isolatic 72 commando handling

Hello
I am experiencing "tail movement" on my 72 750 Commando, and when the bike stand on the centrestand i can move the rearwheel sideway and see movement in the front iso , too much !

I was thinking of first stiffen the front iso , and see they have new isolatic conversion kits on Norvil. Are they good ? or should i just buy new shims for the old type ?

Will a new headstedy improve handling characteristics ?

You need the kit that bolts up the the swingarm spindle tube housing and adds two setbolts to secure the spindle.

I think Windy Eads (Bill) does them. Heinz Keigler just passed away, he was famous for them.

Do a search for "swingarm spindle fix" and you'll find several discussion threads.

grandpaul said:

You need the kit that bolts up the the swingarm spindle tube housing and adds two setbolts to secure the spindle.

Click to expand...

But the spindle repair won't cure loose Isolastics?

Alas the swing arm spindle collars and other spindle clamping methods only help the slack felt from tire patch to back of cradle. Does nothing at all or even accentuates the rear patch pivoting on rear iso to slap the front mount side-side which gives a wiggle motion to forks to allow tire print to follow direction of travel in slightly different path than the loose rear end under thrusting power is doing the real aiming and changing, slightly or completely out of control.
Bikes do a sinusoidal path to stay upright straight head, very slight at hwy speed but enough that Commando faults can pile up to interfere, dramatically.

The fact that there is direct swing arm tugging seen one to one at front motion means there ain't that much loose from rear mount backwards, but implies a loose worn slack gap front isolastic. Tire wear and clutch wobble with chain bounce can aggravate the wiggle/wobbles felt on road. What you may feel sitting still may not be felt riding as usually there is some side steady loads applied sideways to take up slack until they shift to other side for a slight short non-upsetting twitch then fine. I've ridden one of worlds worse Commando, worn everything to 1/4" or more slack in each area! Until the forks got low on fluid I did test flings on it and only got the little twitch then fine. On sweepers it began to build up but still had to press with nice power, now its so bad just following traffic at 45 in 35 marked turns starts a juddering forks to seat, so its the 2nd Commando I don't care to ride again till fixed. The first one was clapped out 850 that didn't jiggle or vibe, just felt a sluggish handler compared to 750 ease and clutch slipped so couldn't even enjoy straight line joys.



I'd go with adjustable iso's as they do need wear compensation now and then, plus can dial in for best effect in you bike, and keep it that way.

Most bang for ease of install for handling is front-breast rod linkage. Head steady can be nice to buffer out more wind gusts and fork jiggles into seat from road texture, but both combined may give up to 20% handling improvement. I find the rear link alone gives like 80% improvement to point I've never ever been able to induce the all too familiar hinged handling I all too easy induce prior.
Top and front link Will NOT prevent hinged/woble, only increase speed some what more comfortable to Then Onset Hinged Horror at in human rate to recover.

Once the main chassis is rod tamed, then the poor Roadholder will still go nutzo so must look into Greg Fualth simple cheap kit I use/developed or the cartridge emulators or real cartridge conversion LAB deveolped. Also fork brace helps fast fort action not to twist em up for spring backs at wrong time angle.

Thank you for replying !!

There is no slack movement in the swingarm spindle , only in the front and rear iso . There are almost 1/4" total slack in the front isolatic.
So my first thought goes on fixing the isolatics.

hobot said:

real cartridge conversion LAB deveolped

Click to expand...

It was John Bould (Lansdowne Engineering)-not me!

fireflake purple said:

Thank you for replying !!

There is no slack movement in the swingarm spindle , only in the front and rear iso . There are almost 1/4" total slack in the front isolatic.
So my first thought goes on fixing the isolatics.

Click to expand...

If you're referring to side to side movement in the front iso that's quite a lot. The poly discs are maybe .125" thick plus another 0.060" for shims. With that much movement you should check to see if the poly discs are even there. Remove the whole front iso can for inspection. Set the clearance with shims to .010" while holding the unit in a vise by the mounting bolt. The front iso is the easy one as it's easy to remove.

Yes, it is. i will check the front iso first and see what i find inside.

Ilf8ed ; I bought my bike from John Yorke who had a shop in Newport beach called Thoroghbred motorcycles , 5 years ago , do you know him ? , since you are in California. He was a nice guy.

OOps.

I started reading the post and must have fallen asleep for the second half of the first sentence!

Sorry.