Posted by jerry on March 5th, 2007 — Posted in Journal, Motorcycling
Progress! The Honda CT110 oversize piston kit arrived and the cylinder has now been rebored to fit the new piston.
And with Sharon starting to be on the mend I took the opportunity during her sleep to start reassembly of Eve’s bike. First the new piston went on smoothly – the new piston pin slid neatly onto the connecting rod and the pisoton was secured with the new piston clips.
After fitting the piston rings it was time to start on the barrel – there was a lot of rust and dirt on the barrel so I cleaned the exterior using kero brushed on and then a drill-mounted bronze wire brush.
Then the tricky bit – fitting the cylinder without breaking the piston rings. After fitting a new bottom gasket I tackled the fitting. Not having a piston ring compression tool I used finger pressure to squeeze the rings closed as I gently lowered the barrel over the piston. This requires patience and eventually got it ride smoothly over the piston.
taking care to thread the cam chain through. Then I fitted the cam sprocket to the cam chain and held it all in place with some thin wire.
Now for the head. I cleaned the carbon out of the combustion chamber and the valves, and removed the remnants of the previous gasket, before cleaning the outside of the head thoroughly and fitting a new head gasket.
I lowered this gently in place and then, after making sure the crankshaft was at top dead centre, I installed the cam through the cam chain sprocket and bolted it in place, using a small 10mmsocket wrench. I set the other socket wrench on the timing end of the crankshaft to stop the cranckshaft rotating when I tightened up the sprocket bolts.
Once in place it was a relatively quick process to install the covers with their respective new gaskets, so it looks nearly complete.
Next step was to refit the carburettor inlet manifold – with its new gasket – and then the exhaust.
Looks like a new engine now! And in many ways it is – it will need running in of course. But before I can test start it I want to get the footpegs and bash-plate back on – so more to come on this rebuild 🙂
Cheers
Jerry
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Posted by jerry on February 25th, 2007 — Posted in Journal, Motorcycling
Well, after about six years faithful service, my daughter’s postie bike (Honda CT110) began getting hard to start, and when it did, it started blowing smoke. I checked the compression and realised that the engine was down to about one-third the compression it should have. The dial read about 32 psi, when it should have been over 100. With a couple of weeks to go before my daughter was due to head overseas we just poured in some treacle-like ‘smoke free’ which brought the compression up to about 42 psi – still very low.
With the bike in storage I decided it was time to find out what the problem really was. My suspicion was a broken oil ring on the piston. I spent one evening last week removing the footpegs, bash-plate sub-frame and the exhaust pipe.
And today I set to work in earnest. It took less time than I expected. I began by removing the carby (two 10mm bolts) then followed the Clymer manual beginning with ensuring the piston was at top dead centre on the compression stroke.
I had also previously made a ‘piston holding fixture’ which you can buy as a special tool or make one from wood. The instructions were in the manual – for info you need a piece of wood 1/2inch x 1-1/4inch x 4 inches. and you just drill a 1/2inch hole in the centre and then cut away from one end until you have a fork – like this
And it worked perfectly.
But I digress… After removing the camshaft and with care to ensure that the cam chain did not slide down into the crankcase the head was removed. I used wire threaded through the cam chain to ensure it remained above the cylinder.
There was some carbon on the piston crown, and some deposits on the valves. The piston holding tool worked very well, but I needed to explore further. On removing the cylinder I found that the piston rings were quite worn, and that the oil ring was in three parts – clearly that is where the problem lies.
So it was time to remove the piston. This is secured to the connecting rod by two spring clips – not easy to see, but observing a small cutaway on the side of the piston, I noted a hint of a clip. With a pair of needle-nosed pliers it was a brief job to remove the clip from each side. I used a short piece of 1/2inch dowel to push out the piston pin and the piston was free.
After cleaning the worst of the carbon with a wire brush and fine emory paper I saw another issue – the top compression ring had at some point worn so thin that it had gouged the groove in which it sat, allowing for movement.
So it is likely we will need a new piston. But the bore seems unscratched and with luck I will be able to find a new piston to match. And that is a story for later in the week.
Meanwhile, there is a rather sad looking Honda CT110, with rags to prevent the entry of dust, sitting in my garage awaiting some new parts.
And the rest awaits reassembly on a nearby table
In the meantime, you can read more about this wonderful bike People actually race these things, and every year there is a Postie Bike Challenge in Australia where people ride these things from Brisbane to Adelaide (2005), or Ayre’s Rock (Ulluru)(2006). And this year 16-27 October the Postie Bike Challenge is from Brisbane to Cairns (over 3000kms) on some of the roughest and most beautiful country in Australia
And here is an online owner’s manual 🙂
Cheers
Jerry
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Posted by jerry on October 10th, 2004 — Posted in Journal, Woodwork
I have long had a fascination with looms – perhaps something about the combination of timber and machinery – but they’ve always been something of an expensive luxury for a hobby. Yes I have built a couple of simple box looms and made the usual scarves and place mats, but multiple shaft looms seemed always beyond my capacity as a woodworker. Others have known about this interest for some time – indeed it came up in dinner party conversation about a couple of months ago with a friend of ours from Art school. At the time I thought little of it, but there was passing reference to being careful about what I wished for…
Then the phone call – it has a couple of broken parts, but it is basically complete – and it is just taking up room in my shed… She wasn’t kidding! So this weekend saw a quick visit with the van.
A nice simple four shaft loom – although the castle has lost the dowels that hold it upright and one of the shaft lever stays is broken, and the reed is rusty… I don’t think I was quite able to hide the boyish grin creeping around the corner of my face. So a real table loom to play with!
The loom is a four-harness (or four shaft) Sheridon table loom, made in Melbourne – I guess about 20 years ago. It is basically complete. So as soon as I got it home I set it on the workbench. I could perhaps have glued the broken harness lever support back together, but decided it would be stronger if I fabricated a new part. I carefully unscrewed and removed the broken part, then wiped the screws with silicon polish to remove the rust and ensure an easier reassembly.
I laid the broken piece on some pine I had lying around, thinking to make a test piece before remaking it in a harder wood.
Then after drawing around the old part, I carefully cut the pine to length on the bandsaw, and then cut in to define the ‘feet’, chiseling out the void below the ‘ramp’. Then back to the bandsaw to cut the curve. Then using the other lever support as a template, marked out where the screw holes should go and drilled them. Finally I used a medium grit on the belt sander (mounted belt-side up in the vice to free both hands) and smoothed out the curved section, then a quick dressing all round. Time for a trial fit:
The fit is perfect and the action is smooth. Still a fair bit of work to do, but it will hold for now while I locate and cut some suitable dowels for the tower (I have found a couple of bolts that are the right size against which to measure the dowels). I still need to remove the rust from the reed comb (although the heddles are surprisingly rust free), replace the harness-raising strings and I suspect I will probably need to do some further disassembly for sanding and refinishing before rendering it fully serviceable again.
And then I may just want to build a boat shuttle – but that’s a future project! Here is the loom in its present state:
Cheers
Jerry
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