Dr650 speed wobble at 110km/h

**johannvr** · 14th July 2009, 22:46

Originally Posted by Woodman

not a Dr but a klr, but I think your problem is tyre combination. when I had
e09 front and rear she tracked true as, but when I replaced the rear only with a t63 the front now weaves and wobbles on the road.
My advice is to ride through it.

Entirely possible. Mine now both T63's though, so not the cause in my case. Have however got one size fatter (130) on the back & not the stock 120 anymore -have wondered before if that may have any side effects.

**Woodman** · 14th July 2009, 22:52

Originally Posted by johannvr

Entirely possible. Mine now both T63's though, so not the cause in my case. Have however got one size fatter (130) on the back & not the stock 120 anymore -have wondered before if that may have any side effects.

i went from a 140(e09) to a 130 (t63), but there are way too many variables to be sure.

**johannvr** · 14th July 2009, 23:01

's true. Like you said - just ride through it.

**warewolf** · 14th July 2009, 23:26

A couple of thoughts:

Lowering both ends will slightly reduce the wheelbase and possibly the trail. Both of those make the bike less stable.

Stiffening the suspension (through damping clicker adjustment or raising tyre pressure - the tyre sidewalls act as the first part of the suspension) will reduce the bike's ability to damp out oscillations before they get carried away. Static push-tests on the suspension don't tell you much if anything about how you've affected the bike at road-speed suspension loads. Too much front rebound or too little rear rebound damping is a cause. More preload usually needs more rebound damping to counteract the stronger spring return force - aren't the DR650's notorious for insufficient rear rebound? Google "motorcycle suspension weave".

Knobby tyres are not known for even wear, in any dimension. Worn tyres in combination with the aforementioned could be enough to tip the balance.

So I would suggest back off your tyre pressures and suspension clickers as a first test.

(Personally I haven't noticed any instability with the T63, in fact possibly the opposite. A sample of one is not statistically significant though.)

**junkmanjoe** · 14th July 2009, 23:42

i check it next to another bike, got him to sit on 100km. i read 110km.

also on the speed readings on some speed check poles around town, doing 60km on my speedo read 52km on the readout..???

**NordieBoy** · 15th July 2009, 07:54

Originally Posted by junkmanjoe

hey any other DR riders out there notice that the factory speedo runs at 10km slower than what its reading...

99% of DR650's read 10% high.

The odo is accurate however.

**Transalper** · 15th July 2009, 09:09

Originally Posted by NordieBoy

99% of DR650's read 10% high.

The odo is accurate however.

I ride with GPS and agree, on straight roads at about 55 on the speedo im doing 50 on the gps and 110 speedo is about 100 on the gps. Helps keep ya ticket free aye.
The faster you go the bigger the difference.

Haven't checked the odo. The GPS cuts corners.

**junkmanjoe** · 15th July 2009, 09:10

oh well at least i should never get a speeding ticket.

**Monstaman** · 15th July 2009, 09:46

Well that means I am weaving at 100k, tried riding through it and results weren't good.

Will piss around with tyre pressures etc, will back off the damping slightly at the rear and will also set the static sag with rider and gear to the same as the rear is slightly firmer.

I will do these in small increments and note the difference, unfortunately with budget suspension there is only so much one can adjust but by all accounts it still works ok, just a matter of fine tuning it to the best I can get.

It's good fun playing anyway

**Crazy Steve** · 15th July 2009, 10:45

Originally Posted by Monstaman

So I lowered my bike on the rear spring bolt, reset my preload to my correct static sag with rider etc, and made it slightly firmer than the front for carrying shit, the shock bolt height dropped the bike 37 mm vertical from the wheel nut.

I dropped the forks through the clamps 20 mm to come closer to geometry however at 110 km/hr it does a little weave on the road, not bad but quite noticeable.

I put the forks back through the clamps level with the top triple again and this has settled it down a bit.

I am running full knobblies at present and wonder if this has a big influence, any input would be cool.

Signed Dr Jekyll or Hyde .... sure

My one does it from 110kph all the way to 160kph....Indicated speed only...

I did notice sitting further back on the seat clams the beast down...And im running TKC Cont...

Would be nice for it to stop......

Crazy Steve.

**Transalper** · 15th July 2009, 12:36

I have an agressive front knobble tyre (Trelleberg? from memory) that does it to my bike. It was annoying but fairly predictable.
Not so bad with a fork brace installed but then that's an overpriced mission on its own which severley limits suspension clearances up front.
I run the rear lowered as per the book and am back to full height on the front.

With a good and stable front tyre on I have also experienced what felt like a front end wobble for the first 300ish km running in the new rear tyre. Obviously it was the rear doing it that time. It was the C02 Mitas? which settled down eventually and become a new favourite agressive rear.
Only had it happen with knobbly tyres.
I have balanced my rims to off-set the rim locks when I installed them, but not the whole deal including tyre, not recently anyway.

**clint640** · 15th July 2009, 12:47

Nice big effective front mudguards like the DR has can also cause a wobble at higher speeds, I wouldn't expect much at 100 but checking it is bolted on straight would be a good idea.

Clint

**Paladin** · 15th July 2009, 19:25

My Dr has had the same speed wobble since putting D606's on it!

But... that same weekend was when I decided to crash the hell outta the bike on Orongorongo on Easter Sunday, so......

might actually not be the tyres!