Hi all. What type of oil would you recommend for my CB175. Would modern semi synthetic be OK or should I stick to mineral oil.
I'm glad I just stumbled across this post, I don't even have 200 miles on my rebuilt motor and i notice that the oil is really dirty. My dad also told me that he used Castrol 20/50 in these bikes at the Honda shop when these bikes were new, I can't use new Castrol because of the wet clutch issue so I have Walmart 20/50 in it right now. I'm gonna look into that silkolene stuff for the next oil change.I've been running mine on Silkolene Comp4 10/40 semisynth, changed every 500 miles, very black even at that low mileage. Engines seem to run OK on it, no oil burnt between changes. 4000 miles on one of the rebored engines now.
I think frequency of changes is the key thing. Back in the day, I used Castrol GTX 20/50 car oil, again changed at 500 mile intervals. That bike was still running fine when I traded it in with 22k miles on the clock. Thrashed unmercifully from stone cold in all weathers.
I use fully synth Castrol Power 1 in the Hornet, changed every 4k miles, comes out looking quite clean.