Monday, 28 May 2018

Shakin' Strumpshaw Steam Rally

This years Strumpshaw Steam Rally provided the perfect opportunity for a decent ride, a lovely day out and the chance to shake out some more SQ4 problems.

Strumpshaw is a village in my home county of Norfolk located on the northern bank of the River Yare around 6 miles south-east of Norwich within the Broads National Park. The village lies a little distance from the river, on the slopes of Strumpshaw Hill, the highest area of land in the Norfolk Broads.

Strumpshaw Hall lies closer to the river, next to the Yarmouth & Norwich railway line from Norwich Thorpe to Yarmouth Vauxhall, first opened in 1844. It is the home of the Strumpshaw Hall Steam Museum, with a collection of traction engines, steam rollers, 100-ton working Beam Engines, a Narrow Gauge Railway, a 1930s Fairground, Mechanical Organs and much Memorabilia collected over many years by the Key family.

The Strumsphaw Steam Engine Rally is held each Spring Bank Holiday Weekend in the beautiful parkland grounds of Strumpshaw Hall. The rally hosts over 50 traction engines in steam and some 350 other exhibits including vintage tractors and heavy horses, stationery engines, fair organs, working demonstrations of steam and tractors, classic cars, trucks, fire engines and motorcycles.

It's the perfect spot for a ride out to meet the grandchildren, especially if the weather promises to be sunny.

The ride down quickly revealed that the steering problem had been fixed by proper adjustment of the wheel alignment, but that the chainguard was still a problem.

This KTM was the only bike to join me in the car park... It looks like all the other bikers registered their bikes as exhibits and got in for free:

The best part of the shakedown was the results from the carburetter temperature testing. After a 69 mile round trip with no misfire, and a 22 mile trip back at 55-60 mph we have these results, taken with the engine running in the yard and measured immediately upon arrival:
  • 208°C on the fins near No.2 spark plug
  • 131°C on the inlet manifold flange - near the offside carburetter stud
  • 80°C on the carburetter flange, 1/2" from the 131°C measuring point but on the other side of the phenolic spacer. That's a 51°C differential across the spacer.
  • 47°C on the float bowl.
Ambient was around 20°C for most of the trip. I measured the other cylinder head temperatures as well and added them to my chart with some previous tests:

Looking at these results, there is an issue around the focus of the thermometer. Normally I point the targeting laser on the plug body from about 15" away, which probably means we are measuring a 2" circle around the plug body; for Test 5 I aimed the laser at a fin and probably ended up measuring the plug insulator, explaining why the temperature is much higher. Consistency is the name of the game as any test engineer will tell you.

It appears that I haven't fixed the oil tank cap leak - maybe the gasket is not thick enough. I think it is better as the oil wasn't in the toolbox this time, but we have not solved that one yet!

And as the day drew to a close, I was left wondering how many of the Strumpshaw Ten Commandments might apply to riders of Square Fours...

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