01' 5 hunny vibratin'son of a gun

[99raptor]

I just purchased a 01' kx500 and the vibration is ruining my rides.I've  talked to a few other big bore 2stroke guys and they say its normal vibration.Would an aftermarket heavy flywheel stop any of this arm numbing,testicle shakin vibe?

[redlined_KX500]

 
I replaced the stock handlebar and clamp assembly with fat bars and their allen head clamp and put some high density rubber grommets under the bar mount assembly.

I also balanced the crank while town down. Vibration wise, feels just like 250 till I crack the throttle

I'm curious about any other vibration reduction others have done to their K5.

[hughes]

Pro Tapers with solid cone mounts helps alot, check all the engine mounting brackets for missing or loose bolts. Worn main bearings?

[Platypus]

I just rode my KX500 for the first time last week and the vibration is quite different.  I am pondering Fasst Flex Bars.   

http://www.brpit.com/pages/products/flexx_bars.html 

There is no doubt they will be the most effective bar available when it comes to reducing vibration.  The cost is the only issue.  I wonder if RG3 ever made a top triple clamp for the 500.  That would be a sweet set up, flex bars and RG3 triple clamp.

[Marc S]

Before I bought my KX500 I heard how bad the vibration is on these bikes and I was hesitant to buy one. I am glad I did, I hardly notice the vibration. Mine is street legal and I do not really notice the vibs at all even on the roads. I wonder if some are worse than others.

Marc S.

[Mick]

I had my crank balanced by an outfit called Surf 'N Turf out of CT.  I know there are several shops that due this but I can't vouch for all of them.  Surf 'N Turf did an excellent job for me though.  It cost about $400 for a new crank rebuild and balance.  Engine endused vibration is cut by a modest 2/3.  You feel that everywhere.  No humming in the pegs, no shaking between your legs, very little felt in the bars until wide open and quiter.  I'm pleasantly surprised how much different in runs as well.
You can use all the bars and triple clamps you want, but it's just covering up the problem.  For an absolute no bullcrap solution you need to balance the crank.

[Platypus]

I had my crank balanced by an outfit called Surf 'N Turf out of CT.  I know there are several shops that due this but I can't vouch for all of them.  Surf 'N Turf did an excellent job for me though.  It cost about $400 for a new crank rebuild and balance.  Engine endused vibration is cut by a modest 2/3.  You feel that everywhere.  No humming in the pegs, no shaking between your legs, very little felt in the bars until wide open and quiter.  I'm pleasantly surprised how much different in runs as well.
You can use all the bars and triple clamps you want, but it's just covering up the problem.  For an absolute no bullcrap solution you need to balance the crank.

So if I choose to buy bars that help absorb big hits and also help reduce engine vibration it's a bullcrap solution?  Guess I better go get my crank balanced.  Funny thing about balancing a crank.  I can't put that crank in the 450 I buy in a year, but those bars will bolt right on.  I try to stretch things out because I don't have money burning a hole in my wallet.  I don't think any soultion that helps is bullcrap.

[don46]

Some of the posts suggest solid mounts or high density rubber mounts, Kawi put the rubber mounts on the 250 and 500 to reduce the vibration transmitted to the bars. The 125 used to have solid mounts and very little vibration. For my money, if vibration was an issue and money wasn't, I'd true the Crank, makes a huge difference in vibration as well as longevity, rubber bar mounts, a good aluminum bar and ,maybe a bar snake to deaden the vibration. Unfortunately, vibration (or at least some vibration) is the nature of the beast.

[Mick]

So if I choose to buy bars that help absorb big hits and also help reduce engine vibration it's a bullcrap solution?  Guess I better go get my crank balanced.  Funny thing about balancing a crank.  I can't put that crank in the 450 I buy in a year, but those bars will bolt right on.  I try to stretch things out because I don't have money burning a hole in my wallet.  I don't think any soultion that helps is bullcrap.

Well yes when you put it that way I'd call it a bullcrap solution.  What you're talking about is a temporary fix.  A bandaid.  What I suggested is not.

When you've got a bar snake and flex bars you're in $360 already...not including bar mounts.  If you're gonna half ass something you'd be better off saving money while you do it.  So park the 500 now if you plan on getting a 450.  Then you'll be sure not to feel any vibration, and you'll save enough money to buy those bars instead of fixing your 500.

[KXcam22]

Easy there boys, any solution to vibration is a good solution.  It seems with the KX it is a bit of a crap shoot as to how well the crank got balanced at the factory.  Big variations! My 92 is super smooth (a lucky crank) others need some serious rebalancing.  This may be one of the root causes of the notorious upper pipe mount breakage.  If you are planning to go 450 soon the fastco is a sano setup, although it only helps the hands.  For those who want some serious RPM and HP out of the 500, balancing the crank is often the starting point.  For dez guys it's a must.  For everyone, a good starting point is to redo all of the engine mount bolts: take the nut off, clean & examine the threads and retorque to torque+10% with red locktite.  Will cut vibs and never fall out.  Cam.

[c-152]

I had heard about the vib problem when I first got my 500.  Everyone told me I was going to hate it but I honestly to not notice it.  My bike has Renthal bars on stock mounts and my pegs are stock as well.  Mine is a 92 as well (maybe a good year at the factory) and I have seen no need to plunk down a bunch of money for it.  I know this might sound stupid but if I were you I would just try to go out a couple more times to see if you get used to it.  That is unless you have a bearing or crank issue and the vibs are so bad they are causing damage.  In that case I would tear into it and replace the bearing and true the crank (might as well since it will have to be torn down)

[billygoat500]

you wanna talk vibration/ My yz-490 was the last bike that i usaed to ride. I still have it but but have upgraded to a 5 hunny. The vibtation of the is like comparing a Jaguar to a 3 ton truck. It took Quite a lot of work to get the vibration down to an acceptable level.
Mounting the bars solid to the tripple clamp and filling them with clear silicone helps a lot. Make sure thet the steering head bearings are adjusted and not worn. Just changing to a better handle bar makes a diff. Stock bars are garbage. All motor mounts and bolts tight.  Loose fuel tank is often over looked make sure that it is tight.  With above mentioned mods and all things in propper working order my bike is a dream machine,luxury big bore.All I have to do is hang on tight.

[Mick]

Yeah it does seem to be a leap of faith as to how close the crank is trued and balanced.  Seems the factory allows for so many grams one way or the other.  Sometimes you luck out and the crank, rod and piston happen to be just the right weight...sometimes you don't *shrugs*  It'd be nice if you could walk into a storage closet full of engine parts and weigh every piece before you bought it.  My '89 was bad, real bad.  The kind of bad that s**ts bolts every ride.

[hillclimber147]

.......The kind of bad that s**ts bolts every ride.

  Been there, done that. Bike of course. Not me!

[FuriouSly]

IF you have replaced a piston, then your crank/motor will more than likely be out of balance.  Even motors from the factory are usually out of balance,  definately hit or miss.  Weighing the piston/rod assembly (rotating mass) and matching them to the crank to minimize rotating imbalances is the major way to reduce engine vibrations.  Of course that takes money and a builder to do it.

If you have enough vibration that your hands are going numb...  that is probably tearing your motor (bearings,  seals,  mounts,  etc.)  and frame apart.  Bolting stuff on to reduce vibs  (bars,  mounts,  lead,  silicone,  etc.)  is good,  in my opinion if you have already balanced the crank.  Putting $ into the motor will make the motor,  frame,  parts mounted to the frame last longer.

I have had the crank balanced/welded when it was ported/rebuilt,  pro-tapers,  solid bar mount triple top clamp,  siliconed the pipe brackets,  and rebuilt the pipe mounts.  IT still vibrates!!  Granted alot less than when I first started,  but that was stock.  After rebuilding it and you go with more compression..  more vibration..  its a relationship you can't avoid.  I have a much stiffer suspension now and that increases vibes as well.  So,  it is probably back to a medium vibration KX5.

I think the best thing that I have found to help reduce vibration is...  Ride in the SAND !!  Like a giant sponge to help soak up the vibes...

Sly