Hey every one hope your well.

was just reading through aprils edition of Bike motorcycle magazine and looking through the awsome spec on the new yzf-r1 and would like some one to explain it in simple terms for me just so i can get my head around it!

another thing that is pretty cool is that 1 fork leg is for rebound (right) and the other for compression damping (left)

Hey every one hope your well.

was just reading through aprils edition of Bike motorcycle magazine and looking through the awsome spec on the new yzf-r1 and would like some one to explain it in simple terms for me just so i can get my head around it!

another thing that is pretty cool is that 1 fork leg is for rebound (right) and the other for compression damping (left)

On a normal 4cyl engine the firing stroles are every 90 deg so over 4 revoloutions you get 4 'bangs'. On the big bang engine you get 4 cylnders firing over 3 revoloutions cos 2 cyl fire together hence the 'big bang engine'. But to confuse the issue the big bang is out of phase with the other cyl i think. Sort of bang,bang, wait a second BANG and repeat

Gives the torque of a twin with the high rpm of a 4. If you ask me triumph did that already the easy way.

Did that help.........?

Not quite correct cynic but nearly.

The pistons on a normal inline four are set at 180 degrees from the next one along the crank so you get

<TDC><BDC><TDC><BDC> all firing at regular intervals.

The R1 Crossplane crank sets the pistons at 90 degrees from each other, so you get

<NORTH><EAST><SOUTH><WEST> North being TDC and South being BDC and firing at irregular intervals, hence the 'big bang' where two cylinders fire at close intervals.

The firing order is 1,2,4,3. It is cylinders 2 & 4 that fire close together giving the 'bang'.

One reason Yamaha used this design was to reduce unbalanced vibration.

It's a bit like a washing machine in theory - If you have a heavy load concentrated at the bottom, the drum will spin off centre. however, if your load is evenly distributed, the drum will spin on it's axis with less deviation and less vibration. I hope this explains what I mean sufficiently.

the crossplane crank is also said to improe the way in which power is delivered from throttle to rear wheel, making it more linear and predictable than a standard inline four.

Thats a very good way of explaining it, its called the big bang as when you hear it its like one big bang as theres only 90 degrees between two firing then a wait of 270 degrees

the crossplane crank is also said to improve the way in which power is delivered from throttle to rear wheel, making it more linear and predictable than a standard inline four.

Hence, the reason Mr. Spies is doing so well on 1 this season.