How to break in atc 250r??

[jakep53]

Ok how would I go about this today I pulled out my blown motor and put my freshly rebuilt engine I got with the bike in... I have yet to start it because I have no idea how to break in a 2 stroke I read a bit about it and got out of it: start motor and let it idle for 10 mins with a few blips of the throttle ( problem I see is being air cooled won't it over heat??) then let the engine completely cool then after its cooled go through all the gears but don't go above half throttle then let completely cool then lastly go through all the gears wot then let it cool and you done.. would this be the right way to go about things?? and what fuel mixture should I run 20:1 32:1 or 40:1?? any other tips greatly appreciated as I don't wanna stuff this up!!

[DohcBikes]

This will be a good thread.

Engine break in is a debatable topic. First of all, it is best to know the engine builder's tolerances because some will build them to take longer or shorter break-in depending on how the builder setup the cylinder and rings. I'll leave it to the smoker guys to recommend oils and mix ratios, but I will recommend that you start with jetting that you know is too rich, because playing with lean jetting on break in is a big no-no.

When I break in a four stroke, even a V8, I am easy on it for about ten minutes, then I give it hell just like if I were racing it. I learned from a very good dirt track engine builder to break them in the same way you will use them. I have never experienced any engine damage as a result of using this method. For reference, I build engines to very tight tolerances.

Looking forward to hearing from the two stroke guru's on this, as i'll be needing the same advice very soon...

[christph]

When I got a new cylinder from Duncan Racing a few years ago, I got a print out with break in instructions. I don't have the details at the moment, but I know it was a gradual procedure. It advised running the engine through a couple heat cycles before riding it, e.g., run it for 5 mininutes, let it cool, repeat. After that you ride it for 20 minutes or so at no more than half throttle, being sure not to lug the engine or rev it out. Do that twice (letting it cool between runs) and then you are ready to fine tune the carburetor for the entire rpm range, do plug chops, etc. After that you're good to go. As stated above, I know there are different philosophies about how to break in an engine. I know for every new machine I've bought the manufacturer recommended a gradualist approach. I think the idea is to give the parts time to mesh and break in together. Frankly I can't imagine running it to the hilt from the beginning. With a new engine you might also have metal flakes in the oil and I don't think you want that circulating through the engine at maximum load.

[jakep53]

This will be a good thread.

Engine break in is a debatable topic. First of all, it is best to know the engine builder's tolerances because some will build them to take longer or shorter break-in depending on how the builder setup the cylinder and rings. I'll leave it to the smoker guys to recommend oils and mix ratios, but I will recommend that you start with jetting that you know is too rich, because playing with lean jetting on break in is a big no-no.

When I break in a four stroke, even a V8, I am easy on it for about ten minutes, then I give it hell just like if I were racing it. I learned from a very good dirt track engine builder to break them in the same way you will use them. I have never experienced any engine damage as a result of using this method. For reference, I build engines to very tight tolerances.

Looking forward to hearing from the two stroke guru's on this, as i'll be needing the same advice very soon...

I have no idea what the engine tolerances are as the guy I got it off got it off some other guys mate and no longer had contact with him and when I pulled out my other engine I found the piston and cylinder to be brand new other that all the scrapes it has now so I think this engine was just rebuilt and the guy I got it off had never ridden it so I don't think it was broken in and I rode it hard straight away!! also wouldn't you want it running slightly rich because it is running slightly rich so I was just going to leave it!!

[jakep53]

When I got a new cylinder from Duncan Racing a few years ago, I got a print out with break in instructions. I don't have the details at the moment, but I know it was a gradual procedure. It advised running the engine through a couple heat cycles before riding it, e.g., run it for 5 mininutes, let it cool, repeat. After that you ride it for 20 minutes or so at no more than half throttle, being sure not to lug the engine or rev it out. Do that twice (letting it cool between runs) and then you are ready to fine tune the carburetor for the entire rpm range, do plug chops, etc. After that you're good to go. As stated above, I know there are different philosophies about how to break in an engine. I know for every new machine I've bought the manufacturer recommended a gradualist approach. I think the idea is to give the parts time to mesh and break in together. Frankly I can't imagine running it to the hilt from the beginning. With a new engine you might also have metal flakes in the oil and I don't think you want that circulating through the engine at maximum load.

thanks for the advise I think thats what went wrong with my last engine that it had just been rebuilt and I didn't know about it!!

[danbur55]

Jake. Out of curiosity can you look to see if the cylinder ports were chamfered. Just struck me that if top end was done and not chamfered could be the cause for yoy

[Bren_downe]

Jake, get on air foolers. Com there's is tons of info and even break in procedures specific to your bike.

[jakep53]

Jake, get on air foolers. Com there's is tons of info and even break in procedures specific to your bike.

yeh I joined up the other day but haven't really had a good chance to check it out!!

[jakep53]

Jake. Out of curiosity can you look to see if the cylinder ports were chamfered. Just struck me that if top end was done and not chamfered could be the cause for yoy

I will check that out tomorrow...so the edges should sorta be rounded??

[RIDE-RED 250r]

I have never encountered instructions from an engine builder/manufacturer that recommends running a fresh engine hard during break-in. It's always a gradual process to ensure proper seating of rings to the freshly honed cylinder. During this process the piston rings and cylinder generate more friction and therefore heat.

I have an ESR big bore top end on one of my R's and the gradual process that you listed is exactly what ESR stated on the sheet I got with the kit. A few idling with occasional blips on the throttle heat cycles.. then the roll up to 1/4 under load heat cycle, then to 1/2 throttle..and so on... The Honda manual calls for the same type of break-in, as do many other reputable builders.

This is indeed a hotly debated topic, but I have yet to see any builder or manufacturer list to run it hard for break-in. People do what they like with their machines, I trust those who manufacture the machine that they know what method yields the best overall results for performance and longevity.

As to premix ratio: There is tons of info readily available on this topic. After doing my own research I decided on Maxima 927 (castor based oil) at 32:1 for both of my R's. One of the articles I found was written by Harry Klemm if I recall. It was very in-depth and informative. One thing I personally would not recommend is going any higher than 40:1, especially during break-in. Many folks blame to much oil in their premix for poor performance.. Well, I can tell you that with proper jetting you can tune to run good at almost any ratio within reason.

Pick what type of oil you wish to run and at what ratio then stick with it. Once that is decided get the jetting tuned in for optimum safe performance. Remember, absolute peak performance is on the edge of too lean. A little burble is OK and will leave you a little wiggle room for changes in temperature/humidity as well as offer a little extra protection on a long full throttle pull..

[nd4speed]

Why not just say how you have broke in your own engine in the past? After my 2 stroke rebuilds I run 32:1 oil ratio as a always run. I start the motor with the choke on. I leave the choke on and i rev the motor lightly to warm up the motor for like five to ten minutes- usually I touch the cylinder until it is too hot to touch anymore. Check for leaks and then re torque all the nuts and studs. Then I ride it around at no more than like 1/2 to 3/4 throttle with the choke left on if possible for like 10-15 minutes. Stop, check for leaks, let it cool, and check the nuts/studs again. Then I ride for like 20 minutes going through all the gears, but never holding it wide open. I swear during this portion of the ride I have noticed the power change and pull of the motor. Stop and check stuff again but usually at this point it s pretty much done. Then I ride it around, not abusing it, for a couple hours and that's that.

[jakep53]

I have never encountered instructions from an engine builder/manufacturer that recommends running a fresh engine hard during break-in. It's always a gradual process to ensure proper seating of rings to the freshly honed cylinder. During this process the piston rings and cylinder generate more friction and therefore heat.

I have an ESR big bore top end on one of my R's and the gradual process that you listed is exactly what ESR stated on the sheet I got with the kit. A few idling with occasional blips on the throttle heat cycles.. then the roll up to 1/4 under load heat cycle, then to 1/2 throttle..and so on... The Honda manual calls for the same type of break-in, as do many other reputable builders.

This is indeed a hotly debated topic, but I have yet to see any builder or manufacturer list to run it hard for break-in. People do what they like with their machines, I trust those who manufacture the machine that they know what method yields the best overall results for performance and longevity.

As to premix ratio: There is tons of info readily available on this topic. After doing my own research I decided on Maxima 927 (castor based oil) at 32:1 for both of my R's. One of the articles I found was written by Harry Klemm if I recall. It was very in-depth and informative. One thing I personally would not recommend is going any higher than 40:1, especially during break-in. Many folks blame to much oil in their premix for poor performance.. Well, I can tell you that with proper jetting you can tune to run good at almost any ratio within reason.

Pick what type of oil you wish to run and at what ratio then stick with it. Once that is decided get the jetting tuned in for optimum safe performance. Remember, absolute peak performance is on the edge of too lean. A little burble is OK and will leave you a little wiggle room for changes in temperature/humidity as well as offer a little extra protection on a long full throttle pull..

Thanks for the advice I went on air foolers and they had this break in procedure just a little more detail so I will do that!!
I run my 4-strokes not really hard but I give em a little but I will do it as above....
My dad is going to go to the Honda dealer and check out what they have got there and then I will go from there!!

when I pulled my plug it was running rich so would it be safe to leave it at that until it's broken in and then fine tune the carb??

[nd4speed]

The motor hopefully has good seating rings which will create more suction and more fuel pulled in so after a rebuild I would experience a rich carb mix with out jet changes anyway so no need to mess with those at first.

[jakep53]

Why not just say how you have broke in your own engine in the past? After my 2 stroke rebuilds I run 32:1 oil ratio as a always run. I start the motor with the choke on. I leave the choke on and i rev the motor lightly to warm up the motor for like five to ten minutes- usually I touch the cylinder until it is too hot to touch anymore. Check for leaks and then re torque all the nuts and studs. Then I ride it around at no more than like 1/2 to 3/4 throttle with the choke left on if possible for like 10-15 minutes. Stop, check for leaks, let it cool, and check the nuts/studs again. Then I ride for like 20 minutes going through all the gears, but never holding it wide open. I swear during this portion of the ride I have noticed the power change and pull of the motor. Stop and check stuff again but usually at this point it s pretty much done. Then I ride it around, not abusing it, for a couple hours and that's that.

Thats the thing I have never rebuilt a 2-stroke and this is my first 2-stroke i've owned!!!! Thanks for the break in procedure I will follow these instructions and the one on airfoolers and it should be good!!

[RIDE-RED 250r]

There isn't a whole lot of difference on the hows and whys of break-in between 2-stroke and 4-stroke. In fact, a 4-stroke has a few more components that should be allowed to break in if a full top to bottom proper rebuild is done.. (cam and rockers)...

Yes though, as long as it is safely rich you should be A-OK for break-in.

[nd4speed]

The question wasnt for you, sorry about the confusion.

Yeah I ride it around and stop fairly often during the last couple hours, and if the jettin is way off during this time I usually have to lean the carb. During the cool down times when I stop is when I look at the plugs.

I read the thing on airfoolers. It is more detailed but about doing like 4 idle heat cycles, which seems like 2 too many to me, but I have done those. I mean heck, after the relief of having the motor start after the rebuild who doesnt like to rev it a little and listen too it and have a breath of fresh two stroke smoke air?

But yeah the airfoolers guide is a good one.

[DohcBikes]

There isn't a whole lot of difference on the hows and whys of break-in between 2-stroke and 4-stroke. In fact, a 4-stroke has a few more components that should be allowed to break in if a full top to bottom proper rebuild is done.. (cam and rockers)...

Yes though, as long as it is safely rich you should be A-OK for break-in.As for four strokes, his may be true for mass manufactured engines but there are a lot of performance engine builders that know how to build four strokes in a manner that does not require nearly the break in time. Some not at all. Just depends on what you want the engine to do and how much it matters that it last as long as possible. As we all know, plenty of race engines get rebuilt and ran immediately at the track on a regular basis with excellent results. Just depends on what you wanna use it for, and how the engine was built in the first place.

[slashfan7964]

When I break in a four stroke, even a V8, I am easy on it for about ten minutes, then I give it hell just like if I were racing it. I learned from a very good dirt track engine builder to break them in the same way you will use them. I have never experienced any engine damage as a result of using this method. For reference, I build engines to very tight tolerances.

Looking forward to hearing from the two stroke guru's on this, as i'll be needing the same advice very soon...

I've been told on a V8 you want to fire it up and then bring the RPMs up to a steady 2000 for a specific amount of time (varies) to break the camshaft in. After that it's all game. I suppose it's relative.

[RIDE-RED 250r]

As for four strokes, his may be true for mass manufactured engines but there are a lot of performance engine builders that know how to build four strokes in a manner that does not require nearly the break in time. Some not at all. Just depends on what you want the engine to do and how much it matters that it last as long as possible. As we all know, plenty of race engines get rebuilt and ran immediately at the track on a regular basis with excellent results. Just depends on what you wanna use it for, and how the engine was built in the first place.

Yes I agree, very true.. And that works for well sponsored professional race teams.. Average guys like us who for many reasons want our engine rebuilds to last as long as reasonably possible? Probably not the best method.

[fabiodriven]

If you're running the same carb that was on there when you blew the old top end you should probably double check your jetting.

[Bren_downe]

Why not just say how you have broke in your own engine in the past? .
Was this directed at me? If so I will say I don't really have enough experience rebuilding top ends to give as much advice as others here could. I recently did the top end on my Fooler, but i also added a lot of performance goodies at the same time. I followed the air foolers guide, that's why I pointed him in that direction.
One thing I'd like to add is find a good quality two stroke oil that's easily available in your area. I run amsoil dominator at 32:1 because it's available at all the auto parts stores and walmart. Lots of people have run that with no complaints. It sucks when you wanna ride and find out that day you forgot to buy more oil!

[fabiodriven]

I think he's just asking for people to say how they've done it personally.

Personally, I just take it easy for a while, putt around, warm it up, shut it off, a few times over. Then I give 'er the beans after a few heat cycles. I've never had one mess up yet.

[atc007]

Good jetting, Clean OILED air filter. Extra oil in the premix doesn't hurt,but does it help lol. Most usually do. Don't over rev it and don't lug it,assuming you're at stock specs. My engines? They're tight. Kbonly might be able to speak to that :) They require a break in for sure. Stock stuff? The team green and Team Honda boys took them from the airport to the winners circle back in the day in less than a few hours sometimes. But as Ridered said, they weren't real worried about them staying together for years :)

[jakep53]

ok I ended up getting YAMALUBE and im gonna start breaking it in tommorow!!

[jakep53]

Ok dumb question the bottle has no ration on it so if I wanted to make 5 litres how much oil would I use?? thanks

[nd4speed]

You need 156.25 milliliters of oil for 32:1 ratio

http://www.onlineconversion.com/automotive_gasoilmixture.htm

[RIDE-RED 250r]

Ratio-Rite measuring cup... Cheap and very handy!

http://www.amazon.com/Ratio-Premix-Mixing-2-Stroke-Measuring/dp/B0088NYRRI/ref=sr_1_1?ie=UTF8&qid=1410136431&sr=8-1&keywords=ratio+rite+measuring+cup

[jakep53]

Thanks for the links guys huge help!!

[dave ytz250s]

ok I ended up getting YAMALUBE and im gonna start breaking it in tommorow!!

If you're going to use Yamalube, make sure It's (YAMALUBE 2R) for premix.
(YAMALUBE 2S) is for injector only.

[jakep53]

If you're going to use Yamalube, make sure It's (YAMALUBE 2R) for premix.
(YAMALUBE 2S) is for injector only.

oh thats handy to know yeah I got the 2s and that would explain why it's got no ratios on it lol time to go shopping again!!

[nd4speed]

Over 15 years ago I used yamalube from a local marine shop cause it was pretty cheap for a gallon. Me and my friend used a gallon of 2s as premix with no problems. But yeah buy the 2R if you can.

We also went to a local small air field and bought LL aviation 100 octane gas cause we thought it would make us go faster. LOL. we were dumb but we came to the conclusion that aviation fuel was not helping us after the second purchase.

So 100 octane LL av gas mixed with yamalube 2s, oh those were the days, wish I was a teenager again.....

I really like Maxima 927 oil for break in and when its hot out. But in the cold winter it gave me issues.

[onformula1]

This has worked for me for a looong time.
I like 32:1 ( I would got to 20:1 before I would go to 40:1)
Torco GP-7 or Motul 800 2T is what I like, but there are many, many good brands out there.
I like full synthetic
Break in- start the bike and run until the head is very warm to touch, let it cool, do it a second time, let it cool ride the trike- don't bog or rev for 5-10 mins.
open it up a little if it doesn't want to rev cleanly ride a bit longer, open it up again try for full throttle straight & hit the kill switch a couple of times as your riding, it cools the cylinder down, try riding at all levels- everything should be good, remember full race engines go for only 8-10 hrs before a rebuild so you don't have to spend alot of time breaking in a 2-stroke engine. I can re ring a piston 2-3 times, clean the piston with green scotch brite, polish the dome.

[crackshot]

I just got done rebuilding my top end on an 82 r. 1 gallon of race gas. 110 octane leaded with 40:1 mix. Oil was a dino type.
Every gasket on top end was sprayed with real kopper kote spray. Torqued to maximum spec.
Started on 2nd kick. Ran it for about 10 minutes at different speeds. Shut it down and let it cool even though it did not get very hot.
Started it again and this time i rode it on hard surface opening up throttle to 1/2. Did this for another 10 min and let cool down overnight.
Next day i checked torque on all the bolts and all were still spec.
Started it up and rode it on hard surface for 20 minutes opening up throttle to 3/4 with blips of wot at times.
I dumped the rest of fuel and mixed up a batch of 110 and amsoil dominator synthetic oil. This is the second engine i broke in this way and the truth is, a 2 stroke takes about 20 minutes to break in. I run all my 2 strokes at 40:1. Seems to do just fine.