I am looking to have Mark at MADASL build me a lovely little track toy for when I return home. He currently runs a 748 called Daisy (available for hire dontcha know) which was the most fun bike I've ever had the joy of riding. Using Daisy as inspiration I would like to run a bike of similar styling and design intent. The theory is that I would use a 749 as a base but re-imagine it so that it actually works when I want it to and is easy to repair if/when I fall off on track days. I've had a couple of days free here as it's Christmas and I've been photo shopping some images I found on the web in to what I would like to end up with and I've been thinking about the list of mods. *Red powder coated frame *Black powder coated swing arm *916 style top fairing - modified to half size as per Daisy. *Slipper clutch Ducati corsa or sigma or some such ball and ramp style *R&G Frame, fork & swing arm bobbins *Fairing tabs removed *Loom rebuilt to better spec than the crap 749's came with *Lithium light weight battery - if it will manage to turn over the engine *New custom exhaust - possibly 2into1 side exit, slash cut gp style or one each side like SS models. *Relocate electricals from lower left side to under the tail in a custom aluminum box. Easy to fix with easy access. *Quick action throttle *Conti Race Attack tyres *Maybe some light weight wheels if a decent deal can be found. This isn't a high priority though as they'll cost a fortune. *Replace the stock ECU with a flash able ECU so as to run without the standard clocks and with a map to suit the exhausts. *Translogic or similar small customizable race dash. *Suspension set up for my weight *New chain & Sprockets, belts, pads, fluids This is the extent of things so far. I'm thinking about binning the standard exhaust as I need to find space to move the electronics to and a couple of side exit exhausts will really make it different. I'm not sure where or how to move them. Maybe a double exhaust exiting on the same side or a single exit on each side or a 2into1 single exit.
The top photo is a 748 by the look of it, is this what you had in mind? A 748 based bike would be cheaper and can be tuned if necessary. Here's my son's Race hybrid 748 courtesy of CJS Ducati. CJS RACING Dyno ECU Flash Mapping Bristol Ducati Cylinder Heads Gas Flow
Ah yes, Daisy is a 748 but I would like to go with a 749, partly because they are a known quantity to me and partly because it's a little different. Also people are starting to ask crazy money for 748s where as a 749 can still be picked up pretty cheaply.
This should be a pretty cool build! I like the photochop you did and always wandered how the tail would look without the loooong standard exhaust :biggrin: Why not a kind of 'Radical' front end though? Always loved the look of the Radicals! Either way though should be great
I've been trying look at exhaust theory, which, it seems is pretty complicated business. Is the basic premise the the lengths of the pipes from cylinder to the exit should be the same length? I've seen a 2 in to 1 on a radical Ducati 750 Daytona model which looked great. Can anyone with greater understanding explain to me how a well made 2 in to 1 exhaust with shorter tubes will affect a 749 compared with the stock or termignoni system?
Don't think it will matter much Tom if you are going to get the bike mapped , the tuner will optimise the fueling to the exhaust. If their are no lambda ports he will measure by sticking sensor into exhaust.
Bear in mind that exhaust technology and air flow dynamics IS pretty complicated, you are right. The amount of backpressure is also relevant to governing torque. And yes, the two pipes should be of equal length in a simple sense. There are people around though that will happily fabricate you an exhaust - you don't need to do all the hard work yourself. But I doubt it would be that cheap.....
exhaust size and match is a complicated thing look at the std 749 999 exhausts front and back are very different….. rear small diameter high speed flow……front large diameter slow flow….how does that match and work?????
trouble is on most systems around half way there will be a cross over so sticking the pipe up the end of the exhaust can be misleading to set up the separate cylinders and that is the best way of doing it, …………thats why there are lambda sensor holes ( which are easy enough to drill and get welded into place) on each separate pipe up near the exhaust port…...
To compensate for different lengths, similar results can be achieved with pipe length, gas velocities, pipe sizes etc, it's all very complicated and best left to experts. (I'm not one) :biggrin: this is a response to post # 11.
Money's not so much of a problem. It's finding some one capable of doing a good job. It also needs to be quiet enough for track day use. I'm building this to race/track. I think I'll have to go down the Nemesis ECU route and ask CJS to map it for me. This project is already going to go over budget, but like Kope999's thread, I probably won't ever have this opportunity again. Hopefully a new loom and a decent map will help prevent any possible gremlins. But the bike I have planned on picking up is the complete anti-thesis of the last 749 I had. It actually works.
i would look at the M197 Microtec ecu………..or stick with a 5.9 std one that has been sorted ..then remapped!
They are different due to meeting emission rules and the fact that the bike being mass produced its easier and cheaper with the limitations on space to just make the exhaust different bores for each cylinder, the different sizes and lengths actually produce the same end result , not the best result , hence why race exhausts are usually a bigger bore and the same length .Oh just seem NZDave's post , I'm with him.
Unless with Toms home made system both pipes into the joiner are equal length ,he did mention in his first post of a side exit system this may/not make it easier to get approximately the same length to endcan ?. Or possible two separate exhausts making mapping to each cylinder easy.
which will need separate lambda holes ….on each pipe regardless of length or more specifically volume to avoid cross contamination..
