Best motor oil for 1978 CB 750 SS with high mileage living in a hot big city?

Ok everyone the site is 2 for 2 with some excellent answers so here is a new one. I have heard the following recommendations some my own鈥?synthetic blend / straight weight oil / and standard grade 20-50 which is in it now. I go against straight synthetic for this bike as I believe oil devoid of paraffin and this motor would not do well together as the motor has no idea that synthetic oil even exists. I am looking for a cooler motor / better shifting and easier clutch pull when the bike is hot.


Thanks!Best motor oil for 1978 CB 750 SS with high mileage living in a hot big city?
I used to work for a Harley Dealership as a technician. Personally, I always went with dealer brand oil for the the bike. The engineers know what ur bike needs and has the manufature put the additives that keep that bike running forever. I've never liked straight synthetic if u have alot of miles on it, u better stick with conventional. If not, u will get oil blow-by. Which is when the oil is so thin it blows by the piston and gets into the combustion chamber.





Back in the 70's When they built a engine it had alot more ';slop'; in it then today's engines. back then if it was off by 100th of an inch ';who cares'; thats as good as they could read. Now, we go down to the 1,000th of an ich, sometimes 10,000 of an inch. Thats why today's engines can rev alot higher.


So, which that said, even a synthetic blend can get so thin that it will be in areas it shouldn't be on a 70's engine. So if u want the longest running life out of ur engine, pull out the service manual see what it requires and use it.


Also, if ur clutch is hard to pull, get ur clutch serviced. Thats normally a sign of a worn throwout bearing or the clutch basket notches are worn out and allowing the clutch disc's to bind.Best motor oil for 1978 CB 750 SS with high mileage living in a hot big city?
My friend the best Honda brand. But you'll just need to change it out about every thousand. Some of the things your trying to counter with oil can only come from replacing old parts with new ones. Your old CB may not fit a latter concept of Smooth running as technology was much different then.


The CB is a great bike excepting her nuances is part riding a classic bike! Have fun!
I've owned, built, rebuilt CB750. Your right about the synthectic. I've always used regular 20-50 for those motors. Never had one fail. AND never EVER use that slick 50 crap. It leaves teflon deposits in you sump that if enough build up will clog you oil screen and passages (which are alot smaller on a motorcycle engine.


For the clutch you need to upgrade from the stock unit. Those never lasted very well on the 750. They really were underdesigned for the power of the engine at the time.
Have you considered using the standard oil %26amp; adding something like ';slick50'; these additives reduce friction in the motor %26amp; therefore heat... they are compatable with wet clutches as the additive only sticks to the metal surfaces...





If you go on the net %26amp; look it seems that the PTFE in slick50 will coat the internals of the engine... but from the information avaliable I would only use it on an engine that has very high milage.. the consenses of opinion seems to be that SYNTHETIC oil is of far more benefit ,, even for old engines..
lucas
I rode an old GS-500 with 50000km on it. When I first changed the oil I wanted to use quality synthetic oil, but was advised to continue to use a standard grade mineral oil. This was because the mineral oil that the bike had previously been running on leaves a mineral residue through out the motor and when synthetic oil is introduced it can dislodge these settlements of residue and therefore reduce the motors performance.





I'd recommend a quality standard mineral oil (that won't burn easterly with city riding). Synthetic oils are mainly for track bikes that run at top rpm's and for bikes that have been running of synthetics from the get-go.





Hope that helps:-)