Ducati Monster Forum

Moto Board => Tech => Topic started by: Forza Asa on July 14, 2011, 03:45:46 AM

Title: problem with vibrations
Post by: Forza Asa on July 14, 2011, 03:45:46 AM
I'm traveling a lot with my Monster and have always done so. Right now Im making the greatest chalange of my life, riding more than 7000 km and I thought I had planned and prepared for everything.

But I was not prepared for my feet going numb on the second day. After two weeks they are still numb and the doctor suspects vibrations damage, something that sadly is quite serious.

When I was on the road suffering badly I went to a garage (happened to be a Harley garage) but anyway they sad nothing seemed wrong but recomended me to change the chain kit wich was badly worn. A day later I did that, posibly the vibrations got less but hard to tell since I cant really feel normally anymore.

I am upset with the garage that did the pree-vacation maintainance that didnt tell me that the chain needed to be change, but I didnt ask in detail either. I just asumed they would do everything acording to the book. Now Im vorried that there is other things they didn't do as well.

But anyway, now Im stuck 1/3 in to the trip, fortunately in my home country, but I don't know how to go on. Does anyone know what can be done to minimise vibrations in footpegs, or what causes them. From the informatin I found about vibrationdamages they are permanent so I dont want to risk it getting any worce and honestly I dont know if I dare to go on with my journey.

Any feedback, tips, chared knowledge and experience is highly appreciated.

Cheers Ã...sa

my blog: forza.greynorth.net (http://forza.greynorth.net)
Title: Re: problem with vibrations
Post by: WTSDS on July 14, 2011, 06:36:52 AM
May not be the vibrations, could be your seating position. I do some 10 hour rides and found adding a few inches of firm foam padding on the seat made a huge difference to my leg comfort. Good luck with yer venture.
Title: Re: problem with vibrations
Post by: RAT900 on July 14, 2011, 07:12:51 AM
Stock seat, bad positioning of hips and knees resulting in constricting blood flow or pinched nerves

and add on the vibrations and the disturbance of capillary flow at the extremities and riding becomes a torment worthy of the Spanish Inquisition

I drop 2 aspirin the night before I ride for more than 2 hours to thin out my blood a little...at my age I need all the circulation I can get anyway

you could try gel soles to insulate your feet some, and thicker soled boots

but your anatomy, coupled with the bike's geometry and vibratory characteristics certainly aren't working for you...

nor is the semi-jockey crouch conducive to long range cruising anyway

good luck...personally 2 weeks of numb feet and the bike would be on a flatbed

and I'd be seeing a doctor and maybe get them to write a scrip for coumadin/warfarin

to get my blood thin enough to seep into the tighter spots to see if I could get my feet to wake up again...or something like that
Title: Re: problem with vibrations
Post by: zooom on July 14, 2011, 07:19:39 AM
year and model of your Ducati? mods? your height/weight/inseam logistics?
Title: Re: problem with vibrations
Post by: bikepilot on July 14, 2011, 07:27:49 AM
Touring boots with a thicker, softer sole make a huge difference.  Also, you can fiddle around with the bike to quell the vibrations as well.  Make sure all the usual maintenance stuff is up to date to ensure that the motor isn't shaking more than it should (TB sync, valve adjustment, belts, plugs, etc).  You can also change gearing (sprocket sizes) to alter the rpm the engine turns at your typical riding speed to get the engine into a smoother band.  Also check that your footpegs still have the rubber bit and that the rubber isolators for the rearsets are in good shape and not deformed or hardened.

Sometimes all that still isn't enough.  Two further ways I've found (generally, haven't tried this on a monster yet) are first to alter the frequency of the rearset by changing its weight (in a pinch once I secured  a heavy car trailer hitch ball to the rearset of a 919, worked a treat).  Second, if your exhaust is attached to the rearset it is probably transmitting a lot of the vibration.  Remounting the exhaust so that it doesn't bolt to the rearset (boomtubes?) can help a huge amount (for example, my Bandit 1250 had the exhaust can mounted to just one rearset, that side vibrated badly, the otherside not at all - motor itself was very smooth).

For your feet, after a 9k mile trip on the 919 in hard race boots my left foot was numb from the vibes - I feared permanent damage, but after about a month it was back to normal. The pinky toe was the last bit to start working again, but all good now.

Also, I'm assuming its engine vibrations that are the issue, wheel balance etc can also cause vibration.  Its easy to tell which, get up to speed where the vibes are bad and pull in the clutch and let the engine to to idle, if the vibes go away, its the engine, if not, its the chassis.  Also, engine vibs change with rpms rather than mph and will generally be a higher frequency.

A bad chain/sprocket can certainly make vibes worse - as chains wear they aren't as uniform in length so as the chain goes around the engine is constantly, but slightly speeding up, slowing down, speeding up etc.

Title: Re: problem with vibrations
Post by: BK_856er on July 14, 2011, 11:29:27 AM
I went to your blog link.  Looks like an epic journey - I'm envious!  I don't have much long-distance experience, but I'll make some observations/comments anyway.

When you say your feet are going numb, is it the ball of your foot, your toes or your entire foot?  Both feet?

Presumably we're dealing with normal M695 vibes and not something new and unusual.  You've had the bike a while, so you would have let us know if the vibes have increased dramatically.  Let's rule out loose clutch or flywheel nuts, etc.  But as mentioned you can try to choose rpms that minimize the vibes (upshift, downshift, alter speed).

You seem to have the stock rearsets with intact rubber isolators and rubber footpeg coating (and not aftermarket hard metal ones).

Suspension probably plays a minor role here, but you are loaded with gear, so maybe something to consider especially if the road conditions are poor.  Tires at correct pressures, suspension sag reasonable?

How about your ergonomics?  With front/rear bags you probably have very limited seating positions.  Try to move around and reposition your legs/feet periodically and take weight off of them.  Seats from all other monsters are 0.75" taller and might give you a more beneficial foot/leg position.

I can second the recommendation for gel boot liners or a more touring oriented boot for your application.  Your Oxtar boots look to be track style and probably don't have too much sole thickness.  I would look to a footwear modification or change right away.  Good luck getting healthy and continuing your journey!

BK
Title: Re: problem with vibrations
Post by: Forza Asa on July 14, 2011, 12:49:46 PM
Thanks all!!!
My bike, year 07, 695, has been mine since new, and it's my third monster so I have experience of normal vibrations, but never had problems.
Before leving Madrid for the journey up north I had my bike in for the 20 000km service so I asumed everything would be in order setting of. But as said I had to change the chain kit wich was badly worn but I didn't realise and garage didn't say. After changing it I though everything felt better, but it is indeed so hard to tell.

My feet are numb on the upper side and an area reaching up on my front side of my leg (sorry english is not my mother tounge).

After reaching Sweden I rested two days in Gothenburg before going to Värmland. When I went riding again I felt that my feet very fast started to trickle. And then also just from vearing tightly knit shoes they trickle. I have no idea if this is good or bad.

I haave been to a doctor but I felt afterwords that I din't get sufficent answers, but a lot of test vere made. Doctor did say that he thought it was damage caused by vibrations. But afterwords I realised that there was no information given on how to act on this, if further riding will make the damage worse etc. Tomorrow I will call again to get test results and hopefully some more answers.

The day the numbness came I had been riding in rather cold weather and in the pyrinees, and then some rther straight and dull road, so I could have pinched a nerv or something. I noticed something was wrong when my foot started to trickle. And then I had a hard time chifting gears becase it felt like I lost my strenth.

The vibrations differs depending on the rpm not the speed and that is as it normally is.

My data then, Im tall (part of the problem I guess) 177cm, 70 kg, inseem length of leg to heal is 87cm. I prefere to put the toes on the foot peg because then my knees fit the tank and the bum and back position is confortable but it gives an agressive angle of the leg-heal-fot (now this is very unconfortable because the boot preasures on the foot and makes it trickle)

I am very greatful for every anwer and idea I can get, I'm not a mecanic so I cant do anything complicated. i have tired to put more rubber on the footpegs but I notice no difference. I'll see what can be done with the boots, Karlstad dont have much to offer but I'll go and check.

As for foot peg options they have said that ther is none in every bike store I been to. And calling Ducati (Biscaya) he said that it is an unusual problem and nothing to do if the foot pegs are the rubbery ones.
Title: Re: problem with vibrations
Post by: zooom on July 14, 2011, 01:06:52 PM
it almost sounds like a disc herniation in your back pressing against a nerve. is the sensation or lack thereof only in your foot or moreso in the whole leg?
Title: Re: problem with vibrations
Post by: Forza Asa on July 14, 2011, 01:23:32 PM
The numbness is on the upperside of my feet and streching up on my legs front/outer side.

My feet also go cold (colder than normal that is)
Title: Re: problem with vibrations
Post by: zooom on July 14, 2011, 01:32:12 PM
sounds like back position may be pushing badly on your L5 and/or S1 discs and pressing out into the sciatic nerve...I am NOT a doctor...I am just talking from experience...back alignment would probably do you some good and/or some sort of brace to make sure you aren't bending over or in a fashion that is detrimental....

IF that is what is going on....
Title: Re: problem with vibrations
Post by: BK_856er on July 14, 2011, 02:00:23 PM
Zooom brings up a good point.  When I've had minor/temporary foot numbness it's always been at the point of contact of the footpeg and and the ball of the foot where the pressure is applied.  My Sidi Vertigos are only about 2mm thick in this area.

Seemingly your issue is partially ergonomic.  You could swap in a non-M695 seat and gain 0.75" of knee room.  I did that and preferred the change.  The non-M695 seats are also not as curved so it's easier to move front/back and find a good position that works for you.  I also have Rizoma rearsets that are almost infinitely adjustable (see below).  Maybe something you can consider.  You loose the rubber coating on the stock pegs, but gain many options for foot placement (and therefore knee position and back angle).

On the mechanical side, also have your shop verify proper torque on the two engine-frame mounting positions.  These can loosen up and might (?) cause additional vibration.

BK

(http://i32.tinypic.com/2med074.jpg)
Title: Re: problem with vibrations
Post by: bikepilot on July 14, 2011, 03:16:15 PM
Also make extra sure that the chain is not over-tightened.  You will get more vibes if it is too tight and it will wear more quickly than normal.  The chain will look fairly slack when the bike is on a side-stand, but will get tighter as the rear suspension is compressed.  The chain needs to have a little bit of slack (at lest 12mm I would say) at the tightest point (which will be when the countershaft, swingarm pivot and rear axle are all lined up in a single plane).

Title: Re: problem with vibrations
Post by: Forza Asa on July 15, 2011, 12:53:57 AM
Thanks! The back is normally my weak spot, but I guess gym payed off sinceI have not had a single problem with my back during this journey.And I sit up very straight while riding, and I have long arms so no problem reaching the handlebars, so I don't think it is the discs.
I'm now awaiting the phonecall from the doctor so I can ask the crucial question "can I continue riding to England without making my problems worse?"
Title: Re: problem with vibrations
Post by: Langanobob on July 15, 2011, 06:01:03 AM
I've done quite a bit of long distance riding on a very shaky '66 Triumph and have  never experienced any sort of foot numbness so I'm sort of at a loss for suggestions.   I think I would try cutting some rubber strips from an old inner tube from a shop and wrapping them around the foot pegs and securing with wire and/or tape.   That might help with vibration.   Plus the previously suggested boot gel insoles.   It almost sounds to me like your boots or clothing might be cutting off circulation to your feet.   Is it possible to buckle or lace them a bit looser?  Or try  different boots?

Best of luck with the rest of your trip.

Bob
Title: Re: problem with vibrations
Post by: Forza Asa on July 15, 2011, 06:46:10 AM
I finally got the long awaited call from the doctor and was told that I can continue with my trip but have to take breaks often and try do decrease the vibratons.

I have tried to put rubber on the foot pegs (bike tube winded around) no good result, will now try to put a bit of camping madrass on there. It's not porible to do any adjustments to the bike here and now no garage I've been to has even had a suggestion of something to do, and there wont be a posible to get an apointment anyway (riding season is very short in Sweden and the garages are fully engaged during these months)

Tomorrow I'll investigate the options of new boots. Since nearest town is Karlstad, (small) my hopes are not big. Othervise 3 dayrides away I get to Lubeck and they have both Polo Motorrad and Louis there so hopefully plenty of options. But it is unfortunate being a woman, most hard core high shafted boots are only male and there fore sizes start at 41 :S What ever's been said and done this is still in many ways a mans world.
Title: Re: problem with vibrations
Post by: bikepilot on July 15, 2011, 07:14:14 AM
You might try some softer material around the footpegs.  Pipe insulation or role cage padding (often the same thing) would probably work well. It will not last long, but its very inexpensive and you can replace it yourself in a few minutes every few days.  Some plastic wire tires should be sufficient to secure it.

Something like this - should be available from most home-improvement, construction or plumbing type places
(http://www.euroace.org/Portals/0/images/High-Rise/pipe_insulation.jpg)

If you can't find softer boots and if your boots are not too tight you could try fitting a cushioned insole to your boots.
Title: Re: problem with vibrations
Post by: OT on July 18, 2011, 05:25:20 PM
Not a bad idea, but be careful that whatever you put over the pegs does not rotate (spin) around the peg, else your foot might slip off if you apply (too much) pressure to the pegs - with possibly serious consequences.
Title: Re: problem with vibrations
Post by: WTSDS on July 18, 2011, 05:36:38 PM
>>What ever's been said and done this is still in many ways a mans world.

I've ridden a gazillion motorcycles and let me tell you the Monster seat/tank arrangement is the least comfortable for my " man parts ".

Title: Re: problem with vibrations
Post by: Forza Asa on July 21, 2011, 02:28:25 PM
Just a thought...
if it is so that my motorcycle now vibrates more than before... what could have caused that? Bad maintainance? Something that wasn't done properly at the garage for the 20 000km service!?

For what I know the vibrations comes from the engine, because they varies with rmp rather than speed and disapears when I pull the cluth.

If it isn't the bike that vibrates more it is me who had gotten more sensitive, but for me it is imposible to say.