OK, I have a 2007 Street Bob, 17,500 miles maintenance has been on time and on the last oil change my mechanic suggested Mobil 1 synthetic, I did this. I now seem to have engine chatter, top end noise if you will. I was told by my mechanic this is normal, is it??? Sounds like valve noise. Anyone have the same noisey problem?

 

This may sound crazy, but check the air cleaner for tightness. I thought I heard unmistakable valve noise, but guess what it was? Someone on the forums suggested this, but I did not believe it til I held my right leg against the A/C. Sometimes the worst case scenario ain't what it turns out to be!

 

Same issue, same conditions (after switching to synthetic at 1k miles). Was also told that it is "normal" and no problems over the past 15k miles. I think the syn thins out a little more at temps compared to the conventional which results in less sound dampening of rocker arm/valve contact, but I'm not entirely sure about that. Gives me more motivation to keep my knees stuck to the tank instead of dangling in the wind.

 

Yea I switched to sinthetic on my last oil change and the noise is louder. I'm going to switch back this weekend.

 

can you switch back to regular oil? I was told no.

 

Thanks, I`ll check it.

 

You can also use an oil stabilizer like Lucas for synthetic oil. It works for me.

 

I see no reason why not. Lots of 'urban myths' when it comes to syn. It's oil. It's just better oil. Won't break down like dino oil.

Engine noise on a Harley?? What's the world coming to? Maybe the syn oil is cleaning up some of the crap in the top end of your motor. It's pretty high in detergents.

Did you use 20W-50 V-Twin? Hope so. Probably did.

Just drive it. Some of it might be the fact that whenever you do something new to something, you're more aware, you're looking for noises, etc. If you think the syn broke loose a bunch of crapola (doubtful) in the motor, change the filter and top it off.

I wouldn't get too worried about it right now. I'll bet you that in a few hundred miles, your engine noises go away. Maybe sooner. Don't know why, but even on cars, fresh syn in a motor can cause slight noises in the valve train for a few miles. I know it did in my old Bronco every time I put fresh syn it -- For the last 200,000 miles.

It does in my newer cars, too. Maybe it'll stop in the next three hundred thousand miles or so.

So, IMO, you're not experiencing anything unusual. Just my opinion but one I've formed after changing syn oil about a hundred times. Or more.

 

Yes, you can go back and forth between synthetic and conventional oils. Some oils (like castrol) even mix synthetic elements with the conventional oil.

 

I wonder if the small amount of extra noise isn't the synth lubricating the parts better, they move freer and as such they have increased noise. I dunno, I use amsoil and my bike is pretty darn quiet in regards to the valvetrain.