To go back to the very start of this thread this is what I learnt about developing a Norton 500 twin over about 5 year on a dyno.
First off unfortunately in NZ at least I have to repeat that only maybe 1 in 4 operators are any help at all when tuning our kind of bikes. And they can wreak things like clutches etc if you dont watch them.
I use the Dyno at Motomart in Lower hut NZ. It is an inertia drum type dyno but it can also be run in brake mode. That means you can do both aceleration tests and tests where you can hold the throttle against a given load and test ignition and carburation at selected rpm. In this mode it is like riding a bike up a steep hil with a steady throttle. If you have a points or electronic set up which you can move back and forth while the engine is running then you can obtain the best timing by testing improvements in rpm. With a magneto this is more difficult unless you have one with manual advance and retard (or make up a way to rotate the mag on the mounting studs).
To keep the price within reason you need to try to make a deal where you pay for dyno time but only the operator time while he is actually operating the dyno. Then he can go away and work on other things while you make the modifications for the next test.
They will expect your bike to have an electric start so make sure you or they have a big charged car battery to rotate the drum and start the bike.
You must be very efficient in the tests to minimise the costs.
I go with a large drawn up sheet of paper with the tests (or else on a spead sheet). My aim is to collect the test data for analysis latter rather than the more conventional practice of tuning the bike in real time.
I found it more eficient to collect the data - analyse it at home and then go to the dyno again with an optimised set up.
BE VERY CAREFUL THAT YOUR RECORDED RUN NOES ARE THE SAME AS THE OPERATORS OR YOU WILL BE COMPLETLY CONFUSED.
So set out your tests, carb, slides, needles, needle heights, main jets etc etc. Have all the carb parts set out on bread boards or multi compartment plastic containers.
If you want to test exhausts or inlets makeup telescopic sliding tubes so you can test header lenghts very quickly by sliding the pipes along. Dont worry about how they are mounted - just hang some sort of jig off the footpeg mounts so you can make the change in a few seconds. Bring gloves !!!! Because you are not testing the final fitted exhaust it is pretty cheap to cut and weld different and sections . For test runs I just hang the pipes anywhere that fits.
I also made up three types of megapones with reverse cones which I could cut and modify.
It is important to do all tuning using the muffler you will need to use at the track.
As has been mentioned several times the point of this exercise is not just peak power (torque) but to improve power (hence torque) in the mid rpm range.The abilty to get out of corners wins races and I made major improvements in the 4500 to 6000 rpm range mainly through header and inlet tract tuning. I will attempt to plot my before and after curves if I can get the photo plot to work.
Im a big fan of sensible use of the dyno. I had no race experience when I started but in three years I had the second fastest 500 clubmans bike in NZ. Most of the learning was due to the dyno and reading of good quality books and articles. Blair, AG Bell, Vizard, Irving, Jennings.
Ok. I got it to work. these runs are all on the same dyno. You can see I started in the low 30s bhp and ended up touching 50 with a much better range below 5000. This is all on 98 octane NZ pump petrol under NZ Clubmans rules. Last photo is Tony at Puke . You can see the header pipe set up. This is exactly the setup on the 50 bhp run. With this set up he could lap the old Puke track in the 1min 11 sec range which is not too shabby for a clubmans bike (SLS brakes etc). You can also see the run date. Jan 2009. Since then I have been banished to the former CIS to save for my retirement and all bike riding has stopped :-(
John
