Wildgoose Chase Moto Guzzi

General Category => General Discussion => Topic started by: SmithSwede on March 07, 2015, 06:42:24 PM

Title: Which Cylinder is Closest To Front?
Post by: SmithSwede on March 07, 2015, 06:42:24 PM
On a 13 Guzzi Stone.  I don't think the con rods share a bearing, so they must be positioned side by side.  So one cylinder must be slightly in front of the other.  OK, so which cylinder is positioned closest to the front wheel?  I can't eyeball it.

Is this arrangement true for all Guzzis throughout history, or does it vary somehow?

Seemed like this was more obvious on my BMW airhead.  Or maybe I'm just going blind. 
Title: Re: Which Cylinder is Closest To Front?
Post by: Antietam Classic Cycle on March 07, 2015, 06:45:40 PM
As you sit astride the bike, facing forward, the right cylinder will be slightly farther forward than the left.
Title: Re: Which Cylinder is Closest To Front?
Post by: dilligaf on March 07, 2015, 06:51:37 PM
OH!  Facing forward.  Got it.  :BEER:
Matt
Title: Re: Which Cylinder is Closest To Front?
Post by: Joliet Jim on March 07, 2015, 06:59:59 PM
i always thought my one leg was shorter, explains alot :)
Title: Re: Which Cylinder is Closest To Front?
Post by: John A on March 07, 2015, 08:33:01 PM
The cylinders are numbered front to back, #1 is on the right, #2 is on the left. It would be opposite if they were numbered left to right.
Title: Re: Which Cylinder is Closest To Front?
Post by: charlie b on March 07, 2015, 08:34:25 PM
LOL, yeah, riding along and I can feel the left cyl 'tapping' my knee.  Then realize I can't feel the right cyl.  I must be sitting crooked!  Then the light comes on.
Title: Re: Which Cylinder is Closest To Front?
Post by: leafman60 on March 07, 2015, 09:10:31 PM
On a 13 Guzzi Stone.  I don't think the con rods share a bearing, so they must be positioned side by side.  So one cylinder must be slightly in front of the other.  OK, so which cylinder is positioned closest to the front wheel?  I can't eyeball it.

Is this arrangement true for all Guzzis throughout history, or does it vary somehow?

Seemed like this was more obvious on my BMW airhead.  Or maybe I'm just going blind.  


As has already been stated, the rider's right cylinder is offset further forward.

Yes, this is more obvious on the BMW boxer engines.

The BMW crankshaft has 180 degree staggered crankpins for the connecting rods. The Guzzi crankshaft has a single pin onto which both connecting rods fit, side by side.  The separate crankpins on the BMW crankshaft position the connecting rods further apart (and the cylinders) than does the single pin crankshaft of the Guzzi.

Getting more technical, the BMW arrangement creates more "rocking coupling" imbalance than does the Guzzi. If Guzzi had knife-and-fork connecting rods like the Harley Big Twin, the rocking coupling effect would be eliminated and the cylinders would not be offset.
Title: Re: Which Cylinder is Closest To Front?
Post by: mtiberio on March 07, 2015, 09:12:22 PM
Guzzi rods share a crankpin/journal/half the bearing. They touch one another side by side. In BMWs, each rod has its own crank throw, and a resulting larger (than Guzzi) offset front to rear.
Title: Re: Which Cylinder is Closest To Front?
Post by: Cam3512 on March 08, 2015, 06:55:40 AM
All I know is it's easier to stretch my legs on my Guzzi.  Keep banging my ankles on the airhead.

Hope this isn't too technical...
Title: Re: Which Cylinder is Closest To Front?
Post by: sib on March 08, 2015, 08:23:42 AM
Yes, the difference is only about 1/2 inch (on my '13 V7 Stone), not enough to notice unless you know, then it seems like too much.
Title: Re: Which Cylinder is Closest To Front?
Post by: Wayne Orwig on March 08, 2015, 08:41:50 AM
Destra
Title: Re: Which Cylinder is Closest To Front?
Post by: mtiberio on March 08, 2015, 05:30:58 PM
On big blocks that have distributors, you can see the factory put them behind the more forward cylinder