Topic: Engine break-in after rebuild

[RebelYankee]

Hi everyone.  Finally got my 1980 CB650C road worthy.  Here is the story of the bike:

Found the bike on Craig's List for $400.  Hardly any rust and had all the parts, including original seat and luggage rack.  Problem was it had two blown pistons.  The owner took it to a mechanic who took the engine apart and removed the pistons.  Because of the holes blown in top of the pistons, an engine rebuild was needed.  The owner didnt want to spend the money so the mechanic put it all back together hand tight, which was awesome for me as taking the engine apart was cake.  The original problem was a blown HG the owner never fixed.

Anyway, I ordered a set of pistons off of e-bay for cheap, put in new rings, gaskets, seals, etc.  Took the head in for cleaning and checked the valves and I ground the valve seats.  Bike started right up after the rebuild and I am riding it arouynd the hood until I can get it inspected. 

So my question is, after a rebuild, what is the proper procedure for breaking in a SOHC4 engine?

I have a little more work to do on the tank (paint and body), and I need a new chain and rear sprocket.  I am keeping everything orginal.

[grcamna2]

Drive it around in the lower gears w/ easy ups on the RPM's to about 5-6K w/o lugging the engine; 'Heat cycle' it i.e. bring it up to full operating temp. and then let it cool down fully and then keep doing that.You should progressively bring the RPM's up a bit more after around 200 miles... Change the oil & filter at 600 miles(make sure it's fresh oil before you begin the break-in procedure) The other members will give some more recommendations 

[calj737]

Popcorn, anyone?

Here we go again...

Rebel- you need only search engine break-in to find a myriad of opinions, anecdotal experience, some technical ideas, and every recipe for "how to" on this one. The only moral I can decipher is: everyone differs. You provide little background other than "bought it for $400 and did this..."

Just ride it and care for  it as you go. You'll be fine. Good riding behaviour and maintenance assure longevity more than anything else. And if you abuse it, you'll know.

Cheers-

[RebelYankee]

Popcorn, anyone?

Here we go again...

Rebel- you need only search engine break-in to find a myriad of opinions, anecdotal experience, some technical ideas, and every recipe for "how to" on this one. The only moral I can decipher is: everyone differs. You provide little background other than "bought it for $400 and did this..."

Just ride it and care for  it as you go. You'll be fine. Good riding behaviour and maintenance assure longevity more than anything else. And if you abuse it, you'll know.

Cheers-

Very useful information.  Thanks for taking the time to reply.  So what else do you want to know about that bike that may help you answer a basic question?  My assumption was that those who would respond would understand the engine rebuild process and what is involved, thereby leaving useful feedback and not giving me grief for not providing enough information.  Would you like to know exactly what I did when rebuilding the engine?  I can certainly provide an in - depth write up if it will help you provide a response worth it's salt.

I understand how the search function works, and use it all the time as evidenced by the fact I have been a member for almost a year and have posted only 2 messages.

Cheers

[RebelYankee]

Drive it around in the lower gears w/ easy ups on the RPM's to about 5-6K w/o lugging the engine; 'Heat cycle' it i.e. bring it up to full operating temp. and then let it cool down fully and then keep doing that.You should progressively bring the RPM's up a bit more after around 200 miles... Change the oil & filter at 600 miles(make sure it's fresh oil before you begin the break-in procedure) The other members will give some more recommendations 

Very much appreciated!  Exactly what I was looking for!

[calj737]

I wasn't admonishing you for not using the "search" function. I was pointing out that there have been dozens of threads asking this same question, and there has been a single "conclusive" answer. I wasn't being dismissive, nor snarky. I was simply preparing you for the opposing answers and advice you'll get.

Some will say: drive it like you stole it. Others, will detail a very regimented process of miles, varying RPMs, and intervals for how long something "should" take. There is no answer, that is "the" answer. As I said, treat it well, monitor your oil and re-torque as guided by the manual, and treat your machine well. That's the best regimen.

Hope that cleared up the misunderstanding.

PS - for what it's worth, I have a different programmer than grcamma altogether. But why create some many divergent paths? Who would you believe? He's a knowledgeable guy and provides good advice.

[RebelYankee]

I wasn't admonishing you for not using the "search" function. I was pointing out that there have been dozens of threads asking this same question, and there has been a single "conclusive" answer. I wasn't being dismissive, nor snarky. I was simply preparing you for the opposing answers and advice you'll get.

Some will say: drive it like you stole it. Others, will detail a very regimented process of miles, varying RPMs, and intervals for how long something "should" take. There is no answer, that is "the" answer. As I said, treat it well, monitor your oil and re-torque as guided by the manual, and treat your machine well. That's the best regimen.

Hope that cleared up the misunderstanding.

PS - for what it's worth, I have a different programmer than grcamma altogether. But why create some many divergent paths? Who would you believe? He's a knowledgeable guy and provides good advice.

thanks for the response I do appreciate it.  This my first bike and I'm a new rider so I'm definitely not going to drive it like I stole it.  I'm not a young chap either so I drive rather conservatively.  I guess my question should have been,  as a new rider,  will I do any harm learning on a rebuilt engine?  Seeks like I should be fine.

Appreciate the responses!

[calj737]

So I will offer some specific guidelines that almost everyone will agree with: after 100-500 miles (your choice), change the oil and filter. At the same time, do re-torque the head bolts. These stretch after initial break-in. In fact, you can do it after 50 miles if you choose, but do plan to do it sooner rather later. It will help prevent oil leaks, and warpage of the head. Use it an opportunity to double-check every system you touched after some road miles. You'll be surprised how many little things you might notice that need a snugging up, a tuck away, or some attention.

You didn't indicate whether there was a re-bore or just a re-hone with the rings, so keep an eye on your oil when you drain it make sure you don't find any surprises in it. Some minimal amount of metal particulate is not uncommon, but chunks, shavings, or pieces is a significant concern. It's a common trick to drain the oil and filter into a fully clean pan, then use a strong magnet and swirl it through the oil to pick up anything that might be lurking. If you do find something concerning, post a picture with a little background, and someone will be along to provide some good advice.

If you're new to riding, welcome. Ride safely, stay alert and enjoy plenty of new adventures!

[grcamna2]

+1 
yes, torquing down the head when cold to the torque spec. is right

[Lostboy Steve]

This is one of those situations where every one has an opinion and I don't know for sure what is fact, from fiction. After I rebuilt my cb550 with a re-ring and hone, I went easy on it for about 100 miles and then I couldn't stand it any longer and gave her hell. I also used the heavy duty studs, so I didn't re-torque. When I bought my wr last year I wanted to do the break-in correctly (whatever that may be) so I followed the dealers instructions of change oil at 200 miles then 500 miles. Don't go "full bore" until the 500 mile mark. After about 250 miles I found this article:
http://www.mototuneusa.com/break_in_secrets.htm

[grcamna2]

That's a good link lostboy;when he talks about "more modern engines",do you think he means 90's+ watercooled machines ?

[Lostboy Steve]

I have no idea, but he does talk about cylinder material and how that seems not to matter. Again, I dont necessarily  agree with him, but it is an interesting read.

[ofreen]

So my question is, after a rebuild, what is the proper procedure for breaking in a SOHC4 engine?

As noted above, there are plenty of ideas on how to break in a motor.  When I bought my '93 BMW R100GS-PD new, I followed the factory break-in procedure. That essentially was no revs above 4000, and the usual admonishment to vary revs as much as possible.  That bike has always used more oil than any of the others I've had. I believe the factory's break-in regime is too gentle, not allowing the rings to properly seat in the Nikasil coated bores. After a few new bikes, i lean toward the 'ride it normally after the first 100 miles' school of thought.

One of the worst things you can do to an engine, and this especially applies to a new or rebuilt engine, is to lug it. Keep it in the appropriate gear for the speed and avoid lugging it.

[grcamna2]

I like how that man in the link describes how you shouldn't hold back too much considering how much more the rings spread out and scrape harder against the cylinder walls under acceleration.I think it's good to know for me in the future so I can 'run it up' a bit more, but like ofreen says "don't 'lug' it" I agree.I like to keep it progressively accelerating and keep that tach. needle moving.I also enjoyed what the man wrote about decellerating... good thoughts.

[RebelYankee]

Guys,

All great stuff.  Thank you for replying!

Jamie