Bigger exh valves on my 650 supermoto.

hello,

I changed my exh valves last week,It was a special set I bought from
D. Lineaweaver,I must thank this person to give some very important parametrics to set up the valves in the right way.( spring height,Protrusion...)

When I bought the bike I was very surprised that all the bergs had the same diameter from valves,something normally is not possible.a 450 with 30-35mm and a big 650 with the same measurements.
After some interesting comments of dale,it was wiser to invest in the exh valves than in the intake valves. So after this we went for the bigger valves.
Some results from my dyno.

completely stock with 180 main 59,4SAE HP or 62DIN hp at the rear.

cilinderhead ported +DOMA exh 178 main and 50 pilot around 61,8 SAE HP or 63,8DIN hp.


now with the bigger valves 180 wat is for now too rich (32degrees C)
63SAE HP or 66DIN at the rear in those quite rich condition.
So normally I must get 64 SAE HP with smaller main jet or 67 DIN HP.

Holding in consideration that my engine is tuned on low and mid especially for supermoto use.top HP at 7800RPM's.Torque at 5600rpm's.
I also ordered the x2 cam ,especially to keep the power on low and mid Rpm's.This cam is not arrived yet.

I could recommend this mod for everybody who has a 650 2004 like mine..

Normally I change 2 things the x2 cam (for little bit more power +life on the chain)
And the second thing I will change is a saddle with a whole in it at the area of the airfilter,this gives about 1 Hp on my former bike.So I have a better airflow.

hello,

In stead of 32mm I had 31 ,5mm with special flow.stock was 30

I make the opening from 28 to 29 mm.problem was to much protrusion 1,5mm changed this to 1 mm.intake on 0,5mm protrusion.

I measured then the distances with plasticine (clay) to maintain a secured distance.

I tested at bench and day after for a session of 30 min,normally i espect no problems.

greetings Mathieu

riding with the valves for about 3 hours and no problems so far.

the last time I put my bike on the dyno;these numbers;

65 SAE HP or 68DIN HP (50---3----180)
torque 66Nm

My X2 cam has finally arrived,but I exspect no large improvement only gentler on the chain.(last one changed on 24-25 hours)

Bases on the last test i could made another mod on the carb,so as for now current setup at approx 20-25degrees C.
48---4th clip----170 main.
This week I will benched this
I had from a Belgian tuner,friend a nice info from the work that Ben Ballard did,very impressive.
I think he will gives us some more details.

Greetings Madero
Mathieu De Rouck.

hello,

I have put my bike on the dyno,

with the latest changes I have about the same power, but the Largerst improvement is that the power comes out faster.

time versus HP versus speed.

Within a couple of weeks I will put in the x2 cam,and then I will put my bike on the bench.

greetings Madero