Running in an engine.

[Irezumi aka Reuben]

Theres seems to be a fair bit of debate as to which is the best way to run in an engine. One that seems fairly prevelant is to ride for 50miles accelerating and decelerating normally not using full throttle/redlining and not sitting at any constant speeds for more than a mile or two. Then after that ride it as you would normally and it will be fine.

Any thoughts on whether this is a good idea or not, particularly on a single?

[Whosthedaddy]

I must admit to not really adhering to breaking in the Monkey in gently for several reasons but mainly due to the fact that if I had only used a few revs it would have been a walking pace.

That said, for a Chinese single cylinder bike, it turned out fine.

Best advice to just use it within reason for the first couple of hundred miles, maybe not?

[G]

From reasearching a variety of threads on various forums, comparing the motoman method with others, there were a lot more people who ran it in 'properly' who said "yes, I'd always run it in properly and it was fine until xx thousand miles", compared to pretty much all that used the motoman method who would say "I've never had a (run-in-related, ie rings etc) problem and I've done xx miles".

[tutton]

Motoman
https://www.mototuneusa.com/break_in_secrets.htm

Poses a big question really as there are some valid points..
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Past: '05 Peugeot XPS '99 Aprillia RS125 '94 FZR600R
Current: '02 ZX636 A1P '51 CCM R30

[Robby]

I would be inclined to just ride normally on a rebuilt engine, with the following exceptions:

If the engine is an old design with particularly loose tolerances (so a brit bike) then I would run it in carefully.

If it was a 2 stroke I'd be extremely careful about warming it up before subjecting it to full load. Would probably wait until temp gauge is at normal temp + 5 miles.

However, if I rebuilt my bike tomorrow (Cagiva river, 500 single) I would be riding it normally by friday. Would also start it off on mineral oil and change the oil and filter at 500 miles.

[Ichy]

No idea about bike engines but I know that all the production car engine builders I've worked for test each engine by running it at full power with a load to simulate a 90 degree incline. The tolerances used are so tight, production methods and materials improved that there is little need for old fashioned bedding in.

I agree with Robby when it comes to rebuilt stuff.
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