Commando pulling to the left

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I have a 1973 850 Commando which steers to the left. I have not got reason to think frame is bent, and I did read that they all do this right up to the Mk 3 & cure is to have disc brake mounted on left leg instead of right. Does anybody else know anything about this & any ideas for cure without drastic expense, as the problem is not massive.
 
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If the rubber donuts in the front isolastic, wear through the circlip that holds them on the tube on which they are mounted, one of them will move to the end with the other one and it will cause a strong pulling to one side. This is what will happen with the old original type on the 72, 750, at least. Might be the same on the 73 850's. I bought my bike when it was two years old and it also had this problem...for 200 dollars, because the owner was convinced the frame was bent. If you have the newer type...not sure if they are built the same crappy way.

Loose swingarm, broken top motor mount, wheels out of alignment, cocked rear wheel(chain misadjusted).....one fork with no oil. All potential, inexpensive reasons. Good luck.
 
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I have owned two 850 Commandos, one of which I bought new. They both pulled to the left, although it was only noticeable with hands off the bars. AFIK, they all do that. When I rebuilt the one I ride now, I reversed the fork legs to position the caliper ahead of the forks as on a MK3. This completely corrected the pulling. I have no understanding of why this is. Now my problem is the oscillation at 30-40 mph, which is another thing "they all do". I never noticed this before but it may be because I couldn't take my hands off the bars because it would immediately dive left. Now I can take my hands off the bars until the oscillation threatens to become a tank-slapper. Why I want to take my hands off the bars is anybody's guess.
 
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drawfo
If you have/had to fear the bike diving to the left, just because you took/take your hands off the handlebars......your problem wasn't and still isn't the front brakes and the location of the brake caliper. If the thing dives just from taking the hands off the bars....there is something else wrong....

I have had all that shaking and occilation thing too over the years, and it invariably turned out to be some simple reason like the isolatics or a funky front tire. The last and for me final reason turned out to be that I had in the seventies, mounted a mudflap on the rear of the front fender and this caught the wind at certain speeds and wiggled the front end rather unpleasantly. The mud flap fell off one day....and the problem was GONE. I have a rock steady bike now, at all speeds. Add a new front tire and, ninety with no hands....no problem. So they don't ALL do it. Some reason for it has to be there somewhere, it shouldn't be seen as just something you have to live with.
 
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PS....sorry dwardo....got your name wrong....my apologies......seems my typing isn't much better than my advice!!!
:lol: :lol: :lol:
 
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Hey, hewhois, the mudflap thing is interesting because I do have one. I might try taking it off. Everything in this bike is new as of 6000+ miles ago. The wheels are aligned properly and everything else is good. The concensus (at least on other lists) is that Commandos seem to have a shake at between 30-40 mph. I think that the Avon Super Venoms may aggravate it and I am sure that having the caliper mounted ahead of the fork, which adds mass far from the steering head, aggravates it once it starts. It seems like encountering a small bump or irregularity starts it and then it increases in amplitude. It doesn't really bother me but when I wear out the tires I think I will try another brand.
 
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Thanks for replies,
Dwardo , your cure for left pulling is the same as mentioned in Commando service notes, but you must not just swap leg to the other side as bearing lockring is now in a direction to unscrew itself. You need LHS leg off MK 3 .I do not want to go to this expense cause I can live with fault. Instability happened on earlier models and they altered the head angle in the yolkes by 1 degree. You could not possibly have early set of yolkes?
 

L.A.B.

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You need LHS leg off MK 3

There is no difference between the lower fork legs on 850 Mk3 and earlier disc models, they are purely swapped over, it's the hub that is different.
 
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dwardo
Do take it off. I had lived with this shake at certain places on the road I travel for as long as I can remember, and it was nerving. Left you always queasy in the stomach. Not much of a shake, like when the isolastics were bad, but just enough to make you get tense before the curves and such, where it always happened. Always the same places and same speed would make it appear. I had been on the phone wilth Les Emery and asked about this and his suggestion was to change to Venoms because the K81s have this center line in the tire tread and it supposedly caused the commando to get wobbles because it causes the front wheel to track and get off on it's own path and direction. Before I could decide to put the money out on the Venoms...the mudflap fell off and the bike got so steady that I had to pick up the phone and talk to Les again. He had never heard of such a wacky reason for front end wobble and was amazed as I was...but it really was the reason for the wobble. Now when I come up the hill and cook it down the incline towards town...I kind of miss it. I kind of wait for the wobble and it never comes. Sort of like a nasty wife. You might be glad she's gone, but you still, for some reason, miss the screaming.
 
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