proper break in?

25 replies to this topic
  • Shawbridge Husky

Posted May 10, 2002 - 01:28 PM


Vegas, PLEASE dump that oil ASAP! Just ask Boit above. He changes oil after every ride! These machines carry little oil to begin with and share tranny and engine oil. It is basically impossible to change oil too often. As you get to know these bikes you will find that yes they are reliable, but the high performance 4 stoke design requires mucho maintenance to keep repair bills down. Your oil at this point will be black / grey and will have the viscosity of water! Don't do as I and learn everything the dumb ( hard ) way.
BTW , get yourself a magnetiuc drain plug ASAP, the Ty Davis ones are the stongest. I now hope that you are totally confused and that we may be able to make you save some greif. :)

[ May 10, 2002: Message edited by: Hugh LePage ]

  • thumper4life

Posted May 10, 2002 - 04:17 PM


either take it from us or take it from your dealer...your dealer probably rides a 2stroke anyways, we all have got fourstrokes. everyone here knows a great deal about what they are talking about, and if they don't, then someone will definitly chime in and tell them they are wrong. :)

  • wylie1

Posted May 10, 2002 - 04:30 PM


Matt here is that article you were looking for that tells us not to break it in easy and why the manufacturers want us to. I agree with frank, "BREAK IT IN LIKE YOU ARE GONNA RIDE IT". :)


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  • Fryboy

Posted May 11, 2002 - 07:06 AM


Wylie1 Great link ! What do the rest of you think about this info??? Am i gullible or what?

  • Boit

Posted May 11, 2002 - 09:21 PM


The article makes some good points. However, there appears to me a bit of undersimplication. The article states that combustion gases follow the path of least resistance and will flow between the rings and piston thereby forcing the rings against the cylinder wall. I agree that any gas or liguid will flow along the path of resistance. However, the article doesn't mention that there is also a path between the rings and cylinder wall of a new engine. Seems to me that the flow of these pressurized gases across both edges of the rings would have a cancelling effect and there would be zero net effect of pushing the rings against the wall. To follow the logic of the article, all the combustion gases would have to make four 90 degree turns in order to push the rings outward. To do this, the gases have to first strike the upper flat surface of the rings, make a 90 degree turn toward, and flow into, the piston groove. Then, hit the piston groove wall and make a 90 degree downward turn and hit the bottom wall of the groove, make another 90 degree turn and flow between the ring and groove until hitting the cylinder wall before making the final 90 degree turn into the crankcase. It doesn't add up to me. If this were true, rings wouldn't last long due to this "forcing" of the rings against the cylinder wall. I believe that the ring tension against the cylinder wall is pretty much steady. It might fluctuate some as RPM's build, but all in all, it's mostly constant.
I totally agree with the article's assertion that the first oil change is critical for the very reasons it states. Also, I agree that babying the engine intially is not the best approach.

  • Shawn_Mc

Posted May 13, 2002 - 02:46 PM


The main reason for changing the initial oil as soon as many mechanics do is that, when maginfied, the cylinder looks like a scotch brite pad. Its not actually smooth. The break in period lets the ring clean this crap up. Also, rings do not mate themselves to the cylinder. They spin on most fourstroke engines. Thats what the cross hatch pattern is for. To spin the rings. There is a process called "soft honing" on cylinders that leaves an almost polished finish. This creates a much better leak down, and the ring tensions can be substantially lowered.

The number one compression ring (top) is the only one that should hold the compression. The second "compression" ring, is actually an oil wiper. It scrapes the oil off the cylinder down and back throught the oil ring. Those vents in the oil ring are to let oil back in, not out.

The compression gases do hold the ring against the cylinder. This idea is put farther by "porting" the piston. Piston ports are drilled into the compression deck, into the backside of the top ring land. This give a more direct path to the back of the ring. But even with out the ports, the compression does go down the ring end gap and behind the ring itself. I would be surprized if some of the bigger engine builders dont know about soft honing. Its a huge deal in auto racing, especially some of the limited spec classes where youve got to use every trick in book for every cintilla of HP you can get your grubby little paws on. If anyone wants to check my tidbits of knowledge, call Darrel Yates, of Yates racing. OR Smokey Yunick.

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