Engine smoking

[yozzer74]

Ha cheers for that Pete and I'm starting to no what you mean about messing with your head .

[yozzer74]

Just been thinking those 4 large o rings that go on bottom of cylinders .if there not on properly would they let oil into barrels and make it smoke .

[Johnwebley]

Just been thinking those 4 large o rings that go on bottom of cylinders .if there not on properly would they let oil into barrels and make it smoke .

  those are to stop oil inside ,stay inside,should have affect on pistons and bores


 go with Pete,run it a bit longer

[yozzer74]

Yeah that's what I'm going to-do really don't want to pull engine out .

[MarkCR750]

Try to avoid constant revs, as above accelerating and shutting off is good for running in, keep going up and down the box, obviously don't thrash it but at the same time don't treat it like a baby, and yes mineral oil for the first 500 miles at least, my new Ducati comes with mineral oil from the factory, it swaps to fully synthetic after a minimum of 600 miles, not sure what revs you should do as max for the honda when running in, Ducati is 6k for 600 miles, the book recommends you find "hilly areas" then 7k for 600, then do as you like, very different engine though , anyway I hope it's just the bedding in that's causing the issue, really annoying if not!

[mike the bike]

find "hilly areas"

Does it give the same advice in the Dutch manuals I wonder.

[Chris400F]

This is what the 400 Owner's Manual has to say about 'Breaking In', suspect the principle is the same for the 750.

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[Johnwebley]

find "hilly areas"

Does it give the same advice in the Dutch manuals I wonder.

 maybe all bikes should be run in either in Wales,or the Highlands of Scotland ?

[K2-K6]

As Pete has said, it may take a few miles to get it right as the rings need to wear to fit the bores.

Looks like you've done the right things by getting the bores prepped as well. When new rings go onto existing pistons and used bores they just don't fit well enough initially to hold the compression up and the oil down below the pistons. They are then reliant on the cross hatching to literally grind the high points off the rings until they are properly matched to the bores. This will take a few miles to happen (probably as Pete has experienced around 100) give or take a bit.

You've an additional consideration using bores and pistons with some miles already on them as there will also be a small amount of wear compared to original new status, so the tolerances there will be more generous. I know there's always discussion about oil type (at any stage of an engines life) but don't feel in this case it will make much difference to you.

Also you are not running in a new motor so as long as there's nothing wrong with the assembly then you don't really need to be careful (apart from making sure you don't overheat it) during initial use. The care needed with brand new engines is principally centered around piston and bore clearance to avoid any heat build up causing any localised seizure of the piston skirt along with subsequent pickup to cause damage.

For your motor it needs to be used over its normal operational range and get some mileage on it to get the rings bedded in before the crosshatching is worn smooth as it won't happen after those sharp edges loose their bite.

I'd get out and ride it,  then change the oil and filter at 500miles.

[yozzer74]

Thanks for that info k2_k6 makes me feel a little better about it .

[mike the bike]

Have a look at this instructional video clip...

https://subtletv.com/baaaUfY/Ichiban_Moto_shows_you_how_to_bore_and_hone_motorcycle_cylinders

[yozzer74]

Ha Ha I've seen a lot of his videos .

[Bryanj]

In the comercial world the Merc V6/8 burns oil if synthetic used but not when mineral used

[yozzer74]

Bryan j you mentioned before that you used Tesco diesel oil can you remember which one

[Bryanj]

From memory there only was one mineral diesel oil