H-D and SYN3

[ICman]

Harley-Davidson has introduced their "new" SYN-3 synthetic oil (20W-50 only), which they say is good in both the engine and transmission (and primary in Big Twins). They previously warned owners against using synthetics for any service.

I have read reports that some Sportster owners have experienced increased vibration after switching to SYN3 in their transmission. Shifting and clutch operation are better, though. Some others report that Mobil 1 20W-50 (not approved by H-D) works just as well, or better, with no vibration.

My question: Can synthetic oil increase vibration?

 

[evelrod]

ICman---My son in law has used Mobil 1 15W-50 in his Harley with no problems besides the usual leaks. No mechanical problems, though. I might guess that HD did not recommend a synthetic because they didn't market one yet and now the say it's ok because THEY have one. If I can use Mobil 1 15W-50 in my race car (63 Mini Cooper) it will probably do fine in a Harley. Ask you question in the Automotive Lubricant Engineering forum. That's where the oil experts hang out.

Believe only half of what you see and none of what you hear.

Rod

 

[Blackjacks]

Evelrod,

If your son has an Evo motor in his Harley then it shouldn't leak oil. If its earlier than that then it will stop leaking when it runs out of oil.

The basic point about synthetics in HDs was that they are primarily roller bearing engines and require a "stickier" oil than a plain bearing engine such as your A-series Mini engine. This is to stop the rollers "skidding" on the races at start up. A specifically designed synthetic would obviously overcome this objection.

Incidentally, have you priced HD oil? Seems cheap enough to me.

As to the vibration issue I dont think that is likely to be an effect of the oil being synthetic, but seeing as it is of a lower viscosity it may be a psychological effect due to the engine sounding slightly different? Though it is possible that it could be an NVH problem related to the mass of the oil in the tank I suppose.