1982 R100RT Rebuild break-in questions

I've been thinking about this for a few months. The question is how to go about breaking in a rebuild on my 1982 R100RT. Back story....I needed a head rebuild so i figured it was a good time to dig in deep over the winter. I did a timing chain and crank sprocket change at the same time so I obviously had to take the bean can off which set myself up for a timing operation when i get things back together. Now i did take pictures of where my "alpha" bean can was set prior to disassembly so I feel i can at least come close when I reassemble things. Also, because my valves needed often adjustment prior to the tear down, I think the carbs are close to adjustment as far as the idle and mixture screws are concerned and i think I can come close enough to adjusting the cables by eye so the bike will be run reasonably well out of the gate. Oh, and I'm also putting in new piston rings at this same time. Here in lies my dilemma.

The info i read on break-in is to start the bike and get the rpm's up to 3000-3500 and then go for a ride, like a 50 mile ride. Snowbum make specific note to not idle the bike too much during this time. None of the write ups i've come across talk about timing the bike or adjusting the carbs prior to taking off. I'm confident but i'm not that optimistic that i will have set the timing exactly as it needs to be set and that the carbs are nicely balanced. That takes time with the bike at or near idle. Surely, I'm not the first to go this route. Please advise. Thank you in advance for all the great info that you will send my way.

I would put a fan in front of the engine and take the five minutes needed to confirm carb synchronization and timing. Then I would go for a ride - rpm up and down just like riding on a nice twisty road for an hour or so.

IMO, if you feel you can get the critical settings in the ballpark and she starts, I'd perform the standard break-in as 'bum suggests and go for the ride. 50 miles seems a bit much...I've always just gone for 20-25 miles...enough to get the engine up to operating temperature. Once back home, you can let things cool and reset valves and consider the next steps.

But if it'll start, that's a good sign. If it doesn't and sounds bad from the beginning, then do like Paul says and take the time to make some adjustments.

Both good suggestions. It looks like i may have to wait until i hit my start button to make the decision on which way i go. What do they do at the factory when the bike rolls off the assembly line?

If you didn't change anything with respect to pistons/rings/cylinders, I think no break-in concerns are warranted.

lkchris said:

If you didn't change anything with respect to pistons/rings/cylinders, I think no break-in concerns are warranted.

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The OP stated:

I'm also putting in new piston rings at this same time

Click to expand...

So, it should be something to think about.

There's a whole chicken and egg problem--your carburetor adjustments won't be right until the rings are sealing, but you can't get out to get the rings to seal unless your carb adjustments are in the ballpark.

I'm going to guess that your carb settings, if unchanged, should be adequate for the first ride. But you will want to spend a moment checking the timing before you go. It probably won't idle, so check the max the first time it fires up. Have the timing light hooked up and ready to go before you hit the button. If you can get a good static timing, checking the starting timing, more power to you. But it can be hard to get that with a Hall-effect ignition.

Have your sync and idle adjustment tools ready to go for when you return from Ride #1, if nothing else needs attention. And expect the idle to creep up with each succeeding ride as the rings get friendlier with the bores.

What do you mean "check the max"?

As i think about this, i will probably want to keep the front cover off the engine when i fire it up that first time in case i need to adjust the timing (bean can adjustment). So i'm looking at at a start and stop sequence either way; whether it needs a timing adjustment or not i'll have to shut the bike off to install the front cover before i take that first ride. Is this ok?

Is there anything i certainly do "not want to do" during break-in?

Jim,

Here's the procedure I've used more than once with no problems...

Adjust the valves. Set the carburetors at all the static factory settings. Make your best guess at the throttle cable adjustments with approximately 1/8" of free play at each carburetor. Set the timing statically the best you can.

Start the motor, rev it to 2500-3000 RPM and hold it there for about 30-45 seconds. Shut it OFF (no idling) and don your helmet and gloves, jump on and take a brisk 5-10 mile ride.

When you return, shut off the motor, prep the carburetor adjusting tools, start it, adjust the carburetors and shut it off.

Let it cool overnight, recheck the valve clearances and timing. After 600-800 miles recheck the valve clearances, timing and carb balance.

ocoinji said:

What do you mean "check the max"?

As i think about this, i will probably want to keep the front cover off the engine when i fire it up that first time in case i need to adjust the timing (bean can adjustment). So i'm looking at at a start and stop sequence either way; whether it needs a timing adjustment or not i'll have to shut the bike off to install the front cover before i take that first ride. Is this ok?

Is there anything i certainly do "not want to do" during break-in?

Click to expand...

Check the max would be check the timing at 3K rpm, or wherever it quits advancing.

You don't want to leave it idling on the first start-up, nor should you expect it to idle well.

Don't use syn oil for break-in, or the rings may never seal. I use a 30 weight oil specifically made for break-in by Brad Penn and have had good results on my Airhead and my VWs. It stays in for 200 miles.

Today was the day

Well, today was the day. 1982 R100RT, rebuilt heads, new rings (from Ted Porter), new timing chain, new crank sprocket, new clutch plate, new tires, a long winter. Cranked it over until oil light went out, turned on the gas and it started right up. Didn't do a timing check, sounded ok and seemed to run well. Went out for a 30 mile break-in varying throttle between 3k and 4.5k. Some quick accelerations in there too. Came home and wanted to check compression while things were still hot. Maybe 5-10 minutes passed by the time I actually had everything connected. Only 60 psi, both sides. Is this just too soon to expect a higher pressure than that or is something seriously wrong? I used 10-40 conventional oil for the break-in ride.

I will be checking the valve adjustment tomorrow after I do an oil change. I will also check the timing and adjust the carbs.

To check compression with the CV carbs, you need to manually open the slides as just turning the throttle doesn't do that. Or best, you have to remove the carbs. Likely you're OK, but by having the slides dropped down, little air can get through to the combustion chamber.

Other than that, sounds like things were pretty successful! Feels good I'm sure!!

Kurt,

I forgot all about that. Now that you mentioned it, I remember taking the carb off the cylinder and letting them hang the last time.

Yes, a great feeling when it started up first shot!