Engine break in

[pro2k]

How should I break in my new top end? I've seen many different ways on the internet and not sure who to believe!

Tom Morgan method:
"The piston and rings require the most care when breaking-in a new engine or “top-end” but normal riding on a hard-pack track is usually ok. The most important concern is engine temperature. Don’t subject the engine to high load=/high engine temperature for the first 60 minutes of riding time. Normal full throttle blasts of 10-20 seconds are ok....."

Eric Gorr:
When you initially start the engine after a rebuild, manipulate the choke to keep the engine rpm relatively low. Once the engine is warm enough to take it off choke, drive the vehicle around on flat hard ground. Keep it under 2/3 throttle for the first 30 minutes

local guy:
Richen carb to where the engine will run just below 4-cycling.
1) run engine at idle for 30sec. let engine cool.
2) run engine for 2 sessions of 2 min. at idle. let engine cool.
3) run engine of 2 sessions of 5min at idle. let engine cool.
4) run engine for 20min at 2000-2500rpm on stand. put a fan at radiator. let engine cool
5) run under light loads for 20min. let engine cool
6) accumulate 1.5 hours of light to med. loads

I tend to agree with Tom Morgan and Eric Gorr on this. The last method seems a bit much but the guys says it will give you more power than you've seen with other methods. Who' s right? I just want to get out and ride it taking it easy for awhile.

 

[dirtbike_madness]

I was reading your other post too. What did you end up going with as far as piston? OEM? Aftermarket, etc.

 

[pro2k]

I went with Weisco. Hope I got her all back together right! Actually, the hardest part was trying to get the radiator hoses all back on in the tight spaces.

 

[rob129]

I'd go with the Eric Gorr method, its served me well. Another excerp from Forward Motion is "not" to richen it up, this will make your engine run hotter. If you take it easy for the first 30 minutes or more you will reap the benefits.

 

[jrg]

ive been doing it the way eric gorr says for years, never had a problem, and have done lots of rebuilds

 

[NacNac250F]

i usually dont even hit powerband for the first ten minutes and then keep it under 1/2 throttle for another half hour then do bursts of open throttle but never hold it. I do all this on the first tank of gas. when i got my 05 YZ125 i did a break in similar to the one the local guy said because thats the procedure it said in the manual. Both work well, I have never blown up any of my bikes and i run them HARD. The only bike i blew up was my 250F three times!! thats why i went back to a two stroke because the piece of **** four-stroke couldnt handle being ridden hard.

 

[rob129]

The only bike i blew up was my 250F three times!! thats why i went back to a two stroke because the piece of **** four-stroke couldnt handle being ridden hard.

:rotfl: Amen brother...............

 

[ps2112]

You must know someone who knows Rod Falkner. The last method you posted is his way of doing a break in. Rod Falkner is a very good engine guy. I myself use his method and also use the Dumonde Tech break in oil. One other addition to the process that Rod advocates(I went to a tuning seminar of his) is the following:
Prior to running the engine spray a shot of brake cleaner in the plug hole and crank the engine (without the plug) 25 times, repeat this process till you get to 500. Yes I know it's a lot of kicking or hand cranking. This whole process cleans the cylinder walls of any oil or grime. Remember break in of a motor is not just seating the rings. There are physical processes going on like work hardening the piston skirts, removing manufacturing stresses in the piston. Others have their own ways, this is how I do it.

 

[pro2k]

I don't know the guy you are speaking of but the guy who told me this process also sells Dumonde Tech products. I did use the Dumonde break-in oil but did'nt have the patience, time, or place to let the bike idle and have fans blowing over the radiators. I did let the bike idle for a minute shut it off, let it cool and then let it idle for another min, let it cool. After that I just ran it around easy on the flat hardpack for awhile and then hit the track for some easy laps. I pretty much just used bits from all 3 of the procedures to break in the engine.

 

[Rich Rohrich]

. One other addition to the process that Rod advocates(I went to a tuning seminar of his) is the following:
Prior to running the engine spray a shot of brake cleaner in the plug hole and crank the engine (without the plug) 25 times, repeat this process till you get to 500. Yes I know it's a lot of kicking or hand cranking. This whole process cleans the cylinder walls of any oil or grime.

That might be the DUMBEST thing I have ever heard. All that oil and grime along with the brake clean will get dumped into the crankcase. So now you have a bunch of brake clean washing the oil out of the main bearings and lower rod bearing , and the initial start up will be with dry bearings and oil that is completely dilluted until the brake clean is finally flushed out of the bearings completely. BRILLIANT. Nothing like starting off a fresh engine with lower end bearings that are pre-damaged. :coocoo:

The engine should be assembled spotlessly clean so spraying ANYTHING through the sparkplug hole is unnecessary.

 

[mtk]

I agree with Rich 100% on that being the stupidest thing you could possibly do to a new engine. Sounds to me like Rod advocates creating new business for himself. Etiher that, or he's just plain stupid.

 

[Micahdawg]

After a fresh rebuild (top and bottom). I hopped on the bike and ran it WOT in cold weather. Grabbed a lot of gears.

I should mention that I was test riding this bike and the guy neglected to inform me that it had not really been ridden after the rebuild!!!!!!!!!!! DOE. Needless to say, if I knew that it hadn't been broken in yet, I would have gone easier on it.

However, I don't really expect anything bad to happen. I would typically go pretty easy on the bike for the first 30 minutes to an hour after a rebuild. Maybe hit the powerband a few times, but try to keep it under 2/3 throttle. That didn't happen with this bike...so if something really bad happens I'll let you guys know.

Micah

 

[ps2112]

We aren't talking about spraying mass amounts just a quick spritz. If you follow the process of doing the dry cranking some small amounts of foreign material will be created between the rings and cylinder walls. The brake cleaner loosens that up and it is expelled out the exhaust port. Irregardless of what Rich says, it works for me and lots of other folks. Rod Falkner is respected in the engine tuning circles. Rich ask Eric Gore about Rod, I believe he knows him personally. The beauty about these forums is being able to share other ways and points of views.
"The hardest things things in life to learn are the things you think you already know"