Topic: Cb650 post rebuild first start questions

[Nicklopic]

I recently completed a top end rebuild on my 80 cb650. I'm wondering what care and procedures I should follow for first start up and any sort of break in to follow. The cylinders were bored 1mm over, new rings of course, and the head rebuilt, springs, valves and that jazz. The motor sat apart since early March of this year. Cam is stock, case was never split and the bottom end is untouched.
I'm wondering if oil pump priming is needed and how to do so, first oil change interval or use of a break in oil, break in procedures... That sort of stuff.

[BRG-BIRD]

There is a lot of information on the web regarding running in your engine and I suggest you do some research to see what you are comfortable doing. I had an upper end (new rings and cylinder hone) on a motorcycle of mine. I took it fairly easy on it for the first 50 miles and avoided much cold engine idling with the enrichment circuit on to keep the cylinder rings from getting carbon build up. After 50 miles I slowly increased rpms and did a lot of engine braking to help push the rings against the cylinder walls to help them mate.

After 100 miles I would occasionally do a second gear full throttle acceleration to close to redline and engine brake. I did no interstate running and constantly varied the engine rpms. After 500 miles I dumped the regular break in oil and resumed using synthetic oil.

This worked well for me, the engine runs beautifully and does not use oil, one thing it did do before the work. Please note this is on a 1996 Triumph Thunderbird. Why did it need the work? The previous owner left a hose off the airbox and it ingested dirt into #2 & #3 cylinder.

Again you should do a lot of research and there are lots of opinions regarding the break in practice and hopefully some of the brighter bulbs on this forum chime in with their procedures.

[1976cb750f836]

No more than 60% throttle, first 50 miles. Do not hold on any rpm, vary the rpm up and down, this helps seat rings. Keep under 7K first 50. After 50, change oil, read plugs, get your jetting caught up, Ride like you stole it!

[Bodi]

Most oil pump priming questions are about dry sump 750s. Their pump has a shutoff valve in the feed line from the oil tank to prevent all the oil just seeping through the pump into the sump: that would cause a no-oil situation on start until the scavenge pump gets oil into the tank. Opening it takes a bit more suction than some dry pumps can develop, thus the priming problem.
The wet sump engines (350, 400, 500, 550, 650) don't have that valve. Or the problem. Not much suction is needed to lift oil from the sump level an inch or three below the pump inlet. I haven't installed a bone dry pump to test (that would be nuts)... but I haven't seen priming failures on these engines on first start after years of storage.
If you have serviced a pump and it is clean and dry, just pour some oil into the ports (under the screen) and spin the drive gear before installing it.
If you need to confirm the pump is working before first start - remove the spark plugs and kick or crank the engine until you get some oil pressure... but it takes a while at kick/crank speed to fill the filter and galleries. You can take off the filter housing and check that oil is being delivered: if it spurts out the feed hole beside the bolt hole, all is well. The pump's main output goes directly to that hole.