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A clutch isn't just an on off switch between the engine and gearbox, it has to work well. Drag and slip has to eradicated, and the leaver operation has to be nice and easy, and it must last a reasonable amount of time before plate and bearing replacement. A well set up clutch can be operated with only one finger. There are some bad clutches out there, the Suzuki GS500e clutch worked well as you would expect, but it didn't come with a spare hand to operate it. To find out what Royal Enfield clutches are like you only have to view the Enfield forums, I bet most clutches designed 50+ years ago will have problems. The best clutch, as far as operation is concerned has to be a modern after market job such as a Bob Newbie. The other option is a belt drive. Not with out it's problems either, belts have been known to strip teeth at low revs, so a cush drive at the clutch and back wheel is defiantly recommended. |
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| I have given up trying to do the clutch on the cheap, converting existing clutch parts to make do and save money. I think I have looked at all the angles, but come up with the same answer, it's just not worth it. A codge job will be a constant source of frustration, if it doesn't actually break down it would be constantly on my mind that it would. So I have decided to bite the bullet and buy a Bob Newby belt clutch. I didn't want to spend anywhere near that much, but I have bought so many clutches trying to get it done on the cheap, that if I sell them it will easily pay for the Bob Newby clutch. What a waist of time. I know better now, and I will plan my next bike better, ie. a narrower v twin engine will eliminate the need for an extended gearbox shaft, which in turn will enable me to use any normal gearbox and clutch combination, a frame with out a gearbox down tube will mean I can use any set of chain cases as the gearbox and engine would be closer together. |
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| Converting the keyway taper Harley Davidson clutch to a 5 spline Royal Enfield clutch. | |
| The clutch centre has plenty of meat to make modifications due to the very large bearing around it. Not a sealed bearing, in fact you push each bearing in to the recess, so not a dry clutch then! Boy did I get it wrong! The centre is steel so it can be welded up with the modified Enfield centre as picture 4 above. It came with an external bearing for the outer reach of the gearbox main shaft, as the shaft is extra long it will need some extra support. Note this belt and pulley system is imperial not metric! If I'm to use a wet clutch it may as well be a cheep Enfield job not a £160 Harley. Back to the drawing board. |
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This is a Bob Newby clutch. He makes clutches for many different bikes, unfortunately I've not seen one second hand. I think you'll agree it's a smart bit of kit. It's a better way of getting the job done than messing around with conversion projects. Here's his website:
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| Clutch: NEB Dry Belt: 21-1-07 ebay £181 with plates / around £500 new |
Search for Grasstrack clutch |
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| The pulley is 78 tooth, 10 more than a Norton Commando. I will now need to get a big engine pulley to match, this means there is more belt surface area on the engine pulley. More surface area less chance of the belt stripping it's teeth. |
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| Clutch: Royal Enfield India: 15-11-06 eBay £20 / £100 new |
Search for Enfield clutch |
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5 speed clutches have a different clutch centre to the 4 speed clutches. So get the right one for your box. Bad design, bad quality metal and bad engineering. The clutch centre and body are a total right off. Enfield clutch's are all basically the same, 2, 4 and now 5 plate. There were two designs of centre (excluding scissor clutch), cush drive and non cush drive. When changing from neutral to first gear you may find that the gear box makes a loud crack as the gears are taking up the shock, this is due to the oil on the clutch plates causing a vacuum and sticking the plates together. The plates have slots in them to help break the vacuum and start the clutch spinning, but a cush drive or belt drive will save a lot of shock through the main shaft and in to your gearbox. |
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| Clutch: Greeves 5 spline: Sold on ebay for £303.50 |
Search for Greeves clutch |
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| This is a Greeves clutch made for the Greeves competition bikes using Albion gearboxes (same
make as Royal Enfield gearboxes) of
the 60's and 70's.
Take a look at the bearing race on the pic on the right, simply held in by a cerclip, tap out when worn and replace. Easy, no messing, good sound design. Build it like a panzer!!
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| Clutch: Norton Commando: 25-12-06 eBay £86 |
Search for Norton clutch |
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| Like
the Greeves clutch above the Commando clutch has a bearing
race. Enfield owners have in the past modified the
commando clutch for use with an Enfield as they are way
better. Note the bronze friction plates, also available is a belt drive clutch.
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| Clutch: BSA A10: 30-10-05 eBay £36. Chain £4.99 |
Search for BSA clutch |
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| Friction pads are cork on old clutches. I didn't like the look of the open bearings although it was way better than the Royal Enfield India clutch. The bsa design was old but well engineered, but no match for an enclosed bearing race, this is the 21st century after all. |
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| Clutch: Triumph: eBay £20 |
Search for Triumph clutch |
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| This type of clutch is to be avoided, it uses a bush where others would use bearings. Basically the same design as the Enfield, it would be ok in the 50's but that was half a century ago. |
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