Jump to content
Sign in to follow this  

Speed wobble

Recommended Posts

Hi All

2 x K7 DRZ400SM.....

Both with the same mods...

Both with same tyres and pressures....

One gets speed wobble at about 80mph...the other about 90mph ??

Any ideas ?

Many thanks guys

Share this post


Link to post
Share on other sites

Possible tire defect? Maybe you need to tune the wheels up a bit?

Share this post


Link to post
Share on other sites

Check the sag with the rider. A heavier (bigfat guy) will reduce the steering head angle, making it more stable.

Check the steering head on the bad one, too loose or too tight. Will cause it. The one that shakes may have a rider in a death grip preparing for the wobble.....

All you can do is go through the bike item by item. Careful about making a host of changes at once as then you may fix one thing and bugger something else. 👍

Share this post


Link to post
Share on other sites

things I have found to make the bike wobble ( I have a SM too )

frunt spokes coming loos or shifting do to doing stoppys with a 350lbs rider

tripel tree bolts needed titened .... frunt axel not installed the rite way ( that was my doing ...have to lurn some how )

air in the tires being off ( I like 30 r and 30 f )

air needed bled out of the forks ( those little bleaders really work )

rear sag or ride highth being off ( this changes your rake and trale of the forks/trippel tree )

sitting to far back on the bike ( it is a durt bike your balls will get used to it )

Share this post


Link to post
Share on other sites

mine does the same, but its because its an S with non dot tires on the street i assumed. perhaps its the geometry of the bike at that high speed, or un-balance wheels.

Share this post


Link to post
Share on other sites

Properly set up these things are quite stable. I went from stock (S) rims to SM rims and never adjusted anything, effectively increasing rake and decreasing trail. Stability is not an issue. I can Make it wobble but it isn't unstable. The only non S part (that's significant here) is the front fender.

I run most of the time between 75 and 80 not an issue.

Share this post


Link to post
Share on other sites
things I have found to make the bike wobble ( I have a SM too )

frunt spokes coming loos or shifting do to doing stoppys with a 350lbs rider

tripel tree bolts needed titened .... frunt axel not installed the rite way ( that was my doing ...have to lurn some how )

air in the tires being off ( I like 30 r and 30 f )

air needed bled out of the forks ( those little bleaders really work )

rear sag or ride highth being off ( this changes your rake and trale of the forks/trippel tree )

sitting to far back on the bike ( it is a durt bike your balls will get used to it )

All that and AFTER you've done/checked EVERYTHING remember this bike set up as an "S" or "E" is like a sail once it gets to 70-80. It's TALL. Knobs will exaggerate the back and forth. Nevertheless, as others have said, it is still very stable in my experience and I have no problem running at 80+ and just going with it and not fighting it. Have never felt out of control or scary.👍

Share this post


Link to post
Share on other sites

If the wobbles arn't that bad, then the problem maybe just your arms are too tight. This has happend to me w/ a drz400s and knobbies at 80mph. The wind hittin' my elbows caused me to shake my own bars. Read about it on TT and took the advice to relax, and the wobbles stopped. Now I do it on purpose just to scare myself a little!

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Reply with:

Sign in to follow this  

×
×
  • Create New...