Weight Loss

Anyone who has ever driven a Ducati Parallel-twin knows the bike weighs a ton. Well lets be honest, almost every bike from the seventies weighs a ton. My first bike was a Jap in line four 750 and it’s weight was 230 kilo’s and it was even 2 years younger that the parallel-twin I own now. But with the weight near a 180 kilo’s for the parallel-twin it isn’t the lightest bike around. As we know now bikes on paper have more power and weigh less than they actually do.
So when your at it you can loose all unnecessary parts. But the point is what do you need and what not? Some parts have to stay on otherwise you will be in trouble with the law or you will move in to a “grey area” where you will always have a discussion. In some countries bikes are regularly checked by licenced garages. Like in Germany every change on your bike will be added to your registration papers even if it’s a change to better brake lines.
You can start by losing your indicators, I hate them because they stick out and you bump in to them when the bike is parked in the garage. I use my hands anyway as turn signal. And that there are loads of other stuff you can cut from your bike.  The original frame as you can see here is quite large and heavy. On the other hand it is a very good frame and it is one of the best Ducati made in those days. Even compared to  modern standards it handles very well. In the mid seventies the budget for getting the parallel-twin on the road was an issue. Ducati had to get it’s share on the marked and clearly had larger priorities than trying to safe weight on a frame. The frame tubes are thick and heavy and especially the metal plates that connect horizontal and vertical tubes are about 4mm thick. Something you will never see on later bikes. If you want to race your bike you can start up your angle-grinder and cut as much as you dare. The original frame weighs 17.2 kilo’s and when you lose some parts of the frame like I did you can get it down to 13 kilo’s. That sounds maybe not to exiting but it is almost a 25% weight loss !  Think about parts like the centre stand fixing on the frame, the  footrests, the upward section where the rear mudguard is held and the battery box. They  are the big winners. But don’t forget the small parts. They are just as important as the big ones, they have strength in numbers and a couple of grams here and there count for kilo’s when your finished. For example the rear mudguard is held by 6 M6 bolts  whitch weigh 111 grams together. This is just only one part of the bike. I asked myself the question why are they using M6 bolts? If you would fix something that weighs 1000 kilo’s on these 6 bolts they wouldn’t even break. On previous bikes I just used Ti-wraps, it’s easy to fix and easy to undo when it’s needed and believe me that my rear mudguard never fell of ! The wheels of these bikes are another problem. They probably will never break or get serious damaged to the opposite of  light alloy wheels. When you want to save at your wheels you can try spoke wheels with light rims or find some Jap parts that might fit.  For the rest of the bike you just have to use common sense, see what you want and which what you can get away with depending on where your bike will be used. Just remember to keep it safe, using one brake caliper on the front safes weight but with this heavy bike it is not a good idea.

When you’re getting to the engine it is a completely different ballgame. Of course these engines were never famous for there reliability so don’t worry when you see parts that are damaged and have been fixed. In this engine a con-rod gave up and hit a part of the camshaft chain guard and took it away. The crankshaft itself looked pretty okay but after measuring the taps I found out that +.025mm bearings were fitted so it must have been grinded down to the first oversize. No worries, these heavy constructed engines can endure some beating and for sure they all had a bad life in the “Roaring Seventies”. When dismantling the engine I noticed that the gearbox looked like heavy machinery so right away the name Laverda comes in mind.  Not all Laverda’s are constructed like they have to live forever but certainly the twins and triples do not hide there heritage. When I compared the gears who drive the camshaft from a Ducati Parallel-twin and a Ducati Pantah I could see that with the later Pantah models they did a far better job in constructing the engine parts. The gear on the left is from the Pantah whitch is almost half the with and weight. Same goes for the gear driving the oil pump, it is ridiculous wide and after travelling quite a distance with the bike there are no signs of wear on the gears. You can machine these gears any way you like to safe some weight. You can drill holes in them or machine them so they get smaller. They will do the job for many years.





Design Flaws


2 thoughts on “Preparation

    • Danny, ik had die filmpjes gezien op Youtube en heb inmiddels contact met de man die de motor heeft gebouwd, info volgt hoop ik nog.
      Nog even terugkerend op je vraag over de electronische ontsteking voor de Parallel Twin . . . daar wordt aan gewerkt.

Leave a Reply

Your email address will not be published. Required fields are marked *