Clutching at straws!

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uktom77
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Joined: Wed Sep 30, 2009 6:54 pm
Location: BUCKS UK

Clutching at straws!

Post by uktom77 »

18s 1952, Burman clutch. Has been ok for a year or two but now it really grinds especially when selecting 1st. I've had it apart, cleaned any slight burrs from the plates, re-adjusted as per book(s) and general forum wisdom. However it still grinds painfully when selecting 1st (not seamless into other gears but ok). I've been out with the outer CC off and adjusted while out but not satisfactorily. Am I missing something or do I need to delve into the (unknown for me) depths of the gearbox?? HELP........ all I want to do is ride the thing.


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dave16mct
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Location: LANCASHIRE UK

Re: Clutching at straws!

Post by dave16mct »

Probably the thrust dowel 35-3-4 on page 22 of the parts list.
http://archives.jampot.dk/book/Spares_l ... ingles.pdf
They can get well worn down and spoils your clutch action. Pull the outer gearbox cover and you can pull it out with the clutch lifter mechanism. I've seen them worn almost flat and difficult to see how they were working at all.
Cheers Dave.
uktom77
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Joined: Wed Sep 30, 2009 6:54 pm
Location: BUCKS UK

Re: Clutching at straws!

Post by uktom77 »

Thanks, I'll have a look in the box o' cogs called a gearbox.

I'm hoping I can get spares if I discover it's cream-crackered.


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Mick D
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Location: Aberdeenshire

Re: Clutching at straws!

Post by Mick D »

Hi

This is a classic symptom of a clutch dragging, (not fully releasing), which is a little confusing as you say you have correctly adjusted it. I would remove the primary chain case outer cover and observe what's happening when the engine is running, (keeping body and clothing parts well away from the moving bits).

I'd look to the adjustment of the pressure plate and it's springs.

Regards Mick
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1608
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Re: Clutching at straws!

Post by 1608 »

Warped and or sticking plates can also cause drag.
uktom77
Posts: 393
Joined: Wed Sep 30, 2009 6:54 pm
Location: BUCKS UK

Re: Clutching at straws!

Post by uktom77 »

Thanks both,

All of my adjusting and testing has been done with the outer dome off (incorrect for ‘52 but much more practical).

I have got it a little better (read bearable) by spend a little more time and fine adjustment at the cable/gearbox actuating arm end.

The thin plates were slightly warped but with burrs cleaned off it doesn't appear to affect separation when running.

Springs were all new when put in a year or so ago and I've played around with the pressure of plate.

It's going for an outing, one way or another, tonight - running repairs may be required........


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oldandsmelly
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Location: DEVON UK

Re: Clutching at straws!

Post by oldandsmelly »

A quick test to see if your clutch is dragging is to put the bike into first gear (engine not running!) and then pull the clutch in and try kicking it over. If all's well, almost no resistance will be felt once any initial clutch stickiness has freed. If it feels like you are having to work to kick it over, the clutch is dragging.

As mentioned previously, 99% of first gear crunchiness is caused by clutch drag. However, that last 1% can be due to the first gear itself wearing. I have a picture of one of my badly worn gears but it won't upload for reasons known to the wise. This is the layshaft first gear and is in front of you when the inner gearbox cover is removed and it can get very scrunged up as the corresponding dogs on the next gear in line tear into it probably after persistent grinding into first gear.
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