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2 stroke oil and ratio trail riding

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I use yamalube r2 in my 250cc at 32:1. I'm at 90 hours and on the original plug. When I replaced the top end I checked the pool of oil in the crankcase and it was right at 1/8 inch. Maybe a little more. The powervalve was just whipped off with a rag. The bike revs to 9000rpm but most of the time on the trail I am at 4 to 7k rpm. It runs well. There is never any burble or hesitation. Even at prolonged low rpm conditions like idling for 10 minutes or a half hour of 1st or 2nd gear 2--4k rpm single track there Personally, I see no reason to go to 40:1 let alone any less. I actually prefer a non-synthetic at 32:1 vs a synthetic at 40:1 although I've been considering giving motul a try. No spooge with either the OEM suppressor or a spark arrestor (fmf). Just a black smokey film. 

Edited by Brian Morrison
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On 1/15/2019 at 4:03 PM, Doc Brown said:

 

Why not use what KTM specifies? 60:1 Crosspower 2T. Done. You can use any other brand provided that it meets the required standards. one point people miss is that the standard alone doesnt tell you all. In case you have a lot of spooge it would not make sense to use an oil with an extra high flash point. Motul 800 has a very high flash point of about 260° C (500 F) and is designed for racers. If you ride lots of technical super slow (first/second gear) stuff and you ride "on the pilot jet" often, its simply the wrong oil. If you race and WOT is used most of the time it is what you probably want.

For all oils you can search the internet for a tech data sheet/technical bulletin to see flash point and other information.

As an example Dominator and Crosspower (be careful to not mix deegrees Celsius and Farenheit ;)

https://www.amsoil.com/lit/databulletins/g1985.pdf

https://www.motorex.com/fileadmin/_pim_product_sheets_/en/Cross_Power_2T_EN.pdf

Thank you for that info. I recently bought some 10 quarts of Dominator for $7 a quart. I was using either Motorex ( when by a shop that sells it) and Sabre from a local hardware store.  It looks as though Motorex has a flashpoint of 230 , Sabre 356 and the Dominator at 201. Which is fine for me as I'm not very often if ever on the pipe. 2nd n 3rd gear single track rider. I do have spooge with the Sabre.  I never really correlated spooge with flashpoint.   Good thread.

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On 2/14/2019 at 9:16 AM, Brian Morrison said:

 

I use yamalube r2 in my 250cc at 32:1. I'm at 90 hours and on the original plug. When I replaced the top end I checked the pool of oil in the crankcase and it was right at 1/8 inch. Maybe a little more. The powervalve was just whipped off with a rag. The bike revs to 9000rpm but most of the time on the trail I am at 4 to 7k rpm. It runs well. There is never any burble or hesitation. Even at prolonged low rpm conditions like idling for 10 minutes or a half hour of 1st or 2nd gear 2--4k rpm single track there Personally, I see no reason to go to 40:1 let alone any less. I actually prefer a non-synthetic at 32:1 vs a synthetic at 40:1 although I've been considering giving motul a try. No spooge with either the OEM suppressor or a spark arrestor (fmf). Just a black smokey film. 

Just picked up a 300xc-w and ran yamalube 2R at 32:1 for the first tank. I haven't checked the jetting yet but the PO was using Bel Ray H1-R at 40:1. I rode it with the Bel Ray before I purchased it and it was crisp and clean running. The Yamalube caused a little bit of spooge and it had a noticeable flat spot in the mid rpm range. Probably a jetting change would be needed to stay with the yamalube. Im switching back to Bel Ray. He had no problems for years on that oil. 

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2 hours ago, Bobatsea said:

Just picked up a 300xc-w and ran yamalube 2R at 32:1 for the first tank. I haven't checked the jetting yet but the PO was using Bel Ray H1-R at 40:1. I rode it with the Bel Ray before I purchased it and it was crisp and clean running. The Yamalube caused a little bit of spooge and it had a noticeable flat spot in the mid rpm range. Probably a jetting change would be needed to stay with the yamalube. Im switching back to Bel Ray. He had no problems for years on that oil. 

It seems the jetting is changed more going from synthetic to mineral vs a change in ratio, ie 32:1 to 40:1.  

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16 hours ago, Bobatsea said:

Just picked up a 300xc-w and ran yamalube 2R at 32:1 for the first tank. I haven't checked the jetting yet but the PO was using Bel Ray H1-R at 40:1. I rode it with the Bel Ray before I purchased it and it was crisp and clean running. The Yamalube caused a little bit of spooge and it had a noticeable flat spot in the mid rpm range. Probably a jetting change would be needed to stay with the yamalube. Im switching back to Bel Ray. He had no problems for years on that oil. 

I wonder why one uses 32:1 when 60:1 is required by KTM. Is it the old urban legend of more is better always?

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1 hour ago, Doc Brown said:

I wonder why one uses 32:1 when 60:1 is required by KTM. Is it the old urban legend of more is better always?

   I think 60:1 recommendation has more to do with an effort to meet or at least get closer to the emmisions requirements than best power and engine life. I've tried 50:1 belray mc1 on a 250cc and when I pulled the top end there was no where near enough oil puddled in the bottom of the crankcase for me. I would say 1/16 inch deep. This is on a 250 maxing out at 9000 rpm. Imagine a 125 turning over 12000. Supporting this is ktm now recommending 40:1 in the smaller bore bikes.

   It is not a urban legend. Tests have proven a Japenese 250cc 2 stroke makes best power at 18:1 and lost 2% going to 32:1 then 9% going to 50:1 over the 18:1 peak.

   I would never use 60:1. I think it is mental. 32:1 is as low as I go. Even if I had a 2019 300xc I would use 32:1, rejet and ride spooge free. I use 32:1 in my 250cc+ and 24:1 in my 125s. My small radio controlled modles I run  2 stroke engines in the 30 to 60cc range turning 8000 to 16000 rpm get 16:1 and the even smaller 3.3cc ones turning 30000rpm get 5.5:1. None drool black goo from the exhaust.

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3 minutes ago, Brian Morrison said:

   I think 60:1 recommendation has more to do with an effort to meet or at least get closer to the emmisions requirements than best power and engine life. I've tried 50:1 belray mc1 on a 250cc and when I pulled the top end there was no where near enough oil puddled in the bottom of the crankcase for me. I would say 1/16 inch deep. This is on a 250 maxing out at 9000 rpm. Imagine a 125 turning over 12000. Supporting this is ktm now recommending 40:1 in the smaller bore bikes.

   It is not a urban legend. Tests have proven a Japenese 250cc 2 stroke makes best power at 18:1 and lost 2% going to 32:1 then 9% going to 50:1 over the 18:1 peak.

   I would never use 60:1. I think it is mental. 32:1 is as low as I go. Even if I had a 2019 300xc I would use 32:1, rejet and ride spooge free. I use 32:1 in my 250cc+ and 24:1 in my 125s. My small radio controlled modles I run  2 stroke engines in the 30 to 60cc range turning 8000 to 16000 rpm get 16:1 and the even smaller 3.3cc ones turning 30000rpm get 5.5:1. None drool black goo from the exhaust.

Cant say anything about RC models here. However I had 300's and 250's running on Erzberg and I think thats a real challenge for any engine, with 80:1 and they had no problem. 60:1 has nothing to do with emissions, KTM requires it on competition bikes as well. If it could harm the engine they would not recommend it. I had my 300 running at 80:1 and the engine internals looked near mint after 140 hours of a hard life. We had a 125 running mistakenly at 50:1 and it revs about 13000 rpm and its between 9000 and 12000 90% of its life time. It didnt do anything negative to the engine. The engine's top end is done every 20 hours, I have never seen that the crank or any other internals showed lack of oil.

The next mistake is "jetting spooge free". Jetting is jetting and spooge is spooge. I'd never jet smaller to avoid spooge. I jet in a way that the bike runs slightly rich, I can live with a certain amount of spooge...

If you got time search the web, there is a study somewhere showing the negative effects of too much oil in two strokes. Most people use too much oil, running 32:1 instead of 60:1 though manufacturers say you can run it 60:1 and give warranty on these engines.  I'd never ever put 32:1 in any of my bikes or those I take care of if the manufacturer requires 60:1.

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     I'm still unconvinced. I have searched and found negative issues such at excess carbon, rings sticking, excessive smoke, spooge, hard starting, erratic idle, fowling sparkplugs, exc. However, when actually experiencing these symptoms it was always caused by too rich jetting. 

    To my knowledge, ktm now says 40:1 on the small bore bikes. It is no longer 60:1. Its possible I am wrong.

  I had less than 1.5mm oil crankcase oil at 50:1 so I cant very well use less.

    

Edited by Brian Morrison

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1 hour ago, Brian Morrison said:

     I'm still unconvinced. I have searched and found negative issues such at excess carbon, rings sticking, excessive smoke, spooge, hard starting, erratic idle, fowling sparkplugs, exc. However, when actually experiencing these symptoms it was always caused by too rich jetting. 

    To my knowledge, ktm now says 40:1 on the small bore bikes. It is no longer 60:1. Its possible I am wrong.

  I had less than 1.5mm oil crankcase oil at 50:1 so I cant very well use less.

    

Go back to page one. Read the third post. Full explanation there.

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Is there a spec for how much oil should be in the crankcase, or this some old rule of thumb?

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1 hour ago, nahvkolaj said:

Is there a spec for how much oil should be in the crankcase, or this some old rule of thumb?

I feel good with 1/8 inch. 3/16" would he alright as well. 

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3 hours ago, Brian Morrison said:

     I'm still unconvinced. I have searched and found negative issues such at excess carbon, rings sticking, excessive smoke, spooge, hard starting, erratic idle, fowling sparkplugs, exc. However, when actually experiencing these symptoms it was always caused by too rich jetting. 

    To my knowledge, ktm now says 40:1 on the small bore bikes. It is no longer 60:1. Its possible I am wrong.

  I had less than 1.5mm oil crankcase oil at 50:1 so I cant very well use less.

    

Im going to stick with 40:1. Bike just got a top end at 125hrs and had Bel Ray H1-R at 40:1 its whole life. It honestly didn't need the top end. Everything was in spec according to the previous owner who is a really good mechanic. My plan is to do the top end every 100hrs (basically at the end of each season) unless there is a reason to suspect it needs one sooner. 

Edited by Bobatsea
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11 hours ago, Brian Morrison said:

     I'm still unconvinced. I have searched and found negative issues such at excess carbon, rings sticking, excessive smoke, spooge, hard starting, erratic idle, fowling sparkplugs, exc. However, when actually experiencing these symptoms it was always caused by too rich jetting. 

    To my knowledge, ktm now says 40:1 on the small bore bikes. It is no longer 60:1. Its possible I am wrong.

  I had less than 1.5mm oil crankcase oil at 50:1 so I cant very well use less.

    

Yes, you are right KTM now requires 40:1 on the small bores and I would not take less oil as these smaller engines rev like crazy. Please do not misunderstand me, I don't want to convince you or anyone. No bad feelings, nor aguing. Make your own experiences that's what I recommend everyone. If you're happy with 32:1 and all is good, why not. Its just me being a rebel questioning things. It seems I have a different opinion on many technical things. Having said this, i don't trust Maxima's Migration sheet as I can't imagine that its based on a serious long time study from a well known institution.

I am not a scientist either so I only can tell what I personally have experienced or seen so far. One thing that is worth to mention is that oil mix ratios may also depend on different oils. While 4 stroke oils are more or less all the same if you take samples with identical specifications two stroke oils of same specs may be very different. I have experienced these differences on liquid cooled kart engines. Its mainly the flash point that varies between 78° and 260° degrees C, which is a huge difference plus the fact that some oils are limited concerning the mix ratios. Castrol Power 1's highest possible mix ratio is 50:1 and Castrol confirms that, other oils can be mixed as high as 100:1.

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8 hours ago, Doc Brown said:

Having said this, i don't trust Maxima's Migration sheet as I can't imagine that its based on a serious long time study from a well known institution.

If someone followed their guidance exactly and used their oils only (and had a appropriately setup carb) and then experienced an oil related failure, they may have recourse against the manufacturer. Maxima wouldn’t publish the guide if it meant risk to them. 

I’m not aware of any relevant and recent university conducted research on this topic so you’ll just hafta settle for internet oil experts.

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On 1/14/2019 at 8:49 PM, shrubitup said:

Quite frankly, the third post does have this question nailed. Pretty darned good information here. Stick with it and you won't go wrong concerning ratios.

 

Is this an opinion? Not at all. I followed the 40:1 oil recommendation my KTM dealer gave me for my 2000 KTM 125 EXC. I ran it for 7 years with this recommendation. Seven years on the same piston and ring in a 125 2-stroke! I read about the new 50:1 synthetics. I was sold. I switched to 50:1 and felt no reduction in power and since I was running many highway miles I felt I was seeing a savings. Soon, my compression was down, but the bike was nearly 10 years old, so I re-ringed. Net year, I was down in compression again, so I re-ringed again, only this time the bore was quite rough. I picked up a nearly new cylinder and ran for another couple years before compression faltered. This cylinder showed signs of wear now too. 

 

So, I formed an opinion, how could I test it? A few years ago I retired from an industry job and found extra time on my hands. I wanted to test all sorts of 2 stroke theories, so I needed a cheap testbed. I found it in bicycle engines. 

image.png.4b6218e0f7129079508d2a41d30bd39f.png

I put this engine together as per its instructions and followed its 16:1 break-in recommendation. The cylinders are a very thin flash of chrome on soft aluminum. It spewed oil out the pipe and fouled a plug on its third tank. After a few hundred kms of break in, I started experimenting. First of all optimizing the fuel mixture and then looking at the effects of oil mixture. This engine is so simple, you can pull the cylinder in about 5 minutes. I never did get to 50:1. Several hundred kms at 40:1 resulted in this wear: 

image.png.f76513f22075ceddcac570e17f8f4ac6.png

Luckily these cylinders are very cheap to replace. 32:1 castor oil actually restored compression of this cylinder to original and allowed new cylinders to run for over 1000 kms with minimal wear. It was an eye opener for me. Synthetic oil and tall ratios are not the panacea I thought they were. At 32:1 mineral oils perform very close to synthetics as far as sealing and wear resistance. Synthetics mainly have superior fouling qualities. Castor exceeds both mineral and synthetic at wear and sealing but of course fouls more, which is part of the reason it seals so well. 

image.png.bbebff3ede9c52cf29034860493574b0.png

It was a lovely summer, putting several thousand kms on several bicycles and experimenting with porting, head design, exhaust and intake configurations. Can you imagine putting over 100 kms on a bicycle in an afternoon ride? With the right oil mix I found these cheap and simple engines are very reliable and long lasting. Unfortunately I was not very successful at retirement and find myself working at a more than fulltime job again. 

 

So, what I know for sure:

  • More than 32:1 oil mix tends to surrender compression and wear, regardless of the type of oil
  • Manufacturers are recommending thin ratio (50:1, 60:1) for emissions and sales reasons, not power or longevity
  • Castor seals and wears very well at thick ratios, but is very dirty and expensive and doesn't like moisture
  • Synthetic works moderately well at thinner ratios, and cleans well, but cannot do the impossible over 40:1
  • Mineral oil is a great compromise in the 24:1-36:1 range if you really need to save money on oil.

I have a couple early 2000s KTM bikes (300 and 380) that are still running their original pistons. I run synthetic at 40:1 for light trails and 32:1 for hard running. I run my street driven 125 on the same mix and expect a long life at highway speeds. Not trying to sell you on anything, just sharing that I came from a 50:1 mentality and ended up here. 

image.png.e9dfe80759e04f96e09ae949ef63ac5e.png

 

 

Edited by sbest
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I'm running Maxima K2 synthetic at 60:1. I don't give a shit anymore if I get some spooge out of the tail pipe, it's a god damn two stroke and that's gonna be part of it sooner or later. As long as the bike is running well I don't mind a little spooge.

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5 hours ago, Muffintop said:

I'm running Maxima K2 synthetic at 60:1. I don't give a shit anymore if I get some spooge out of the tail pipe, it's a god damn two stroke and that's gonna be part of it sooner or later. As long as the bike is running well I don't mind a little spooge.

I run the same. I get a little drip down the silencer's end cap at the end of a ride. I know this thread is almost nothing but anecdotes, so here's mine. I ran my Suzuki 250 at 50:1 for 15 years, and in that time it got two new pistons. It got a rod kit (crank pin started wearing) and a new 4th and 5th gear with the last piston. That bike saw lots of hard desert use, including several races. My takeaway was to start using gear oil in the transmission.

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13 hours ago, sbest said:

Manufacturers are recommending thin ratio (50:1, 60:1) for emissions and sales reasons, not power or longevity

Appreciate that your share your testing with this small engines and I believe most what you say, just the above is an exception. Neither 50:1 nor 60:1 has to do with emission. Fully synthetic oils work with 60:1 probably better than non-synthetic oils. Gas Gas as an example recommends 50:1 with fully synthetic oils or 40:1 with standard oils. That confirms part of what you said.

The TPI's run between 125:1 and 40:1 depending on engine load and revs and in the future I think mix ratios will become less once the mix ratio will indeed be considered as emission relevant.

Like you I did quite some testing and run two 300cc KTM engines (2015 and 2017) with 80:1 instead of the recommended 60:1. I pulled the cylinder at 140 hours and the internals looked like mint, just the rings were slightly (!) out of spec. I know a Gas Gas 300 which is running 100:1 since day one and is used for MX riding aswell. The engine is still running. I would not recommed that but it is interesting as the owner just said I want to know when it seizes. That we both use oils that are designed for use up to 100:1 is clear. We also tried 100:1 in a high reving RC engine (24000 rpm) and it worked without problems. The oils we used were Fuchs 100 and Amsoil Saber Pro. I stopped using Amsoil when Amsoil said I should not use it in a two stroke motorcycle engine, though it worked fine for hundreds of hours. I run my first Gas Gas (2018) with 80:1 for 40 hours, the new owner uses 60:1 and now has 90 hrs and the engine is still running good.

If I'd be a WOT rider or rev very high I'd probably go back to 50:1 but I am not riding WOT very often. I do believe that one can trust in the manufacturers recommendations.

Edited by Doc Brown
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I know I will contradict myself and my previous post on this topic but here it goes.

 

Since I redid the top end I decided to fix the jetting and maybe run a little more oil. I was getting spooge with a real (measured with a medical syringe) 50/1 in the beginning, after the top end and the jetting changes I was getting very little spooge at almost 50/1... or so I thought.

 

I had a 100 ml plastic coffee cup that I assumed was 100 ml, and I was dumping that oil in a little less than 5 liters of gasoline. Out of curiosity, I measured it and it was 130 ml... so I was in effect using 38/1 to begin with.

 

Last Sunday I decided to add a little more oil and I put the same amount (the 100 ml that magically became 130) in 4 liters of gas. Given that there was about half a tank of 38/1 and 130 ml in 4 liters works out at about 30/1, i had about 3% oil in there.

The riding was 1st, 2nd and a little 3rd gear (max 1/2 throttle), fall down, pick up bike and repeat ?

 

Well, what do you know... Still minimal spooge. Granted, it's a little lean on the pilot but nothing the air screw can't fix, we are really close.

 

The moral of the story is that I am a believer in the right jetting. I used to shake my head in disbelief when someone mentioned more than 2% . In my case it doesn't spooge, plugs survive just fine, and the power valve was clean.

 

I say jet correctly, use a quality oil and a little extra won't hurt as long as you don't overdo it.

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