ceriani air conversion.

[dave higgins]

Has anyone any experience or info on converting 35mm ceriani forks over to full air.
I know this can be done & know roughly how, but if anyone has ever tryed it, or knows someone who has used this technique, i would be interested to hear any details/ pitfalls....

[cchapp4]

I would also be very interested inthis (air conversion).?
I have seen a few Greeves with air valves protruding from the Ceriani tops but cannot understand how the compression of the folk movement allows the forks to breath without turning the seals inside out and thus loosing the oil and the little damping once had.

[dave higgins]

The forks are pressurised, air is compressive, oil is not, but the ratio`s & pressures between the two are critical to achieve a working unit.... other than that, i do not know.
But i do know its been done..... druid are you out there!!!!....

[John Wakefield]

Air forks

Panther used Oilomatic/Dowty air forks back in the 1950's. These were for road use but I dont think they were entirely successful and many got modified to springs. I remember having a set on an old 350 Panther used as a 'field bike' they had to be kept pumped up & also leaked oil. Of course they were not in the best condition & no chrome fork tubes in those days.

[Brian Thompson]

Scottish Air Fork Conversion

Wotcha Dave,

I tried this on my Scottish, and the biggest problem I had was getting a decent seal at the other end.

Mind you, I did manage to get 3,000 psi into the b*****s before the grouting blew......

I did hear that a young apprentice tried it years ago at the factory, using parts from an old football, but Mr Greeves made him take them off.....

Brian.

[Colin Sparrow]

I tried this on my Scottish, and the biggest problem I had was getting a decent seal at the other end.

Brian.

I tried it unsuccessfully using a walrus - being me I was bound to get it wrong...

[Brian Thompson]

Lew.

Tusk tusk....

A few questions though Colin.....

1.) Have you written another book it about? Already?
2.) Why have you used a pseudonym?
3.) Why is the Walrus 'worried'?
4.) Are those air forks on the bike the Walrus is riding?

Soz Colin, couldn't resist......

Cute Walrus tho....where can I get one? (No, not the book, a REAL WALRUS....!! )

C'mon guys, you've gotta admit it.....where else on the internet can you have a tech discussion on ceriani air fork conversions and walrus's in the same thread....quality!

Brian.

[Brian Thompson]

Air Forks In Action! (Boing boing boing!)

Brian; 'You know, these new fangled air forks are really rather good!'

Basil; 'Make a note Vic....and call matron! TOO MUCH PRELOAD!!!!!!'

Brian (the other Brian.)

[dave higgins]

Thanks for the input chaps, i was looking at brians pic of the scottish with the shrieder valve attachment on the left of the top yoke, alls not right here i thought... then after a while it twigged....what a plonker!, everyone knows the early scottish air valve was on the other side..........
phil, i was thinking along the same lines as yourself, its something i may try, i was just trying to weigh up the pros & cons.
You can achieve more travel, ( barely ) because you don`t have the problem of a coil bound spring, its a considerable weight loss, around three pounds, on the other side of the coin, the performance is an unkown, both fork legs must retain the same pressure, & what about oil seal failure whilst on the track......
The sensible thing to do is get the bike up & running with the standard set, then try it on air later, see how it compares.....
On the other hand.... it could be a lot cheaper if the rider lost three pound in weight.....

[aa will]

hi back in the seventies we used to convert the bultaco forks to air when we fitted chairs to them by drilling and tapping the top nuts to take the valves from the british leyland hydrolastic suspension, as fitted to minis /metros, they were designed to work with oil so did not fail like an ordinary schrader valve did used them for years with no problems,and it saved having to fit stronger springs or pre loading the forks to take the extra weight of the sidecar and passenger, we also fitted them to fantics montesa,s and lots of other trials bikes . will.

[Brian Thompson]

Great thread mate!

Hi Dave,

Yes, I am indeed a plonker (as well you know.....), and yes, I fitted it to the wrong side....

But seriously (if we must), regarding equalising pressures between legs, some set ups I've seen utilise a link pipe. Maybe Will (hi Will by the way, great to have your input on here) has tried this...?

Another issue I've heard about that can cause probs is that of the forks getting very hard right at the bottom of travel, which stands to reason.

I'll consult the suspension Jedi's at work this week and report back.

We need Marcelle34A on this.....you out there M....?

Brian.

[dave higgins]

Good point brian, about getting harder towards the bottom, i`ve only read one website on this subject & it does bring up all these points discussed by every one...
Phil, its not pre 65, but pre 74, which allows 7 inches on the front, & i don`t think you actually get that from a standard set of cerianis, the rule book only states the travel, not how, so ok on that i reckon....

[Brian Thompson]

Air fork balance pipes.

Hi Phil,

With due deference to DC (), wot these then.....? (see attached pic.)

Here's a few more; https://www.google.co.uk/search?sour...=isch#imgdii=_

Admittedly, these may NOT be 'full' air conversions, but hey, it's a thought....

Dave; Here's a alink to that thread with those ceriani's, attached to a rather tasty Beesa; http://www.britbike.com/forums/ubbth...&Number=473979 Might be some good info there for you.

Brian.

[Brian Catt]

Interesting thread! My little Honda TLR200 has air valves on the top of the forks that according to the Manual should be pressurised up to 6psi for normal roads but do not exceed 42 psi for rough road riding. I don't think I have ever bothered, or felt the need to pump up the front end, more like the back, which I have bottomed several times!

[griffon380]

air forks

Hi Dave,
I bought a 250 Griffon from America with repositioned rear shocks and air conversion to front forks. I have the bike in bits but will "dig out" the photos and post.
Craig