Vibration

[knumbnutz]

Hey All,

 

So I finally got to ride the new beast yesterday around the block and back to strub in new tyres.

Seems to run well, makes plenty of power - seat of the pants says around 100hp, but it has a fair amount of vibration. No noises though, just vibration. Like Sportster vibration - lots, certainly not from tail shaft either.

I am just about to do oil, filters, etc, done wheel bearings, tyres and pads already.

 

What would cause vibration like this, flywheel, TB out of balance ?? any clues

 

regards Neil

[knumbnutz]

My new bike - 

[Jim in NZ]

Hi Neil,

You will get knumbnutz if you ride too far like that!

Assuming engine mounting bolts etc. are all tight, I agree with you, I would put my money on the throttle bodies being unbalanced. You will need vacuum gauges to synchronise them properly. It's definitely worth the trouble.

You will always get a bit of low-frequency vibration at certain speeds, so if you came from a smooth multi-cylinder you might just be feeling normal vibes. But if that Coppa Italia in the photo is yours, you will know what to expect.

Cheers,  Jim.

[fotoguzzi]

Hey All,

 seat of the pants says around 100hp,

LOL!

 

stock? maybe 75-80hp..

[Scud]

That luscious paint job adds an easy 20 HP on the butt-dyno. The powerband is very usable, which contributes to making it feel like more HP. Was the bike good and warm? Did you get a chance to see how it runs at higher revs? Mine likes 3,500-6,500 pretty well. A proper tune is always a good idea. It should not shake like a Harley Sportster.

[motoguzznix]

Neil

 

There is a lot of work done on your bike. When I look at the polished exhaust system - I know this because I did this work on my own V11. 

 

I own a MY 2000 KR V11. Despite an accurate tune up with carb synching, CO checking and so on my bike suffered of very serious vibrations. Out of this reason I dismounted the engine at 9000 km and balanced the crankshaft. With this measure I got rid of the vibrations. I read a test by Alan Cathcart in a motorcycle magazine where he also complained extreme vibrations on the tested V11. Some early V11 engines seem to vibrate, most don't. 

 

If a correct calibration of the engine does not cure the vibrations, yours seem to be also one of those. Mine is now as smooth as any V11 if not better. But it is a lot of work getting the crankshaft out of the engine...

[knumbnutz]

Thanks for the replies. I say "feels" like 100hp because it feels more powerful than my ducati which dynos at 89hp and it is basically a 2valve race spec 950 motor.

 

Ernst, it makes sense if some of the cranks were out. I rode a V11 back in 2003 and certainly do not remember any vibration, so this is why I was asking if its me or the bike.

There has been a lot of work done some of it is good work, some not so.. There was a starter button wired up next to the old one, under the mirror and I was told they couldnt fix it. 

So I took the tank off last night and did a service and fixed the starter. The connector from the start/stop buttons was not in correctly and the relay was not working. So I fixed those and removed the clutch switch - what a silly idea. Just another lace to fail IMHO.

Starter Button works a treat now and I have removed the 2nd switch.

 

Found the sump plug is stripped, thats the next job. Fixed the sagging rubber under the tank. ALL the hose clamps are destroyed from over tightening, never seen such a thorough job !.

Machined up a 27mm nut to get the filter plate out. What a pain in the ass to get it back on. New grips , new mirrors, billet brake cover... waiting for a Clutch and rear brake cover because the knuckledragger previous owner doesnt know where the old cover is ... the rear master reservoir has no top cover FFS. May go clipons yet and footrests seem very smooth - may need to replace those.

 

One thing that really gets on my nerves is everything needed lubrication. The brake, clutch , gear lever, side stand etc were rusting at the pivots. The pivot pints in the levers are worn and the clutch and brake lever holes are well worn and I have some sharp looking cnc levers to replace them. 15years, 50000km and never lubed anything ... LAZY and a personal pet hate .

 

Getting there though. At least it was cheap.

 

 

Neil

 

There is a lot of work done on your bike. When I look at the polished exhaust system - I know this because I did this work on my own V11. 

 

I own a MY 2000 KR V11. Despite an accurate tune up with carb synching, CO checking and so on my bike suffered of very serious vibrations. Out of this reason I dismounted the engine at 9000 km and balanced the crankshaft. With this measure I got rid of the vibrations. I read a test by Alan Cathcart in a motorcycle magazine where he also complained extreme vibrations on the tested V11. Some early V11 engines seem to vibrate, most don't. 

 

If a correct calibration of the engine does not cure the vibrations, yours seem to be also one of those. Mine is now as smooth as any V11 if not better. But it is a lot of work getting the crankshaft out of the engine...

[fotoguzzi]

"One thing that really gets on my nerves is everything needed lubrication."

 

don't forget the driveshaft, total of 3 zirks, front one is a pain to get at, a swivel nozzle will help. do it with the axle insitu so the shaft doesn't stretch when you put lube in the center zirk.

[Stick]

The neat thing about the grease fittings on the shaft:  When you position the rear one at 6:00, the front one is at 12:00, so there's no guessing.  I finally felt the front one over this weekend.  I cannot see it, but you can feel it by entering from the front:   Jam ur hand in there, and take one finger and angle it forward.   Wow, it IS there!

 

Now I just have to see if my new kit of grease gun fittings -- if the rotatable one will work in there.

 

Stick

[fotoguzzi]

as to vibration.. make sure both tires are balanced. and steering head bearings tightened to spec... also the forks have compression in one and damping in the other leg, some miss match in settings could set up some vibration?

I doubt the TB sync would cause that much vibes accept at idle.

note that the steering neck/frame bolts right to the timing chest of the motor, vibration is inherent in the design so if the motor is not well balanced you shake..

[droydx]

Your bike looks like a nice compilation of several bikes.. I'd say the handlebar set up is adding to the vibes. It looks like a conversion, with a riser perhaps. I note there are no bar ends...my stock LeMans really tamed down the vibes with a heavy set of bar end weights, change of grips. It's an easy cheap "try before you pry". Open your engine!

 

Andy

[Bob Hartman]

I’d noticed some new vibration in the handlebars (02 Le Mans, 22.5k mi) and hoped new tires would fix it. That wasn’t the case.

When I pull the clutch in at speed and everything smooths out; images in the mirrors become perfect.

So it’s engine or transmission related.

Adjusted the valves, only one was .001” out. Installed new plugs and adjusted the throttle bodies using vacuum gauges.

Surprised to see they needed a few turns on the white knob. This helped at low revs, especially when pulling away. But still the tingling, especially after highway miles. Lubed the shaft splines when changing the tires.

I see people getting good results with bar weights but would like to address this at source, given it’s relatively new. Anything I’m overlooking?

[Lucky Phil]

Cant remember but does the 02 Le Mans have the single plate alloy flywheel?

 

Ciao

[Chuck]

 

a few turns on the white knob

*Something* is wrong.. it shouldn't take more than a partial turn..

[Bob Hartman]

I think the Scura had the light flywheel assembly.

 

Chuck, I should have said turns back and forth on the white wheel, the sort of thing you do dialing in.

Replaced the manifold rubbers and cleaned the butterflies and throttle bodies, too.

 

Still, raises the question of whether an injector needs replacing. Only 22,500 miles, but 16 years old...