1974 Norton Commando 850 MK2A - Isolasticity (part 6)

[@johnx.k.4603]

Watched the isolastic series again before my install and it made it so easy. Yes, a rubber mallet was needed to encourage setting the unit back in the frame and case..Thanks!

[@TheMightyGarage]

Hi John. Glad you found the series helpful and that it made your install much easier! Cheers, Mike

[@jimh.5286]

Very interesting video! In 1975 I had a Yamaha XS-1 650cc 4-stroke twin, which was a real paint mixer. It was uncomfortable at any speed above 45 mph due to vibration, much worse than the Triumph that I had ridden. So I devised my own rubber engine mounting system. The bike was then quite smooth, but the engine moved around so much it scared me - wouldn't be good if the engine fell off at 80 mph! So I chickened out and removed the rubber mounts...sold the bike. I should have bought a Norton.

[@johnmcclain3887]

This is the first time I've seen the "isolastics" adjusted, that seems a rather finicky job, but well done. I don't envy you working on the rear "isolastic", it does look a bit more difficult to access. Thanks for showing this!

[@snbailes1]

magic

[@BLVDSURF]

Your videos helped me install my new front iso's this weekend - Thank you. Although, my final "snug" reading was .008, not .010. The Old Britts instructions suggested .006, so I believe I'm OK between you two. I'm using your videos to replace my swing arm next... and wondering if you have video of replacing the rear iso's? Thanks for sharing - I dig the style and presentation on your videos.

[@micpotato8158]

Helpful video mike.....does the adjustment mechanism have to be on the timing side ? It just looks awkward to get to.....do you think having the adjustment mechanism on the primary side would be okay? Any input from viewers also appreciated as I am considering this ..regards Mic

[@TheMightyGarage]

Hi Mic, yes, I do think the adjustment plate would work on either side. I can't remember there being anything that would have prevented it from being on the left-hand side instead of the right-hand side of the bike. Cheers, Mike

[@R90scj]

Too slow to watch the whole video, had to fast forward. Sorry old chap. The 69 went away, wanting 850's. Still own a 73 and 74 Roadsters plus a 74 Interstate with original tyres and break in decals. International Norton Rally 1st place show winner of very low miles. Being a non vernier with shim adjustments only I never had a increased vibration problem by adjusting down to 0.006" clearance, this measured after the isolastic mounting bolt has been torqued to spec as the tube will compress slightly. Also the thread slack as mentioned above. I want my islastics to maintain their clearances a long time riding. Teflon greased washers, the isolastic clearances are stable vs installed dry accelerating washer wear. Also the two metal contact surfaces are lapped smooth vs having the rough machined surfaces against the washer again causing that hinged in the middle bike feeling like loose swing arm cradle bushings also creating that sickening handling feeling. Going on 50 years and counting owning right hand shift only Nortons......~~=o&o>........

[@chrisbashall6670]

Could the internals be installed the other way round, so the adjuster is on the other side where there is more space? The overall width would still be the same.

[@TheMightyGarage]

Hi Chris. I'm sure you're right. Yes, I think they should fit in either direction. I might try this next time I look at the internals. Cheers, Mike

[@fragola1149]

Don't do it, because the collar on the adjustment side of the isolastic being larger, it will not match the frame lugs. You can do it using strength, but you will find the gap in the shims to be uneven the way round because the motor being off line line in the trame.

[@hotwheel6663]

You do the rear yet mate?

[@TheMightyGarage]

I haven’t done them yet! I ran out of time and energy to do them 😉 Hoping to do them one of these days, possibly over the winter. Cheers

[@les3066]

As you found out there's no point attempting to set the vernier adjuster accurately 'on the bench'. The "back off by 'x' holes" method isn't accurate enough in my opinion. Also, the clearance needs checking at various stages during the through-bolt tightening process, as tightening the bolt can reduce the clearance due to the slight 'play' in the adjuster thread. An easier method, in my opinion, is to insert a feeler gauge of the chosen dimension, tighten the adjuster collar against the feeler, back it off until the feeler just slides then begin tightening the through-bolt with the feeler in position. If the assembly begins to grip the feeler as the bolt is tightened then slacken the bolt and increase the adjuster clearance until the feeler slides with the bolt fully tightened. Same for the rear vernier Iso.

[@TheMightyGarage]

Les 3066 Thank you Les for this information. Yes, I’m sure that I will be checking the clearance again soon after I’ve had the chance to ride and ascertain any notable difference in vibration. This is just the initial setup for now. I appreciate the point about checking the gap during the through-bolt tightening sequence. I’ll try that for sure. Cheers, Mike

[@54macdog]

Makes open heart surgery look a breeze!