Oops... 5w30

Putting 5w30 oil in my XJ550 seemed like a good idea at the time what with how sluggish my bike was feeling with 20w50 in a crisp new Hampshire fall. However, looking at the posts in this forum it seems I've made a terrible mistake. As far as I can tell it's running smoother than it has all summer but I don't want to cause myself future headaches. How soon will I start noticing symptoms and what will they look like? My wet clutch was already slipping prior to changing the oil but now it's running great. Although to be honest that probably had more to do with replacing the rusted clutch cable and properly adjusting it. Look forward to your feedback.

P.S. - By cold I mean sub 40s

 

Your engine was made with much looser tolerances than modern engines that call for 5W30 oil. Don't wait for symptoms. Change the oil now. Your plain bearings and cylinder walls will thank you.

 

The low-friction additives of automotive oil that displays the "Sunburst" on the label, where you read "5w30",
soak into the clutch friction pucks - so get the oil out quick !!

 

First off: MOTORCYCLE OIL only. JASO-spec, motorcycle oil. Doesn't come in 5W30 AFAIK.

Secondly: Yamaha says 20W40 when it's warm out, 20W50 is fine; and 10W30 when it's cold out.

Motorcycle oil. 10W30. And do change it right away before it soaks into your clutch.

 

Darn... the worst part is I was thinking 10W30 when I bought it and didn't really notice until after I had put it in. I thought I was getting the Royal Purple MC oil but I was wrong. Prior to that I was running the 20w50 Lucas HP MC Oil which felt sluggish. The engine was a salvage that I unsiezed so the cylinder walls are already shot and probably the bearings too. I'm not too worried about the clutch plates as I have a spare set in the old engine so I'm considering just running it for a while to see what happens. The last time I used an automotive oil by mistake the impact was immediate and I'm just not seeing that with this. What's the worst reasonable scenario I can expect?

 

Blowing the motor up. You need at least a 10W-basis weight oil.

 

Especially if you thing the bearings are already worn or damaged. That 5w30 you have in there will not provide enough of a boundary layer to keep the hard parts from bumping. Since you say the engine feels sluggish with the recomended oil, and you already beleive it to be in need of a rebuild, my best advice is to shop for a replacement engine and park the bike before you end up dealing with an engine seizure at 65 MPH.

 

Well that's definitely a terrible situation. Let's avoid it. I already lost one engine... I don't want to lose another.

 

From all the other materials I've seen there seems to only be upsides to using a 5w30. It only flows at the thinner weight when cold allowing the oil to get more circulation quicker. As the engine warms up it is the same viscosity and has the same protective qualities. Is there something I'm missing here? Is it because the bikes operate at a higher RPM than an automobile engine?

 

The TOLERANCES in the motors today are vastly different than what they were in 1978 when your motor was designed.

Remember that 5W30 is 5W oil that "behaves like" 30W when it gets warm. IF it gets warm (cold weather and all that.) That, and I've never seen conventional 5W-anything motorcycle oil.

Or blow up another motor. Up to you. It may already be too late depending on how much and how hard you've been running it.