Stark Varg “weave” (steering wobble)

I picked up a Stark Varg MX a couple months ago and have put about 20 hours on it so far, trailriding.

I mostly love it, but from that very first ride around the neighborhood after putting it together, I noticed it doesn’t like to stay pointed in a straight line. It kinda weaves, slaloms on its own, or “swims” like a fish. It’s most noticeable on pavement and gravel transit sections but on the trail it’s hard to put the front wheel exactly where I want it - it feels like the front wheel is loose somehow. At first I thought it was just brand new dirt tires on pavement, but the issue persisted.

Things I have tried that have not seemed to help the issue:
- Changing the tires (I wanted to run Tubliss /
gummy tires anyway)
- Tightening the following to spec: Steering head nut (loosening the associated pinch bolt first), fork leg pinch bolts (upper and lower), front axle nut and axle pinch bolts, rear axle nut, docking station (handlebar) bolts, handlebar mount lower bolts.
- Adding rear preload to get proper race sag (I am 240lb, so will install a stiffer spring soon too).
- Checking wheel bearing play (no play)
- Checking front wheel spacers (it would be obvious if these were in there backwards right?)
- Checking the front end for play (i.e. standing in front of the bike, locking the wheel with my feet and trying to pull the handlebars left and right) - no clunking or abnormal play that I could tell.
- Checked front wheel spoke tension. I don’t have a spoke torque wrench but I tapped all the spokes and they all sounded fine.

My next ideas:
- Maybe loosen the steering head a lot and see if the issue is noticeably worse? This same bolt on my Tenere is like 140Nm, is it possible the Stark spec (I forget if it’s 12-14Nm) is way too low?
- Stiffer rear spring (in case this is a geometry issue)
- Get a spoke torque wrench and actually torque the spokes up properly?

After that it might be a trip to the mechanic, and/or finding someone else local with a Varg who would be willing to swap bikes to see if they’re all like this. My benchmark is mostly Yamaha 4-stroke dirt bikes, which are renowned for being very stable, but I feel like no bike would weave like this.

Do you only notice it on asphalt and at higher speed?
If so try balancing the wheels using spoke weights. I've seen reports of as much as 100g needed.

If you are noticing understeer or oversteer than try to check the fork legs alignment using this device:
My test for problem in this area is to ride perpendicularly on the steep incline. If the front slips or bucks than there is malalignment somewhere.

Also check the chain/axle alignment.
If you like gizmos, there are laser alignment tools for not much money.

You could also try lowering the forks in the triples. That should settle the front end assuming the rear geometry is correct, but there are tradeoffs.

Thanks for the tips. The weave is apparent at low speeds - like 15-20mph on asphalt - it’s not a high speed wobble like I’ve seen on YouTube (but thankfully never experienced). At very low trailriding speeds it manifests as vagueness in the front end. I ordered in the MotionPro fork alignment tool - seems like a more systematic way to confirm front end alignment vs bouncing and guessing like I usually do. Will be useful on my other bikes too, even if it doesn’t solve my immediate issue with the Varg.

Try sitting more forward.

Also, tighten that steering stem nut as hard as you can. This is your steering damper and stabilizer. I run mine pretty tight, it gives me a calmer front end at all speeds.

So I did an experiment today - I tried the steering nut at 3 different torque settings: 2nm,
12nm and 20nm, and rode the bike around the neighborhood at each of the settings, trying to replicate the conditions of that initial test ride when the issue was so prominent. Unfortunately, the weave wasn’t super apparent today at any of the settings. I did feel some tightness / resistance to turning at the stiffer torque setting, which I didn’t like. So, mission accomplished?

Maybe, maybe not. After I packed away the tools it occurred to me that low tire pressure might mask the issue on pavement, ugh. That or some of the digging around torquing random front-end bolts to spec yet again fixed the issue. Or maybe some steering components have finally broken in?

When I googled around for the issue generically (across all dirt bike makes and models) I heard that leaving that steering stem nut too loose OR too tight can cause weaving - if it’s too tight the bike can’t self-straighten with the steering.

When the issue surfaces, riding on the front or back of the bike doesn’t make a difference.

New supermoto wheels should come in the next few weeks, and I’ll move to a stiffer shock spring soon too - so maybe those changes might shed light on the cause too.

tyre pressure and ride height both at the front and rear
are the main factors to consider
suspension adjustment too.

Soft spring soft tyre add some torque =wobble wobble
A bit like taking high speed weave out of the front of any dirt bike.
Start by running higher tyre pressure.
I switched to a 14 front sprocket it actually caused some spring wind up in the rear.(pitching)
Balance is the key .The bike does struggle with that being so overweight.
The more I soften it the more it is all over the place.