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Re: My '73 Norton 850 Commando handlebars vibrates at...
I love these bikes. Vertical twins of this era vibrate, is just how it goes. Engine design was simple back then and no counter shafts are used, so there is a degree of vibration at low revs produced by 2 big bore pistons that will make the handle bars get a real bogey on at idle. If the carbs are out of sync,or need a tune, then you may have a lazy clyinder at idle that is producing the vibration also. Not sure if your bike has them, but some have rubber bushes that mount the handlebars. These can get sloppy with age and may need to be replaced. Another trick if the vibration is anoying you is to mix some lead shot with silicon and fill the ends of the handle bars up to "weight" them and reduce the vibration.
click here to see one walking on its center stand. Notice the way everything is vibrating on this old girl.
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Hi Anonymous, and the usual suspects are:
1. Wheels and or tires unbalanced, worn or damaged.
2. Eng ine/ transmission/vehicle not aligned properly.
3. Primary chain badly worn or links tight as a result of insufficient lubrication or misalignment.
4. Engine to transmission mounting bolts loose.
5. Upper engine mounting bracket loose.
6. Ignition timing incorrect/poorly tuned engine
7. Internal engine problem.
8. Broken frame
17 years is a long time for engine rubbers on a v twin. But if the vibration is only in the handlebars, you might want to fit some heavier handlebar end weights. They are there to absorb vibration(they act as dampers.) But, if the vibration is in the engine, it may be worth checking the ignition timing. On a Big V the ignition only needs to be out by a small amount to set up a noticeable vibration.
It doesn't look too bad. Parts were my greatest concern for you, but they abound. I did a Google search for "71 Norton Commando parts" and found many sites for parts, wiring diagrams and exploded diagrams. One site that I liked (it was a quick look-see) was genuinemotorcycleparts.com. Other sources for parts included eBay. Give the Google search a try.
The right side handgrip is the throttle sleeve assembly and grip combined. To get it out, first, adjust both the throttle cable and the idle cable (both cable going into the throttle assembly) to give you as much slack as possible. Loosen the two bolts that hold the front brake master cylinder on and move the master cylinder towards the center of the handlebars just a bit. The remvove the two bolts that hold the right handlebar switch housing together. Carefully move the top half away. There are a lot of wires in this housing and you don't want to break or pinch any of them.
Now, you can see the round part of the throttle sleeve and where the cables connect to it. Each of the cables has a ferrel on the ball on the end of the cable. Do not lose these ferrels. Work each of the cables with the ferrell out of it's hole in the throttle sleeve. Lower the bottom half of the switch housing and remove the throttle sleeve from the handlebar.
Now, before installing the new sleeve, lubricate the handlebar, the inside of the throttle sleeve, and the round part where the cables go with white lithium grease. Slide the throttle sleeve back up on the handlebar and reverse you disassembly procedure to get it back together. Be very careful not to pinch any of the wires when you reassemble the swith housing. Once you have the housing together but before you tighten it down, slide the throttle grip toward the center of the handlebars until it stops and then back it off about a half inch or so then reposition the front brake master cylinder as close to the right switch houseing as possible and tighten all screws.
Adjust the throttle cable and the idle cable so that they each have just a bit of slack in them. Twist the throttle grip to the wide open throttle position (engine off of course) and let it go. The throttle should snap back to the idle position. If it doesn't, work with the throttle until it does.
Failure to insure the proper throttle operation could lead to a loss of control of the machine resulting in serious injury or death. This job MUST be done correctly.
you are going to need to rebiuld the forks. it is not a hard thing to do but if it is your first time doing it then you may want ot go and have it done for you. they have went out on the clutch side there and that is why you are getting the vibration there in your handlebar
Your bike may need the harmonic balancer chain adjusted. Th will notice is noise is very prominent at engine idle and low RPM's. When this chain get lose you will feel the vibration even in the handlebars if it is loose enough.