Commando Fork Conversion to Honda Cartridges - Update from Cosentino

Chris Cosentino just posted this on the MC-chassis design forum, with some interesting details on his conversions. It was in response to someone asking if anyone had tried putting modern cartridge dampers inside Norton forks.

"I sell this as a drop in product for vintage Norton Roadholder, some Ceriani, and Triumph T140/150 forks. There are some pics at: https://www.cosentinoengineering.com/products/

It is an improved version of a sketch done by Kenny Dreer that I was shown and that many other people have done on their own. My kit retains the compression damping adjuster by making the lower damper retaining bolt hollow and putting the needle and fluid return path inside it, which I think is the only retrofit kit that does it. I use 2006 CBR600RR dampers as the donor part, Honda part number 51430-MEE-D01. Once you get later than this year the forks from various manufacturers have 'big piston' dampers which don’t fit inside the smaller 34.5mm and 35mm forks. The damper body fits just inside the Norton tubes. I have to machine off the hydraulic bump stop to fit it in, but the damping improvement is well worth it. Most people with these bikes complain about top-out clunk which this eliminates since the damper has a built in top-out spring.

Everything in my kit is easily replicated for a one-off with a manual lathe and the parts to measure.

I had to have new springs wound as part of the kit since the Showa cartridge body is much longer than the OEM damper body, leaving a lot less space to fit a proper spring. Normal street bikes with 180lb riders usually use 40 or 45lb/in springs. Lightweight single cylinder racers like Manxs use 25 or 30lb/in. My springs are 25mm OD x 355-380mm long. Love those mixed units!



Chris Cosentino
COSENTINO ENGINEERING
812 Jersey Ave. 3rd Floor
Jersey City, NJ 07310
201-392-1400
www.cosentinoengineering.com"

Ken

lcrken said:

Chris Cosentino just posted this on the MC-chassis design forum, with some interesting details on his conversions. It was in response to someone asking if anyone had tried putting modern cartridge dampers inside Norton forks.

"I sell this as a drop in product for vintage Norton Roadholder, some Ceriani, and Triumph T140/150 forks. There are some pics at: https://www.cosentinoengineering.com/products/

It is an improved version of a sketch done by Kenny Dreer that I was shown and that many other people have done on their own. My kit retains the compression damping adjuster by making the lower damper retaining bolt hollow and putting the needle and fluid return path inside it, which I think is the only retrofit kit that does it. I use 2006 CBR600RR dampers as the donor part, Honda part number 51430-MEE-D01. Once you get later than this year the forks from various manufacturers have 'big piston' dampers which don’t fit inside the smaller 34.5mm and 35mm forks. The damper body fits just inside the Norton tubes. I have to machine off the hydraulic bump stop to fit it in, but the damping improvement is well worth it. Most people with these bikes complain about top-out clunk which this eliminates since the damper has a built in top-out spring.

Everything in my kit is easily replicated for a one-off with a manual lathe and the parts to measure.

I had to have new springs wound as part of the kit since the Showa cartridge body is much longer than the OEM damper body, leaving a lot less space to fit a proper spring. Normal street bikes with 180lb riders usually use 40 or 45lb/in springs. Lightweight single cylinder racers like Manxs use 25 or 30lb/in. My springs are 25mm OD x 355-380mm long. Love those mixed units!



Chris Cosentino
COSENTINO ENGINEERING
812 Jersey Ave. 3rd Floor
Jersey City, NJ 07310
201-392-1400
www.cosentinoengineering.com"

Ken

Click to expand...

Ken,
I have his kit on my bike now for 2 years now and am very pleased with both the way they fit and how they work.After 2-3 different settings along with fork oil weight for my small size, I think it is a nice upgrade.Plus excellent customer service for all my questions,etc.
Mike

I've been discussing the CBR600rr damper conversion with Ken and John here after I was underwhelmed with the landsdownes performance riding on my local streets This prompted me to do a good bit of research on the evolution of damper technology to answer some questions. Essentially, street riding is not race track riding. Because street riding has a wide variety of surface conditions, dampers benefit greatly from shim stack technology to allow for both smooth surface high performance and "not so smooth surface" high performance in a single damper. A damping system without dual circuit performance can only adjust to one surface condition at the expense of the other. Adjustable fixed orifice dampers may work well for a race track where the surface is consistent but they work less well for a street bike. Modern bikes have this shim stack valve technology where you can tune both smooth surface performance and rough surface performance without sacrificing one for the other.

The modifications require some custom made parts, and some modified stock parts, a knowledge of shim stack technology (which is seemingly a form of voodoo) plus all the standard depth of knowledge that primitive fork dampers required OR you could just buy the Cosentino damper set up where they do all the work for you.

As with my cast aluminum wheels conversion, I started out on this project to cut the cost of getting modern shim stack dampers into my forks and by the time I'm finished I will have probably saves some money, but not all that much. I'm not done with my conversion, so I can't say yet how it performs. From my research I know that the low velocity circuit will be easier to tune than the high velocity circuit which will require cartridge disassembly, valve disassembly and experimenting with different shim stack configurations. Shim stack expertise is not easily acquired or found anywhere, so you either have to rely on some guru to help you or you are experimenting. (like me)

There's also aftermarket high performance valving that can be added at a price (racetech gold valves) That's about it for now since I am not finished with my project. Much thanks to Ken and John (kommando) for their help and advice, and Chris Cosentino for his information (and for actually making a commercial version for those who just want to buy the next level of technology) I'll give a report on the initial performance once I get my first configuration installed. I'll add the relevant specifications so that information is available to everyone here.

Here's a helpful website page for those who want to go way down the rabbit hole of suspension: https://www.peterverdone.com/archive/suspension.htm

o0norton0o said:

Here's a helpful website page for those who want to go way down the rabbit hole of suspension: https://www.peterverdone.com/archive/suspension.htm

Click to expand...

Good luck with your quest.

Thanks for posting that pvd link. I've been looking for something like it for a while.