I am having a bit of a problem shifting gears.

It goes up and down the transmission OK with the engine not running, but takes some force on the lever and some high revs to get it to shift with the motor running, especialy 1st to second.

I have checked the clutch for adjustment and oil level and that seems OK.

I have had similar things on other bikes after a lay up or rebuild and the box starts stiff but soon gets slick after the motor has run abit, but this feels much harder and the gears engage with a bang.

This bike has been stood for quite some time prior to me buying it, so I dont know how it was before it was put into storage.

Do you think it will get better with some use, or does the transmission need pulling out for inspection. Cant think why it would be so different with the engine running, and slick with it off.
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Russ

MC21SP

First thing to do would be to change the oil, especially if you don't know when it was last done. Also check the gear change linkages, I know that caffeinejoe90 had some problems changing gear, but it was easily fixed. I'm sure he'll make a post if he sees this thread.

There is some play in the gear change arm part of the linkage, which I was thinking of modifing as I hate play anywhere it shouldnt be.

But a replacement part would be easier. Wont be buying new after checking how much they are from Lings.

I'll see what caffeinejoe90 has to say before the tools come out.

Cheers
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Russ

MC21SP

My first thoughts are that the gearbox has been rebuilt incorrectly at some point.
Maybe a thrust washer or two in the wrong place, or missing even? This could possibly cause some binding of the gear cluster when the engine is running. The primary drive gears are helical cut, maybe something is amiss there, causing some side thrust under load?
If it was me, I'd whip to box out and check that it's been assembled correctly.
Last time I checked one I used the parts manual to check the position of the various components.
You need to get the thrust washers the right way round too. The rounded edges from where they've been punched out need to face the gear. The sharp edge should face the circlip.
One thing worth checking is the seating of the spring for the selector drum positioning arm. It has a roller that sits in the indents to hold the drum in position.
When refitting the cassette, you need to make sure you push the rear end of the spring into its seat on the crankcase. If you don`t do this it sits between the mating faces of the cassette mounting plate and the crankcase. This distorts the plate, in turn, loading and binding the shafts and making the gearbox very stiff and hard to operate.
I`d check this first.
Sorry for the essay!

Thanks for the essay, thats helped focus my thoughts.

You are confirming what I was dreading, that something isnt quite right in the way it has been put together.

I suspect something internal as opposed to the selector, due to it only being tight when the motor runs.

I am a bit gutted realy, as I was ready to take it down for an MoT after rebuilding nearly everything else on the bike. The transmission wasnt even on my radar for ant attention due to the bullit proof reputation they have.
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Russ

MC21SP

I was just throwing my assumptions about. You might find it's something completely different and easy to remedy.
I do think the only way to be sure is to pull the gearbox out.
It doesn't take that long to do. Obviously have to drain the water and oil. Take the sprocket off, gear change linkage, etc.
Hopefully you'll find the problem quite easily.

Thanks for your comments.

I'll have a look whats going on in there over the weekend hopefully.
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Russ

MC21SP

Pulled the box out and found the following:-

The tops of the teeth of the water pump gear were floating around in the oil, but none in the actual gear box. These had been sheared off but the pump still works ok when the gear is engaged properly.

No thrust washer on the water pump shaft, no suprises there.

The circlip on the selector shaft wasnt located in its groove, making the shaft have a lot of lateral float.

All thrust washers and circlips in the box were present and correct with nothing obviously amiss in there.

The box isnt back in the bike while I wait for parts, so I dont know if it is fixed yet, but the bits of plastic sheared from the pump and the selector shaft circlip may have been causing some problems.

One small thing that I am mad with myself is I broke one of the webs between the tangs on the clutch basket when my locking tool slipped. It took two of us to remove the nut, one holding the locking tool and the other swinging on a breaker bar. That nut must have been put on by a gorilla, because it took one to get it off, the rattle gun wouldnt touch it.

Do you think that the basket is still OK to use as the web couldnt be providing any real strength to the basket?

Should get a chance at the weekend to put every thing back together, so I will know then if things have improved.
_________________
Russ

MC21SP