Author Archives: Sophie Whiptank - aka Bart

About Sophie Whiptank - aka Bart

I'm just a bloke doing some stuff, the more interesting bits I post on my blog. Scroll down far enough and you'll see me riding from Melbourne Australia to Birmingham, England in 2014. But now I'm working on another project, a single cylinder motorbike engine at 2750cc!

Setup for checking runout

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When the crank has been finally pressed together, we’ll need to check the run out. Ideally this will be zero, but is something that must be checked if longevity is going to be achieved! (And I do plan on the engine lasting!).

Minor runout could be adjusted with subtle use of a mallet, or for anything more serious machining one shaft. Or even making an eccentric sleeve. But hopefully none of these will be required.

The idea of the v blocks is to mount the whole crank assembly in the bearings on the timing side. The lot can be spun by the conrod and a clock on the other side measures any runout. Easy!

Patterns with style

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Dave popped round with a set of patterns he’d modified to be more in keeping with the barrel. Achieving a good look aesthetically isn’t something every pattern maker would necessarily think about. Dave’s time as a model shoe maker and designer really shows.

I like what he has done as an example and now we’re cracking on with the main items. I expect it’ll take 3-4 weeks to get something we can drop onto the drawings, then filleting and artistic flare to finish off. A bit longer than the original time estimates, but hopefully ready for casting before too long.

Chain guard

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The sleeve drive will be a duplex chain, and like all chains it needs tensioning. Like old Notions the tensioner is ally, which Bob has made a great job of carving out of some leftover billet. It’s a lovely looking thing, the sort of artifact you’d pick out at an autojumble just because.

Shame no one will see it when it’s in situ! Apart from the 44T sprocket, all of the steel components are finished. Time to give Dave a nudge about finishing those patterns!

Sleeve drive sprocket

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The sleeve drive sprocket has been drilled by Bob to allow for a vernier adjustment. The 9 holes allow the sprocket to be fitted to the timing shaft in a number of different positions.

With 22 teeth not being visible by 3, three mounting holes would allow the sprocket to be fitted three ways, each time a tooth ends up in a different relative position. To refine this further, three sets of three mounting holes have been drilled.

Why? Well during final assembly the valve timing will need to be set. This will be achieved by setting the piston at the point where a valve opens, moving the sleeve into the correct position and then bolting the sprocket to the timing shaft.

Sounds so easy when you say it!

Meanwhile…

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While Dave works on the patterns, a little job I’ve been meaning to get around to I finally got around to! The Kawasaki brakes seize monthly during the British winters. Government sponsored rust fairies abound when they put salt on the roads. Might as well be riding through the sea!

The brake pistons are steel which is hard chromed. Ok for a while but the chrome is thin and eventually flakes off. New pistons are pricey and don’t last more than a couple of seasons. I knocked up a pair in 303 stainless steel, which should last a long time! (Longer than the rest of the bike looking at it).

So the front is rebuild and the rears will go in this afternoon. The mighty KLR 650 will be back up and running for winter – if I ever get to go anywhere 😷🥶🏍

A Pattern Maker

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Meet Dave. Dave swims like a fish, no, wait – that’s a 70’s government advice cartoon urging you to learn to swim.

Meet Dave, our new pattern maker. Dave cut his teeth making patterns for his apprenticeship, before branching out into wooden shoes. He’s fairly local and s biker too, so it all fits together nicely!

We’ve spent a few nights running through our project, the drawings and some patterns from other engines. Dave has suggested a few foundries to try around Leicestershire, so that’s next on the list.

It should take around 6 weeks give or take, so I could have a set of patterns in my hand for my Birthday. Or maybe, even, the castings!!

Grinding me down

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Down to size and a very nice finish to boot. The cylindrical grinder did a good job on the sleeve drive pin, which now fits the ball on the sleeve a treat.Hardened steel grinds better and I will be making more use of this machine in future.

I hadn’t done much grinding before, but this has inspired me to get the 3-phase supply sorted for the Jones & Shipman 540 I have languishing in the garage.

Thirst quencher

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Well not really. Much as this looks like a cool cocktail, it’s the sleeve drive pin being quenched. The whole jar became too hot to handle, so there was plenty of heat in the pin. Rock hard! Now to temper it.

When it had come to a reasonable temperature, we gave it a wipe and warmed it up again – this time to a dull red. From there into the oven at 200°C for an hour, before allowing to cool slowly.

Next up, it grinding to size on the cylindrical grinder.