Exhaust valve.

It seems that many new bikes are fitted with a flapper valve in the exhaust these days, Ducati being one. If you look back through the posts you will find that I took the exhaust valve motor out of my 848 and fitted a little box to fool the ECU into thinking that it was still fitted. Well I have another little box the same.

This picture shows the oil filter from a previous post but the exhaust valve gubbins is in the same area. The valve itself is under the triangular cover to the rear of the green circle, it is held on with three bolts. Just under the front of the green circle, the cable that runs to the motor, which is in the lower front of the fairing. is just showing, 

First thing that I did was to take a short video of the motor with the bike running to see when it was closing the valve.

This actually proves nothing apart from the fact that it is working. In my  view anything that is making a restriction in an exhaust system for no known reason is a waste of time, and does nothing for efficiency.

The motor and cable has been totally removed along with the brackets. This saves a bit of weight, not that I’ll ever notice while riding, and gets rid of that ugly cable hanging down. The valve itself is still in the exhaust but is wirelocked in the open position.

Time will tell if the modification has any effect on the way the bike runs, or on economy. It is very easy to reinstall everything if needed.

All that I need now is a spare exhaust box to see how easy it will be to cut open, remove the catalytic converter, and weld closed again. That is one modification that I know from experience makes the machine more economical and boosts mid range torque.


Titanium (Ti)

Throughout my life working on aircraft I have used Titanium bolts. They are used for a number of reasons two being strength and lightness. The Ti that we used on military aircraft was about a third of the weight of a steel bolt of the same size, and was coloured a blue/grey. The picture below shows three titanium bolts that were laying about in the bottom of my toolbox with one steel one as a colour comparison. The titanium ones all together weigh about the same as the single steel bolt.


The place where titanium is very useful is in very high heat areas like exhaust systems and jet engines. I have, in the past, heated one of the Ti bolts up till it was glowing red and hit it with a lump hammer, that did not even distort the threads and I could screw a nut onto it by hand afterwards.

Titanium is freely available these days from many places as people want lighter bicycles and lighter parts for racing motorcycles. The wheels and tyres are a great place to save weight as lighter a front wheel is, the more it will stay in contact with the road over uneven surfaces and the less gyroscopic effect the spinning wheel will have on the control of the bike.

Back to the reason for this post. The four bolts holding the brake callipers on my 848 looked a bit tatty, the chrome was scuffed in places and although most people would never notice, I did. I looked into changing them. I could buy 4 bolts claiming to be titanium from ebay China for the same price as it would cost to buy one of those bolts from the leading company in titanium fasteners in the UK. The link to the ebay ones is HERE.

They arrived today so the first thing that I did was weigh one against an old steel one as fitted to the bike, the pictures are next.DSCN0483


As you can see there is 15 grams difference, that makes 60 grams for all four – this bike should fly with all that weight saving 🙂

The next picture shows the difference when fitted.


The top bolt is the steel and the bottom one titanium.

All the super bike racers out there are now going to want to know about the huge performance increase with these fitted, well after going out for a spin and a coffee, the bike feels exactly the same as it did before. It may be the fact that I drank a small coffee but it could be that the 0-60 acceleration was 0.00000000000007 seconds slower afterwards, but there again I had €1.20 less coins in my pocket. I must stop being sarcastic about people spending a small fortune on carbon fibre to save the weight of half a litre of fuel!

My aim was achieved, the bolts look nice.

Exhaust valve 2

As promised, this post will complete the exhaust valve elimination mod.

In the last post I had left the bike with a temporary bodge (aircraft term), a metal profile to make the ECU think that there were still cables fitted operating an exhaust flapper valve. I have covered a few kilometres with it like that and was happy with the way the engine feels, but unhappy with the bodge, see the next picture:

oldmotorThe Bodge is the scabby bit of metal on the motor, it may look bad but it fulfilled its function. Much nicer things to see in this picture are the two nice titanium bolts that hold the small motor to the bike. The motor was removed and turns out to be quite a heavy lump. Here it is looking lost on the garage floor:

motorThe replacement for the motor was bought from ebay in the US as item number 280869731831. It was made by a company called Vizi Tec and sold buy a seller called Blautee. Total cost including postage to France was around £40. Delivery was very quick, but I was surprised when this is what I received in the post:

DSCN0170sA personal note from the seller wishing me a happy birthday! I cannot quite read his name, and have no idea how he knows my name or that it was my birthday, but thank you for that little bit of paper, it made my day.

DSCN0171sThis shows the size of the box compared to the great lump of a motor. Before anyone notices, it is only the ruler that was made in England and as soon as my wife reads this and realises that I have stolen a ruler from her desk I shall be in trouble! The website of the manufacturer can clearly be seen in the picture, I assume that it is made in the US but can be bought all over the world easily from ebay.

new boxNow compare this picture with the picture of the motor fitted above and you will immediately see that bulk and weight has been saved by doing this mod. You will note that there are two tie-wraps fitted to mine, but the kit comes with just one, the reason is that I have a tub full of them and you never know – one might break.

With the motor and the cables removed from my bike it is probably nearly a kilo lighter. That should be great for performance, but there again if I carried less change in my pocket I could also save that much weight and still would not notice it when I ride!