Car oil in bike

I've heard both sides from everyone about the usage of car oil in motorcycles: Older bikes used regular car oil before synthetic and additives came around and should use regular car oil, synthetic is better, yadda yadda....you know...that whole thing

This is the best explanation I've read so far:

http://www.bikenomads.com/wiki/index.ph ... l_in_bikes

 

I used car oil once and the clutch started to slip…drained it out and replaced with bike oil and after about 100 miles the clutch stopped slipping. My 2 cents for what its worth.

 

never use synthetic car oil in ANY wet clutch system. the clutches will slip and in some cases chatter. i see it on the MX track with new riders all the time.

conventional dinosaur oil works fine. if you want synthetic, motorcycle specific synthetic oil is available in several different flavors, and does not cost too much especially considering how little the bike requires.

 

I use synthetic oil in both of my bikes. The Honda Shadow has Amzoil (motorcycle specific) in it and my 750 Yamaha has Royal Purple in it. No issues with the clutches slipping in either one. Most car oils are not made to be used with wet clutches and will cause them to slip because of friction modifiers that are added to them.

 

Agreed. We've had literally dozens of folks here post about clutch and/or starter clutch problems, and it ended up being nothing more than an inappropriate oil.

I like to run the recommended 20W40 in my 550s, and it's getting harder to find; I think Spectro is about the only manufacturer these days. Of conventional oil.

So I'm going to TRY Castrol ACT>EVO 4T Semi-Synthetic for motorcycles and see what happens. It's supposed to make clutches happy so we shall see... It's in there now, I haven't ridden or even started the bike except to circulate it right after the oil change in the fall.

Stay tuned.

 

I haven't worked out my oil selection for use when my rebuilt engine is finished, but my 30 year old engine is currently using Penrite HPR40 car oil (non friction modified). Great stuff for old engines.

 

If you read the article you'll see a lot about SF and SG service class oils that were the standard for automotive oils before catalytic converters and more stringent fuel mileage requirements.

Many motorcycles, including current ones, specify an SF service class oil.

Wal*Mart sells Accel 10w40 SF oil for $2.17/quart. It's in a black bottle with a red and yellow label that specifies for pre 1988 passenger cars. It's what I used in my XJ and it accounts for at least 90% of the oil I use in the shop.

I used to use a lot of Rotella (mineral and synthetic), but the fact that their reformulation carries an SM service class has scared me away from it.