how do you break-in a rebuilt two-stroke engine? some say run it hard,but i think it would blow a piston if you did run it hard. anyone know THE TRUTH!?

 

Run an oil mixture of about 24:1 so it is well lubricated.
1. Start the quad and let it idle for about 5 minutes with a couple small blips of the throttle.
2. Let it completely cool
3. Repeat step 1 for about 10 minutes.
4. Step 2
5. Step one again for about 15 minutes
6. Let cool
7. Take it for an easy ride, not using more than 1/4 throttle for about 15 minutes.
8. Let cool.
9. Go for another ride not exceeding 1/2 throttle.
10 Let it cool. (by now you should notice that cooling is important)
11. Go for another ride. Ride normal but don't rip into it(full throttle)
12 Guess
13 You are pretty much good to go.

this is a farely Thorough process. This ensures a really good break in.
I will admit I didn't do all the steps, but it is a good idea
I did something like two idle sessions and one riding session. Seemed to work.

 

I would take it out for a nice easy 20 minute ride. Don't go above half throttle . Let her cool off good. Take it out again for 20 minutes. Don't good above 3/4 throttle. Cool down again.The motor should be loosened up by now. Then take it out and ride it like you normally would. 24:1 mixture is great advice to. Everybodys has their own way to do it. I'm just telling you mine. Have fun!!!!!![img]i/expressions/face-icon-small-happy.gif[/img]

 

One of my old dirt bike buddies says "I use the 30-30 method. Thirty feet or thirty seconds, whichever comes first." I love that.[img]i/expressions/face-icon-small-happy.gif[/img]

 

no two people will agree on how to properly break in any bike.

On my blaster, i let it warm up idling, then let it cool down and i just ripped into it after that.

I was told by a yamaha service guy that after the first few strokes the piston should be where it is always going to be. So its safe to go right into it.

I've heard about 10 different ways. I say pick one that suits you and do it!

 

personally i like the idea of heat cycles ,cool down , idle,cool,ride,cool....thats a good idea!

 

from what i understand it is the heat cycles that are the most important, & the first 2 cycles are the most critical. after those 2 cycles the piston doesn't expand/contract as much and you are usually good to go, the other cycles just help it last longer by helping seat the rings better & not going gonzo right off the bat...... but always remember to warm it up before a ride too.

 

I would definately listen to everyone on this , i know its difficult to not give it full throttle but proper break in is critical. TRust me i was racing my banshee after my 1 hour break in and it cost me 400 bucks and a lost weekend. Take the time and do it right unless you like the sound of losing 40 lbs. of compression . It sounds like this.............................................. blehehehe...bleh...bleheh...ble... heh.....heh...heh....he.......h........ ugh.

 

you only need to be sure that oil ratio is rich like 32:1,then when the engine is warming up,to check for proper coolant operation system,when coolant is bleeded enough,you can run it at full operation temp,but varying the throttle the first couples of tanks and LET it cool down after each hard rides of time.

 

This is how I break in a motor pressure and vacuum check for leaks do two cooling cycles first let it run for five minutes then let cool second run for 10 minutes let cool,run motor to do a plug check 1/4,1/2,3/4, full throtle if all looks good we race it after that ,and my sons motors see about 12,000-13,500 rpms never have had a piston failure or seize.

I do not alter the fuel oil mixture I run, I stay with what I run normally.