Is conventional oil really quieter in a TwinCam than a full synthetic? If so, how much? I'm currently using synthetic and my brother uses conventional. At cold start-up there is a considerable difference in valve train noise. Mine is much noisier. Mine is an '07 and his is an '09 and both have between 10,000 and 13,000 miles. There is a noise difference when the motors are hot too. Is it possible the noise is due just to the different oils?

 

I don't know why dino is quieter than syn oil, but it is. My 09 RG had a loud tick at 2500 to 2800 rpm when hot. This was when I used Mobil 1 20/50. I switched back to HD 360 and things got a lot quieter. I can tell a difference at all engine speeds. Im sure syn can handle more heat and stay in the bike longer, but I change my oil every 2500 mile anyway. I will not go back to syn. I ride with to many guys with 40000 all the way to 124000miles that have never seen a drop of syn. All this crap about cooler running engines. I didn't see any rise in oil temp when I changed back. Temps run about 220 to 232 degs. and thats what I saw when I used Mobil1. Quieter running and about half the price, what a deal. Now that said if was going to leave it in for 5000 miles I would put up with the tick-tick.

 

This question comes up every now and then, but here's my take on it. It depends whether you have a windshield or not, have a stock exhaust or not, what general overall shape your motor is in, whether it has a stock cam or aftermarket cam. Lifters that may not pump up, and hold pressure when run for a few minutes may cause valve train noise. Whether you ride with a half helmet or a full face helmet. Some guys insist their bike is quieter with dino oil over synthetic, and there's those that say synthetic is quieter then dino. It might have been the guy that built your motor, first day on the job. That's what I consider when two identical bikes go at it and one is just a bit quicker. And lastly I guess it depends how good your hearing is.,,

 

Comparing two different motors to each other, IMO, is almost pointless. Every motor is different. Me and a buddy bought our bikes on the same day and his motor had a lot more valve train noise from day one. In my personal experience my motor was more quite with syn, but the next guy may tell you different. Either way I would go with the syn.

 

I wouldn't think that an engine would be noiser or quietier if the oil was or was not a synthetic.

I think it would have be be more releated to the viscosity of the oil used.

Although both oils may be a 20w50, one oil may be blended to higher viscosity in the SAE 50 range.

A thicker oil damps more noise.

 

I switched from 20/50 dino oil, to 20/60 synthetic, and my engine did get noiser. I don't know why it happened, but I still feel better running the synthetic.

 

Syn oils transmit more mechanical noise in many enignes. This is not an indication of engine wear.