Hi everyone, this is my first post on this forum.
I’ve rebuilt the engine and gearbox on the 650ss I bought back in 2013. Thanks to Dale Middlehurst for initial work, but the whole thing was in an awful state. The crank had never been touched, and the bike had been driven into the ground. So it’s been a pleasure to set things to rights (I hope!). Thank you also Pete Lovell for various jobs like sleeving the cam follower tunnels, as well as endless advice.
So I’ve done nearly 400 miles, and what struck me immediately was the vibration through the bars. I had one of these bikes back in the late 70s, but had forgotten how bad it was. I’ve now gone to a 21 tooth clutch sprocket, but mainly have improved things by fitting rubber crescents on the handlebar clamps. They’re cut to length from strip about 2mm thick, then filed down toward the ends. The difference is enormous. There’s no blurring in the mirror at all, and no discomfort.
So I wonder whether any other members have tried this? It does seem to have solved the problem as far as I’m concerned.
I have flat bars on my 99 and it's not too bad, but I have also tried the riser bars like yours and suffered from the annoying vibrations and white finger. My cure was to buy a kilo of lead shot and pour it into the bars and seal both ends. The bars now weighed about 40 times what they ought to ;) but what a difference to the nasty vibes. I have subsequently returned to the flat bars for authenticity's sake on my 99, but for comfort's sake I may well be refitting the riser bars in the future and if needs must will look into a rubber mounting either like yours or like the BSA/Triumph P clamp. Sacrilige to drill the top yolk though.
Yes, mine had these bars when I got it. I changed to straights, and then soon went back to the risers for comfort (old hips!) and also because cable routing was easier. It hadn’t occurred to me that the vibration was worse with them, but it sounds right. It would explain why I didn’t remember it being such a big problem with my first 650ss, which had straights.
The lead shot was a good idea.
I completely agree about drilling the yoke. You can try the rubber strips, it was only an hour or two work. I had some rubber I got back in the 80s for something I’ve forgotten now. It keeps coming in handy...:)
Hello well I own a very early Norton Manxman 650 and it has 8 inch high bars as standard and there is not much in the way of vibration going though these handelbars and I own a 1954 Dominator it has Rubber mounted handle bar set up as Standard so may be you can use this set up from a !954 dominator head stock and bar mounts , Now many of you hate high bars but who is having the last laugh ,So give me eight inch high bars any time, I have had clip ons and flat bars you can keep them , there for sadists! that like vibs though there bodys To Me the high bars give you a nice look and good for just enjoying you ride out with the wind in your helmet pudding basin one fit blue lenses on your glassis you find you see better, you can just enjoy your ride at road speeds with out breaking the law and speeding, at high speed we all been there and broken the speed laws and got away with it many times but ther comes that day when you get court out So do try not to ride like a loonatic Has we did when we were younger and stay safe yours anna j
Thank you Anna, clearly my bars aren’t high enough. I need the full 8 inches...
I will obviously try not to drive like a loonatic (as I did when I was younger), though it’s hard not to break the speed limit when it’s 50 on a perfectly good road. I just use wraparounds which are not blue, so not so cool, but I find I can see ok.
You stay safe too, regards Steve.
I am wondering whether the vibration is caused by the new pistons, which I assume you fitted when the engine was rebuilt. Some of the available pistons are much heavier than the originals, messing up the balance and causing serious vibration. A member posted recently that he had this problem, which was so bad he had to dump the new pistons and get new ones of a different make. I have a 650SS-engined Wideline which I rebuilt with BHB pistons, and despite have flat alloy bars, do not find vibration intrusive; unlike my T110.....!
Maybe investigate the source, rather than masking over the symptoms?
Quite often, when owners fully rebuild their engines they fail to notice that they are fitting replacement pistons that do not match the weight of the originals. I have come across some replacement pistons that were 30% heavier than the original set. Consequently building an inbalance into the engine. It always pays, with all the 650 and 750 motors, to have the crankshaft reblanced to match any change of pistons.
Thanks Ian and Philip. You make the same point, and you may be right. I did not have the crank balanced with the new pistons and rods. Tbh, there are so many different opinions on the matter that I just stopped thinking about it.
Whether or not that was the best choice, I’m happy with the engine so far, and don’t plan to strip it down again for the time being. As Bob wrote in the first reply above, the problem may be more to do with the bars, as his straights don’t vibrate as much as when he used bars like mine. I do think that if there was a serious problem of imbalance, it would not actually be curable by little rubber mountings, and that I’d feel excessive vibration throughout the bike, and not just in the bars.
I also think that if the engine wasn’t happy it wouldn’t feel so good to drive. So I’ll see how it goes, maybe in a couple of years if I feel like it, I might have a look again. Anyhow, thanks again for the input.
More recent handlebars tend to be thinner-walled tube in my experience with stainless bars being the worst offenders in this regard. A change of bars, even a similar pattern might make a difference.
...and a rebore will lead to heavier pistons..
The 1954-5 bikes had rubber mounted handlebars, but you will not be able to fit this top yoke to your '60s bike - assuming you can find the parts. The yoke width was increased from 7" to 7 3/8", so they do not interchange. There were lots of other changes to the forks, such as sliders with a longer lug to engage the brake plate.
I have read in the past that some riders have had success with stuffing the ends of the handlebars with lead of one kind or another.
Had to do with changing the frequency resonance???
Can't hurt to give it a try as it is a reversible option