Variations from "oem" isolastic clearances/headsteady

I have read as many of the "isolastic" threads as I can find here but didn't really find much on the subject of other than stock clearance settings.

I know that the book calls for .010 and I have seen somewhere - though I can't recall where - that the police in the UK adjusted them for .006. Fred Eaton, (Old Britts) sets his racer to .001. The Norton Owners Service notes suggests .005 "or less" - as long as there is some clearance.

Frankly, I'm wondering if it makes much difference at all, Back in the 70's I raced my '71 Commando with the isos at .010 ('cause that's what the book said). I was working on becoming a professional bike racer and decided I'd be the next Mike Hailwood. I routinely grounded parts on curves with the oem 4.10 tires on both end. So, since I, and lots of other folks managed some pretty decent lean angles, is all this "better handling" stuff a bit overdone? Of course, I would not even attempt those same lean angles now but that's my age/fear kicking in and, of course, when we were in our early 20's, we had neither of those things!

I wonder the same thing about the various aftermarket headsteadys. Again, if we were able to drag the pipes with totally stock stuff - including the original head steady that was prone to crack - how much practical handling "improvement" can there be with any of this? I have read plenty of posts about how X headsteady made a stunning improvement in handling. But what is the stunning improvement? If you can drag the pipes in a turn with a completely oem suspension setup, what "improvement" can you make with "better" parts?

Anyway - do folks generally use the .010 or is there major differences in handling/vibration by going to different settings?

Oh, yeah...after two years of racing I realized that although I was a racing legend in my own mind, the riding talent of folks like Mr Hailwood et all were so many orders of magnitude beyond mine that I decided to keep my day job!

I wondered abou that too. Seen the 1968 Isle of Man Production TT race? Pretty impressive watching Fastbacks nudging 100MPH laps on whats basically a rural road with hills n dales. I heard a rumor that the factory did fit an Iso top head steady. The top of the range privateer racers such as the London dealer Gus Kuhn was a prolific race team up to the mid-70's and won a whole bunch of trophys against Tridents, Rocket 3s, Honda 4s and Kawasakis. The English circuits are pretty demanding and they ran mostly on stock K81 Dunlops. Certainly the Norvil proddie racers went one step further and lifted the engine over about 1/2' and hung the pipes over the right hand side for even more cornering clearance but it the Iso setup was no more than rear, front and top and allegeldly at ".005 clearance.

Mick

Hi Mike, nice story which reminds me same thoughts when we were young and not internet addict.....those were the times, I rode my interstate like you with worn out K81, and no ideas about iso clearances, just because I had been told I had the best Roadholder .........everything is in our mind!!!!

After some 39 years on various Commandos all with the stock head steady, I decided to take a flyer and installed a Dave Taylor head stead five months ago.

I put along, don't come anywhere near grounding things, and have never raced.

But, I can say that I have noticed two "improvements" with the new head steady.

1) Immediately after installation I noticed the bike felt "straighter", and especially on curves, my guess is the DTHT eliminated the heads former
ability to more from side to side. This feels good to me.

2) Vibration, a little less, and I notice the vibration lessening at a lower RPM than before, smoothing at around 3500 instead of 3900.
Don't know why, perhaps others will say what is actually happening.

I paid about $150, for me a cheap, and nice improvement.

The 1970's K81 tyres are the best tyre I have ever used. Wore out quickly. I do not know if the modern K81's are as good.
Always set my isolastics to as near to zero as possible, as did a chap I used to know who raced them. He had a problem with scraping exhaust pipes.
A few months ago I fitted an iso head steady, I think it is better at high speeds, certainly not a night & day difference. It can only be better I suppose.
There is no difference in vibration between a .001" or a .010" clearance that I have ever noticed. The .001" clearance will eventually wear to .010", but if the clearances become big, the bike becomes a problem throttling off into bends & can nearly throw you off.

It always seemed like adjusting the vernier Isolastics loose made the vibration less noticable and adjusting tight made it handle better. When you're riding with some modern sportbikes and they stop to tighten up the suspension for the twisties, you can tighten up the Isos.