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View Full Version : Interesting engine break in theories.



burnoutboy
10-07-2006, 03:47 PM
If you have some spare time, take a look through this guys page. He states how an "easy break in" can cause the rings to not seal properly e.t.c.


What's your guys opinion on this??

Dammit!
10-07-2006, 03:58 PM
No link. ;)

gravelord
10-07-2006, 04:06 PM
wheres the link ??

burnoutboy
10-07-2006, 04:07 PM
Ooops
http://www.mototuneusa.com/break_in_secrets.htm

Levithan
10-07-2006, 04:33 PM
Hmm, im skeptical about all of this. When he says dont idle in the garage during break in, i just dont understand that. I ran mine in the garage once i got it all back together, gave it a few revvs, then just idled it up and down for a lil bit. Then the next day i took it out ad broke it in in second and 3rd gear. The bike runs really strong, so im assuming that its been broken in correctly. Anyone else have thoughts about this?

Macs
10-07-2006, 04:42 PM
I had a mechanic tell me once to break it in like you would drive it. Be hard on it. For some reason that has stuck in my head and every engine i have built i have done that exact same thing. at the track all the guys will tell me that they replace there topend every season. Well i have a 2002 YZ250 and never had to put a top end in it. Compression is still right were it needs to be. I dont know if the break in had anything to do with it or just luck. But everything i have built and broke in that way has lasted. even the things i built for friends or sold to fiends are still going strong.

Tri-ZNate
10-07-2006, 05:12 PM
yep thats the way my buddy broke in his YFZ. Started up 3 times till warmed, let it cool then beat the piss out of it. Beats my buddies other YFZ which used the "easy-does-it" method. Switched riders and same result.

kcop
10-07-2006, 05:42 PM
I thought as long as you don't keep it in the same rpm range you should be okay

Billy Golightly
10-07-2006, 06:20 PM
If all your doing is rings I think this is probably fine but if your doing anything else, main/rod bearings, or in a 4 stroke cam, rockers, etc. You better take it easy for a little bit first and let things loosen up before you beat on it.

jason 32
10-07-2006, 08:24 PM
??? hummm
well breaking it in hard will glaze and burn up the rings and cylinder-- possibly to a point where they won't ware as easily as normal
slow will allow it to ware and seat better and last longer /break in isnt done in 10 miles lol ,but possibly the most damage -or ware will be done quicker in the first hour ?? think about it --
rings are not just for scraping the oil off the cylinder wall-- thus this is why there is less compression with ware
well unless God is going to bless your bike lol .....

Unclediezel
10-07-2006, 08:43 PM
Key Word here is "BEAT"

"Deep" acceleration is not necessarily "Beating" on it. I would definitely avoid Full throttle 15000 rpm blasts in first gear, but full throttle from 3rd or 4th gear isnt an issue. However , Once your up to speed , allow the engine to decel on its own, engine vacuum is highest during decel.The added vacuum in the cylinders will suck the rings to the top of the grooves, and as metioned, accell forces the rings outward. this "FORCES" the rings to conform to the outer most surface, which is the cylinde wall and the ring groove. Rod and mains, dont have an ideal situation for break in....They take a pounding at idle and full rev. Camshafts depend on a higher rev to break in because of spring pressure. If you let a fresh motor IDLE to a break in, your cam will wipe out because of Too much "Duration" of spring pressure . you want the cam up and down as rapidly as possible because you dont want spring pressure prolonged at the top of the "EGG"....It wont hurt the bottom, because the spring pressure is ( Well ..Almost) -"None"

A certain amount of "HEATCYCLING" is a good thing. No engine ever built is Geometrically "PERFECT". Centrifugal force pushes things out from center.. The faster the center moves , the further out ward it pushes. You actually break-in an engine to Accelerate WEAR!!!!!. The hard break in ensures that the wear you put on your engine in the first few miles, Will be in the right "PLACES" based on intended usage. If you putt it around at idle, the wear will be ideal for Idle situations. If you break it in hard, the wear patterns will be better suited to making power.--- ( Although I have a hard time mentally---With "PUSHING TO THE LIMIT" on a fresh Motor")