Reluctant to change up after 3rd or 4th gear.

[Kawasaki Jimbo]

60 miles into a 75 mile journey I noticed my R1 (5PW, 2003) was becoming intermittently reluctant to change up after 3rd or 4th gear. The gear lever moved up but that's all that happened, although at other times 4th to 5th to 6th was readily available. 1st, 2nd and 3rd were absolutely fine, and changing down from any gear was fine too.

Rolling checks on arrival at my destination, engine off and with the bike in 1st confirmed that the clutch biting point is where it should be in terms of lever throw. Attempts at clutchless changes on the road hadn't made a difference. The engine oil is only 1000 miles old and the level is good.

On my return journey I think it helped if I applied gentle downward pressure before changing up, as if to seat the gear lever, although I stopped that when I accidentally changed down and nearly launched myself over the front. The drive chain is on the slack side of the specification (where I like it) although I might tighten it up a little to see if that helps.

I'm worried that this is the start of something serious. Has anyone heard of this issue before? Thoughts please.

[doggone]

Bent selector(s) maybe. Not too serious as gearboxes go.
They are like a fork which pushes cogs to and fro.

[Nobby the Bastard]

I'd be looking at the spring that returns the mechanism back to the centre. Either way you'll be stripping then entire engine.
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trevor saxe-coburg-gotha:"Remember this simple rule - scooters are for men who like to feel the breeze on their huge, flapping cunt lips."
Sprint ST 1050

[Kentol750]

+1for selector... easy fix....massive job.
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Some bikes.

[Ste]

Sell the bike?

[Kawasaki Jimbo]

Damn! The springs and levers behind the gearchange mechanism cover look alright so it does seem likely to be a damaged selector fork and an engine-out job. I don't understand why this has happened.

[MarJay]

I've had this before. It's usually crud or lack of lubrication on the shift linkage and/or poor chain adjustment.

Adjust your chain, and thorougly lube your shift linkage at ALL the ball joints.

Then, and only then if it still seems to have an issue, you can start hitting the panic buttons a bit.
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British beauty: Triumph Street Triple R; Loony stroker: KR1S; Track fun: GSXR750 L1; Commuter Missile: GSX-S1000F
Remember kids, bikes aren't like lego. You can't easily take a part from one bike and then fit it to another.

[Kawasaki Jimbo]

Luckily, it looks like Marjay was right. Upon reassembly of the gear shift mechanism I greased the rose joints at each end of the gear shift lever and the problem has gone. It still seems odd that it only affected the upper gears, so I'm wary. Back on the road though!