harder shifting after riding for a while?

another issue with my CB125F, I recently noticed how after riding for around 20 minutes, gear shifts get a bit stiffer and not smooth (sometimes getting from N to first is impossible & 1 to second always goes to neutral despite how hard to kick).

*bike shifts super smooth just after starting an slowly gets stiffer

I used 5W-30 synthetic oil instead of 10w-30, could this be why? Or is the bike just inherently like so?

Thanks!

I would have thought 10/ 40 would be more appropriate . You might find some improvement if you tighten up the clutch cable a little bit .

I can't see it being the oil? 5-30 would be a better winter oil but it will still have the same flow rate as 10-30 when hot. Edit: Just looked it up, fastbob is right, 10-40 appears to be the correct oil for that bike.

just had a quick google, according to the first link, 10/30 in sub 15 centigrade temperatures and 10/40 for higher, so 10/30 in winter, 10/40 in summer

But I doubt it would make that much of a difference on selecting gear, I'd suggest that something in the gearbox is expanding more than it should when its warmed up so that's where my attention would be going, though change the oil to the correct grade as due course

ive just checked the owners manual and it said I should use 10W-30

if you sit at lights with the clutch pulled in and in gear does the bike creep a little?

you could also try this on a paddock/centre stand

forget oil

Start looking at clutch plates! I bet when they warm up they are expanding enough to cause friction

if you sit at lights with the clutch pulled in and in gear does the bike creep a little?

you could also try this on a paddock/centre stand

forget oil

Start looking at clutch plates! I bet when they warm up they are expanding enough to cause friction

I second this approach

if you sit at lights with the clutch pulled in and in gear does the bike creep a little?

you could also try this on a paddock/centre stand

forget oil

Start looking at clutch plates! I bet when they warm up they are expanding enough to cause friction

The bike does not creep, although wheels do rotate slowly on a paddock stand with the clutch pulled in?

if you sit at lights with the clutch pulled in and in gear does the bike creep a little?

you could also try this on a paddock/centre stand

forget oil

Start looking at clutch plates! I bet when they warm up they are expanding enough to cause friction

 

The bike does not creep, although wheels do rotate slowly on a paddock stand with the clutch pulled in?

I would pull the clutch apart and check for warpage but before that make sure the clutch is adjusted as per the manual

Sounds very much like oil that is too thin to me, not letting the gearbox bits slide around like they should. Though normally you would find it is difficult to find neutral, not to get first..

Some googling suggests the CB125F is air cooled, no way would I run 5w30 in it personally.. 10w40 all the way.

Sounds very much like oil that is too thin to me, not letting the gearbox bits slide around like they should. Though normally you would find it is difficult to find neutral, not to get first..

Some googling suggests the CB125F is air cooled, no way would I run 5w30 in it personally.. 10w40 all the way.

the book recommends 10w30 he put 5w30 in the only difference there is the viscosity when cold and not when hot

I'd like to see the page of this book, surely it recommends several different grades for different ambient temperatures? I'd be sticking with 10w40 regardless but I'm maverick like that

But that's for a CBF125 which many people also run on 10w40..

Is there no graph with the overlapping bars like this?

check chain adjustment .