Post break-in power gain?

mik_str · Post by **mik_str** » Tue May 17, 2011 10:06 pm

I was just wondering if anyone here has a well-founded estimate as to the power gain an engine gets from a well executed break-in? I had the tech who rebuilt my engine use the dyno breakin method put forth by Motoman (http://www.mototuneusa.com/break_in_secrets.htm). I have put on about 2500 km since then (no constant throttle or casual riding, constant on-off throttle with agressive acceleration and deceleration, along with three oil changes since) and the bike definitely feels stronger now that it did when it left the shop. The initial dyno numbers were 122 bhp and 77 lb-ft. I will be getting it dynoed again this summer but was wondering what I can resonably expect for final numbers following my methodical and patient approach at breaking in the new mill.

I have tried researching the matter (on Google using various searching criteria) but all to no avail.

cheers

alec · Post by **alec** » Tue May 17, 2011 10:16 pm

i've just put everything you just wrote through google translate and it was as confused as i was lol, can you tell i have an engine phobia

gilson · Post by **gilson** » Tue May 17, 2011 11:04 pm

Hi Mick. I did read about this aggressive method of wearing in an engine rather than the 'taking it easy for 6000 miles' method. It's common on race car and bike. The theory goes something like the rings and other moving parts form a better seal when aggressively worn in. I was impressed what I read and it made sense to me. However I've never had a new engine to try it on!

benny hedges · Post by **benny hedges** » Tue May 17, 2011 11:12 pm

ive had a few new engines and followed the makers run in until i got bored.
others ive rebuilt myself, especially strokers and ive caned the tits off them from and they ran better.
you'll have a proper flying machine there min once it loosens up proper.
the gains are cos of lowered friction as it wears in.. and seeing as you're running ceramic bearings and stuff the sky's the limit

warby221 · Post by **warby221** » Wed May 18, 2011 6:54 pm

Ran in the engine I rebuilt for the storm a similar way

As far as I know and was told by a friend that use to race a lot itâ€™s to blow in the rings as he called it.
IE the pressure on top of the pistons force the ring out in to the bores and beds them in better making a better seal.

But this only takes about fifty miles or so to get rid of the honing marks off the bore and before the bores have time to glaze over then it should be gently gently for the bearings to bed as they need to polish up with the journals.

As for increase in HP when there bedded probably 3-4% when the friction drops a way and the engine runs cooler but thatâ€™s just a guess

tony.mon · Post by **tony.mon** » Wed May 18, 2011 9:49 pm

Ah, science.
Wonderful thing, science.
I just thrash mine because I'm impatient, but this time I ran in in more gently because it was icy with snow and every time I tried to accelerate or brake it started sliding......
Good thing? Bad thing? Either way, it's done, and it runs and doesn't leak oil.

Ideally you'd build two more engines and run in one way each, then compare.
Can't imagine anyone actually doing it, though.

mik_str · Post by **mik_str** » Thu May 19, 2011 1:53 am

Here you go Tony:

"Our test results on 2004 models. 2 zx10's that were babied dyno'd 142 hp. A GSXR 1000 babied dyno'd142 hp. 2 zx10's, using this formula had 155 hp the other 156 hp, and many GSXR 1000's using this formula had 149 hp all on the same dyno's with in 2 hours." taken from the folowing Web site:
http://usu.net/sites/motorcyclebreakin/breakin.html

Now, I am well aware that something being on the Net does not make it necesarily true but the fact that experienced tuners who are "in the know" have developed painstaking and very specific (hard) procedures for breaking in engines is proof that this part of an engine`s life is extremely important to both its ultimate output and longevity and, as alluded to previously, the preferred methodology seems to point in the direction of a fairly hard run-in (at least based on the fairly extensive research I did prior to staring the process on my rebuilt lump).....

tony.mon · Post by **tony.mon** » Thu May 19, 2011 8:42 am

Thanks for this, Mik- I have seen it before but not noticed that they had back-to-back comparisons.

Is the author! paid per exclamation mark? !!!!!!!!!!!!!

Love the quotes for oil prices at less than a dollar a quart- I just paid Â£34 for four litres of oil here in lovely cash=strapped England.

Luckily it doesn't leak or use any, so just a little top-up occasionally if I'm using it every day.

Now I have the high-comp pistons in it uses a bit more, mainly because I chose to fit standard size pistons into an already-used engine, having had it honed, and although clearance is within tolerance (just) it wasn't worth going 1st oversize. I would if I do another engine for a Storm, though, as I get more carbon black in the oil from ring blow-by than I used to.

Currently I just do regular oil changes and live with it.

mik_str · Post by **mik_str** » Thu May 19, 2011 9:46 pm

My bike (pre-rebuild) had over 140,000 km and was still not burning any oil (the tech who opened it up said the insides looked VERY good, still some cross-hatching on the cylinders in fact). Anyhow, as I was already spending a bunch of money rebuilding the engine to new (replaced all bearings, chains, valves,...) I figured I would go whole hog and get larger pistons with perfectly parallel (ie. non-tapered) cylinders. The closer for me was being able to participate in a custom production run (minimum order size is 4) of 0.5mm OS pistons.

VTR1000.ORG