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Discussion Starter · #1 ·
Hey guys, In the next few weeks I'm going to have my motor rebuilt fresh except for the crank, assuming that there aren't any problems with that. I have heard a few different opinions on breaking in motors, and I'm curious as to how I should be riding my sled with a new motor. I've heard that you need to take it easy for the first few hundered miles, and i've heard that you can get on it and ride it how you'd normally ride it.

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Mix the first tank of gas 50:1 then ride easy on the first tank. Give it different amounts of throttle as long as she doesn't go past half throttle. Give her a proper breaking and she'll love you long time.
 

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For the 5 motors I have run through my D8, Mix 40-1. I run it WOT right away, but for no more then a few seconds at a time, vary the throttle a lot, don't hold it at any given stop for two long, keep your RPMs moving. After the first tank of gas I hold it WOT for a bit longer, but not to much yet, then after the second tank is burnt through I ride it like normal. WOT anywhere for how ever long you feel like holding it there. Lots of different ideas as far as breaking in a new engine.
 

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High RPMs arent a bad thing in short bursts, lots of different throttle positions, and mixing the first couple tanks with oil is never a bad idea. Do this for the first 400 or 500 miles and then ride it like ya stole it.
 

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Does anyone know exactly what happens when the motor isn't broke in properly beside a shorter life. I am wondering.
 

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600xc4me said:
For the 5 motors I have run through my D8, Mix 40-1. I run it WOT right away, but for no more then a few seconds at a time, vary the throttle a lot, don't hold it at any given stop for two long, keep your RPMs moving. After the first tank of gas I hold it WOT for a bit longer, but not to much yet, then after the second tank is burnt through I ride it like normal. WOT anywhere for how ever long you feel like holding it there. Lots of different ideas as far as breaking in a new engine.
I do it exactly the same, except I mix about 50:1.
 

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600xc4me said:
For the 5 motors I have run through my D8, Mix 40-1. I run it WOT right away, but for no more then a few seconds at a time, vary the throttle a lot, don't hold it at any given stop for two long, keep your RPMs moving. After the first tank of gas I hold it WOT for a bit longer, but not to much yet, then after the second tank is burnt through I ride it like normal. WOT anywhere for how ever long you feel like holding it there. Lots of different ideas as far as breaking in a new engine.
Do the same here.

kingofkings said:
Give it different amounts of throttle as long as she doesn't go past half throttle
You WANT to hit WOT once and a while, only for a second or two. If you don't go WOT, the rings don't seat properly.
 

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I to hold it WOT for a moment when breaking it in with a lot of throttle variation and also premix the first two tanks. Then i ride the hell out of it.

Like mentioned before, everyone has their own take on it.
 

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Discussion Starter · #10 ·
Thanks everyone.

by kingofkings
Does anyone know exactly what happens when the motor isn't broke in properly beside a shorter life. I am wondering.
[/quote]

I'm also wondering this..
 

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If you don't break the engine in properly the rings won't seat properly, causing loss in performance and engine life.


The reason you hone cylinders(put the crosshatch pattern on them) is to make a grit to grind the rings. This allows the rings to be worn down a little and fitted to that specific cylinder. This is why you re-ring now and then and always re-ring when you get a new piston or cylinder.
 

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When I rebuilt my engine (one piston/ring, gaskets and a little cylinder sanding) I didn't do anything special to break it in. Took it easy for the first tank of gas (not full, about 100km to 150km worth I'd say). Since then I've been running it the way I'll be riding it (both easy and balls to the wall). Never mixed any oil or anything special. No issues at all thus far.
 

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The reason you mix oil is to make sure the engine is getting oil, just in case the oil injection system isn't working.
 

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Empire087 said:
The reason you mix oil is to make sure the engine is getting oil, just in case the oil injection system isn't working.
And its nice to have some extra getting to the rings for better seating.
 

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If you just did a top end on your sled there is really nothing you have to do besides put it together correctly. You should just make sure the coolant lines are bled and your gaskets are installed properly. I would just make sure that you assemble it with using your normal 2cycle oil as assembly lube. Modern single ring and dual ring pistons only go on one way if you have to intall them at all. There is no seating process. It is either in the correct position or it isnt.

Breaking in a bottom end is simple besides the preparation (making sure oil lines are bled and working properly) Mix your first tank or two if needed. The most important thing you do is HEAT SOAKING the motor completely several times. This can be done in the garage with the hood up so you can monitor it. Simply run the sled to full operating temps shut it down let it completely cool and do it a few more times this is more than enough for a 2stroke.

All this talk about running it for 1/2 - 3/4 throttle for blah blah blah. WOT for 2 second bursts blah blah blah. Its all horse shit. The motor simply needs to reach full operating temps and soak the crank all the way through.
 

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Empire087 said:
The reason you mix oil is to make sure the engine is getting oil, just in case the oil injection system isn't working.
Makes sense. In my case I just did the top end (cooked it a little because a head gasket blew out). I left the motor installed in my sled with the oil injection and whatnot still hooked up. Lots of room to work in the engine bays of these older sleds with a single hood piece (ZX chassis).
 

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I will say, the zx chassis and the z chassis, aswell as a number of poo chassis. they are pretty easy to work on, everythings not all jammed inside the frame. On my sled when i did the top end rebuild i just put new cylinders and pistons while leaving the engine in, was really easy to work on.
 

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GreenMachine00 said:
Well it was a crank bearing that went on my motor so thats the process i'll have to go through.
[/quote

Recommend wide boy bearing kit when you go through the crank bearings, and would have the cases inspected for spun bearings. If you need cylinders honed, make sure you get a good cross hatch, critical in catching oil for proper break in, and make sure you use a non synthetic blend oil (Injex, mineral oil, etc)during break in. Clean your valves, go through your clutches, and most importantly, on motor re-install, make sure clutches and motor plate are aligned to spec
 
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