Dying breed

Are “real dual-sport” riders are disappearing and the big bore, single cylinder motorcycles, like the KLR 650, a dying breed?

Everide put together a short, but very informative video on this topic. I would be very interested what do you think. If you feel so, you can send your thoughts to us through our contact page.

Here is the video.

MC mod

There is a mod from Eagle Mike, dubbed as the MC mod. In this mod, the exhaust cam has been advanced with one tooth (counter clockwise). They are claiming 7%-10% torque and horse power increase thanks to this mod and no downsides. No more oil or petrol consumed.

This last statement is a bit strange for me, because you cannot get extra performance out of thin air. This made me curious about what is in the background of this mod technically.

The engine is going through the four strokes as:

  1. Exhaust
  2. Intake
  3. Compression
  4. Combustion

4StrokeEngine_Ortho_3D_Small

Looking at a camshaft, the sequence would be as follows:

  1. The exhaust lobe pushes open the exhaust valve and the piston comes up to push the exhaust out, then starts to close.
  2. The intake starts to open, just as the exhaust is closing, piston goes down, and the intake valve closes.
  3. Then both valves stay closed for the compression and combustion strokes.

This means that the first lobe to come through the rotation will be the exhaust lobe, immediately followed by the intake lobe.

camtiming

Overlap is the point where the exhaust valve is closing, and the intake valve is just opening. To increase overlap, you have to RETARD the EXHAUST, and/or ADVANCE the INTAKE.  To reduce overlap, you have to ADVANCE the EXHAUST, and/or RETARD the INTAKE.

In our case, the MC mod is reducing the overlap between the operation of the exhaust and intake valves. In cam tuning it is known to increase low RPM power, and causing no change or reducing the high RPM power.

From the point of an outsider (me), looks like when the exhaust valve closes earlier, no air/fuel mixture can escape through the exhaust valve and also, maybe, a bit higher pressure will be present in the cylinder when the piston starts to move upwards.

For me, seems that there is no “negative” effect of this mod, because the extra power is earned from saving a bit of air/fuel mixture by not letting it escape through the exhaust valve, but I don’t have real experience in internal combustion engine tuning. If you find my logic faulty, please let me know and we can discuss it and I will update the post accordingly.

Here is a video of guys doing the MC mod.

 

Shopping

If the weather is not suitable for a ride on the weekend, you are welcome to visit the KLR Ramblers online apparel store. Grab something for your loved ones or for yourself, and show to the world your affection towards your ride. :-)

Click here for the online shop.

webshop

Before you would ask, what is happening with the profit, the store is non-profit. Any gain on sales (if there will be any) goes towards operational costs or recycled into the KLR Ramblers rides.

How do you pack for your road trip?