Quote:
Originally Posted by under2x
I think it mainly breaks down to liability. If manufacturers recommended that for your first ride you open it up as much as possible, people are going to crash their shiny new bikes. If you scare them into keeping the rev's down, then they can't really go too nuts on a new bike.
|
Quote:
Originally Posted by DaveM
James,
the term "lugging" refers to using a higher gear and having the revs below that zone in which the machine can pull comfortably without wanting to shake itself to bits.
In other words straining the engine instead of using the area in the rev range wear power is more easily used.
DaveM  |
Breaking in or as I prefer to call it lapping in has nothing to do at all with crashing and liability. That comment is absurd and not worth commenting about.
motoman's contentions are basically concerning the piston/ring/cylinder wall relationship.
Actually with the modern engine, modern metallurgy, metal finishing techniques and clearances this really isn't an issue anymore. In the olden days when we used to final finish a cast iron cylinder wall with 400 grit stones and with steel rings it was an issue. Now with finishes down to the 4 micron level and the alloys used this area isn't as critical and is usually accomplished during engine run in after assembly. You would really have to screw the pooch to hurt this interface. That's why the piston photos don't impress me very much.
The lapping in process, if you will, uses the oil interface between the parts that move against each other like the bottom end and top end to clean and put a final polish on things. This is especially important with the crank and rod journals and cams.
With their differences in materials the parts heat and cool differently.This is also a way to stabilize the internal temperatures of the parts with differing materials allowing them to normalize with respect to each other.
Think of wanting the final interface as being two pieces of glass with oil between. This is what I want and you can't get that by caning it's backside off from the first startup. These engines are built really really tight and a localized hot spot, for instance on the crank at one journal could be enough to warp the crank a tinsey bit and when you are talking about clearances in the 1/10ths. now instead of 1000ths. ex. .001 = one thousandth of an inch, .0001 = on ten thousandth of an inch. When you hear someone, a good machinist more than likely refer to a 1/10th. he's referring to a very tiny bit.
As an example of shaft bow, like crankshaft, Because of dissimilar materials in a jet engine with a straight shaft designed to spin at 35,000 rpm new engines will on occasion freeze up after shutdown because of this dissimilar heating and cooling of components.
Also while I'm thinking of it to get this the engine needs dirty oil. Really. So I wouldn't be in to big a hurry to change over to full synthetic oil. I changed my break in oil out at 500 and put the same thing in then again at 1500 miles and didn't go to full synthetic until 3000 miles.
I could feel stages of lapping in at 3500, 5000 and 7500 miles on my '02. So I don't consider one of these engines to be broken in until around the 7500 mile mark.
My contention is that if one wants to cane the living bejeebers out of their bike that's fine. But don't quote some hillbillies blog as gospel around here. I can prove him wrong on so many counts it's ridiculous.
When he builds an engine for a car that trashes the national superstock record in it's class by 3/10ths. like I have then I might consider listening to him. I have sent his site to professional high-end engine builders. Like people that work for the skunk works at Ford, the head of flow and an engine builder for Kendrick MotorSports and at John Forces camp. These guys are all old friends and competitors and aren't rubes but work in the highest tech. labs in motor sports. None of them have abandoned their practices and jumped on Mr. motomans wagon that I know of.
As far as lugging
DON"T. The quickest way of all to trash an engine. This is using too high a gear for the RPM. The throttle butterflies are way too open and way too much pressure is going into the combustion chamber. The engine is totally out of it's proper torque range in the bottom and just doesn't have enough leverage to accomplish the work asked of it. In the torque/leverage end of things it's like whipping a Shetland pony to try to do the work of a Clydesdale. The end result is fried valves, hammered piston tops, collapsed rings and lands and totally hammered, flattened and trashed crank and rod bearings.
That's why I couldn't understand someone wanted to put taller sprockets on their bike as these are over geared as it is from the factory.
BAD, BAD, BAD
Well, have fun and do what you want. It really doesn't concern me. My bike is wonderful the way I did it.
Oh, BTW, if there is a problem and an issue don't think that the factory can't tell what was going on inside one of their engines.
Don
I wov levers.
Linear Mode
