New isolastics....what can I expect?

I've replaced my 40+ year old isos with new vernier type rubbers including rears. The bike has always vibrated but was hoping to see an improvement with new parts. If these are properly adjusted, just how much vibration can I remove. As is, the mirrors are useless below 2500 rpm (can't see shit) and rear fender bounces badly. How do you guys tweak these to get optimal performance?

If you don't have the spring off the head to the frame, adding that may help. It helped mine but only at idle or slightly above, I didn't notice any difference much above idle. I'm sure others have their way of adjusting, but I found the factory spacing for the iso's works as good as any for me. Of course if you loosen them way up, the vibration stops, but I can see fine out of my mirror at any engine speed. I've never found any sweet spot for mine but it's not objectionable, my hands and arms don't go to sleep like my old BSA B33 single 500.

Mine take a few 100 miles to soften some and fine tune gap if adjustable. Might try higher tire pressure if road texture allows that. I'm a confrimed fan of bevealing off some the front cushions and adding extra cushions to rear. My factory Combat goes numb around 2000 so much more pleasant to stay in 4th below hyw speed usually d/t to traffic ahead and mirror rather clear view on either side but L blurs a tad but no R which is a bit of mystery but nothing I can feel thank you. Top spring adjusting as mentioned helps low down. If head steady Lord mounts in a strain sitting still they can add to the low rpm vibes getting through. My factory Combat was bit annoying in waves on/off felt below 3000 even after few 100 miles so diddled head steady to neutral to get good peace. i'm so ashamed to show my way. Also may have to shim head steady to center on frame better if engine off set not exactly right from the factory or d/t accidents. I'm so ashamed to show this but so pleased afterwards.

[video]https://www.youtube.com/watch?v=4mm7tyrK350[/video]

dragonfly said:

I've replaced my 40+ year old isos with new vernier type rubbers including rears. The bike has always vibrated but was hoping to see an improvement with new parts. If these are properly adjusted, just how much vibration can I remove. As is, the mirrors are useless below 2500 rpm (can't see shit) and rear fender bounces badly. How do you guys tweak these to get optimal performance?

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You can expect it to shake a lot below 2500 rpm. Somewhere between 2500 and 3000 it should get smooth.

The tighter the verniers are adjusted the more vibration you will feel but the tighter will be the handling. Jim

Much discussion has taken place around this. (Search the archives). Not all iso rubbers are created the same. Some folks have noted that the vernier rubbers are harder than pre-vernier rubbers.

Stephen Hill

Don't like hydrocarbons or sillycon on my rubbers nor the soap moisture sealed in so now use talcum powder and a 3 lb sludge on wood block pad so boom bang bing done. Hard aired tires and factory gaps sure ride nice if ya can tame the spring backs.

What are you ashamed about. Original rubber top mounts. I still run those on both commandos'. What was moving in your picture, the whole engine assy or was that the bending of the top mounting.
Dereck

Shamed by judgements from likes of Rohan or JimC. First engine lifts on iso's then the plate head steady bends and twists and springs then the under tube twists just detectably. I did not have to strain=grunt on crow bar. Head steady is one of Peel hand me downs. Oh yeah I also later bench grinder waisted Trixies top rubbers some to get bit more smooth sense which does let weave wobble on set a bit earlier but only if pressing racer like turns, which is tabbo to me on untamed anything. I rode Trixie w/o head steady to see if that was element in sense of engine getting through and forget about it till 15 miles later on hwy let tires cross dual yellow paint lines in easy sweeper at almost 60 to have sudden Hinge onset that shot me into opposite lane a while trying to save my life in time. Was more cautious after but took opportunity to explore the ease and ways to onset THE Hinge, recovery it and try to delay it but mere academic as just don't ride any ordinary cycles to danger zone so ease and comfort and sound and torque are my Commando priorities. Trixie was never much a viber but did take some weeks of diddles to get er about as good handler and smooth as any un-tamed Cdo can be.