L-twin engine vibration. Why?

[helicopterjim R.I.P.]

Jim.......................................................vaffanculo! 

 

Dai un bacio a Marie da parte mia.

 

Just kidding pal.

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Gee Antonio. I can't find that first word in my Italian dictionary! Lucky for me I grew up in Ontario (a good Italian name, no?) and the town where I grew up was about 35% Italiano. I learned that word when I was 5 yrs old. Lucky you were kidding my friend!! I did laugh!

[Admin Jaap]

Don't say anything bad about Solex or Tex will tell Jaap

41601[/snapback]

 

Yeah, I'm the big badass term...moderator from Holland

[Lex]

So Ducati and Moto Guzzi got it wrong when they called their bikes in-line and transverse, respectively?

41632[/snapback]

 

Where did they make these statements? No having seen what you speaking of I can't make any specific comments.

 

Whatever the source, having owned both a Duck and a Goose I wouldn't take anything in an English version of their literature too seriously. My V11 Sport owners manual and workshop manual would have to improve to be good enough to be called a rough draft. My personal highlight is the drawing of the rear wheel in the V11 workshop manual that gives the tightening torque for the axel as (IIRC) 28 NM, that is only 92 NM less than the correct setting. It looks like some Guido confused the setting for the disc fasteners with the rear axel.

 

Again, I don't know the source but is it possible they are talking about the cylinder orientation? A Guzzi's cylinders are, indeed, transverse but engine orientation is defined by the crankshaft and therefore Ducati's are transverse and Guzzi V-Twins are in-line.

 

Having worked in marketing for most of the last decade I'll also throw in that most of what you read from any manufacturer was written by a marketing type, not an engineer. Look through the literature of any manufacturer carefully and you will find things that are obviously wrong. I made the mistake of buying Motorcyclist this month, not once but three times in the article on the MT-01 they state that Yamaha made the chassis more rigid by mounting the swingarm outside the frame. This has to be a quote from some marketing puke. Silly me, I thought things became stiffer if you moved the pivots further apart, the MT-01's look to be 6" to 8" (150-200 MM) apart, most other bikes are nearly twice that wide. Now that Yamaha has revealed this breakthrough I'm sure the 2005 M1 MotoGP bikes will have really narrow swingarm mounts pivoting on the outside of the frame.

 

Finally, not speaking Italian I have now way to know proper Italian terminology. One example how language/ cultural issues can muddy simple things I found in the automotive world working on German cars. I was going nuts trying to find things on my '68 Porsche, everything the manual said was on the left was on the right, every thing on the right was on the left. The situation was finally cleared up by mechanic at the local Porsche shop. In America left and right are from the drivers POV, in Germany left and right are based on the POV of the transmission looking toward the engine. Therefore in a BMW or Mercedes everything is the same, in a rear engine car like the Porsche this flips left and right. Maybe Italian engineers base the description on the cylinders, not the crankshaft as is done by English speaking engineers.

 

Lex

[helicopterjim R.I.P.]

Finally, not speaking Italian I have now way to know proper Italian terminology. One example how language/ cultural issues can muddy simple things I found in the automotive world working on German cars. I was going nuts trying to find things on my '68 Porsche, everything the manual said was on the left was on the right, every thing on the right was on the left. The situation was finally cleared up by mechanic at the local Porsche shop. In America left and right are from the drivers POV, in Germany left and right are based on the POV of the transmission looking toward the engine. Therefore in a BMW or Mercedes everything is the same, in a rear engine car like the Porsche this flips left and right. Maybe Italian engineers base the description on the cylinders, not the crankshaft as is done by English speaking engineers.

 

Lex

41661[/snapback]

You should try aviation! Everything relative to operating the aircraft is from the pilots seat point of view. Everything relative to maintenance is from the engineers point of view which is looking at the aircraft from the front. Also the engineers view isn't necessarily right and left. Sometimes it is no. 1 and no. 2! Great for cofusing new co-pilots and apprentices!

[stormsedge]

Rocket, I went with rubber faced footpegs and cushy grip wraps with heaters in them...cut down some of the vibration. Keep smiling. k

[pete roper]

OK! Now what the heck is this?

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It's a Ner-a-car Jim. Very inovative for it's time HCS and all!!!

 

Pete

[helicopterjim R.I.P.]

This is a Ner-A Car!

The other one is a Megola!

[Guest HDGoose]

try this:

 

Twin engine Vibrations

[Steve S.]

I like that 'cause it shows the secondary imbalance at 2*RPM across the frame when a 90 degree v-twin is installed as God intended, longitudinally! I still don't see the asymmetrical piston acceleration accounted for though. The other missing element is the torque around the crankshaft center as a result of acceleration and decelleration of the rotating mass. This is a large part of the varying vibration we feel when the engine is loaded, especially at lower RPMs.

[rktman1]

Thanks for the responses. I have enough info here to keep me busy for a while.

 

I'm not too concerned about the LeMans' vibes. It's my Sunday ride and not my commuter bike. I know this will piss-off the more serious riders but I enjoy cleaning the LeMans and then just sitting and staring at it. It is one of the most beautiful bikes I've ever owned.

 

Tim