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Royal Enfield WD/CO engine strip


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After many hours, the Crank is trued to .002" each side and the end float is adjusted to .009". I'm happy with this. The two studs through the cheeks as well as the top crankcase studs need to be done up each time of checking end float. It's all very tedious as the main bearing rollers have to be collected and reassemble each time the cases are split. It's going back together again now. Ron 

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Rik, I spent 2 hours in Ainsley's workshop and saw the whole proper process of truing the crank. (He's done hundreds of them) It was a case of bumping the wheels in just the right places and squeezing in a vice and wedging apart to achieve what we were happy with. It was spinning freely in the case at the end of the session. Ainsley did it out of friendship and determination and wouldn't take a penny.

Then I spent half a day on the end float. Sorting through different thrust washers and shims to achieve about equal each side. 

I'm sure lots of these engines are not built to the makers tolerances, but I'm trying the best I can while I'm at it.

I would like to know why Hitchcocks "end washers" and "thrust washers" are identical? When the parts list clearly quotes different numbers and gives them different names. I have a selection of thicker Thrust washers, some of which only have witness of the roller ends on one side, so turning them round produces a flat face again.  Ron

 

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PS. Ainsley asked if I'd checked the clutch for balance. So I'm looking into that as another means of something to do and learn during lockdown. Ron 

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Hi Ron...obviously your getting bored with lockdown .I can send you a RE WD/CO to restore for me if you want , to keep you occupied. I won't charge you too much for the entertainment value of this as you are a mate ! .🤣  Great article ,really interesting, so thanks for the posting. Stay safe.

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Hi Andy, good to hear from you, and thanks for the kind offer to let me restore your bike. I'll give that some seri.......Oh I already have😜

Look forward to riding with you again. I've already had both covid vaccine jabs.......Just need the rest of the World to get theirs!  Ron

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PS. Yesterday I assembled piston, barrel, timing gear and magdyno. It was another one of those occasions that took about 15 goes to get the ignition timing  spot on at 3/8" BTDC. Always a good idea to gently lap the pinion onto the mag shaft taper while it's on the bench, which I hadn't thought was necessary on this occasion but wish I had.  Ron

 

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That was quick work Ron!

I’ve had another look at my notes from my discussion with the dynamic balancer place. They said that the cranks would need to be balanced to within 0.5 thou. As mine were 4 thou before I stripped them, and you have managed to get yours to 2 thou, I’ve come to the conclusion that 0.5 thou is I achievable for a 1940s split crank.

I’ll be eagerly awaiting your first test run to see if you’ve reduced the vibration. I’m currently thinking of putting a standard piston back in as I don’t think I’ll be able to get the engine balanced professionally with the higher compression piston. 

I’m on the edge of my seat waiting to hear the results of your work. I’m crossing my fingers for you.

Regards,

Tom

 

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Tom I know you're aware that Balancing and Truing are two different aspects. Truing to get the mainshafts running to within the RE manual tolerance of within .001" runout is quite tricky.  It's so easy to give things a final tweak when you're nearly there, then go past the goal and have to start going backwards.......and forwards....and so on.

Balancing  is the unknown/guesswork factor. Since I've tried it at a static factor of 60% with a possible slightly out of true crank, I'm hoping for a better result with the crank as it is now and an altered factor to 56%.

Within reason now though, I'll probably accept what I get......Or buy a Honda!      Ron

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I lapped the valves in, although it hasn't done many miles since new valves, guides, springs. The engine is now built. Just the primary to do. 

I had a very frustrating half hour yesterday, trying to determine where the rear chain was clinking on the chain guard or mudguard. It's very awkward to see the complete chain run behind the tool box and pannier. Turned out to be the combination spanner that I'd left on the silencer mounting nut, pinging against the spokes on the other side....Doh!

Ron

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Lol, a cheap and easy fix at least. I think we’ve all been there. Last year I left house for a short trip to the shop and as I got to the junction of my estate, about 500yds, I saw a wheel nut lock key sat in the road. When I came back I stopped to pick it up as it looked like the one on my Range Rover. Sure enough it was a Range Rover nut key identical to mine. I’d left it sat on one of the nuts when I did some work on it a week earlier! That was a Doh moment and a bit of luck.

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  • 2 weeks later...

It's all up and running now. But as soon as I wheeled it out for a test run, it started raining. I'll try again tomorrow. Ron

 

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Yes it runs nicely Andy, but impossible to tell about vibration through the frame until it's ridden. I found before, that the vibes ironed out at about 50mph. But who wants to ride everywhere at that speed. Ideally I want it to smooth out after 40mph.

Hoping for a dry spell. Ron

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Hallelujah! I managed a 10 miles loop today and I'm chuffed to little tin fittings with the outcome.  The engine smooths right out at 40mph in top gear (30mph in 3rd gear) and stays smooth up to just past 50mph, which is absolutely all I want. 

Next please!!   Ron

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Hi Rik. Well my crank was finally statically balanced to 56%. But that is with it's heavier than standard weight piston. I wouldn't want to suggest that figure to anyone using a different piston. And of course, different engines resonate differently in different frames, which is why designers adopt a happy medium, and why some bikes suffer from more vibration than their sister bikes.

I'd love to borrow a crank with standard piston that is running smoothly and get the balance facture calculated, just to see what the designers had in mind for these. But it would seem that the usual practice for these type of engines of around 58% would be a good guess. 

Ron

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