Breaking In an Engine?

[Johnt3]

Hey guys I was having a "Discussion" at work about the proper way to break in a freshly
rebuilt engine. I'm of the opinion that you should run the thing pretty normal and not baby it.
What are your opinions and why?

 

[rusty rocket]

I know when you break in a new v8 you want to run it around 2500 to 3000 rpm for 20 to 30 mins to break in the cam. dont know if its the same for a cycle engine though.

 

[mikehants]

The general guide is after ensuring that the lube system is working correctly.
Ride as normal but don't let the engine 'labour'. This means to keep in the correct gear for the speed travelled, you may feel that you are changing gear more often than normal and dont over rev the engine.

Do this for about 500 miles and it should bed in the engine nicely. After that...

Have fun.

Mike.

 

[Paulrxs650]

The cam issue you refer to is for case hardening the cam lobes and lifters. Common amongst high lift cams on performance car engines. Basically the cam is ran in special lubricant at a specific RPM for a specific amount of time, this RPM is the calculate RPM as to which the least stress is placed on the cam.
For bike engines I have always ran them conservatively for the first 500 miles, then dropped the oil changed the filter, refilled with oil and rode it normally thereafter

 

[gggGary]

It really helps to have dialed in carbs and ignition so it is getting a clean mix. It is so common to have guys rebuild the motor and THEN try to fix the carbs.

Advice I see often is don't lug it, don't over rev and vary the RPM. IE don't go sit at 60mph for two hours on a fresh motor. I'd guess you want to consider how it will get used. A race bike will get a more rigorous "break in" than then a bike destined to be a cream puff, garage queen.
Kinda related; we had an old Toyota mini motor home, it had always been an old mans pride and joy. My buddy ran it hard and fast across the desert. The cylinder wall wear stopped rather low, never having being run at high RPM. When he took the revs up, the stretch slammed the top rings into the ridge, disaster followed. All the top rings were broken when we tore it down.

 

[peanut]

there seems to be a lot of different recommendations around these days.
This site reckons you should run in a new engine 'hard'
http://www.mototuneusa.com/break_in_secrets.htm

which is the complete opposite of conventional wisdom but then modern engineering and materials have changed a lot since the 1950's

I think I'll stick with the slow and easy running in method personally until I see some proper scientific evidence it isn't effective.

 

[Paulrxs650]

Yep, I think many people have a wide range of theories. In race bikes I have, they get a full thrashing out of the box. However that is with new modern engines with relatively short stroke.
I think, whichever way you choose, if its getting caned, its not going to last as long

 

[peanut]

I used to have a really good book by Vizard on tuning A and B series engines (minis etc )
I seem to remember that he recommended an initial full throttle burst for initial bedding in then just vary the rpm for the next 1000 miles or so.

With race engines I guess they haven't got the time to ease an engine in gently for 5000 miles

 

[Paulrxs650]

Mine are lucky to last 5000 miles
In that I mean the bike is usually wrecked first!!

 

[gabecustom]

i went to MMI and one of my instructors used to build custom bikes and rebuild engines.. i asked him this very same question, this is his response to me on a completely new engine brake in; run it for 50 miles not taking it above 3000rpm and drain the oil. with new oil run it for another 75-100 miles not taking it past 4500rpm's. again drain the oil and refill with new, replace oil filter and ride the motorcycle normally for another 1500miles. change the oil and filter and at this point start your 3000mile service intervals.

just what i've heard from a someone with 30years working on and building motorcycles.. so take it for the grain of salt that it may be..

i've also heard of guys braking in there bikes on the dyno.. o, Peanut's got the web site! Well in brother!

 

[peanut]

Mine are lucky to last 5000 miles
In that I mean the bike is usually wrecked first!!

I only drove my BSA Lightning 5 miles and went over the handlebars !

I drove out of the MOT testing station and over the bars I went with the bike on top of me . The front brake lining has delaminated from the shoe and jammed in the drum ...imagine if I had been doing 40-50mph

 

[scabber]

I use regular motor Valvolene cycle oil. Ride like you stole it. mototuneusa worked for me. Drain oil 300 to 500 miles, I like full synthetic oil after that. Checked compression 195 LBS both cylinders. Yours may vary depending on what pistons you run.

 

[XSLeo]

I do a simular break in as described in peanuts link. In the first fifty miles I find a stretch of road, a bit of uphill helps. Get the bike to around 35 mph or so in 3rd or 4th gear, a good firm roll on to 50 or so then back off the throttle to coast back down to 35 then repeat as much as you can. After that change the oil, Ride a bit mellow for the next 100 miles or so, never lug the engine or run a constant rpm, change the oil. Then ride as usual.
The roll on/coast down seats the rings better and faster than easy running.
The close oil changes help flush out any crap from the rebuild, so inspect the oil and filters closely for anything.
I guess the firm roll on could be WOT, that's what the repair manual for my van says. As soon as you get the engine back in the vehicle and running take it out and do WOT from 30 to 50 mph at least a dozen times to properly seat the rings.
Leo

 

[Johnt3]

Thanks guys for all the information. I think I'll stick with my original thoughts plus what XSLeo and MotoMan have said. Makes sense to break in with "small window of opportunity to get the rings to seal really well ... the first 20 miles !!".

 

[funky]

This is what i am going to do use a running in oil first....this helps the process... and assuming that the carbs are set up roughly right and timming is there about the timming chain tension has to be correct and valve clearances are correct also these two have to be right befor carbs being messed with Remember timing chain first then valve clearance second,,, last the carbs these can be slightly tweeks as you go along to keep the bike running NO HYPER THROTTLING >>>JUST SPEC IDLE PLEASE


HEAT CYCLE DO NOT REV THE ENGINE TOO HIGH >>>GET IT IDLING NICLEY
.... Run a heat cycle starting at 10 seconds to 40 seconds start engine.. run up for 10 seconds let cool down to normal temp... start engine run for 20 seconds and again let it cool to normal ambient tempriture I.E what ever the tempriture is aronud you...
Do this until you have got to running the engine for about 40 to 50 seconds stints... ...dont forget to let it Cool down between each cycle .... this is to flow oil around the system and wear the rings in slightly and not to create too much heat shock which will reduce the chance of mechanical welding ... Hot spots on the rings created by peak areas of contact due to the rings not being symetrical to the bore ....


HEAT CYCLE 2
Once cooled down ride the bike for one mile going through the gears up and down as needed trying not exceed 2500 to 3000 rpm then let the bike cool .... avoid traffic remeber tempriture to much heat is no good your engine is air cooled
Slowly increase the distances remebering to use the gears and engine breaking and not exceeding 3000rpm,, try and avoid traffic as these engines are air cooled this aids the ring to be seated correctly ... at 100 miles change the oil and filter check plugs and timming this will give you an idea as to mixture settings and having the right timming would be advantagous during or at this stage the bike will tell you if it timming is out when you ride it so ride round the block passing your home, workshop, or garage now and then so adjustment can be performed as needed

Ride the bike with a degree of mechanical sympathy which means without going bonkers mad on it and RED lining it but having a little cheeky crack on the throttle now and then for short periods of time seconds rather than minutes OK until you have reached 400 miles then change oil and filter RATIONALE being .... Running in oils are recomended for only 200 mile stints thats where 400 miles come from and the running in process produces particles and acids and other contaminants in the oil so thats why we change it often to protect our new components during the running in process
YOU ARE NOW ALMOST THERE

Change oil to any good quality 4T engine oil for your tempriture zone or conditions depending where in the world you live Your engine is now almost run in do another sensible 100 miles as above with your regular chosen oil having your little cheeky blast of speed avoiding the local law inforcement and its Job done Ride it like you stole it and have fun

Change the oil and filter every 2000 miles to maintain a good engine remembering to check settings of timmimg chain Valve cleance and carbs as per spec to your year of engine .
This is the advise i got from the eginneer that rebuilt my engine and has worked on the 650s for many years and know his stuff ....

All the best Funky

 

[TwoManyXS1Bs]

Sir Funky! Ask your overhaul buddy if he's ever seen signs of iron powder on the plugs in the first 500 miles (800 Km?). We used to see that occasionally on Hondas 500 mile checks. Comes from rings seating. So, always did plug changes at that first check...

 

[fredintoon]

Hey guys I was having a "Discussion" at work about the proper way to break in a freshly
rebuilt engine. I'm of the opinion that you should run the thing pretty normal and not baby it.
What are your opinions and why?

hi Johnt3
don't let it lug, don't make it scream, change the oil a lot.
It's always worked for me.

 

[peanut]

good write up funky

interestingly enough David Vizard (one of the Worlds leading engine builder/ tuner /author ) has recommended initial bedding in of rings in a new engine in just a few minutes

I have several of his tuning books which make very interesting reading.

So does A G Bell.
' Initial bed-in of rings is achieved by giving the engine a full throttle burst for a few seconds and coasting for a few more seconds. This should be repeated at least 12 -15 times with the engine at normal operating temperature. Accelerate the vehicle in top gear from the slowest speed it will pull in that gear.'

Apparently full power forces the rings out against the cylinder wall and snapping the throttle shut creates a vacuum pulling up extra oil to lubricate and cool the bores.

Having said that I am not sure I'd have the guts to do that with a freshly built engine its all right for these F1 engine builders with all the money in the World.

 

[funky]

Peanut I feel the same way to be honest it frightens the shit out of me because of all the effort and money
But what to do I cant just sit there and worry about it and look at the engine on the floor of the work shop..
I think the high reving advise is for mainly water cooled engine as tempriture can be controled but with the Xs you have to be aware of too much heat initially and getting it fully set up as you go through the process.
Anyway i think the high revs thing will bring heat up then rings will expand and bed in along with the oil pressure pushing on them its probably a conbination of the two.
From what I understand and I am no expert its about finding a good medium creating enough friction to bed in the components and controlling the heat with the xs
All the best Funky

 

[funky]

Hi Dudes Rebuilt Engine in

the only thing I have on my mind now is where do I set the timming i did mark the back plate on the Pamcoe but the part the back plate sits in was changed im looking for pictures i took of the position but just in case were the best starting point. My Engine is 533 con rods 707 cc standard 360 degree ...
All the best Funky