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Changing premix during rebuild

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I'm going to switch from castor 927 to HP2 this time around. My top end is off and I can look down between my crank halves and see a nice residual oil level in my bottom end. Should I try and get it out of there somehow and replace it with the new premix I'll be using or just not worry about it?

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thats what castor does, leaves a thin coat of oil residue, i would leave it, no big deal

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I personally would remove it in the interest of cleanliness. Once removed, replace it with a little of the new flavor and drive on. I am a clean freak when doing internal engine work, so that is just part of my routine. It's probably not neccessary and wont affect anything either way, but just an old habit for me. Good luck!!!!

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I'm going to switch from castor 927 to HP2 this time around. My top end is off and I can look down between my crank halves and see a nice residual oil level in my bottom end. Should I try and get it out of there somehow and replace it with the new premix I'll be using or just not worry about it?

Don't do it! I did that over a year ago and in a recent tear down it was the most measured wear of any oil I have ever used was with the HP2.

Stick with the 927 or the K2. The K2 is an excellent 2 stroke oil and never wore out my top end like the HP2 did.

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Pre mix oil cycles through your motor rather quickly. If you feel the need to remove "old" premix you're not getting any advantage IMO. For if you switch to brand X it will quickly replace the 927 at the bottom of your crank after a few hours anyway. :thumbsup:

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Anyone else have trouble with Honda's HP2? I always thought it was good stuff?

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Why are you guys running HP2? Yamalube 2R is great stuff, you guys don't like it?

MAX!!!

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yamalube is outdated oil. so much more has developed in the world of premix since that oil came out. and it has yet to be updated. i run castrol ttr. stuff is amazing. smells great, have yet to foul a plug still, and muuuch less measurable wear than with yamalube.

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I never had any issues with the HP2 stuff running it at 32:1. It smoked less, didnt spooge and didnt cause any abnormal wear

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Pre mix oil cycles through your motor rather quickly. If you feel the need to remove "old" premix you're not getting any advantage IMO. For if you switch to brand X it will quickly replace the 927 at the bottom of your crank after a few hours anyway. :thumbsup:

Thanks this is good useful information.

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the oil debates are always a joy. there are brand loyalists, dealer rec loyallists and cheapskates. I fall into cheapskates. I have several 2t engines and many snowmobiles (which burn about 10gal of fuel a day) I have one sled, a 1997 yammy that has seen every brand of "cheap" oil. it has over 7000 miles on it now. 4000 miles is considered "wore out" for a mtn sled. my long term testing has told me this......all oil lubricates. some oil smells better, worse different then others. some do seem to cause a bit more gunk on power valves. thos that do gunk the power valves oils that I would trust for longer term storage of a 2t engine, they are typically dino oils that tend to "stick" to the crank better and not allow moisture in there place. full synthetic seem to be a poor choice for longer term storage, but do a fine job of lubricating......nearly as good as what you can go down to the auto store and buy.

my advice for oil after a rebuild is.....pick one, make it plenty rich the first couple tanks and then enjoy.

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I never had any issues with the HP2 stuff running it at 32:1. It smoked less, didnt spooge and didnt cause any abnormal wear

You wont really know how good an oil is until you stress it beyond its ability to lubricate. Call it the "safety zone" and the HP2 has a narrow one.

In my case, my motor is a YZ 144 that pumps out nearly 40HP on the dyno at 11k RPM. The race fuel I use is off the charts in order to control detonation.

So all that said, HP2 did not cut it under this kind of abuse. I'M sure many have had no problems with HP2 under normal conditions.

Like with fuel and tuning a motors octane needs, the quality of your oil needs to be evaluated in the same way and how much of a "safety zone" you need.

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I run Walmart brand supertech outboard oil in my 01 yz250. I beat the living hell out of my engine!! Absolutely zero problems, I was running blendzol but supertech is 40 bucks cheaper for a gallon! My bike runs awesome dont believe the hype that you need more expensive oil.

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I run Walmart brand supertech outboard oil in my 01 yz250. I beat the living hell out of my engine!! Absolutely zero problems, I was running blendzol but supertech is 40 bucks cheaper for a gallon! My bike runs awesome dont believe the hype that you need more expensive oil.

plus one

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Ah, oil discussions...... Pick one, jet accordingly and you should not have problems. Run dirt cheap oil, run $8 a pint oil, all up to you. I run hp2 in mine and jet correctly and have NO PROBLEMS. I run mine between low/mid rpm single track and WFO on transfers from single track to single track and have not had problems with lack of lubrication. The important thing is to JET JET JET!

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I agree, riders that trail cruise or ride mostly stock can run the cheap stuff, some even claim they can run 100 to 1 ratios. Only an idiot would do that, but it happens.

But one thing I do know, If I ran the gas oil mix that most here can get away with in my motor it would grenade.

125/ 144 riders that ride mx should use the best oil they can find, 250 riders not such a big deal as most can't run it hard enough to matter unless the 250 is pushing well over 50HP.

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I wish someone would come on here with scientific evidence that their oil selection directly caused engine meltdown. It be nice to have scientific proof documenting that.

there was a test that was posted on snowest a few years back..........saved me a boat load of money.

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