As the final weeks tick away before the first sprint of the season in April it is gratifying to know that you have a spare engine in the workshop in the event of a major blow up.

 

I have fitted one of those cheap Chinese rev counters -they take a pulse signal from the points wire. It seems to move but leaves me with a question mark over any accuracy !

 

 

Having closed the timing cover I found that the engine is too tight...something obviously binding .

 

 

 

 

 

Bush on timing side inlet camshaft clearly is still too close to shaft as it is shining bright.

 

Checking gap

 

checking matching gap on engine side of timing covering.

 

I have this spare timing cover but I note the bush in it is also shining bright showing rubbing.

 

Lowering height of cylinder as an experimental alternative to a longer conrod -required due to lower piston compression height.

Not easy when the task is just on the border of the capacity of my lathe. Low speed is the answer though.

 

 

 

Always seems a shame to have to strip everything apart at the end of the season but I am putting in a different engine so everything within the cradle must come out. I have tried doing it by leaving the gearbox in and raising the engine but it is more trouble than it is worth.

 

Having recently bought an old oil pump  found it to be seized through not used. This is very common as the main body is made from Mazak- the British trade name for Zamak. It is an alloy which shrinks with extended age. This feature is fine if used regularly as it takes up wear on the pump wheels but leads to seizure if left idle.

It was used due to being cheap and very easily die cast- being zinc based- for jobs like this. The only solution I have found is to dismantle the pump with great care - heat the body so that it is too hot to hold ( it is cold in the photo!) and use circlip pliers and much metal polish such as Brasso to free each impeller wheel round and then when each is done do it for the assembled pump.

 

Now that the season is over and work can start on the bike I decided to build a new engine with a lighter flywheel after having much thought over the pros and cons of flywheel weight. There is much in the way of arguments for ' heavy' as the momentum gives explosive acceleration due to the kinetic energy stored in the flywheels when the lights turn green.

 

However I am experimenting with a badly corroded set of flywheels so they would have needed dressing anyway. I loath turning cast iron as it comes off as crumbly dust which gets everywhere. I have heard of people trying a magnet at the tool to try and collect it but I just brush it down.

Woke at 0400 hrs to find that on Sunday morning the 12th Oct that at there was heavy fog. Set off anyway in the dark icy fog heading for the last event of the season at York- over 5 hrs much of it in the fog.

 Was hopeful that engine problems were now rectified. Saw the sunrise on the A66 heading for Scotch Corner and the start of the run down the east coast to York.

Got there to find that the fog was even thicker at the track. Waited until lunchtime but showed no sign of clearing. Headed back for long drive and found the fog had cleared on the M1 but too late to turn back; plus I had no way of knowing if it was still bad in York.

An unhappy end to the season.

Driving though glorious Yorkshire on Sunday morning I saw many of the yellow painted bikes as a tribute to the Tour de France...unfortunately the weather was not as kind for the York raceway sprint meeting I attended. It was wet. The great  organisers as is common practice let the cars have much of the early time when it looked like it might dry up.... this delay for bikers meant we did not have much time for spanner work if things were needing it.

 

 

When things did go wrong and the old girl refused to pick up revs...... I found the primary chain was so tight you could play a tune on it...no time left...off home for a 5 hours drive.

 

You can see the wet here. I don't mean me.

 

 

...these pics are Richard  Cravens wonderfully developed Vincent / Norton....I took at York. Quite a character...but don't be fooled...he still shows  the young guns the way.

 

 

 

 

 

 

Always a good idea to try positioning new bare flywheels with a length of wooden broom handle in place of mainshaft to check all is approximately as calculated. Not least the available distance between them for the conrod !

 

A crack in the originals can be clearly seen close up running towards the mainshaft from the oil feed outlet on the inner wall . Probably would not get much worse if only subjected to light road use but sprinting is too much of a risk.

 

Norton simply used cast iron for their road going OHV singles so it is to be expected that after a half century of use this might be weak spot to reveal itself.

 

Found a use for old CD or DVD discs. Download a timing disc from the internet and glue it on. Although in theory the bigger the diameter the more accurate the reading I find that it is more easy to mark zero for TDC without making up a bit of stiff wire and finding a place to attach it.