Running in a new top end.

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Bobs850

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I have read most of the posts regarding how to drive a bike at varying speeds during the initial run in after a top end rebuild.

Are there any tips for what you should do during that initial period when you first fire up the bike in the garage?

Thanks.
 
Presume new rings etc., squirt a little oil into the sparkplug holes & kick over a few times without the plugs. This will make sure everthing is running freely. Replace plugs, run for a few seconds, if everthing is alright, gently run for a minute or so.
Then get on it & go up & down the road. Running in is up to you, lot of debate about that one.
Mineral oil only to run in.
 
Flo said:
Presume new rings etc., squirt a little oil into the sparkplug holes & kick over a few times without the plugs. This will make sure everthing is running freely. Replace plugs, run for a few seconds, if everthing is alright, gently run for a minute or so.
Then get on it & go up & down the road. Running in is up to you, lot of debate about that one.
Mineral oil only to run in.
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If we are talking new bores and rings I would disagree with pretty much all of that.

If its just a refurbished cylinder head I don't think there's any real procedure, just get out and ride it.
 
Gonna get a lot of opinions, from varying speed to "ride it like you stole it".

My opinions:

Fire it up, hold 2500 rpm for 30 seconds and shut it down. Check for oil in the rocker boxes and in the return side of the tank. You NEED oil. If you have a pressure gage, even better.

If timing has been messed with, fire it up again and check timing.

Ride it. After the first 50 miles re-torque the head and check valve clearances. Tighten the exhaust nuts.

When I bought my Norton new in '75 the dealer said no highway riding for at least 500 miles. Take that FWIW.
 
New pistons, rings, valves. Timing has not been messed with. Been doing a lot of reading on this site and others. The top end was put together dry. This is the first time I have put one back together dry. This time around I am going to lean towards the ride it like I stole it approach. I was gentle when I did the top end on my 75 850 and it has always had a puff or two of smoke when you shut it off after a long ride. Nothing serious. I have chased head oil leaks on my 72 750 and after about the third time of retorquing the head, the leaks have pretty well gone away.
 
Bobs850 said:
New pistons, rings, valves. Timing has not been messed with. Been doing a lot of reading on this site and others. The top end was put together dry. This is the first time I have put one back together dry. This time around I am going to lean towards the ride it like I stole it approach. I was gentle when I did the top end on my 75 850 and it has always had a puff or two of smoke when you shut it off after a long ride. Nothing serious. I have chased head oil leaks on my 72 750 and after about the third time of retorquing the head, the leaks have pretty well gone away.
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That's the approach I used.
Use proper running oil if you can it or the lowest grade you can get.
Don't let it sit at idle for any time, get it warmed up on the road and under some serious load in short bursts as soon as you can, let it cool off between bursts.

Job done
 
Running in a new top end.

Plenty of oil when putting it together. Always swamp my cam followers, pushrods, rockers etc. with a squirty can after assembly. Rode this motor for 40 miles fairly gently, then went for it. It is going like a dream now & is powerful.
If you want to thrash the bollocks out of straight away & risk a seizure, up to you.
If you run it too gently, or use too good an oil running in, you could glaze the rings up, so have a happy medium between riding hard & gently.
I feel a lot of disagreements coming along, Ha Ha.
 
The good new is that it fired up on the second kick. No strange noises. No smoke. I reveved it to 3000 grand a few times and let the bike warm up. Those old Dunstall power pipes sound good.

Time for a few short blasts around the neighborhood.
 
This is an interesting conversation. What oil should be used for break-in?

The cheapist mineral oil you can get!
 
I will correct my statement above. The pistons, cyliders, and rings were cleaned and left to dry before I put the barrels back on. I did give the rockers, tappets, etc plenty of oil. Sorry for the way I stated it originally.

In the past I pretty much followed the manual and had plenty of oil in the cylinders. I guess with todays multi weight oils that is not the way to go.
 
Running in the rings dry, just a bit of oil on the piston skirts, does appear to be the modern convetional wisdom.

I've never done it that way personally, but I am gonna have to make a decision soon as I am re-ringing the Commando this winter.

Not to start an oil thread....!
 
The top end was put together dry.
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Done lots of Nortontwin engines. By experiment did overhaul two engines where I left cylinders, pistons and rings dry. Both engines started smoking badly after a couple of minutes. Took the barrels of again and the rings were worn out (both engines the same). Did a light running-in hone on the barrels and new rings on the pistons and put it together again with plenty of mineral oil as usual. No smoking what so ever!
 
I rebuilt my Bonneville with new Hepolite rings left dry, and it neither smokes or appears to use any measurable amount of oil.
I also rebuilt the top end of my Commando, using no oil on the old Hepolite rings and again no problems, but I believe this is only supposed to work with black finished cast iron rings as supplied with Hepolite pistons, and not chromed piston rings?
 
When I assemble an engine I clean the cylinders in soap and water and then solvent. Then I take an oily rag [non-detergent oil] and wipe the cylinders down thoroughly. It's suprising how much grit an oily rag will pick up on newly honed cylinders. Then I wipe the cylinders as dry as I can get them with a paper towel and assemble them with just a fingerprint of oil on the piston skirt. The most important part I have found is don't let the engine run very long after starting it the first time without applying a load. I let it warm up just enough to feel heat in the barrels and then ride it like I stole it. I do shift at around 4000 rpm for the first 20 miles or so and then don't worry about it any more. I use non-detergent 30 wt for the first 50 miles and then go to whatever I plan on using . {Mobile I] Done lots of motors this way without any worries. And never had a seizure on a new motor. Jim
 
use a non detergent ,single viscosity oil for best results. change it after a reasonable amount of miles, say 500?!

keep the revs down, as the rings will have a tendancy to flutter a bit until seated properly. to encourage the rings to seat, find a long shallow hill, if possible, and use a "ROLL ON" approach. use the torque to pull you up the hill. the high pressure combustion gasses will help to push the rings against the cylinder wall ,helping the sealing process. ( under reasonable RPM)
as far as wet or dry assembly, using too heavy of an oil could lead to carbonization. when fitting dry,, use a torque wrench to find the breakaway torque, then the running torque to keeping things moving, and of course, to look for "tight spots" during rotation.
 
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