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Post by liffy16 on Apr 3, 2012 12:33:22 GMT 1
my rd250lc has a bad shake at 70-80mph bars start shaking quite bad,no play in swinging arm,tyre pressures okay,rebound okay front and rear .any idea's folks thanks colin
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Post by rich on Apr 3, 2012 12:45:44 GMT 1
Tyres squared off, play in headrace bearings?
Also check wheel alignment with string or straight edge, is frame straight?
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Post by 47x on Apr 3, 2012 13:12:56 GMT 1
rear tyre can also cause this,check rear wheel-bearings,plus what rich says.hth
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Post by arrow on Apr 3, 2012 15:23:24 GMT 1
I had this on my 250lc once, turned out to be front wheel balance. I always do my own now.  |
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Post by flames on Apr 3, 2012 17:18:16 GMT 1
from what i remember of my 350lc this was a very regular occurance.i always thought they came built in.i had a few tankslappers on my old blade,one @ 130,and that was nowhere near as scarey as the ones i got on my lc @anything over 60.when i put it back on the road i will spend some time trying to cure them.
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Post by liffy16 on Apr 3, 2012 17:26:58 GMT 1
great feedback folks many thanks bike was mot'd last thursday
frame is straight and solid,no play in any bearings,avon roadrunner on rear, metzeler on front is starting to crack on sidewall.think i will try new front tyre and balanced as arrow pointed out good call
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Post by flames on Apr 3, 2012 17:31:50 GMT 1
that may be half your problem.......lc's dont like mismatched tyres at all!!!
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Post by arrow on Apr 3, 2012 17:33:23 GMT 1
I balance both the wheels to within 2.5 grams and the bike is rock steady at all speeds. Also check tyre runout mate, on mine the tube was caught under the tyre bead on the front wheel and I had to sort it.
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Post by crash on Apr 3, 2012 18:16:40 GMT 1
had this problem back in the day on my 12 month old 350 f2 front tyre part worn,i replaced with new one it felt like a new bike again.
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Post by bigal1 on Apr 4, 2012 10:49:27 GMT 1
I had this on my 250lc once, turned out to be front wheel balance. I always do my own now. 2nd that |
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Post by daglad on Apr 6, 2012 20:37:49 GMT 1
i assume that because you were doing 80mph you were not on her majesty's finest tarmac are were infact in a controlled enviroment under strict instruction from a professional rider with at least an acu international super licence and with a medical team on stand by, plus taken the time to have written an accident disclaimer so the land owner was covered for any eventuality, all this after filling in a method statement and an emergancy plan.
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Post by marsbar350 on Apr 6, 2012 20:41:23 GMT 1
get one of norbos steering dampers ;D
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Post by billy on Apr 7, 2012 14:53:35 GMT 1
I agree with marsbar350, get a steering damper. It helps alot. My LC was also a b**tard and would wobble all the time, sometimes it was rather hairy and I almost crashed lol. Anyway, I got hold of a steering damper (fairly cheap model, though it is adjustable) and thought I'd try it out. I didn't expect much tbh, but it actually helps a whole lot. I have NEVER had a wobble when using the steering damper. I can go WFOT on bad, bumpy old roads with no drama whatsoever.  |
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Post by airbraker on Apr 8, 2012 10:15:51 GMT 1
I was behind a bike on the m27 that had a tank slap at around 70/80. I shite myself I was so shacken up watching him that I had to pull over to get my self back together. Its something that I only had once but managed to fight through it but that was years ago when I was young and invincible that was on an x5 I was going to fast and there was a big head wind I think the front end just became too light and unstable.
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dazaha350
Weekend rider
wild side of life
Posts: 71
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Post by dazaha350 on Apr 8, 2012 10:32:34 GMT 1
i get this on my hybrid, becomes unstable at 80+. rear end is jacked up by 50mm wich quickens up the steering. really need a steering damper  |
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Post by rich on Apr 8, 2012 10:33:31 GMT 1
Steering dampers can help to calm a bike that's a bit unstable. That's why race bikes often run them as they are set up for quick steering (forks dropped through the yokes etc) so are often on the verge of instabililty. If a road bike is wobbling that badly then there is usually another cause (tyres, suspension) and fitting a damper will only cover up the problem without actually fixing it. Fit one by all means but fix the original problem first!
Edit: just see above post, yep jacking up the rear or (lowering the front) will make it more unstable so a damper will help.
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Post by mellow on Apr 8, 2012 10:58:44 GMT 1
IF...you want tankslappers buy a 1st generation R1  scary |
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Post by gazzatt2 on Apr 8, 2012 21:14:47 GMT 1
IF...you want tankslappers buy a 1st generation R1 scary had tank slapper on my mates fire blade at 90+ my 06 R1 has a damper only ever had a slight twitch |
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Post by mellow on Apr 8, 2012 22:00:51 GMT 1
mine does too now |
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dazaha350
Weekend rider
wild side of life
Posts: 71
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Post by dazaha350 on Apr 9, 2012 11:47:21 GMT 1
mine does too now ;D ;D ;D |
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phil38
Thrash Merchant
Posts: 426
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Post by phil38 on Apr 10, 2012 12:40:17 GMT 1
that may be half your problem.......lc's dont like mismatched tyres at all!!! Fully agree. Mismatched tyres are a bad idea on any sports bike as the profiles don't match and can cause weird handling. Anything with a cracked side-wall wants binning and should be an MOT fail Squared of rear tyes and shocks too-hard/ no damping left can also cause wobbles |
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scary
