Want Input - Initial engine startup

I'd like some input. Here's the background - I purchased a ’75, in boxes, almost 10 years ago. Over the years I slowly cataloged all the parts, got the frame and body work painted, plated the fasteners, built the wheels, rebuilt the engine and trans - see where this is going? So, after a pretty big assembly push over the summer, I’m pretty close to attempting starting up. (If you're interested in the gory details see https://www.doovsprojects.com/projects/category/1975-norton-rebuild)

Some particulars the of this build that you should know:

1) All these parts have not been together in a long time and never with me as the owner
2) I rebuilt the whole thing
3) I removed the electric start altogether
4) It’s got a new cam and ground lifters, new pistons, rebuilt head, etc
5) It’s got a statically timed TriSpark
6) Brand new Premiers

I plan to use a non-synthetic oil for break-in and will dump some oil down the push rod shafts and prime the oil pump too.

Now it’s my understanding that there are several things that need to be accomplished at initial startup.

1) Never allow it drop below 2500 rpm in the first 20 mins to bed in the cam/lifters
2) Don’t kick it over more than necessary
3) Good to vary the rpm and load above 2500
4) Check for oil returning to tank (I have an oil pressure gage too).

I’d also need to

1) Adjust my carbs
2) Adjust the timing
3) Make sure the thing shifts and stops
4) Adjust everything else I forgot along the way.

I really won’t be comfortable on the road with other cars and such, until I can get through this stuff. So here’s my proposed strategy:

Start the bike in my garage, with the goal of keeping it above 2500 rpm. Attempt the adjust the carbs a bit to keep it running OK. Use fan(s) to keep it cool, cycle between 2500 and 4000 rpm, and basically run it this way for 20 mins. I’m just not confident enough the rest of the bike is roadworthy enough that I would want to jump on it and go anywhere.

Shut it down, let it cool. Change the oil, torque the head, adjust the valves and dynamically set the timing.

Attempt to take it out on the road and see if it stops and shifts properly. At this point I should be able to let it idle a bit so I can set the carbs, etc.

Any Input?

Thanks! David

Everything you said sounds good except running it in your garage for a prolonged period of time with no load. IMHO you need to hit the road ASAP and load the motor to start seating the rings. In 20 minutes on the road the rings would likely be seated. In 20 minutes in the garage nothing would happen except unnecessarily heating the engine up with no load.

If you do the garage method get a monster shop fan blowing on the engine.

If you don't feel comfortable taking the bike on the road you can do what you suggest above but only run it for say 5 minutes
You could do this several times before you ride the bike

Cam break in is top priority, mine started 4th kick and I opened it to 2500 from there, 20 minutes varying rpm above 2000 with a carpet fan on the motor.

Just establish static timing and baseline carb settings to get it going, worry about dynamic timing and carb fiddling later

I run it first start ,for about 5 minutes or so stationary keeping rpm above 2000. Then cool down and retorque head and adjust valves. Next start up, I let it warm up for a few minutes then check the timing and start to ride it. Keep the rpm under 3500 for the first 100 miles but running up and down the gears. Retorque and adjust valves and change oil and filter. Gradually increase rpm during next 500 miles, then another retorque valve adjust and oil change. Especially important to do the retorques with a composite head gasket. I use regular dino motorcycle oil. Make sure it is SG grade. Carbs should only need adjusting for idle if you have the right needle jet and clip position and main jet. You will probably find it hard to get a consistent idle until the engine is fully broken in.

Sound advice.

You will have to retighten the exhaust rose nuts too.

The best thing to do is get it on the road as soon as possible, static timing is pretty close and if carbies are jetted right it will only take a short time to set and have the idle a little higher, if its starting on first or second kick it pretty close, then get it out on the road without labouring the motor, you can do minor adjustments as you go.
I have done this on every rebuild on my own bikes as well other bikes I have rebuilt and in 45 years have had no problems at all, I always use cooper head gaskets and only retorque the head at 500 miles, my way of thinking is some over retorque the head gasket.

Ashley

I wouldn't want to spend 20 mins in a garage with a Commando running at 2K to 3K revs. Last time I did major engine work on mine, I started it up with strobe light connected, set ignition timing as soon as I got it going. Ran it for a few minutes to check oil was circulating and no major problems or leaks. Then put my bike gear on and circulated round the block for about 20 mins keeping the revs above 2.5K.

If you do decide to run it in the garage, please wear ear protection.

Ian

What did they do at the factory?

maylar said:

What did they do at the factory?

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That’s what I’ve always wondered!

The last time I built mine with a composite gasket I took the advice of a ‘good ole boy’ who was quite a successful Commando racer back in the day.

“We just always used to over torque them a few ft/lbs when we built ‘em”

So I tried it. Bingo, hardly any movement at 500 miles.

So, my guess is, that what the factory did.

Anyone know for sure?

Fast Eddie said:

That’s what I’ve always wondered!

The last time I built mine with a composite gasket I took the advice of a ‘good ole boy’ who was quite a successful Commando racer back in the day.

“We just always used to over torque them a few ft/lbs when we built ‘em”

So I tried it. Bingo, hardly any movement at 500 miles.

So, my guess is, that what the factory did.

Anyone know for sure?

Click to expand...

Given Jim's thread on the torque limits of head threads I'd say that's a bad idea. They barely survive the factory specs (and sometimes don't).

maylar said:

Given Jim's thread on the torque limits of head threads I'd say that's a bad idea. They barely survive the factory specs (and sometimes don't).

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Yes, I’m inclined to agree with you now, but I still suspect that’s what the factory did then...

No idea what Norton did but at the Longbridge plant this is what happened with the A series engine in the mid 70's.

As the engine was assembled down the line one of the last operations was fitting and then timing the distributor, the engine was without spark plugs, pressurised oil was fed into the engine which was then spun with an electric motor and a strobe used to set the timing. No water cooling was used or needed and oil was recovered but the engine had been primed.

Once off the end of the line it was then sent to Hot Test, here the plugs were fitted and fuel, oil, electricity and coolant applied before the engine was fired up and run through a series of live running tests for 15 mins.

Torque wrenches had not long been introduced, lots of production engineering time taken up trying to get the wrenches to apply the right torque for a full shift.

At the same time Honda supplied us with 1300cc engines for the Triumph Acclaim, they came in dry and had never been run, put straight into cars and fired up as they left the line before going to the tuning booth for running tests.

Failure rate off the vehicle production lines was 100 times higher for the UK hot test engines than the untested Japanese engines.

ashman said:

The best thing to do is get it on the road as soon as possible, static timing is pretty close and if carbies are jetted right it will only take a short time to set and have the idle a little higher, if its starting on first or second kick it pretty close, then get it out on the road without labouring the motor, you can do miner adjustments as you go.
I have done this on every rebuild on my own bikes as well other bikes I have rebuilt and in 45 years have had no problems at all, I always use cooper head gaskets and only retorque the head at 500 miles, my way of thinking is some over retorque the head gasket.

Ashley

Click to expand...

Agreed on all. I start it outside, make sure oil is returning, drop in gear and go for a short ride. I never let one idle on the side stand and not long on the center stand. The only thing I retighten after the first ride on a Norton is the exhaust nuts. I do strobe the timing after the first ride and then go right back out for another short ride.

BTW, since I started using a little nickel anti-seize on the exhaust nuts when initially assembling, they get much tighter when assembled and don't tighten much on the retighten. After that retighten I've not had problems with them coming loose.

kommando said:

No idea what Norton did but at the Longbridge plant this is what happened with the A series engine in the mid 70's.

As the engine was assembled down the line one of the last operations was fitting and then timing the distributor, the engine was without spark plugs, pressurised oil was fed into the engine which was then spun with an electric motor and a strobe used to set the timing. No water cooling was used or needed and oil was recovered but the engine had been primed.

Once off the end of the line it was then sent to Hot Test, here the plugs were fitted and fuel, oil, electricity and coolant applied before the engine was fired up and run through a series of live running tests for 15 mins.

Torque wrenches had not long been introduced, lots of production engineering time taken up trying to get the wrenches to apply the right torque for a full shift.

At the same time Honda supplied us with 1300cc engines for the Triumph Acclaim, they came in dry and had never been run, put straight into cars and fired up as they left the line before going to the tuning booth for running tests.

Failure rate off the vehicle production lines was 100 times higher for the UK hot test engines than the untested Japanese engines.

Click to expand...

.... a very good example of quality control practices... there is a lot more to that subject than most people ever realise.

Thanks everyone for your input. I hope to try to get it going this week.

napanorton said:

Thanks everyone for your input. I hope to try to get it going this week.

Click to expand...

My new/reground camshaft came with a small tube of special grease to apply to the lobes with instructions to run it in at (I think) 2000 rpm for several minutes upon initial start . With a dire warning of bad things would happen if these directions were not followed exactly.
This is fact from the camshaft manufacturer not fiction.
Ride On
Dave

Yep, an improperly broken-in cam can fail in 500 miles or less, leaving a lot of cam and lifter metal particles to be cleaned from the engine interior and all the engine bearings replaced... Follow the cam maker's instructions!