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Engine break in. More or less mix?

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I decided to make a new thread on this instead of derailing the current mix thread. If the parts come in I should have my 250 running by the weekend (:thumbsup:) But I have a question:

For engine break in, should I use more mix or less? I've heard guys say to add more, and I think the manual says something like 15:1(!) for break in, but wouldn't that inhibit the rings from seating like synthetic would? On the other hand, If I run less, then the other parts won't be lubed up as fast for their first running. Maybe that's the reason they say 15:1?

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There's no point to do anything wierd for break-in. just stick with the factory reccomended 32:1 all the time and you'll be good.

The manual says 30:1, but they are using the metric system over there (liters / milliliters)... We use ounces and gallons, so multiples of 2, 4, 8, 16, 32, 64 are easier and 32:1 is close enough.

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I just lube everything up with 2 stroke oil while im in there and make shure theres a bit in the botom of the crank. Mixing more oil into the fuel would cause the bike to run leaner.

I just stick to 40:1 my regular gas mix and heat cycle the bike. Ill start the bike and let it warm up on the stand first. Then cool. Then ill go for a small ride trying to stay low in the rpm's. Then cool it down. Then the last ride I blip into the main but dont hold full throttle.

After all that I ride as hard as I want.

Im going to put a new top end in my spare 250 today. EG Low Mid stock bore jug 92.

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S14 2510s, I do pretty much the same break-in process on my bikes.

If you usually run 40:1, then yeah, there's no reason to change it just for break-in.

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run the oil you normally run, at the ratio you plan to run.

heat cycle the motor in this manner

start and set it so the bike idles, wait until the bike has warmed up enough its un comfortable to hold your hand on the cylinder. Let bike cool down for good 30mins-45mins or until the cylinder is close to ambient

repeat 3 times, then either do a heat cycle with a little bit of revs (not WOTjust blips) or short ride. then let cool down again and you should be good to go.

(disclaimer this is what ive done for years and what the best 2stroke engine builders have recommended me for many years, if its not for you then do it your way)

i have 45 pilot jets in my bikes, with the JD needles Second and first clip and 172 mains, stock slides and power jet. (posted this because the OP is only 30min drive from me)

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The different ratio for break in never made much sense, really. If there was a better ratio to use, I believe it shoudl be used all the time. Lets also pretend you had a ratio that left more oil behind than it burned. Eventually the case would fill up.

But that info has been in the manuals for at least 30 years....

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I think I may try the motoman break in on my next topend. Some think it is crazy but after reading through some of his stuff it makes sense to me.

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I think I may try the motoman break in on my next topend. Some think it is crazy but after reading through some of his stuff it makes sense to me.

Yeah, I'm thinking of trying this as well. The only difference is that he is talking about thumper engines. But I have heard other places talking about breaking in smokers hard, too... Hmmm...

Thanks for all the help guys!:thumbsup:

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i did all my break ins per motoman. meaning no heat cylces, no easy on the stand bliping.

simply ride the bike from zero to full open throttle from very low speed and up but never goes to powerband. the more load on the bike the more the rings form on the walls thus creating good seal. my CR80 i open the pipe yesterday and believe it or not, the piston from top to bottom was like new. no blow by from above and below the rings.

the crown was black but dry and could still see the 47mm letterings from wiseco piston just by taking a peek at the sparkplug hole.

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i did all my break ins per motoman. meaning no heat cylces, no easy on the stand bliping.

simply ride the bike from zero to full open throttle from very low speed and up but never goes to powerband. the more load on the bike the more the rings form on the walls thus creating good seal. my CR80 i open the pipe yesterday and believe it or not, the piston from top to bottom was like new. no blow by from above and below the rings.

the crown was black but dry and could still see the 47mm letterings from wiseco piston just by taking a peek at the sparkplug hole.

Well, I decided to give this a try... It didn't turn into a pumpkin while i was riding it so I guess only time will tell... Lots of lugging in higher gears, sometimes cruising a little ways while dragging both brakes. This bike is so much fun to ride!

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Yup use what you normally run... Ive been doing it since I started riding and never had a problem. I normally run 40:1 in my 125 and 250 smokers so thats what I run for break in. In my 144 I use 32:1 so thats what I use for break in.

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Well, I decided to give this a try... It didn't turn into a pumpkin while i was riding it so I guess only time will tell... Lots of lugging in higher gears, sometimes cruising a little ways while dragging both brakes. This bike is so much fun to ride!

cool but its not just lugging around.

this is how i do it.

i first shift to 1st gear and as it beggins to roll i shift to 2nd gear. at VERY slow speed i turn of the throttle and i bang the throttle fast WOT while the motor is still trying to build RPM. by the time its almost near the lower powerband, i then release the throttle and let the bike come to a VERY slow moving vehicle.

i then do thesame thing over and over and also do that from 3-5 gears. youll notice that if yiou do this in 5th gear, the motors internall tranny will shake alot. its not gonna do anything but since 5th gear is ALOT of load, might help the motor off its load by going a bit faster than previous but still, that the motor will have a bit "hard" time to build RPM.

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Yep, that's pretty much what I was doing, although perhaps not as methodically... I was having too much fun!:thumbsup:

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cool.

hey, did yoiu lube up tthe bottom end REAL good with 2stroke oil before assembly?

i usually pour 2t oil in the 2 small holes on the side of the bottom en cases where the main bearings sit. i also pour oil right on the connecting rod bearings when i pull the rod straight out.

after this i check that when i roll the conrad one round, i can see that the bearings "CATCHES" oil with it as it goes down and up. if it does then yoiu know its pretty lubed up. i love how it looks like the bike is about to explode (from the neighbors view) coz of the insaly smokey exhaust. :thumbsup:

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Yeah, pretty good. I had a syringe with oil in it that I used all throughout assembly. I squirted some down the main bearing lube holes.And yes, it was smoking pretty good when I first fired her up!

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I use the same ratio but will let the engine warm up a little bit longer and take it a little bit easier before totally hammering the snot out of it.

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NOT trying to thread jack, but...

what do you guys think poor break- in would do to a top end? I've always ridden my bike gently for the first 30- 40 minutes with NO cycles and then ridden normal after that. I just did this on my 125 and I am now afraid to inspect the cylinder for fear of what i have done..... :unsure:

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Your bike is fine. The REAL important things are ring end gap, piston clearance, cylinder condition. Don't go nuts with the oil, it will just build carbon in the ring grooves sooner.

Its a 2-stroke, its gonna pull in fresh oil the moment you start it. No need to do any freaky break-in rituals. The rings will form to the cylinder regardless. How hard you ride it will determine how fast this happens.

Edited by Vaped

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