Last Saturday we took the bike to the DLRA Test and Tune day at Tailem Bend test track for some test runs and tech inspection. The track is a
1.4 km bitumen strip with test runs being down and back.
This was a very educational day and well worth doing as it showed up a few minor things that need modifying.
Main reason was to get the carb jetting reasonably close. We started of with a 320 main jet and a 108 needle jet with the needle in the highest position.
Run 1- Being the first ever ride and on a track I hadn’t been on before I took it very easy.
First thing I learnt was that what felt like a reasonble riding position in the shed wearing thongs, shorts and t-shirt, turned out to be totally uncomfortable to the point of being almost unrideable with boots, leathers, helmet and gloves and a moving bike. With the low handlebars it felt as if I was going to fall over the front of the bike. The footpegs were too high and tucked up which made it extremely difficult to change gear. The riding position was set up based on pics of the Richards Triumph that run at Bonneville in the fifties and early sixties. Obviously young, short, Americans in the fifties were capable of different body positions than older, tall, Australians in the 2000’s.
Back at the pits we raised the handlebars a bit and adjusted the gear lever. This made it bearable for some more runs. Checked plugs which were a bit dark.
Run 2 – Felt a bit more comfortable so went up in speed and found it started 8 stroking at mid range.
Back to the pits where we dropped to a 290 main jet.
Run 3 – Much better run. A bit flat in the mid range but once the main jet took over it would start to go. Got a bit of clutch slip on this run.
Back at the pits a plug checked showed we were maybe starting to get on the lean side of ideal so we went to a 310 main jet.
Run 4 – Still had the mid range flat spot but went well as we went up the rev range. On the return run the bike started to feel a bit different.
Back in the pits we found the rear wheel wouldn’t turn as easily as it was before and we narrowed it down to a tight gearbox, probably a layshaft bush being a bit tight. Dropped the carb needle one slot to sort out the flat spot but due to the gearbox decided on no further runs as a locked layshaft results in a locked rear wheel. We also found the twistgrip may be a bit small and not actually opening the throttle fully.
Tech inspecton went well with just a few more bits needing to be lock wired.
Yesterday I pulled the gearbox out and found the r/h side bush had got hot and was a bit tight but fortunately hadn’t done any serious damage.
So I will make another bush with extra clearance, the footpegs will be dropped about 1 1/2", the handlebars will be raised another couple of inches and I might reposition the seat as well. Need to buy some more jets and confirm whether the twistgrip is OK or not.
So I have a few jobs left to do in the next 5 weeks before heading off to Speedweek Lake Gairdner.
Cheers Mossy
