Workshop session - Saturday October 5th 2024
Saturday October 5th 2024
Kawasaki Z250.
Graham and Don worked to try and ensure the fuel levels were correct. Kawasaki in their infinite wisdom only specified a fuel level and did not provide a float height. Initially the bike was taken outside and started up. Having previously run reasonably well, it now ran like a dog and quite a lot of fuel overflowed from the carburettors. Oddly the fuel levels were quite low. Taking off the float bowls revealed why it had been running so badly. One of the bungs blocking off the pilot (AKA Idle/Tickover) jet was now missing. Don recalled that at the previous session the carbs had been taken apart outside the hall and set off in search of the missing bung. Miraculously he returned a short while later having found the small black bung on the ground outside. I say miraculously because it could so easily have been hidden amongst the small shingle that covers a lot of the ground outside the hall. With a bit of judicious bending Graham took an educated guess at what height the floats needed to be. The fuel had been roughly 5mm too low so he lowered the height of the floats in the upturned carburettors to get it somewhere in the region of the 1mm - 3.5mm below the gasket face that it needed to be set at. THe carbs were then reinstalled and the bike once more taken outside to be run. This time it ran far better and with some adjustment of the pilot screws was encouraged to tick over very nicely. This was something of an achievement as the Z250 could be difficult to get ticking over back in the day. Please refer to Don for a lesson on Carburetor orientation. Without a rolling road it may require a road test to determine the correct main jet size, however with the jet sizes increased by roughly 10% the engine revs more cleanly. To correctly assess the main jet sizes it may require switching off the engine, pulling in the clutch and coasting to a halt from a full throttle run. The unusual manoeuvre means that the colour of spark plugs can be seen without allowing it to be altered by running the engine at smaller throttle openings. This is where a rolling road comes into its own.
Kawasaki KZ550 LTD.
At the previous meeting Graham had used his ancient Suzuki genuine carb balancer’s to balance up the bike’s four carburettors and spent some time working with its pilot screws to get the best tickover. This week Don replaced the carburettor tops. The engine is running a little noisily at low speed so some investigation may be needed. At the end of the session Graham filled the replacement fuel tank the club had purchased second hand with rust remover to try and clean up the internal surface.
Dnepr 650…
At the previous session the engine had been misfiring and sounded as if it was spitting back through the valves on the right hand cylinder. No amount of twiddling with the air screw seemed to have an impact on this. Then the engine came to a sudden stop. At this season Annabelle and others pulled the cylinder heads and cylinder barrels off the engine. It was then very apparent that both pistons had started to seize in the cylinder barrels to a lesser or greater degree. The right hand piston in particular had significant scuff marks between pistons rings and the base of the piston. It is just possible that there was insufficient clearance between cylinder and piston as the pistons had been replaced by the bike’s previous owner. Amongst her vast supply of Ural/Dnepr spares Annabelle found a pair of cylinders and cylinder heads, so the bike can be rebuilt fairly quickly.
Honda Vigor…
Mal continued working to improve the appearance of various components, most notably the front wheel. With luck it would soon be time to put the front end of the bike back together to take advantage of its new steering head bearings.
In other news…
Jialing 125.
Work on the bike had stalled, although Don had worked to complete a respray of the fuel tank. The rest of the bike remains in a state of disassembly waiting work to make it look a little better - we really to get our act together.
Yamaha TX 500
No further progress made on this project at this meeting although we did now have the piston pin circlips so work to reassemble the engine could resume if only we could find all the bits of the engine ,such as one of the outriggers that supported components that were driven by the crank shaft. Hopefully we would manage to find it all.
Jose continued work to rebuild his moped with some assistance from other club members. Having been largely taken apart to be clean up and polished, it was good to see the bike nearing completion once more. Jon continued to make progress towards getting his Ducati 250 running once more.
During the session Kieran Byrne gave the assemble toolbox talk on Health and safety in the worksho. This time he covered health and safety around the use of hand tools, something that it all too easy to disregard with painful consequences.
An extract from Keiran's toolbox talk
In another exciting development Mechanic Phil, Kieran and others set about removing the Ivy that was growing over one of the two large windows at the end of the hall. It had completely covered the window and once it was cut down a huge amount of extra light was allowed into the workshop. However, the main motive was to allow access to remove a cracked pane of glass and replace it with plywood sheets that allowed an extractor fan to be installed as part of a system to limit the spread of airborne spray paint. A Paint Spraying tent had also been purchased to help constrain the paint particles. Would it all work?