Rear suspension units!

[themoudie]

I thought that I should just post a wee note about rear suspension units and my experiences after 17,000 miles.

Used a pair of Sebac units when first putting the 450 MKIII back on the road and they lasted 500 miles! The threaded seal retainers on the top of the damper having unscrewed themselves, with the offside retainer detaching itself, releasing the nitrogen/oil charge all over the rear of the bike! As the units had been purchased more than 1 year prior to fitting there was no valid warranty and upon notifying the supplier and factory, no reply from either.

The Sebac units were replaced, with a pair of Hagon units, they only supply the 300mm between mounting eye centres, rather than the original 310mm and were fitted with the 90lb springs. After approximately 15,000 miles of regular use over all types of Scottish highways, byways and the odd unmetalled farm track, the damping felt, non-existent and so it proved to be upon dismantling both units, partial resistance at different places in the strokes of the dampers on compression and on return!

So, what to do? Throw large amounts of dosh about, throw not inconsiderable amounts of cash at previously fitted units that have proved questionable in their serviceability, or buy British and small? I chose the latter and was pleasantly surprised at the cost, quality of finish, service and we'll just have to see how long they last. A pair of NJB Classic road shocks, with 310mm between eye centres, chrome springs (90lb) and bushes to suit my mounts, were £107 + £10 P&P, using Royal Mail 48 hour service, which Royal Mail managed to flunk by 2 days and it was I who requested their service, not Norman.

I'll let you know how I get on with them and whether they outlast Sebac and Hagon?

Good health, BillR

[Duccout]

Hi Bill,

This is one of those conundrums that depends on how deep one's pockets are. Top quality rear shocks from people like Maxton, Nitron, K-Tech and Ohlins are horrendously expensive, but are worth every penny in comfort and performance; unfortunately most of us would judge that spending £1000 for a pair of shocks for a bike that is worth a few thousand pounds is crazy! The best shocks that I have used were from YSS (on my Ducati GT1000) but the price is around £500; I also like those from Protech in Wiltshire which are about £380 and both of these are fully rebuidable, so they have (theoretically) unlimitied lifespan. I have adjustable Hagons on my 250 and they work perfectly and I have no complaints, but how long they will last is to be seen.....

You pays yer money etc.....

Cheers,

Colin

[blethermaskite]

Here's a chance for you all to have a laugh at me I am still using the original marzocchi shocks on my 74 350 mk3 ...I rebuilt them 40 years ago having found flaking chrome on the damper rods and leaks. I has the rods hard chromed and fitted new seals, the seals started to fail again about 10 years ago and were replaced....been working fine since.....I have always found them to be a good performer (for me).
Cheers George

[Boxprod]

I'm not laughing, Bill - I've done exactly the same with the same bike.
Just done a 300-mile round trip to see my son and family, and although I creaked a bit, the bike was fine. Especially the still comfortable rear Marzocchis!
Pete.

[Boxprod]

Apologies, George!

[Duccout]

The original Marzocchis on my 1975 350 were perfect, so no laughing from me either!

Colin

[themoudie]

Thank you for your experiences.

My original Marzocchis were written off, when I wrote off the right hand side of the bike at the Redhills roundabout, just outside Penrith, back in 1978 and they were pretty manky by that time, being 4 years old and little chrome remaining! The body of the righthand damper was bent and dented, as was the damper rod. Hence the junking of the Marzocchis. I fitted a pair of Hagons and they lasted very well, as have other Hagon shock absorbers that I have fitted to both the Duke and other machines, hence my feeling peeved at the latest pair only lasting approximately 15,000 miles.

However, the Wilbers monoshock on the SRX 600 Mono and the Konis fitted to the twin shock SRX 600, both give a superior ride to that of the Hagons. Both makes having been fitted by previous owners, prior to my ownership.

My friend uses adjustable damping YSS's on his Guzzi's and Commando's and says they are excellent.

Good health, BillR

[LaceyDucati]

Bill,

310mm units are available from Hagons, you just have to ask. Fit the Hagons upside down and you will most likely find they work fine, the gas can separate in the units, which is most likely the issue. You may have noticed many racers fit the units upside down for this reason and you also lower the unsprung weight. I first fitted mine upside down 30 years ago after advice from an old boy a Hagon at the time.

Regards Nigel

[A.I.M]

During the restoration of my 250 Scrambler I decided to replace the original Telesco units with YSS GMPYSSSTD6, with 310mm centres and marketed as being suitable for a 180-220 kg bike. At the time they were about 150 euros a pair, probably a bit more now. Although I can't say I am a highly challenging rider, they have performed well so far. However it's too early to tell how long-lasting they will be.

[themoudie]

Aye Nigel,

Thank you for the information and advice on the Hagon's potential gas separation.

Exactly what I thought, but these are definitely cream crackered! Having inverted them, minus the springs, pumped them in and out in the vice, I get no resistance on the compression stroke and a return of 50mm, before the rod sits like a stuffed duck and has to have it's neck pulled to return to the fully extended position. Goosed! 'Nough of my awful festive puns.

Out again today for a canter through central Fife, down to Elie, where the wind was gusting 40mph+ from the west and the windsurfers were having a grand time and the sand was 100mm+ deep all up the shore street, where the beach tries to take over. Firm, yet compliant suspension both front and rear now and the back tyre nicely scrubbed in. Now to get a set of grips from Doug, as the current ones are falling apart.

Good health to you both, BillR