Clutch used to pull to 13k+ without a hitch and now with an oil change it slips at 12k. I used regular Pennzoil 10w30 (or 40...?).

Oil the culprit or unusual coincidence?

 

Is this the same type of oil you were using before the oil change?

 

Probably overfilled it. Check your oil level with the bike on the ground, and level (off the stand).

 

I'll check the level, thanks. Didn't know that could cause it. And I've herard conflicting info about how to check it...bike straight up and down as well as bike on stand (sinceon the standmakes the dipstick straight up and down).

Unsure of the previous oil, this was my first change since the previous owner had it. I didn;t know if regular car oil was safe for bikes (but I read on here most people use it).

 

Well, it makes it straight up and down, but that's because it's the only way you can get from the clutch cover to the oil pan.

You should check the oil level like it would be when it's actually running. Not to mention the oil pickup is one the bottom of the pan, so there's absolutely no reason to overill it (for lean angle).

 

Get that Pennzoil sheee-attt out of your bike,especially if it's 10w-30.10w-40 Honda GN4 isn't that expensive.