Starting the bike after piston change

[Einar]

Hey everyone,

What do I need to keep in mind before starting the bike after having redone all seals on the cylinders/pushrods + changed one of the pistons
(some of you might recall some posts a while back about piston change / compression rate difference / cylinder rod thread repairs etc).

As she has been drained of all oil and had both cylinders disassembled, I am wondering if there are any precautions to take before firing her up.

1) Can I just fill her up with the required amount of oil and give it a go?
2) Do i need to circulate the oil throught the engine somehow before starting?
3) Do I need to follow the "new bike service procedure"/600 miles inspection described in the maintenance schedule?
4) Any other precaution I am not thinking of?

Your input is as always highly appreciated.
Best regards,

[tunnelrider]

Hi Einar,

Congrats on getting her to this stage!  I've recently just got my old girl back on the road after a top end rebuild with new piston rings, seals etc and donor con rods.  Once I had new oil and filter in her, a few cool beers in me and ready to fire up I used Snowbum's advice for the first start up and run in afterwards - follow this link:

http://bmwmotorcycletech.info/break-in.htm

One of the things he says is 'don't baby the start up - once running increase the revs to 3000 rpm, hold for 15 secs then up to 3500 - 4000rpm for up to a minute.'

I got lots of smoke pouring out of one of my cylinders on this initial start up but just ran with it and reckon I became neighbor of the month too.  It settled down on the first ride and doesn't smoke at all now.

The first 10km especially try to vary the revs 3000-4000rpm as much as possible and completely back off the throttle regularly at least every 800m or so initially to suck oil up into the rings and valve guides. After 10km it can be at greater intervals but for the first 50km do this regularly and vary the revs, not exceeding 4500rpm in the first 150km.

After 600km of mainly commuting to work (50km round trip, about 16km at open road speed)  I threw the rule book out the window and went on 1000km 3 day open road trip last weekend, going at faster revs (up to 5500 rpm) and not backing off.  I took her up to 6000 rpm for brief periods.  Still going well.

This is an exciting time, seeing all your hard work pay off Einar.  I recommend enjoying the procedure treating yourself to lots of cold beverages.  Good luck, I'm sure it will be fine.

 

[Tony Smith]

Hi Einar,

Congrats on getting her to this stage!  I've recently just got my old girl back on the road after a top end rebuild with new piston rings, seals etc and donor con rods.  Once I had new oil and filter in her, a few cool beers in me and ready to fire up I used Snowbum's advice for the first start up and run in afterwards - follow this link:

http://bmwmotorcycletech.info/break-in.htm

One of the things he says is 'don't baby the start up - once running increase the revs to 3000 rpm, hold for 15 secs then up to 3500 - 4000rpm for up to a minute.'

I got lots of smoke pouring out of one of my cylinders on this initial start up but just ran with it and reckon I became neighbor of the month too.  It settled down on the first ride and doesn't smoke at all now.

The first 10km especially try to vary the revs 3000-4000rpm as much as possible and completely back off the throttle regularly at least every 800m or so initially to suck oil up into the rings and valve guides. After 10km it can be at greater intervals but for the first 50km do this regularly and vary the revs, not exceeding 4500rpm in the first 150km.

After 600km of mainly commuting to work (50km round trip, about 16km at open road speed)  I threw the rule book out the window and went on 1000km 3 day open road trip last weekend, going at faster revs (up to 5500 rpm) and not backing off.  I took her up to 6000 rpm for brief periods.  Still going well.

This is an exciting time, seeing all your hard work pay off Einar.  I recommend enjoying the procedure treating yourself to lots of cold beverages.  Good luck, I'm sure it will be fine.

 

Agree with all of the above, but I would leave the plugs out and the coil disconnected, rocker covers off and crank until I saw puddles of oil under the heads. At least then you know you are oiling and that the rocker gear is being lubricated.

[tunnelrider]

"Agree with all of the above, but I would leave the plugs out and the coil disconnected, rocker covers off and crank until I saw puddles of oil under the heads. At least then you know you are oiling and that the rocker gear is being lubricated."

That's right, didn't mention I left the carbs empty and turned it over until the oil light went out before turning on the fuel tap.  Cheers Tony good point.

[Einar]

Great pointers! Thank you for the valuable and detailed input.

Haha I can imagine it must have been a sight for sore eyes when you applied for that neighbour of the month award!

It's definitely been a steep learning curve. Will read the snowburn link and then head out to fire her up! Fingers crossed.

Will update later.

[montmil]

After an initial 50-100 miles, suggest checking head and case studs for correct torque as head gasket and any jug-to-case gasket goop may have compressed slightly. Also, confirm or adjust valve lash.

Good to hear you're back up and running. [smiley=thumbsup.gif]

[Einar]

Hi everyone.
There bike started without any problems. Smoke from the exhausts for the first couple of minutes but it seems stable now. I rode her about 50 miles over the weekend. All seems good and despite a lower compression rate on one side I don't feel any noticeable difference.
Thank you for your support and input in getting me back on the road.
Einar

[Einar]

Hi everyone.
There bike started without any problems. Smoke from the exhausts for the first couple of minutes but it seems stable now. I rode her about 50 miles over the weekend. All seems good and despite a lower compression rate on one side I don't feel any noticeable difference.
Thank you for your support and input to get me back on the road.
Einar

[tunnelrider]

Happy riding!  I changed my oil and oil filter after about 450km.  There was not much in it except some small pieces of probably Hylomar blue sealant I used between the jugs and engine case in the oil filter pleats.

[Einar]

Good to know I will do the same.

Trying to keep things no higher than 4500 RPM first 500 km, then oil + filter change filter with inspection of metal debries etc. Readjustment of valves and retorquing bolts as well as carbu-sync as necessary.

Amazing how easy this all sounds now, knowing that when I bought her back in August I was green..largely thanks to this forum...the easy-part, that is, not the green-part!

However I don't plan to change gearbox, wheel drive and swing fork oil. Any reason I should change those too?

If no major issues, I was planning to start driving her as normal.

[montmil]

However I don't plan to change gearbox, wheel drive and swing fork oil. Any reason I should change those too?

Gear oil is cheap as are the needed crush washers for the drain plugs.

Gearbox, swing arm and final drive are all easily done in less than one hour of your time. Have you confirmed current levels? The swing arm is all but impossible to accurately measure the level so a change of lube will get it right. Use caution when snugging up the final drive oil level check bolt. Too much torque on that steel 10mm bolt and the aluminum threads in the final drive case will strip quicker'n you can say, Oh, S##t

By changing gear oils, you can then log the date and establish a service benchmark in your bike's service records. Pretty sure you have begun keeping written records of all the work you've done, correct?

[georgesgiralt]

Two things often overlooked are the brake fluid and the fork fluid.
IMHO you should change them if the bike is new to you and keep track of it as Montmill said.
A good set of new oil is all that keep our bikes happy and long lasting. And it is cheap too.

[Einar]

Thanks for the response.

All oils were changed when I bought her in August 2015.

My question was more linked to whether or not a piston change / this type of repair job would require a change of other oils ? I don't see any direct impact on shaft etc but perhaps on gearbox?

That's correct Monte, I keep a maintenance log for each of my bikes, even the 125cc. I will make a note in it not to overtorque that screw.