Thursday, 26 September 2013

Dumping the Gizmo

My Honda CBF250 has recently developed a small but annoying fault. At its usual cruising speed of about 60 mph it occasionally stutters. It feels like it's about to run out of fuel. Otherwise the bike is running fine. I checked the spark plug, air & fuel filters, cleaned the carb and even replaced the coil with no success.

I then found reference to running problems associated with a faulty air injection valve. This is located behind the cylinder head and has a pipe running to the cam cover and the air filter. A smaller pipe runs to the inlet. I assumed that this was for emissions reduction. I don't know how it works. A breather from the engine to the air box is ok and I guessed that the pipe to the inlet was a vacuum switch but why? The unit is called the "air injection control valve" in the parts book which implies that it supplies air to the inlet, but that would seem to affect the mixture. Anyway I disconnected the inlet tube and plugged it. After a run today it seems that problem has gone.

The valve does not appear in the Brazilian repair manual I have so it seems it's not vital.

Air injection valve
Pipe to inlet blocked


Wednesday, 25 September 2013

FJ Clutch Slave Cylinder Fix

My Yamaha FJ1200 has a hydraulic clutch. This is a mixed blessing. The clutch is light & smooth but also the seals in the slave cylinder are prone to leak. Over the last few months I've had to top up the fluid a couple of times so it's time to replace the seal. This is a straightforward job. 

The slave cylinder is above the oil filter casing. Note loss of paint due to fluid leaking.

Slave cylinder


Seal kit

Cleaned up & new seals fitted


Since an oil change was due I repainted the filter casing

Thursday, 5 September 2013

Run to Hadrian's Wall

Hadrian's Wall is the best known Roman construction in Britain. It crossed the north of England from the Solway Firth in the west to the River Tyne in the east. It was constructed 122-8 AD and formed the northern boundary of the Roman Empire. This boundary moved north to the Antonine Wall in central Scotland (see my posting here) 20 years after construction but returned to Hadrian's wall after a further 20 years.

The wall was a huge construction. It was 72 miles long built mostly of squared masonry. 3 metres wide and 5-6 meters tall. There were 80 small forts along the wall and two turrets between each fort. In addition there was a ditch dug in front of the wall for added protection.

The wall was abandoned in the 5th century and its stone subsequently used for building materials. There is an excellent road (the B6318) that runs parallel to the wall over its central section. This is very straight but with crests & dips and great views of the rugged landscape. This road looks roman but was built in the 18th century unfortunately using stone from the wall in its construction.

There is a walking route along the wall and this was being quite well used when I visited.   

The wall at Walltown Crags

The remains of a turret at Walltown Crags

Near Haltwhistle

The FJ at a section of the wall near Walwick. The defensive ditch is on the left.