Saturday July 12th 2025

 Saturday July 12th 2025

Suzuki GSF 1200 Bandit…

Ioin prepared and sprayed the rocker cover, restoring it to its original finish.  Graham, Heinz and new member Richard then set out about re-fitting it using the brand new rocker cover bolts that had been supplied with the bike.  Once the rocker had been carefully fiddled back into place so as not to disturb the rubber seal that runs around its outside edge. They went to fit the new bolts.  Four of the eight bolts fitted, the other four could not be persuaded to screw in.  It was then that it became apparent that someone had fitted some sort of thread repair kit to four of the bolt holes and at the same time reduced the thread size from 8mm to 6mm.  An attempt was made to cut a 6mm thread onto one of the new 8mm bolts, but the difference in diameter was too great.  So it would be a case of getting the silver spray out to tidy up the modified bolts used by the previous owner.  They had been ingeniously modified but cutting the threaded portion off the mushroom shaped head and drilling through it so a 6mm Allen bolt would pass through the head of the original bolt.

Ducati 250 Single…

Keiran, Jon and Graham searched for that illusive spark and it was quickly discovered that to get a spark the core of the ignition coil had to be earthed.  Once an earth wire had been added there was a strong spark.   Then it was time for a bump start.  Almost immediately the clutch was engaged the bike fired up and kept on running.  All the patience and tenacity had at last paid off.   The was still some fuel overflowing from the carburettor and a little oil escaping from the bottom of the clutch cover but it was running and what a lovely sound it was.  With no definitive settings for the carburetor curing the overflowing fuel, would be a case of raising the float height a couple of millimeters at a time until the fuel overflow stopped whilst trying not to weaken the mixture so much that it caused other problems.

Mash 400 Dirtstar (The Mash Report)

Advice from members of the ‘Mash Motorcycle UK’ Facebook group led our thoughts (Well mine anyway) to the fact that there is an automatic decompressor fitted and if it fails to operate properly, it can lead to the symptoms we have been having.  The time had come to remove the rocker and have at the auto decompressor.  Guy, Heinz and Graham set about removing it, which was a simple case of removing the head steady and removing the numerous eight millimeter head bolts securing the rocker once the engine was a top dead centre on the compression so that the valve rockers were not under load.  With a judicious tap with a hammer and a drift, the rocker cover came away from the cylinder head, revealing the camshaft and the automatic decompressor.  In fact, it revealed what Graham identified as two automatic decompressors.    One decompressor is designed to try and stop the engine from ‘kicking back’ and has a one-way clutch that locks the decompressor body to the clutch if the engine starts to spin backwards.  Firing in the backward direction would inflict a heavy impact on the electric starter mechanism or worse, inflict it on your ankle if you were trying to kickstart the bike. Although there seemed to be no workshop manual for the Mash, Graham had managed to find an online manual for the Shineray 400.  Shineray is the name bikes using the same engine are marketed under in China.  Graham’s continued research found that the engine is a close copy of the Honda 400 single fitted to the Honda CB400SS and XR400 singles.  A search of You Tube revealed a couple of videos showing varying of detail how the decompressors work.     More research was needed to identify the best resolution.  Some had suggested grinding the projection of the right-hand exhaust rocker so that the decompressor no longer touched it.  However, this would mean there would be no relief for the poor old starter as it tried to spin the engine against the full force of the single cylinder engine’s compression. 

The two automatic decompressors can be seen at the bottom of the picture just inboard of the sprocket flange.

Was this damage on the base circle of the cams significant?

Kawasaki KZ550 Ltd…

Keiran carefully attached the small ‘Chassis number plate’ that Andy had made so that we could retain the bike’s original frame number.  He then spray-painted it black, making it hard to tell that it had been added at all.  In the forthcoming weeks, Keiran would be applying for a new V5 document so that the bike could become tax-exempt owing to its age.

Kawasaki Z250 Scorpion (Circa 1980)

Keiran installed new Speedo and Tacho cables and started the engine to check for correct running.  This was another bike that Keiran would be sorting out a V5 registration document for it, so we could get it on the road.

Piaggio Velofax...

Keiran spent a little time refitting some of the bodywork but ran into diffiiculty when the ignition switch overheated. The engine had lost its spark and would not fire up. Graham recalled that when the bike last ran, it hadn't been necessary to have a battery fitted, so hopefully the lack of spark could be overcome once more by correctly wiring up the leads relating to the ignition.