KTM 125sx. I am getting excessive vibration in the handlebars.

[LAKE PLOWMAN]

 

I am getting excessive vibration in the handlebars. I am missing a pipe Spring, just ordered a new one. New Renthal Twinwalls, New Fmf Factory Fatty, and Stock Rubber Cones. Whats the issue, We have tried alot?

[crider400]

 all motor mounts including head stays are snug and torqued? 

did you notice vibration before you installed your bars? All the bar mounting snug and torqued? 

How many hours on your crankshaft/main bearings? 

[ReinV]

1 hour ago, LAKE PLOWMAN said:

 

I am getting excessive vibration in the handlebars. I am missing a pipe Spring, just ordered a new one. New Renthal Twinwalls, New Fmf Factory Fatty, and Stock Rubber Cones. Whats the issue, We have tried alot?

I had 2013 KTM 450 and had same problem - could nod figuer out why. Maybe something to do with steel frame?!

[LAKE PLOWMAN]

Steel frames have more flex than aluminum^

[zibbit u2]

Did you replace the top end recently with a different brand of piston?  Could be a weight difference issue causing vibrations.

[Hans Schmid]

New Twinwalls are going to transfer vibration more. They are considerably stiffer. Equally so, worn out motor could be the other factor if everything is tight externally. If it all checks out, could just be in your head. 

[Trailryder42]

If the bike is new to you, just know that, a KTM 125 has quite a buzz normally and might seem like there's something wrong if you didn't know any better.

I would ask, it's excessive compared to what?

Edited February 26, 2019 by Trailryder42

[7Tktm]

As above, you really need to give more information. Is it something that has just happened and the bike was fine to this point, or have you just got the bike? How many hours on the motor? They are pretty vibey little engines anyway. We used to use twinwalls, but found they were way too stiff so cut the bridge piece through the middle and merely used it as a bar pad mount (Tony Cairolli used to do the same). We now only use Fatbars, together with PHDS mounts on our 125s and vibes are manageable.  It is important that the engine bolts, swing arm bolt and braces are torqued up correctly and the rotor is correctly torqued up.  If it is a 2016 on 125 there have been some issues with the rotor which was new for that year on. Bob

[LAKE PLOWMAN]

19 hours ago, zibbit u2 said:

Did you replace the top end recently with a different brand of piston?  Could be a weight difference issue causing vibrations.

we did, but withanother vertex piston the same as before

 

[7Tktm]

You've still not said if this a new occurrence on a bike you've had for a while or if you have just got the bike and you think it is vibrating excessively.

[LAKE PLOWMAN]

i have put 12 hours on the bike, it is a 2017, its has 83 hours. I blew it up at about 79 hours, then we put a new vertex piston on it, along wiht all the ohter stuf and the vibration got really bad.

[7Tktm]

Hmm. lot of hours - do you know if the rod bearing and mains have been done? Presume there was no up and down play on the rod.  A piston change definitely wouldn't cause excessive vibes. I would def check the rotor as well - both failed on our 16s - the liner which covers the magnets  is glued in and came adrift on both, one actually broke into pieces when it came into contact with the crankcase. Bikes started fine but performance was real poor and the vibes increased but not maybe as bad as you are describing. Bob.