Speed wobble

[jcrocker]

Hi all , I put the MZ on the the track with Nesba this Saturday, it was blast except for getting past like standing still in the straights. Over several sets of tires I still get a pretty bad front end wobble over 95-100, I'm gearing it back up so i was hoping someone had some good cheap advice for eliminating this ( I've heard new bars to steering dampener, I'm hoping to wait till next season for the dampener )

[phlat65]

if you are in seattle, why haven't we gone for a ride yet?

sean 425-478-0290

[phlat65]

by the way, what did you set the rear sag at?

[jcrocker]

I'm going to oyster run this Sunday with some people if your interested ? I was kinda liking the idea of being the only one in town with a cool baggie, but definitely lets go for a ride. ( my rear suspension is set all the way tight ( making sure that's what you were referring too )

[phlat65]

what is oyster run?

the the sag (difference measured from the rear axle to somewhere like the seat to fender junction with the rear wheel off the ground, and you sitting on the bike in full riding gear) at 95mm or so. with to much spring pre-load (too little sag) it weights the front too much, and vice-versa. probably the most important adjustment due to the long travel suspension.

if you have the reduced height, set it to 75mm or so. leave the "clickers" at their stock settings, then ride it, and only adjust 1 thing at a time in small increments.

what front tire and pressure are you using?

[jcrocker]

hey, oyster run is a motorcycle rally up in anacortes http://www.oysterrun.org/ I'm meeting some people in redmond at 10 am. We're going to take back roads up there.
I haven't checked the sag ( no garage) but I'm running 30 psi on the front.

[beamisinbtw]

I had the same problem on my Baghira here is my solution custom billet aluminum bracket with a scotts stabilizer

[beamisinbtw]

this bracket was manufactuered using a cnc machine and can be done again, send me an email and i will provide the info.His name is Dave Hall and we are in melbourne florida.holla!

[jcrocker]

too funny it looks like we have the same pick up truck too

[phlat65]

hey you are still around!! we shall ride this spring. we should get a group up to Mt. St. Helens.

[jcrocker]

sounds good , I love st helens

[Dirt]

Confirming this same problem on a Baghira -- only a decade later! Standing on the pegs and getting my weight over the tank seems to help a little; thus, my sense is there isn't enough weight on the front wheel (just for starters). Raising the front forks (lowering the triple clamp on the sliders) helped a little and I'm guessing jacking up the rear might also help (though haven't done that yet).

Posted a similar question to this list several years ago (but never found this thread unfortunately!) to find out if the bike had a problem and was ever so helpfully admonished by several folks for wanting to go 90+ mph. Apparently, a few folks in the UK simply use these bikes to go to church?

LOVE the cnc'd steering damper solution shown above from Dave Hall. Placed a call to him and am waiting to hear back to see if he can still make one and related details. Surely, he still remembers this project a decade later!

UPDATE: Dave had the bike there and fit his part to the bike, but didn't keep any of the digital files, so no solution. But at least it can be done!

[GordonH]

No mention of head bearings. Check 'em. They may be loose, shot or both.

[Dirt]

Head bearings are in good shape and IIRC, are properly torqued. Front wheel is statically balanced. Checked this all a few years ago, but haven't ridden the bike much since. Recall that there was no improvement after taking it all apart and reassembling, though. Aside from this issue, the bike is a joy to ride (at legal speeds)!

Can anyone who is NOT experiencing Bhagira wobble at 90+ miles/hr (150 km/hr), with supermoto wheels, weigh in to confirm their high speed stability?

I continue to wonder whether this is a bit of a design problem affecting ALL(?) Baghiras , or whether my bike specifically has some issue that needs to be diagnosed and corrected. (Although, I'm seemingly not alone based on the OP and the Scott damper installation).

If it's my bike, maybe rear preload is too soft? Front springs or forks are borked somehow (previous owner was very heavy)? For point of reference, I weigh 150 lbs (68 kg) and haven't checked static sag, etc lately, so I could (should) do this before I start spending $$$ on a solution that I might not need?

As for the possibility of some kind of peculiar engineering issue, the one peculiar thing I noticed is that the front axle is in FRONT of the forks. This seems a bit odd, since many (most?) axle designs for other bikes are either centered or trailing the front forks, for reasons of stability. With the leading axle, if the front wheel misbehaves at all, the results seem like they will easily amplify (or so my warped theory goes!). Guessing the axle is placed in front to permit a larger front wheel. But with the supermoto wheels, no need for the extra clearance.

[DAVID THOMPSON]

look real good at the rear for any thing thats out of order
tire beaded up on rim ok ? tires in good balance very important for high speed

the tail sometimes wags the dog