Replacing Front End

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davamb

davamb

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One of the bike's previous DPOs stuck what I'm told is a Ceriani front end on my bike and I can't say I'm too pleased with it. In fact it lets the whole bike down. I've been looking into cartridge options as a way of improving matters, but not had any luck so far - the options for 35mm damper-rod forks are basically non existant. Toss in the fact that the disc brake conversion is suspect to say the least means I am now looking around at other options:
  • Buy a used Commando front end. Great, but I've yet to see one come up for sale here and I ran a Wanted ad for some time too.
  • Build a whole front end from parts. Probably expensive, but would mean I could run one of Don's disc-brake packages. Could perhaps still bung cartridges inside just fork tubes, legs and triple clamps.
  • Adapt a complete front end from some other bike. Would still like to keep my cast wheels though. Could also be a cartridge candidate.
Thoughts? Ideas? Other options? There's a great bike hiding behind this crap front-end. Of that I'm sure.
 
When you say "cast" wheels what wheels do you mean?
What commando do you have a 750 or 850? As you no doubt know the rake of the headstock is 1° greater on an 850
Cheers
 
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The Cosentino and Maxton inserts are adaptations of Showa 20mm cartridges, the issue is the method of how they are fixed into the bottom slider. On BSA/Triumph OIF and Cerani forks without sealholders the bolts used to hold the cartridges in also keep the stanchions inside the forks, if they shear then if the wheel leaves the ground the wheel can come off, it's happened in scrambles in the UK. So these bolts need to be hi tensile, to adjust the compression damping they need a hole drilled in them weakening them.
 
Another option is different springs and cartridge emulators like Race Tech. I have them in 35mm Betors I installed on my Triumph.
They are compression adjustable only and rely on the damper rods for rebound.
 
You must also consider the fact that the offset of the triple clamps may be different than stock. Some of the Commando triple trees also had an angle built into them. The forks were not parallel to the headstock (that always struck me as weird). These issues will not affect the dampening attributes of the forks, but could negatively affect the steering geometry by changing the rake and trail.
 
Thanks for the responses chaps.
@baz here's a pic of the bike. No idea on the brand, been told by those in-the-know here that they're Morris Magnesium. Doubt it, they'd be worth more than the whole bike! Don't really care what they are, they were put on in the 80s and I like 'em!

Replacing Front End


@gortnipper and @kommando - thanks, same with the forks. Not even sure they're Ceriani. Will send queries to Maxton and Cosentino and see what they have to say.
Let you know how I go.

Edit: here's a pic of a fork in bits from a couple of nights back:

Replacing Front End
 
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You can often find fork bottoms on E- Bay, then you could buy the modified damping kit from Madass which contains all of the internals including springs, then a pair of fork tubes and an overhaul kit from one of the Norton vendors. I think you could probably do this for around $500.

The forks in the photo look like Harley/Aermachi 350 with one fender tab removed.
 
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I have the Madass conversion on 2 bikes it works great, no need to complicate things further! at least it looks stock, all the other parts are cheap enough to find............
 
Thanks chaps. @dave M and @manx850 - the Madass solution is certainly the way I'd like to go! Have made contact with Chris Cosentino and he reckons he might be able to assist with a cartridge insert, but the poor Aussie dollar at the moment means a solution around $1k5, and it will still be crap in the brake department. Time for an eb search for bits I think...
 
There is a pair of disc fork bottoms on E-bay USA right now for US$100, also complete left and right forks on separate auctions at 300 each.
 
I believe those are REH forks. Popular after market upgrades back in the day and used by builders such as Dresda in their race bikes.

They should be able to be made to work perfectly satisfactorily, I’ve raced with them and don’t recall thinking they were an issue. But if you really want the best performance out of them then I’d be sending them to Maxton or similar. This is an expensive option however so only you can decide if that’s the way you wish to go.

It would probably be cheaper to replace with stock forks. But IMHO they look quite period Cafe Racer and it’d be kinda a shame. The same cannot be said of the front brake set up though... that looks a bit scary frankly...!
 
The Production Racer slider will mount your caliper and retails at £190, you just need to find a plain slider for the other side.
I've seen complete stanchion, bush & seal packages on EvilBay for around £80. I'm guessing they're EMGO. I've used them and the quality is good - stanchion sizing was spot on.
Madass 140's Lansdowne dampers probably represent the best VFM, and I like how they work - much better than the originals.



I have a pair of Seeley Mk 4 forks with Maxton at the moment, and their fixed compression, adjustable rebound dampers are over £400, plus they have to re-work the sliders to accommodate their hardware, so the final bill will be a fair bit more.
 
I use Ceriani forks from the 1960s on my Mk3 Seeley - no issues. They look nothing like your forks. But I'd point out that, in that photo the bike is not sitting level. Perhaps you have more travel but weaker springs ? With Cerianis, damping should not be an issue if you use 15 grade fork oil. When you are riding the bike fast, the suspension should pull down due to the hydraulics and find it's own level. More suspension travel is not the be-all and end-all of good handling, your motor is not turning out 100 BHP.
 
davamb
great looking bike, I would get a second calliper, disc and a pair of Production Racer sliders with modified internals as mentioned by B+Bogus.
Uprated Roadholders in fact, but that would suit the look and function of your bike perfectly, you may find the front alloy wheel already has holes for a second disc. I use Maxton modified Roadholders and love them. A rear disc would complete a functional setup.
 
Sorry for the delay in resposes guys, been off on a Phillip Island Ride Day and had to spend some time prepping the TRX.

Have been in touch with Maxton, Cosentino, Madass and RGM in the interim and the responses have been interesting - but all seem pretty expensive, not helped by the weak Aussie dollar at the moment. I mean in the realm of at least $2k. Interestingly, Maxton thought the forks were not Ceriani; more likely Marzocchi. I'll summarise the options later, but I'm beginning to think it's out of my range to do something about (have just blown my tax return on what is probably the last FullAuto head in the State, of not the country, so wallet is not terribly happy ATM.)

I did find the time to pull both forks to bits, clean them up and refill with proper fork oil (one leg down to about 20cc). Went on my local test loop and thought the front end perhaps really not that bad. The brake is bloody useless though - if not outright dangerous, so maybe I should focus on improving that today and look at the front end later - perhaps next year's tax time!
 
What exactly are your forks doing that you don't like?
As you are focusing on the damping I'm assuming the spring rate is about right and you want to control it a bit?
What is the offset of your yokes?
Have you tried dropping the stanchions through a little?
There's a few things you can try with damping , different oil , blocking off or altering the oil passage holes etc
Also apart from the mounting of the front caliper what's wrong with the front brake?
What master cylinder do you have?
If you look at the way some early race bikes were converted from drum to disc with a plate that was drilled for the axle to pass through
And the other end clamped to the slider,or bolted to the torque arm/mudguard bracket to mount the caliper , you may be able to do this on your bike
Maybe with the caliper in front of the forks
 
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