F: Frame AVO COIL OVER WANTED HELP PLEASE

[oexing]

High pressure air pumps for these are € 10.- from Ebay and all, remember the bikers do this business for decades, no weight at 200 gr . No central air shock I think, they shall go to original position , two of them, at half load air. The small cylinder with all the valves will likely point to the road ? Bushes could be rubber-types, suitable bushes are spares from same business, but not really spherical I think. The IGUS do small spherical bushes with 5 degrees acceptable, got some of them in my Fournales mods. See link below for Igus, metric certainly , from 8mm bore up to 16mm bolts.
The 250mm/75mm types are all with side extra cylinder, I could see some alu shrouds , black and polished, pushed onto the airshocks for original looks . . . .

Vic
IGUS spherical slim type:
IGUS bushes

air pump 300 psi:
Ali pump

Fournales modded with IGUS:

 

[twobyfour]

In answer to Norman's request for feedback:
1) 275lb spring on a single shock is not strong enough with a fully-sprung seat (95 kg rider,) in my experience. The 275lb spring had to be set to near the maximum allowable preload and the damper compressed to within 5mm. of the bump stop during a ride on 'normal' North Yorkshire roads. I changed to a 325lb spring, which is much better and allows more movement. I have the AVO rear damper with the re-positioned rear mount. It works well but the rear mount does seem like a bit of a bodge (sorry, compromise!)
2) A pair of coil-overs would appeal to me, particularly if they could be 'disguised' to resemble original spring boxes.
3) If not spherical end mounts, then metalastik type mounts would allow some movement so that there is no sideways thrust on the damper rod(s)
4) Vic's air shocks look nice, but at what cost? (This comment is based on current Fournales prices.) They may be the absolute bee's knees, but......
5) Suntour air shocks...aren't they for bicycles, or have I missed the point (again?)

 

[oexing]

These Suntours are for bicycles - but would they be illegal on motorbikes ? Methinks lots of modern goodies on Vincents were decently illegal if somebody cared . . .
The Fournales on my bikes were found used on Ebay, five of them and heavily modified for 250mm length and 80mm stroke. I put an o-ring for extra bump stop on the piston rod, so now 77mm stroke. The last of 6 required was made all at home from rounds of stainless and hardchromed piston rod, plus valve components. Not a complicated job, just lots of hours , no CNC near me. So yes, the SR bike airshocks would be a low cost alternative with very sophisticated tech inside, look for servicing them in YT clips , no match by AVO and all. So I do believe they look worthwhile to get you two of them - not much more than one pre-monobloc or other parts in Vincent-currency . . .
As to costs, you have to see the complete picture: When you have to send shocks to specialists for spring changes or internal settings, buying new springs each time, shipping costs plus wasted time and all, I´d rather want shocks that I can mod at home, on the road if you like too. So after all, not a very bad deal for the money . . . .

Vic

 

[Chris Launders]

If the Suntours are for bicycles then they won't be capable of carrying the weight of a Vincent and rider alone, you would need three minimum, one for the riders weight as on a bicycle and two for the bikes weight, given the a Vincent weighs around twice what a rider does.

 

[oexing]

These airshocks are used on bikes with single rear shocks, on linkages too. And in YT you can see a biker hopping down a rough trail on the rear wheel only. So my guess at 200-300 psi they carry quite some weight. Certainly you´d put two at the Vincent rear, so weights are 50 percent per side - which would be some 200-250kg at rear wheel. So then less than 150kg per airshock. Seems to me suitable for the SR types. Please look into the YT clips for getting an idea about shock loads and installations in linkages on those bikes.

Vic

 

[Peter Holmes]

Do these cycles attain a speed of 100mph whilst carrying luggage and a pillion passenger?

 

[oexing]

Cannot see what speed got to do with shocks. Do Vincents many meters of air jumps on rough terrain ?? On one wheel with 100 kg rider on it ?
Do all Vincenteers carry luggage plus pillion passengers all the time ?
Sorry, I cannot tell yet, but the SR airshocks might be quite useful and very adjustable - unlike AVOs and all, that you have to modify , or rather have them modified heavily once you change operations on your particular bike , like for fully sprung - pillion use - lightened racer equipped and so on. Nothing can be achieved with one shock out of the shop for all purposes, so no need to blame airshocks without knowing. I do not know sizes of pistons in these airshocks, so cannot tell what that is in load forces from 20 bar/300 psi.
What I do know are reports about unsatisfying settings when getting AVOs for all sorts of Vincents and expecting to behave just as wished without the dealer having been informed about all configurations of that bike.

Vic

 

[greg brillus]

There are loads of inexpensive Pit Bike shocks on ebay that would easily do the job, only real issue is getting some suitable springs made.......but that's not such a big deal once you know what spring specs and rates you need........The ones I had on the race bike in my pic to left were $100 each new off ebay back in 2013, and weigh about 1 Kg each complete.......The rear used a 300 Lb spring (fully sprung seat) and on the front about 170 to 180 Lb spring.......worked very well.......if only my road Vincent had as good a suspension as that i'd be stoked........

 

[A Nut]

I should have mentioned that in addition to the rear Protech shock that they made for the Victor that Kevin had a go at making a front damper for me. The problem that we had was making it short enough (closed) to use on the front. I can't remember what figure we ended up at but whatever it is it works ok. I had to machine the 5/16" BSF thread on one of their damper rods myself as all of their kit is metric. Protech then fitted the top fitting from a standard Vincent damper and a plastic shroud from one of their old type (BMC) Mini dampers. We experimented with the damping rates and it currently is on the softest setting they can provide. It still has another 13 harder positions that I can play with!
Now that winter is here I am prepared to remove the front damper from the Victor and take it down to them if anyone else is interested.
Brian Werrett

 

[A Nut]

Further to my post yesterday, I have been in touch with Protech shocks and offered to return the front shock that they made for me 6 years ago so that they can see what they need to make. As regards the rear Series D shock the one on my Victor is shorter so if anyone has a standard D shock they may need that to copy. My email is b.werrett10@hotmail.co.uk
Brian