1978 YZ250 oil and gear lube?

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Jan 25, 2014
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south haven mi
So i picked up a YZ250 on trade it has less than an hour on a .60 over wiseco piston and rings at least thats what i was told but i believe the guy.He said he mixed the oil 32.1 and its a bear to start to say the least.I believe a lot of this is due to the oil which is just cheap 2 stroke oil.When i was growing up we always used Bel Ray MC1+ as it smoked less and we used to run it at 50.1 or even 60.1.What is a good oil i can use thats readily available and what ratio should i use?And what should i use in the gearbox and how much if anyone knows? Thanks !
 
You can always continue to use the MC-1. It's still a strong product offering and recommended precisely for old bikes like this.
 
A 1978 YZ-250!! Just like Bob Hannah used to ride! Oh, how I used to want one of those...with that big aluminum mono shock swing arm...

Sorry, I’m stuck reminiscing and not answering your question...

The Bel Ray MC1 is still around. So is Golden Spectro, which used to be my fave... mix either at 50:1 and make sure your airbox stays sealed. That vintage YZ used to leak air around the filter.

Congrats!
 
Certified JASO FD oils have proven to be the best for engine lubrication vs exhaust cleanliness. Buy the cheapest JASO FD you can find and be worry free. Depending on how hard you ride, I would suggest a ratio between 32:1 to 50:1.

Sometimes expensive oil make you feel better, but remember that in your application you wouldn't be getting better lubrication from it.
 
Transmission oil; 10w30 diesel oil (cheap) or 10w30 Motorcycle oil (expensive). Just make sure you change it often.
 
I'd counter with the recommendation to mix a quality oil at the ratio the manufacturer requires. 32 to 1 is likely the proper ratio.

Our two stroke oil testing clearly indicated that ring and cylinder wear reduced as the oil quantity increased. The ring and cylinder wear just above the exhaust port is directly connected to oil ratio. It's especially important to use more oil with the increased clearances of forged pistons. It's also very important to have jetting correct and sufficient octane.

You could, for example, use a 100 to 1 mixture and measure fair results on the piston skirt. But you will see increased ring wear above the exhaust port. Leading to eventual blowby and overhaul.

There is no real magic with two stroke oils. They provide adequate protection by quantity. It's no surprise that from a wear standpoint, we saw no real difference between TCW-III mixed at 32 to 1 and boutique brands. Carbon and other issues (such as power valves) are another story.

I've stated this many times, but in our testing 8 or 16 to 1 provided the best HP, 32 to 1 was good enough to keep wear in check (unless it was a super high output engine 50+ HP 125cc) 50 to 1 and 100 to 1 had ever increasing wear and less power.

The increased HP does come at an operational cost, as 8 to 1 is nearly impossible to manage. However, when you must win, you do what you need to.
 
So where do I get the jaso ? And I assume the gear box needs zinc if your recommending diesel how about T6 5w40 or mobil Ow40 or no? I have on hand is why I ask. I have a case of this oil but it's not syn? So the newer smokeless oils are not really better at lubrication or help not foul plugs?
 

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More modern oils are better in general. But the one you mentioned, MC-1 is one of the early low smoke oils. If you're at the right ratio and your carb is set right, you shouldn't foul plugs.

The gearbox doesn't necessarily need zinc, it needs protection. Zinc additives just happen to be a very commonly used type to provide that performance. If they aren't "resource conserving" oils they will probably work but wont' necessarily be guaranteed to be good for the clutch.

The JASO rating mentioned is kind of specific for motorcycle oils and guarantees wet clutch performance. If an oil is JASO wet clutch rated, it'll have a stamp like this on the back:

JASO-box.png


with the "MX" replaced by an "MA", "MA1", or "MA2"
 
I just want the best bang for the buck 2 stroke oil thats readily available did you see the oil i have? What can i get locally wm or meijers or should i go to a motorcycle shop and buy 2 stroke oil? As far as the crankcase does WM or meijers have anything for the gearbox?
 
As far as the crankcase does WM or meijers have anything for the gearbox?

What viscosity does the manual call out to use in the gearbox? If it can use 10W-40 I'd use Valvoline 10W-40 motorcycle oil (JASO rated) in the gearbox. Walmart usually carries it at ~$4.50/qt.
 
They used to recommend SAE30....these days they say 10W-30. Straight 30 would be shear proof in a gearbox, no change in shift feel with use. They say a syn 10W-30 is the same as a mono these days anyway.
 
gearbox says 10w40 yamalube is recommended. I Have cases of sae 30 QS but would buy the valvoline jaso at WM if its better? I also have a case of the marathon tc3 in the pic above should i use this or jaso fd as was recommended? what is a good brand thats available at WM or meijers?
 
gearbox says 10w40 yamalube is recommended. I Have cases of sae 30 QS but would buy the valvoline jaso at WM if its better? I also have a case of the marathon tc3 in the pic above should i use this or jaso fd as was recommended? what is a good brand thats available at WM or meijers?

A YZ250 can't take more than a couple quarts in the transmission I'd think. If it calls for 10W-40 then I'd go with the Valvoline 10W-40 at Walmart for around $4.50/qt.

Valvoline 10W-40 MC Oil (front).jpg
Valvoline 10W-40 MC Oil (back).jpg
 
gearbox says 10w40 yamalube is recommended. I Have cases of sae 30 QS but would buy the valvoline jaso at WM if its better? I also have a case of the marathon tc3 in the pic above should i use this or jaso fd as was recommended? what is a good brand thats available at WM or meijers?

If you have cases of 30 QS I would use that. One bottle of TCW3 won't hurt the engine, but you should switch to something better after.
 
ok thanks i got the bike for a steal i may as well try to preserve it what is the best 2 stroke i can get at WM and is that good enough or should i go to the a motorcycle place and buy what? gearbox calls for 1.5 liters that seems like a lot.
 
Give us the list of the 2T oils available at your WM that we can tell you the best one or if you need to go online/moto shop.
 
they just have basic 2 stroke oil they show castrol go online which is made for bikes i will have to look for it when i go.It sounds promising its not synthetic but is JASO
 
they just have basic 2 stroke oil they show castrol go online which is made for bikes i will have to look for it when i go.It sounds promising its not synthetic but is JASO
 
Castrol go 2t is certified JASO FB and is an excellent oil for air cooled application. I have personally tested Castrol 2t in one of my Yamaha RD400 and it worked great.
 
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