Does anybody have any experience of matching a late 50's ES2 engine with a dolls head gearbox in a rigid ES2 frame? I have done this and very early on I had to get over the issue of the engine sprocket and clutch not lining up. I finally got over this by firstly getting a new sprocket that held the primary chain closer to the engine, and also cutting down a spare sprocket to create a spacer that holds out the clutch slightly further than usual (see image).I thought that was that, BUT now I have the bike running I'm having issues with the clutch dragging ever so slightly. I've been through all the usual dragging clutch remedies including adjusting the rod and cable correctly, checking that the clutch plates and basket are clean and not warn and not warped at all. I've tried a slightly longer rod, tried releasing the clutch outer housing on all 3 screws, and tried looseningâ the primary chain a bit which did help a little. I even tried bending an old clutch lever to allow for a longer pull on the handlebar. I've also checked the end float on the gearbox shaft which seems perfect. The gearbox lower bolt fits snugly so the hole is not warn, and I have the correct washer in place on the top bolt. All this with no joy as it still drags. When I kick the engine over with the clutch pulled in, the clutch spins fairly freely for a few spins, but every now and then (every 5 kicks or so) the clutch catches slightly (this being enough to cause dragging when the engine is running)Having ruled out all the obvious I'm left thinking it may be down to my spacer, but I'm fairly sure the clutch is spinning true, so can't see how that would affect it.Any experience anyoneâ has of marrying up a dolls head gearbox with a later engine would be welcome as I want to get this sorted so I can take the bike on it's first proper ride.
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Hi Aled If the engine and…
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Thanks for the feedback No…
Thanks for the feedback Norm,
The sleeve gear bearing is new, so I can rule that out. The clutch plates are all flat (checked on an flat metal engineering surface), and clean with no visible groves on the basket anywhere.
The clutch has just come out of another bike where it worked fine, so I'm fairly confident it's in good running order. But as you say, something is causing the plates to catch each other, I just need to work out why.
I will check all the plates and basket again this weekend.
Aled
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I'm guessing you know tha…
I'm guessing you know that the engine sprockets come in 3 different offsets? And a new RGM clutch spider might pull the clutch out a bit further, it did on mine. Both could help aligning the clutch if that still is your problem.
Dan
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Aled You are on the right…
Aled
You are on the right track with all your thoughts on the subject so I hope my comments were acceptable. If you have no grooving then I would point the finger at the solid plates being out of true; just 0.005" will make them slip and drag.
Also if you have a newly build clutch, even with old fibre inserts, it needs an hour or so to settle down. Make sure you oil it with a light oil when assembled. Even when perfect the odd dragging and noisy gear engagement is 'normal', so don't expect modern behaviours!
Norm
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Hi Aled
If the engine and clutch sprocket teeth are 'reasonably' in line then stop worrying about them. Use a straight edge across the teeth - I doubt that one can detect 1/16" of misalignment and the chains probably won't notice 1/8". Bikes run with 1/4" error, but that is not good.
The clutch has a set of plates driven by the clutch drum, alternating with a set of plates driven by the gearbox splines. All the plates can (should) float about in their slots. If the clutch is dragging then these plates are being forced into each other by something other than the spring pressure plate (assuming you are successfully keeping the pressure plate away).
Serious misalignment can cause this, as can a moving gearbox or worn sleeve gear bearing. But a common problem is distorted plates (in certain configurations they make a bigger stack) and wear grooves in the sleeve gear splines or basket splines. If there are wear grooves big enough the plates will try and nestle into those and deflect into each other. It is usually the soft basket splines rather than the harder sleeve gear. If you find that there is little such wear then get a new set of plates (RGM) - it is often the plain ones that distort; you can sometimes measure this on an engineering surface.
Norm