Everyone knows about the big ol' clunk you get when shifting into first at the start of the day. No biggie.
My problem is that when I shift into second, I get a grinding sound/feeling through the shifter before it locks into second gear. 3-5 are no problem. Am I getting too high in first, causing all the gearing to spin on its own? Adjust the clutch? I just changed the oil (Castrol 10W40 Dinosaur Bones) and it still happens.
I also noticed that even when the clutch is completely disengaged (lever pulled in), the rear wheel spins when up on the centre stand and I can't stop it with my hand. It does not spin when in neutral. I know this would be remedied by adjusting my clutch. Maybe it is because the oil is just cold? I last noticed this when I had just started up the bike without taking it for a ride to warm up the oil. I should check it again with a warm engine, yes?
Are these issues related?
The clutches in these bikes are wet clutches: even when the engine is warmed up and the bike is on the stand, the rear wheel will spin when it is in gear with the clutch pulled in. The plates never actually disengage, like dry clutches do. Rather, when the spring pressure is removed they let the oil from the little grooves between the corks get out, which lubes the face of the cork-steel contact surface. There are also tiny dimples on the steel plates that hold some oil to help the quickness of this disengagement, to improve shifting speed. When the clutch is released, the oil must slip into the dimples and those grooves between the cork, or out of the way altogether, to engage the clutch again.
If you have a CB750, don't use 10w40 oil except in cool weather (less than 20 degrees C or 50 degrees F). The oil gets too thin in the bearings of the crank and the gear splines, which makes the crank wear faster and the gearbox stiff to shift.
If the 2nd gear fork is a little bit bent, or if the dogs on the C5 gear are rounded from too much shifting with too light oils (and the resulting drag which reduces dog depth penetration to the C2 gear), the shift into 2nd gear can be clatter-y like a ratchet until it engages. If it stays in gear under power, you're in good shape: if it tries to jump out of 2nd gear under heavy throttle, then maybe consider taking the gearbox out next winter and have APE fix up the C2-C5 gear dogs/slots for you: this costs about $300 with (US) shipping both ways. In the meantime, if it becomes a nuisance with jumping out of 2nd, just do like many other bikes that suffer this: wind up 1st gear a little more, then double-shift to 3rd. I know at least one chopper rider who did this for many years (12, to be exact) until he sent me his engine.
