LMIV - One side pushing more air than the other

[bentombed]

not sure if this is a problem or if i am inventing a problem

when the Bike is at idle there is significantly more air coming from the left pipe than the right, the idle is pretty well balanced and the bike rides really well, it's just not pushing the same volumes of air from each side.  is this something i need to worry about?

[John A]

Nope, it only happens at idle

[pete roper]

One hopes it isn't pushing 'Air' or you certainly have a problem!

I'll get my coat.........

[wirespokes]

Really? The exhaust is stronger on one side than the other? I'll have to check mine.

[oldbike54]

 Left side is the lead cylinder .

 Dusty

[pete roper]

Yup, firing intervals of 270/450 make it so.

[wirespokes]

Let's see if I'm understanding this: The left side fires, then 270 degrees later the right side. When the right side fires, the left side is still exhausting and draws some of the pressure through the crossover to the left side, which makes the right side exhaust weaker?

Good thing I never tried balancing the carbs by testing exhaust pressure.

[pete roper]

Nah, it's the amount of time between the power strokes. In the long interval the crank slows appreciably more due to frictional losses and so, as the piston is then moving slower there is more time for the gas in the burning charge to heat up and expand before the exhaust valve opens. Basically both sides, in theory, will expel the same amount of gas, it's just the  time taken before the exhaust valve opens enables the gas to be *Bigger* on the 'Lazy' side.

Pete

[wirespokes]

That makes sense, and I can even understand it. Here's something I knew nothing about and would be scratching my head over once I did, and here you've got it all figured out.

[Chuck in Indiana]

That makes sense, and I can even understand it. Here's something I knew nothing about and would be scratching my head over once I did, and here you've got it all figured out.

He's not nearly as dumb as he looks..     

[John A]

Nope, it only happens at idle

I think I'm wrong, seems like if I'm riding a Guzzi that is in tune miles after miles I can sort of sense or feel two singles under me.

[bentombed]

Nah, it's the amount of time between the power strokes. In the long interval the crank slows appreciably more due to frictional losses and so, as the piston is then moving slower there is more time for the gas in the burning charge to heat up and expand before the exhaust valve opens. Basically both sides, in theory, will expel the same amount of gas, it's just the  time taken before the exhaust valve opens enables the gas to be *Bigger* on the 'Lazy' side.

Pete

ahhh - that explains everything! thank you. 

[bentombed]

Left side is the lead cylinder .

 Dusty

thank you - I feel that information should be in guzziology somewhere to ease the minds of mechanical dummies.

[pete roper]

He's not nearly as dumb as he looks..     

I beg to differ.

[12SCraig]

Good on You knackers.

Dr Knackers.

[wirespokes]

I beg to differ.

At least he's not self conscious about it!