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HOW2: Overhaul Clutch (Small Honda's +)

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Brolly Dolly

Joined: 23 May 2010
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PostPosted: 19:26 - 14 May 2011    Post subject: HOW2: Overhaul Clutch (Small Honda's +) Reply with quote

Written a couple of these How2's now: -
HOW2: change Oil & CLean strainer (Small Honda's +)
HOW2: Make a Cornflake Paket Gasket!
But it was wanting to overhaul the clutch that prompted me doing both, because to get at the clutch you have to drain the oil and take the primary drive cover off, same as to get at the oil strainer. So, wont go over all that again. If you need to do your clutch, I recommend checking your oil strainer at the same time, so follow the instructions in that How2, then do this when you see the clutch!

Clutch in my CB125 Super Dream, seems pretty common to a lot of small Honda's. Certainly the twins that use the 'benley' bottom end, and the CG125, and its derivatives and many, many copies. So this should help if you have a City fly or an XR125, or a CB100 or something, too.

Clutches in little bikes, Tef tells me, get worked hard, especially so in learner legals, and a lot of clutch problems, aren't a case of simple adjustment, but the clutch being worn out. But the good news is that it really isn';t all that scary to fix, and its not that expensive, either. Needs five friction plates and four springs, which I got of e-bay for under 20.

Only difficult bit is, you need a special tool. Honda Service tool, 07716-0020100, a socket for a slotted nut, on the end of the shaft in the middle of the clutch. Helpfully the Haynes Manual suggests you can make one..... I got Tef to do that bit!
Right, THIS is the Clutch! so follow directions in HOW2: change Oil & CLean strainer (Small Honda's +), as far as getting ready to put the cover back on, and then do this lot first!

Bit I'm pointing to with my finger is the friction plates, the bit I'm pointing at with the cable tie, the springs, which we are going to replace.

Here's the brand new ones off e-bay, and you ought to soak the new clutch plates in clean engine oil over night before fitting them.

So, having followed the How2 for doing the oil strainer, you'll have drained the oil and taken the primary drive cover off, cleaned the oil strainer and prepared the casing faces for a new gasket, ready to go back together.

First thing to do on the clutch is to check the release lever in the cover. The little lever on the shaft pushed the pin poking out the middle of the clutch, so check it for wear or damage, and make sure its tight on the shaft, and can move freely.

Tef says that when these bikes get dropped, its not uncommon for the brake lever to get bashed into the case, and that can bend it, making it hard to turn the shaft or get full travel on it.

Next remove the pin from the middle of the clutch.

The Haynes now says to remove the sleeve from the middle, and the bearing it sits in, so you can undo the nut with the funny spanner. Only trouble is, while the Haynes gives a nice picture of how to make the spanner, it doesn't tell you how BIG to make it!
So we had to take the plate off the front of the clutch, first, to get at it and find out!

There's four 10mm bolts, each holding down a spring. I tried undoing one at a time, but the plate kept tilting as I did, making it hard, because they Jammed. Tef kept telling me to undo them evenly doing half a turn at a time on opposite bolts. Bluddy NAG! The bolts turned OK for me, but Tef said if they dont, use the same trick we did to unde the nut on the shaft and put the engine in a high gear and hold the brake pedal down to lock the transmission & hold it still.

with that out the way, I could get at and remove the clutch springs.

and finally see this nadgery nut!
MrHaynes wrote:
This tool is available as Honda Service tool, 07716-0020100. If this is not available, fabricate a suitable tool from a length of thick walled tubing. Refer to the accompanying illustration for details, cutting away the segments shown with a hacksaw to leave four tangs.

Tef didn't have any thick walled tube apart from a bit of old Range rover exhaust pipe that was a lot too big, and he had doubts that it would have been strong enough anyway.

However, he does have a big box of old sockets, he keeps to use for drifts and things, and a 3/4" socket was just the right diameter. So he used a magic marker to draw the shape we needed, then because the socket was hardened tool steel, cut it with an angle grinder, rather than a hacksaw to make this.

Its not exactly pretty, but it worked!

He started by cutting out some metal, then tried it for size, then just kept taking a bit of metal off each tang until it fitted. took him about wenty minutes in all, and made from scrap, didn't cost much either.

With the bike in a high gear and his foot on the brake to lock the transmission and hence teh shaft the nuts on the end of, Tef manfully loosened off the slotted nut for me...

which I then took off, along with the washers behind it.

Then I could take the clutch 'pack' out of the drum.

Time to take the 'pack' apart.

There are five friction plates, and between them four plain plates, with the flange on the clutch hub one end, and a master plate at the other.

They all simply slide apart, and then all you have to do is take out the old friction plates and put it all back together with the new ones instead.

NOW! They Haynes says that 'assembly is the reverse of dissassembly'... only we did it 'wrong' didn't we because we didn't know how big to make that spanner! So we put it back together wrong too! It WORKS but its a bit fiddly, and the master plate kept falling off the back of the clutch hub, so we had to keep taking it apart and putting it back toegther again other wise the plates didn't get pushed together and the clutch didn't work!
It was easier to get the slotted nut back on though, but the way the Haynes says, putting the springs and plate back onto the hub to hold the plates and hub together before fitting it back in the drum, is probably easier, IF you can get your imporvised slotted nut socket through the bearing home in the middle of the plate.

So doing it the awkward way.... Plate pack back in teh drum

slotted nut back on & tef tightens it back up again

New Springs fitted to the hub

The 'old' springs were a heck of a lot shorter than the new ones. Tef says that they relax and loose thier strength over time, which is one of teh reasons old clutches dont work so well.

Then the plate on over the springs

Sleeve & bearing in the middle, and the pin down the middle

And its all looking like it was to begin with, only it should work really well now.....

BUT if you have done it this way.... before you slap the cover on and fill the engine with oil, just do a trail fit of teh case without the gasket and just a gew case screws and make sure that that master plate isn't jammed!

And that's it!

As HOW2: change Oil & CLean strainer (Small Honda's +), a new (or cornflake Paket made) gasket can be fitted, and teh cover bolted back on.
Real bikers build their own Renovated and Riding a 1986 Honda CB125TD-C called the Pup. Full Licence
13/09/2012, 1994 Moto Guzzi 750 Strada
Can-Do Girl that does spanners TOO!
TheSmiler: binning it is better than going around a roundabout the wrong way
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World Chat Champion

Joined: 31 Mar 2011
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PostPosted: 22:20 - 14 May 2011    Post subject: Reply with quote

Very nice guide, it does look like my NSR 125 inside. I am lacking the clutch holding tool (is that what you created? I wasn't sure on that bit), so I don't dare to go into the clutch system, for fear of breaking it beyond repair.

Definitely helps to see the steps though, well done!
Ted : "Maybe he's agoraphobic."
Dougal : "Jack scared of fighting? I don't think so, Ted."
Now : Yamaha R6 Previous : 99 Honda Hornet, 01 NSR125R
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World Chat Champion

Joined: 06 Feb 2010
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PostPosted: 23:59 - 14 May 2011    Post subject: Reply with quote

Well played!
looks pretty much the same as the NSR, the bit you fabricated was for the castle nut...
Will have to get around to making one myself, 15 bucks my nadgers!

I think I will have to have a stab at fabricating a fly wheel puller for the NSR to as i dont fancy paying through the arse for one and the flywheel is on there so tight (I spent about 3 days trying to get it off, eventually strapped it to the back of the bike (spare engine), <30 seconds with the tool).

Best regards

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World Chat Champion

Joined: 18 May 2007
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PostPosted: 17:35 - 15 May 2011    Post subject: Reply with quote

there is no "clutch holding tool" basically you put the bike in gear which physically connects the clutch basket (the bit you dont want to turn) to the rear wheel. then have someone hold on the rear brake while you undo the nut Thumbs Up

also, it works better in a high gear because............ well, trust me, it does. HTH
killa wrote: Im an ass man myself
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Spanner Monkey

Joined: 12 Jan 2011
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PostPosted: 18:18 - 15 May 2011    Post subject: Reply with quote

Thanks for this its a great help as I was thinking of of doing this with the CG at some point soon Thumbs Up
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