HELP! low speed (10-40 mph) frontend death wobble?
HELP! low speed (10-40 mph) frontend death wobble?
I'm so frustrated!
here's the back story...bike was in an accident, frame damage, swing arm damage, bent tubes, etc. bike was not salvage so I repaired after a fat insurance cashout. we have "the frame man" here in Sacramento who in nationally known/respected for straightening and did so.
bike was torn down at a professional shop, sent over and all things repaired. new tubes, corrected frame, etc. the trees were fine...done. bike was aligned with the motor and was in near perfect spec, per frame man. it was put back together and my front end was rebuilt using the same Ohlins cartridge internals.
I ride away and rip out of the lot...let off throttle around 30-40ish and WHOA! the bars whip back n' fourth as I let go of them to adjust my shirt.
it's pretty damn bad...intense, and unsafe. like I'd 100% kay it down if I let it go. happens every time.
so we take off the front wheel and check it's balance, fine.
I have 2" over cartridge front end, and 14-14.5" rear shocks. the bike before damaged for a couple weeks. it rode fine. I ride away, and now it's not.
I've adjusted rear height thinking it was a geometry issue, I've tweaked pre-load on the front end...what the hell can it be?
my bike is tall and everyone is telling me it's too tall. plenty of guys do 2" over and tall shocks...and again, it rode fine before. so wtf???
I'm so perplexed.
please help with brainstorming ideas...ask away if there is anything you need to know I didn't include.
here's the back story...bike was in an accident, frame damage, swing arm damage, bent tubes, etc. bike was not salvage so I repaired after a fat insurance cashout. we have "the frame man" here in Sacramento who in nationally known/respected for straightening and did so.
bike was torn down at a professional shop, sent over and all things repaired. new tubes, corrected frame, etc. the trees were fine...done. bike was aligned with the motor and was in near perfect spec, per frame man. it was put back together and my front end was rebuilt using the same Ohlins cartridge internals.
I ride away and rip out of the lot...let off throttle around 30-40ish and WHOA! the bars whip back n' fourth as I let go of them to adjust my shirt.
it's pretty damn bad...intense, and unsafe. like I'd 100% kay it down if I let it go. happens every time.
so we take off the front wheel and check it's balance, fine.
I have 2" over cartridge front end, and 14-14.5" rear shocks. the bike before damaged for a couple weeks. it rode fine. I ride away, and now it's not.
I've adjusted rear height thinking it was a geometry issue, I've tweaked pre-load on the front end...what the hell can it be?
my bike is tall and everyone is telling me it's too tall. plenty of guys do 2" over and tall shocks...and again, it rode fine before. so wtf???
I'm so perplexed.
please help with brainstorming ideas...ask away if there is anything you need to know I didn't include.
Stellar HDF Member
Joined: Sep 2012
Posts: 2,099
Likes: 214
From: Delawere
Hmmm...Just throwing this out there,are your bars forward of the triple trees? Sounds crazy but Ive seen bringing bars back help. Also,if you have any other a stock front mount in pull it and put a new factory mount it. Id start there I guess. Youll get it eventually. You could also play around with tire pressures.
Last edited by HrdNox; Jun 13, 2018 at 05:02 PM.
I do, a chopper haus, but I had it on before. I did tho, add a rear sputhe stabilizer...they mounted it when they aligned the motor with the newly trued frame.
Last edited by adamsrotors; Jun 13, 2018 at 05:38 PM.
Outstanding HDF Member
Joined: Mar 2015
Posts: 2,840
Likes: 900
From: Philly Suburbs
A couple of months ago I took both hands off the bars at about 40 mph to close a zipper on my jacket. As soon as the bike started decelerating, the front end started wagging back and forth aggressively. I was worried, because I had a passenger on the back. Gently taking hold of the bars created no further drama, and the rest of the ride was fine. Later I wondered whether it had anything to do with carrying a passenger, so I tried it solo... Same thing. I added about a 1/4 turn on the steering head nut... Problem solved.
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Road Master
Joined: Aug 2008
Posts: 1,246
Likes: 251
From: Belle River Ontario
I have to ask, was it cheaper to have a guy, no matter how good they are, straighten a frame instead of just replacing it?
ive seen them pretty cheap ....
anyway, if this is happening right after the bike is back together...then something is off, either the frame is still tweaked or the front end is tweaked or the neck bearings are not adjusted correctly...how is your sag.? Tire ? Tire pressure? Is it the same wheel? Maybe it’s bent....lots of possibilities
ive seen them pretty cheap ....
anyway, if this is happening right after the bike is back together...then something is off, either the frame is still tweaked or the front end is tweaked or the neck bearings are not adjusted correctly...how is your sag.? Tire ? Tire pressure? Is it the same wheel? Maybe it’s bent....lots of possibilities
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Joe Kucinski
Seasoned HDF Member
Joined: Oct 2015
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From: Pine Flat Dam/South Bay Area, CA
Could be tires, too. A lot of times low speed wobbles are caused by a few things that are a little off. Tires, air pressure, steering head bearings & adjustment, wheel bearings & end play, chassis alignment & powertrain mounts, weight distribution, windshields, handlebars, etc. Don't think it's just one thing that's the cause.
Could be tires, too. A lot of times low speed wobbles are caused by a few things that are a little off. Tires, air pressure, steering head bearings & adjustment, wheel bearings & end play, chassis alignment & powertrain mounts, weight distribution, windshields, handlebars, etc. Don't think it's just one thing that's the cause.
In an accident with frame and front end damage, it's sometimes forgotten that the actual impact that bent the frame and forks was transmitted there via an 'initial' impact with the the front wheel itself, through the wheel bearings and up.. ...
So, as well as checking tire pressures etc, jack it up and spin the wheels to make sure they are straight, centered and no kinks etc. Also check wheel bearing play etc. inspect the front hub carefully (particularly around the bearing seats for cracks or distortion). Also inspect the tire carefully to ensure it has no lumps, bumps, bulges, etc which could indicate internal carcass damage in the impact.
.
Last edited by Davdoodles; Jun 14, 2018 at 02:09 AM.