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Discussion Starter · #1 ·
hey guys, i just installed my bender racing engine, should be around 85-90 horse, major work done, bored out too 500,i have a psi pipe,boyesen reeds, 38 mm mikunis,comet 308, i just got it running and took it out for a few short test burns, i have it running on pre mix, plus the oil injection, bogs off idle due too the premix im sure, but im gonna need help with the jetting, im running 152`s now in northern saskatchewan, its been about -10 celsius when im trying it out, it seems like twice the power of a normal phazer when i get it up too 3/4 throttle, but am not pushing it yet. i need too know about how long too run it before i do the full throttle kill the engine check the plugs test!!!, i may have 5 mins on it now and 2 sets of plugs because it fouls them if it idles more than 30 secs.thanks guys
 

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If it was a brand new engine, you should have taken it out and just rode it hard for about 5 minutes. That would take care of the break-in.

As for the fouling, sounds like you've got the carbs set too rich.
 

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Discussion Starter · #3 ·
you think right outta the box hard for 5 mins? i know im running rich for now, i wanted too make sure i had enough oil in it for the first while, i was easy on it, but not babying it, i paid too much cash too blow this d amn thing up right away. i wasnt sure how much oil would get too the crank bearings and in what amount of time, when i do any automotive engine theres always an initial prime too get everything wet!! then i know its not gonna blow up in 10 mins,lol
 

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Yeah, it's good to let everything get oiled up, but two stokes will lubricate themselves pretty quickly. The reason I say run it hard is because you need to set the rings. By breaking the engine in slowly, you're not really setting them that firmly, which may result in poor compression or other problems down the road.
 

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Can't say as I agree with the ride it hard break-in theory.

Adding premix for the first tank is good to do, just don't run it too rich. Personally I'd run no richer than 50:1 mix. When it got to about a half tank I'd top it up with straight gas giving about 100:1 for the remainder of the break-in.

For about the first 10 hrs or so avoid prolonged full throttle runs, avoid working the engine hard (wet snow or lugging the engine) and avoid prolonged operation at a constant speed, you need to vary the speeds you break it in at.
 

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I've got a good website that makes a very good case for the "hard break-in theory", I just have to find it again, then I'll post it.

Just curious why you don't thing running it hard right away is the right way to break in an engine.
 

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Originally posted by Canuck
[br]Can't say as I agree with the ride it hard break-in theory.

Adding premix for the first tank is good to do, just don't run it too rich. Personally I'd run no richer than 50:1 mix. When it got to about a half tank I'd top it up with straight gas giving about 100:1 for the remainder of the break-in.

For about the first 10 hrs or so avoid prolonged full throttle runs, avoid working the engine hard (wet snow or lugging the engine) and avoid prolonged operation at a constant speed, you need to vary the speeds you break it in at.

Agreed with, it seems like if you run a engine hard off the bat it seems to have more problems down the road
 

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How? I'm not trying to get confrontational, I just don't quite get the rational that you're using to conclude that running it hard right away will somehow lessen the lifespan
 

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Just like anything, if you break it in hard and put it away wet, you're gonna have problems. You have to take it fairly easy and work it up as u go along. If you just hammer on it for 5 minutes and put it away, thats no good. You have to let the motor warm up, run it through the paces, avoid hard accelerations at first. You have to let the rings set nicely in the cylinder walls and not destroy them the first run. Even my little 2 stroke rc car, I had to run 5 tanks of fuel to break it in and I couldn't hit full throttle until then. It's tempting to go nuts and ream on the throttle of a nice motor, but u gotta take it easy. Best way, let a grandma do it. Mine SRX was broken in by a retired 50 year old woman. She told me she bought the sled to piss off her children and nephews. They'd be out buzzing the lake all day tunning their sleds., trying to go faster. She sais she'd sit in the cottage for a few hours watching them, go warm up the sled, go for a quick ride, then go race. Kick her son's but and then put it away. I saw her last winter on an Apex lol.
 

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When I break in a motor, I basically start it up, let it warm up, then take it out and ride it pretty good for about 10-20 minutes, then shut it down and let it cool off. It sets the rings firmly, and sets everything in good. An engine isn't like a muscle that needs to be slowly stretched until it's good to go hard, you set it good once, it's good to go from there on. I'm still trying to find that website about break in.
 

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Here it is.

http://www.mototuneusa.com/break_in_secrets.htm

He's talking about 4 stroke motorcycle engines, but the same concepts will apply to old 2 strokes all the way through the new 4 strokes.
 

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i still dont belive in the hard break in theory, i run it rich it start off in spurts go quarter throttle for a while let off punch it let it half throttle for a while let off 3 quarter throttle for a while let off punch it let it off satrt over do it twice then go to full throttle for a little bit what you think is safe let off and make sure it is running cool at all times doing this, but make sure it is oily in there. ive done this in cars and sleds and dirt bikes seems to work perfect.
 

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Discussion Starter · #13 ·
thanks for the info guys, i pre mixed it with premium, took it for a few short easy runs, last night i gave it a few good runs, at about 3/4 throttle it sounded like it was pinging, so i parked it and tonight i added octane boost, but never got a chance too take it out( its-25 celsius tonight) i ordered a pail of racing fuel, 112 octane i think from my napa supplier.Should i run this 100% or maybe 50/50?????? i dont want this engine detonating!!!!
 

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Every engine manufacturer I know of recommends a gradual break in, something like the one Canuck posted. This represents thousands of engineers over decades of time. I will put my money on them.

A new engine is full of microscopic sharp edges and uneven spots. When you run the motor for the first time, you are doing the final machining. All the parts have just been introduced to each other and they need time to become intimate with each other.

The rings will seat in. Why would it need to be done in the first 5 minutes?

It probably would not happen anymore these days with improved machining and tolerances, but years ago engines would sometimes sieze up if they were not broken in easily.

Do not believe everything that is heard or read. A great deal of what is on the internet and put forth by "experts" is untrue. That is, except if someone reads the National Enquirer and watches wrestling on TV.
I sure hope O.J. finds the real killer.
 

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Well, I'm still sticking with my harder break-in, hasn't failed me yet. I've had more problems with engines that had easy break-ins
 
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