdave wrote: So a race motor gets ran about 5 minutes on a dyno
then they do FULL POWER pull's to redline
but a rering on a 30 year old motor needs 500+ mile's ?

That is what came from the factory printed on the tach of each new kawi. It was clear sticker that said 4000 RPM max for first 500 miles, 6000 RPM max for 500 - 1000 miles. There was also supposed to be a service (valve clearance check and head torque with oil change) at 500 miles. Those stickers came on every new bike sold when I bought mine in '79.

daveo wrote:

koolaid_kid wrote: LOL. I agree with multiple checking on torque. I prefer to rev to redline, but not under a huge load. It allows the rings to seat properly without glazing. Some prefer to rev the blazes out of it, maximum power, but I cannot agree. Nor can I agree with the gentle break in, just does not make sense. So I compromise.

I was advised to put a light film of oil on the threads and bottom of the head-nuts before installing them.
Is the correct (re-torque) method to break loose each nut before re-tightening? If so, would that be just after initial heat/cool cycle, or anytime thereafter as well?

Just torque them same as when you installed it initially.

bountyhunter wrote: ...... It was clear sticker that said 4000 RPM max for first 500 miles, 6000 RPM max for 500 - 1000 miles. There was also supposed to be a service (valve clearance check and head torque with oil change) at 500 miles. Those stickers came on every new bike sold when I bought mine in '79.

I agree. Since every Kawasaki came from the factory with similar break-in instructions why wouldn't the same procedure be followed for new rings and cylinder honing (with or without new pistons and bored cylinders)? Maybe there's something I don't understand (so please educate me), but I would think new rings and honed cylinders would need the same break-in whether they came from the factory or from a 30+ year later rebuild.

Maybe break-in would be different for a pure race motor that isn't expected to go 80-100k miles before a rebuild and which cannot be ridden hundreds of miles off the track before being raced, but for a street bike engine I would expect the break-in procedure to be the same as when the bike was new. Ed

bountyhunter wrote: Those stickers came on every new bike sold when I bought mine in '79.

That same sticker was on the speedo on the 1973 GT80 I got
brand new but we're not talking brand new motorcycle's
It's a 30+ year old motor that has heat cycle'd more times then you
can count so what's to break in on a rering but seating the ring's

zukdave wrote:

bountyhunter wrote: Those stickers came on every new bike sold when I bought mine in '79.

That same sticker was on the speedo on the 1973 GT80 I got
brand new but we're not talking brand new motorcycle's
It's a 30+ year old motor that has heat cycle'd more times then you
can count so what's to break in on a rering but seating the ring's

That helps explain it to me. So is the long 500/1000 mile new bike break-in period intended to let things like cam bearing surfaces, rod plain bearings, etc. break in gently, but the rings/cylinder walls don't require such a lengthy procedure once the rings are seated? Ed

I could not find the original article I once referenced, but here is another.

Rings are not going to seat in 100 miles, they need to be loaded and unloaded by taking it up to 4000 RPM then letting of till reaching 2000 RPM this forces the rings tight against the cylinder then allows for them to relax, This is what will keep them from glazing' as they will do if you keep the motor at a steady high RPM
The requirements are quite different on a race motor that will be torn down much more frequently than a street motor that you are trying to get as many miles on before having to do a teardown and re-ring, looking for the last tenth of ET on a dragstrip, Your mileage my vary

Discussing break in is like arguing religion. :laugh:

Found this break-in article made by LA Sleeve. This company has been in business since 1945 specializing in cylinder sleeves.

www.lasleeve.com/downloads/4-stroke-break-in-procedures.pdf

Bottom line:
They recommend running the bike in the garage at 2000 rpm for 15 mins with fans blowing on the engine. Let it cool then do it again, this time varying the rpm from 1500-3500 rpm. Jetting should be a little rich, definitely not lean.

First real ride (10-15 mins) is not to exceed 1/2 throttle and 1/2 max rpm's. Accelerate and decelerate constantly.

2nd ride recommends up to 3/4 throttle and 3/4 rpms.

3rd ride etc, until the first tank of fuel is gone, and you can go full throttle but keep rpm's down to 3/4 scale.

2nd tank of fuel and they talk about doing jetting checks and such using full throttle and reving the engine out. Basically, the engine is fully ready to run after the first tank.

Sort of flys in the face of all those super conservative suggestions by the various motorcycle manufacturers. I'm pretty much convinced that these recommendations are designed to give the new rider a chance to get used to the new bike. Wonder how many guys would get killed if Kawasaki told KZ1000 owners to use 3/4 throttle and 3/4 rpm after the second real ride and full throttle on the 3rd?

The only thing that bugs me about that article is that most of it is written with respect to off road bikes, trikes, quads and snowmobiles.
I don't know if any of that makes any difference but I do agree with your other assertion that the 0-500, 500 to 1000 miles, factory break in... is also based on breaking in yourself on a new machine.

missionkz wrote: The only thing that bugs me about that article is that most of it is written with respect to off road bikes, trikes, quads and snowmobiles.
I don't know if any of that makes any difference but I do agree with your other assertion that the 0-500, 500 to 1000 miles, factory break in... is also based on breaking in yourself on a new machine.

I put my money on a far more aggressive break-in. That's what the aircraft engine guys do and they don't mess around.

i agree .you need cyliner pressure to seat the rings do not pussy it or they will never seat.