TOPIC:

I find this interesting. Obviously everybody knows what the manual prescribes.. no more than 1/3rd throttle for 500 miles and vary the engine speed.

I was searching for air cooled engine break-in and actaully found a VW site by accident that talked about really running the piss out of it to get the rings to seat, and that seemed interesting to me, and also somewhat intuitive.

I found this article today, actaully reposted somewhere else but with this link to the original site.

www.mototuneusa.com/break_in_secrets.htm


It seems very tempting to me, espeically since I am only after breaking the rings in.

The only thing I really don't like is the suggestion to use automotive oil for the first however many miles.

break it in the same way you are going to ride it.just do a couple early oil changes.

Trav wrote:

...It seems very tempting to me, espeically since I am only after breaking the rings in.

The only thing I really don't like is the suggestion to use automotive oil for the first however many miles.

There is a peculiar kind of logic to the man's theories, and with today's improved oils and metallurgy, I'm sure he's obtained results.

Change Your Oil Right Away !!
The best thing you can do for your engine is to change your oil and filter after the first 20 miles. Most of the wearing in process happens immediately, creating a lot of metal in the oil. Plus, the amount of leftover machining chips and other crud left behind in the manufacturing process is simply amazing !! You want to flush that stuff out before it gets recycled and embedded in the transmission gears, and oil pump etc...

That part is spot on.

Q: If break- in happens so quickly, why do you recommend using petroleum break- in oil for 1500 miles ??

A: Because while about 80% of the ring sealing takes place in the first hour of running the engine,
the last 20% of the process takes a longer time. Street riding isn't a controlled environment, so most of the mileage may not be in "ring loading mode". Synthetic oil is so slippery that it actually "arrests" the break in process before the rings can seal completely. I've had a few customers who switched to synthetic oil too soon, and the rings never sealed properly no matter how hard they rode. Taking a new engine apart to re - ring it is the last thing anyone wants to do, so I recommend a lot
of mileage before switching to synthetic. It's really a "better safe than sorry" situation.

I see what he's getting at.

Basically, the higher-viscosity natural oil allows increased friction with the cross-hatched hone acting as a "file", and wanking it up pressurizes the rings against the cross hatch to get the job done.

Don't ask me to guarantee his claims, but he does make a fair amount of sense.

The biggest safeguard to a fresh motor is indeed that quick 20 minute / 20 mile oil change.

Secondly, he advocates a controlled "hard" break in, not merely *running the pi$$ out of it*.

Beyond that, there's a creeping line of thought these days that since synthetic oils came along, naturals are junk, which certainly isn't true - back during WWII, they ran commonly ran the snot out of 18 and 27 cylinder air cooled radials at overboost ratings with little in the way of break-in periods on natural oils that can't hold a candle to today's.

Myself, I'd think that 300-500 miles of natural oil break-in for street riding would be fine, but I'm not him.

Let us know how it turns out...

Errr...

One proviso I'd add to my previous:

What I know about the 550 motors wouldn't fill a shot glass, but were I to consider that procedure on a 1000 motor, I'd make sure to lube the holy hell out of the valve stems and guides when assembling the motor beforehand - and knowing the low oil pressures they run at, I'd make sure it was warmed up *real good* - enough to know there was plenty of oil in the cam channels before I'd go wanking on it....

I rode the snot out of it after rebuilding the topend, just took it easy the first 5-10 minutes until the motor was nice and warm, then cracked it open. I used (still do actually) a good quality petroleum based oil, like the guys said, do some extra oil changes. I did one right away, 2nd after the first real short ride, one more two weeks later (hell I don't have a speedometer haha) and now every month or two, depending on how much I ride. Oil's cheaper than parts

the first 20 min of any engine break in is the most critical, make sure that you keep a fan in front of it if you are going to run the engine for some time without moving

I plan on running it just enough to get it stable, about hte time it takes to get my gear on, and then taking it out, about a short quarter mile or so down the road to the main local two-lane road (I live in the boonies) and going from there, and getting into it with steady fairly hard acceleration. I don' plan on just cracking it, but as the bike feels like it wants to go, I'll go.

The only other thing I worry about is jetting. I've got latest model (84/85) Gpz550 carbs, and a dynojet kit that has #136 mains for a Gpz550 with pods and a 4-1. CoreyClough is doing the same kit on his bike (which IS an 85 GPz) and he was using that setup before, and seems to think it will work fine after the 615 upgrade as well.

I don't want to have to try and tune this thing while it hasn't even run for 20 minutes