I know this is a bit of a religious topic but everything I read on the net seems to be geared towards brand new motorcycles with all new parts.

I should be picking up my GS this week fresh from a top-end rebuild.

There seems to be a lot of debate over this: http://mototuneusa.com/break_in_secrets.htm

If you are not familiar with that exact article, basically it's a suggestion that it requires high cylinder pressures to properly seat rings on a freshly-built engine. Not talking about the concurrent force on rod bearings, wrist pins, crank bearings, or heat generated in these bearings due to rpm, but purely seating rings.

If this is true, and it sure does make sense to me as an engineer, then it would seem that a motorcycle with a top end rebuild and (in my case) over 20K on the bottom end would best have the rings broken in by running with frequent WOT and closed throttle as suggested by the divisive mototuneusa site.

So for the GS-twins experts out there, are there special circumstances or considerations I need to take into account about these particular engines?

My current plan is to take the bike on a 20-mile ride straight out of the shop (if it'll run 20 miles in a row, it never has as long as I've had it) that runs through sparsely-trafficked backroads with speed limits in the 45-50 mph range where I can easily go WOT and off-throttle frequently in 2nd or 3rd gear. Does this sound like a bad idea?



FWIW with cars I have long been of the "drive it hard from day 1" school of engine break-in and it's served me well in the past. But it's way easier (and more sane) to do WOT and off for 20 miles in a car that goes 0-60 in two gears and 6-7 seconds than it is on a motorcycle that goes 57mph at redline in first gear and gets there in under 4 seconds.

I mean, if your bottom end has 20k on it and all you're doing is a fresh top end aren't the rings already broken in?


When I did the break in on my engine (new rings, honed cylinders, cleaned and lapped valves, new valve springs, ported and polished head) I took it on the expressway and just held the RPMs up for a while.  Good amount of engine braking too.  Then changed the oil after just a few hundred miles, and didn't look back.
Ran great the rest of the time I had it.

Hey mr72 this makes sense to me. The process described in the article is very similar to what we used to do with rebuilt Toyota Corolla motors used in club rally cars in the late 1970s (Yep, I'm that old  ).

The only real difference is that it was assumed the process took longer - maybe it did on those more roughly machined motors. The process of using graduated steps of acceleration and deceleration, building from 30% through 90% of red line in five or six step, ran over a period of about 160 ks (100 miles). Then an oil / filter change.
It seemed to work. The only 'evidence' I have for this is that the guys would avoid getting an engine out of a car that had had the stereotypical 'little old lady driver who only used it to go the church' - these motors would religiously (terrible pun - sorry) fail quickly under hard work. Even low kilometer motors with good compression numbers would fail sooner than you'd expect.

One of the reasons I like GS500s so much is that they have all the technology of a 1974 Corolla. Maybe they should be treated that way?

Quote from: Watcher on October 18, 2016, 03:33:24 PM
I mean, if your bottom end has 20k on it and all you're doing is a fresh top end aren't the rings already broken in?

In this case top end rebuild includes rings and honing the bores. In fact they don't really do valves besides cleaning and verify that they seal, and fit new seals and gaskets. Valves with 20K are nearly new, I guess.

Top end rebuild?
Unless the work includes........

Decarbonising all parts.
Check of valve seat condition and relap
Check valve stem runout against service limit
Chech valve stem/guide wear against service limit
Replace valve seals
Check spring lengths against service limit
Check camshaft runout etc
Check camshaft bearing diameters and clearance etc
Check block/face flatness
Check valve clearances
Check of all tapped holes inc plug location.

......the term is something of an exaggeration

From your description you have had a re-ring and hone and a cursory look at the head, nothing else. Did they even measure  piston/cylinder wear by the usual method and give you the figures.......all 24 of them?

Yes....lots of conjecture surrounding running in but as is so often the case people will listen to whoever sounds the most convincing or shouts the loudest. Most of it is total overkill and can be dismissed. What you have to remember is that this is an aircooled twin from the 70s with massive clearances. Not some multipot, high power, high reving, liquid cooled, fuel injected exotica with a crank balanced to G1 that runs as tight as a lobsters arse!

I have re-ringed about 10 now, 3/4 throttle/revs for 500 miles with a top quality low volatility oil works for me. So apply the science, waste the time, spend the cash if you wish but you won't notice a thing or see any gains.....not with this bike at least.

Quote from: sledge on October 19, 2016, 01:49:35 AM
Top end rebuild?
Unless the work includes........

Wow, so now you are smarter than my mechanic, too.

Anyway, after your self-aggrandizing, mostly-arrogant and utterly irrelevant response, you did finally post one useful piece of information:

Quote... remember is that this is an aircooled twin from the 70s with massive clearances.

Which is exactly why I am asking the collective here for input. Because it's not an engine from the 70s with massive clearances, it is an engine that in the fourth quarter of 2016 is getting new rings and bores honed and very likely not with massive clearances typical of a 70s air-cooled engine from the Suzuki factory. And also the bottom end of the engine is not in need of breaking in, regardless of how it was when originally manufactured, so in any case the original break-in procedure for the entirely new engine may not apply. 1970s-era engine break-in procedures probably didn't even apply when it was new, which is irrelevant, since it's not new.

I guess that is an assumption on my part: my mechanic who was not even born before the 80s is not using 70s era parts, tools and techniques to rebuild half of an engine from a motorcycle made in 1992. It's a fair enough assumption since the majority of work this mechanic does is on modern race motorcycles, so it'd be pretty bizarre to have some collection of vintage tools set aside just in case a customer comes in with an air-cooled motorcycle that needs a repair. But it's a possibility, I admit.

I've got to hand it to you sledge. You show tremendous commitment and hard work in consistently coming off as such a colossal jerk.

Quote from: sledge on October 19, 2016, 01:49:35 AM
...

lots of conjecture surrounding running in but as is so often the case people will listen to whoever sounds the most convincing or shouts the loudest. Most of it is total overkill and can be dismissed.

...

I have re-ringed about 10 now, 3/4 throttle/revs for 500 miles with a top quality low volatility oil works for me..

I've removed everything that doesn't actually relate to the question at hand and I'm not really sure if you're advocating for or against a break-in... The first part sounds like you think its not necessary, but then you describe what sounds like a break-in process as what "works for you". Maybe I'm just misunderstanding you.


Additionally, and I'm trying to give you the benefit of the doubt here by assuming you're at least trying to be helpful, you've been really presumptuous in basically every post I've seen of yours. You assume a lot about a situation with no real evidence of anything or detailed information about the situation. Why would you assume that mr72's mechanic didn't do the rebuild right? All he said was "I should be picking up my GS this week fresh from a top-end rebuild." and "In this case top end rebuild includes rings and honing the bores." Why is your immediate reaction to that "well, he didn't list out all the little things the mechanic was supposed to do while doing the job, so he must not have done those things"? You've just made an enormous logic leap, and everything you said other than what I quoted above is basically a non-sequitur of you just trying to impress everyone with your knowledge of what a top-end rebuild is.

In your posts, you seem like you really want a reaction of "Thanks so much sledge! You're so knowledgeable and smart!  ", but you're not going to get a positive reaction if all you do is act like you're trying to show how much smarter than everyone you are. You're the one who told me before to focus on what is said, rather than who says it. So focus on the question at hand. Don't just rattle off a bunch of checkboxes for what you think a "top-end rebuild" is. The question here is: After having a top-end rebuild, do you think that a GS500 engine needs to be broken/run in? Why, or why not?

Quote from: qcbaker on October 19, 2016, 08:45:21 AM
Additionally, and I'm trying to give you the benefit of the doubt here by assuming you're at least trying to be helpful, you've been really presumptuous in basically every post I've seen of yours. You assume a lot about a situation with no real evidence of anything or detailed information about the situation. Why would you assume that mr72's mechanic didn't do the rebuild right?...
...is basically a non-sequitur of you just trying to impress everyone with your knowledge of what a top-end rebuild is.

It's not even just that.

A normal person, especially if they truly were trying to be helpful and who possessed the knowledge that sledge seems to, would respond to this with something like, "Hey, by the way, since you are getting a top end rebuild done, you might not be aware of a bunch of little things that are normally included in a top-end rebuild, so you might want to double check and make sure the mechanic is getting them all done for you. Here's a list..." and then go on with the exhaustive list. It'd still be presumptuous and maybe even misguided but at least it would not be immediately discarded as useless ranting. But instead he chose a condescending post which might actually contain useful information if you can carve away the useless attitude from around it.

The thing is, I don't know whether my mechanic knows all of this stuff, but I assume he does and these guys are doing business mostly by word of mouth and referrals just a couple of miles from my house, and they are bending over backwards to try and build a long term relationship with me as a customer. And they guarantee their work. So whether sledge is an expert or not is totally irrelevant. I'm going to trust the mechanic to do the job right because if he doesn't, I'll be coming back to get it done over, on their dime. The whole point of me taking it to a mechanic is so I don't have to know or care about all of this.

But once the motorcycle is given back to ME, then I am responsible for breaking it in correctly and riding it. The mechanic will certainly advise me as to how to break it in but I wanted to collect some wisdom from the forum so I can make the best choice for me. If the mechanic tells me something opposite of the prevailing wisdom of the forum, I'll know something is up. If the mechanic tells me just what I expected after hearing from the forum, that not only helps me build confidence in the mechanic, but I will have been armed in advance with useful information.

But you keep telling us....you are an Engineer 

Quote from: sledge on October 19, 2016, 09:53:43 AM
But you keep telling us....you are an Engineer 

Sick comeback mate. Everyone is impressed. Trust me.

Everyone?

Nah......trust ME 

Damn every post i read now has sledge and mr72 at it.  I did learn one thing about this though. The tolerances on a gs500 are alot more forgiving than most other engines, because it wasn't engineered to hit such a tight margin. Massive valve clearances. This makes me happy. I haven't even checked mine but have been wanting too, given there really isnt anything off about how the bike runs as far as i can tell other than carb clean or rejet needed.

I now have alot more faith in my old engine, due to that one line sledge has decided to gift upon us mortals. (p.s., you guys should try being friends. You know after somebody stabs the other or whatevers about to happen. You both seem to know enough that i can learn from either of you guys. Doesn't necessarily matter who knows more because too me its more than me regardless of that answer. Some psychedelic mushrooms would quench the ego and cool it off)

I also wouldn't be too concerned about the break in procedure. What could you possibly gain from the different methods? 36 hp instead of 35 hp? Some oil consumption instead of a moderate amount of oil consumption? Like sledge said, the GS500 engine is early 80's technology at best. Very little has changed since the 450 version of the motor which wasn't that different from the '76 GS400. The brand new rings are designed to the original specs and the tolerances are the same as what Suzuki specified back when the engine was new. The modern mechanic doesn't change that.

A couple barely pertinent examples of the GS's ability to care not what you do to it:

My GS once sheared and annihilated its starter clutch bolts. Most of the pieces of the bolts were eventually found in the sump after I unknowingly let the bike run with those pieces circulating in the engine. The GS didn't care.
I installed the wrong sump pump gasket and rode the bike for 5 more miles of city traffic with the bike's oil light on at idle. The GS didn't care.
A mechanic routed my carb hoses wrong, and the bike ran so lean that the bike got hot enough to melt its own wiring and my pillion's boot. After replacing the wiring, the GS didn't care.
A Jeep wrangler backed over my GS. The GS wanted some new plastic.
I've crashed my GS 4 times at speeds 15 - 45 miles per hour. The GS does not care.
After I bent a valve on the head of my GS learning that there is such thing as engine timing, I swapped a new head and jugs on without measuring any of those important measurements that sledge listed. The GS didn't care.

Just go pick up the bike, hope the mechanics fixed all the problems, and ride the darn thing how you like to ride.

Thanks, Bluesmudge. This all is in line with the "bulletproof" and reliable reputation of the GS500 in general, but mine has been anything but. I think I was just a little paranoid since it seems like everything had to be perfect just for mine to basically run, I didn't want to wind up back where I started by botching the break-in.

It's impractical to do the "ride hard" break-in method of WOT riding anyway, but I'll probably avoid "babying" it for the first 20 miles and at least give it some hard throttle during that time, but I'm not sweating exactly how. I mean, the mech at the shop is likely to run it on the center stand at idle for 15-20 minutes anyway just to get the carbs dialed before letting it go, and he'll likely take it on a test ride to boot. For all I know it'll be mostly broken in by the time I get it back.

I'm going back to doing something I can actually control and fully understand today: paint. I should finish the tank paint today and I'm chomping at the bit to get the bike back so I can paint the wheels and fender and get it all put together. Funny how going to a motorcycle rally and show on Saturday just made me really want my old beat-up bike back much more than it made me want to buy that Ducati Scrambler.

Its okay, you are an engineer. You can't help but think that way