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ezekielvictor

Full synthetic no good for '98 YZ400F... True/False?

16 posts in this topic

I had my '98 YZ400F at Scotts today so they could figure out a problem with the weld-on damper mount kit from the previous owner. I told the guy I ran Silkolene Pro-4T SX 10W-50 ester-based full synthetic in the bike, which made him gasp. :bonk: He said for this old bike the full synthetic would slip past the rings and I'd lose a good amount of oil like that. Said I should be running a semi-synthetic. Is this true? Now that he mentions it, I do notice that I go through some oil here and there...

What brought up this discussion was that my clutch which is all rebuilt including push rod and cable still sticks like a mofo with the lever pulled all the way in. And any help with that would be appreciated. :thumbsup:

-Zeke

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I know you said you rebuilt it, but I have to say this because I had the exact same problem with my clutch. I didn't rebuild it, but it had been a little overdue on the oil change, so I took the whole clutch assembly apart and rubbed generous oil all over the plates. I actually scrubbed everything with my finger tips to make sure I had gotten rid of all the old oily residue. When I put it all back together, I started it up and let it run for a few minutes, and it was back to normal. Like I said, I know you did a rebuild so this probably doesn't apply, just thought I'd say.

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Regardless of how old a bike is, it isnt going to let oil slip past the rings unless something is wrong. If you are losing oil you likely need a new top end, or at least new rings. The problem is not oil related.

Edited by ttr250dude

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Well, that makes me feel better because I have a big ass case of this expensive oil. ;D

Any thoughts on the clutch problem I'm having?

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It jut amazes me when people make claims and don't have a clue what the he$: they are talking about. I strongly suggest using a high end true synthetic oil in these motors. I have an 09 yz450 with just over 400 hours on it and we have used Redline 10-40 motorcycle oil after breakin. Redline is a group V polyol ester oil. A true synthetic. The motor still runs strong, starts first or second kick and uses no oil. The motor has never been opened up. We run the Rekluse Pro and it is still on the original clutch. I might add that this bike is ridden hard by my son inlaw and he is a fast b rider that rides motocross and single track.

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(he) Said I should be running a semi-synthetic. Is this true?

No. Everything he told you is BS, to be blunt. Your bike is going through oil because it's old, and probably needs rings and valve seals. It would do that regardless of which oil you put in it.

  • Synthetic oil causes oil consumption
  • Synthetic oil keeps ring from seating
  • Synthetic oil makes your clutch slip
  • More octane = more power
  • The check's in the mail
  • Increased deficit spending will reduce debt
  • Printing money will stimulate the economy
  • The government will take care of you
  • It's never been crashed

...All of these statements are in the same category.

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More octane=more power

That has started more fights than anything else in racing. I'd bet only 1 in 1000 racer's understand this.

I'm very happy to see you post that comment Gray.

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Ok, guys, lets be nice. I am not full of bs, or on drugs or any of this stuff. And we certainly know the oil is like religion argument.

Saying that, Ezekial has a high mileage bike that is seeing D37 desert raicing. Full synthetic oil is more slippery than conventional oil. At extended high RPM it is more likely to pass through your rings and lose oil accordingly. On a bike like an XR650 when you have 2.5 qts of oil running through you dont notice it a whole lot. On a bike like a CRF450 when you have 650cc of oil in you will notice it more and it is a bigger deal. When I have a customer that is real good about changing oil all the time it is no big deal. MOST of my customer are not so good about changing oil and think they can run a synthetic and forget about it. You tell me what advice you would give at that point in time.

Just a final case in point. Team KTM USA runs full synthetic oil in the SX and MX races with relativly short motos and they run semi-synthetic in the offroad teams that are open throttle for far longer.

Thanks-

Eric

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Eric,

Please don't take offense, at least not from me.

With all of the tremendous respect you, your products, and your company have rightfully earned, I have to say I really thought the caveat regarding synthetics must have come from one of your employees. The fact simply is that the statement that synthetics are "slipperier" than conventional oils is, in itself, a long standing mischaracterization and an overgeneralized view of the nature of synthetic oils. It is frankly as far off the mark as the notion I contend with here on the site that one stainless oil filter is like any other.

By far, most synthetics will not show an increase in oil consumption in older engines, although what we very often we see is synthetics of any given basic viscosity that are much thinner when cold, i.e., 5w or 10w-40 rather than 20w-40. These oils, until recently, were also very seldom capable of retaining their full high temperature viscosity for any length of time in an application in which the engine shares oil with a transmission, and the result is that the oil ends up much more like 10w-30 or lighter in a surprisingly short time. Under those conditions, the lighter oil viscosity can lead to oil sneaking by the rings. And, especially in a tired engine, a lot of the oil consumption tends to occur before the engine warms up, and the low cold weather viscosity is more to blame for that than the origins of the base stock. Since the offending oil was a synthetic, all synthetics get lumped together when the blame is assigned. Nevertheless, the idea is a myth.

As long as we're talking about oil consumption, I think it should be understood just how little oil is tolerable in the combustion chamber if low oil consumption is a goal. All that it takes for an engine that operates at a conservative (these days) average of 6500 RPM to burn 400cc of oil in two hours is 1 microliter of oil in the chamber during each power stroke. That's one one-thousandth of one CC. Pretty small. Modern rings and seals are pretty amazing.

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Ok, guys, lets be nice. I am not full of bs, or on drugs or any of this stuff. And we certainly know the oil is like religion argument.

Saying that, Ezekial has a high mileage bike that is seeing D37 desert raicing. Full synthetic oil is more slippery than conventional oil. At extended high RPM it is more likely to pass through your rings and lose oil accordingly. On a bike like an XR650 when you have 2.5 qts of oil running through you dont notice it a whole lot. On a bike like a CRF450 when you have 650cc of oil in you will notice it more and it is a bigger deal. When I have a customer that is real good about changing oil all the time it is no big deal. MOST of my customer are not so good about changing oil and think they can run a synthetic and forget about it. You tell me what advice you would give at that point in time.

Just a final case in point. Team KTM USA runs full synthetic oil in the SX and MX races with relativly short motos and they run semi-synthetic in the offroad teams that are open throttle for far longer.

Thanks-

Eric

I'll try to be nice. I do use your ss filter and will use nothing else. I use your steering stabilizer and will use nothing else. I also use Redline polyol ester fully synthetic oil and will use nothing else.

The first problem you are talking about a crf. Single ring pistons are going to burn oil especially a Honda.

Not really buying the synthetic oil being more slippery thus passing by the rings theory.

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Eric, can't blame me for looking for opposite sides of the issue, right? :thumbsup: I appreciate your advice, you know. I didn't move my kill switch but I did reroute the cable so it wouldn't be sticking out like you said. Also bent my clutch lever tab back straight and adjusted it up right. We'll see how that tweaked damper mount is this weekend...

Thanks again for all the help! Well, now you'll for sure remember me when I come back in for more stuff in the future. :bonk:

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Zeke-

No worries, I just didnt want people to think it was just random spew coming out of some sales guys mouth and that there is some validity. let me know how the damper set up works and if we can do anything else for ya!

Thanks-

Eric

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... I just didnt want people to think it was just random spew coming out of some sales guys mouth and that there is some validity. ...
Oil discussions do always tend to get a little larger than life. Like fuels, there is far more misinformation and misunderstanding connected with the subject than good hard information, and the marketing sector of the industries involved is unfortunately to blame for quite a bit of it.

Often, some things that are true to an extent about some oils in a class are either not true of all such oils, or true for reasons other than those assigned to the problem, and inaccurate conclusions are reached, and myths begin to grow from them.

Nevertheless, stuff like the drug comment are uncalled for in an intelligent discussion.

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I have an old Jeep Cherokee with 135,000 miles on it. It started to use some oil not alot but some. 1 to 2 quarts every 2,000 miles.

A buddy owns a garage and he told me to try Castrol Syntec 5-30. He said it would cut down on oil consumption. I was very, very skeptical but he was right.

3,000 miles and still no measurable oil used.

Maybe alot of what you see on the intornet is just BS?

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