Commando with VFR750 Fork/brake Conversion

acotrel said:
You say the trail and the fork length match, but you might be comparing the two machines. If the donor machine has a different rake or front wheel size, the yoke offset from it might give a different result to the one which you might expect. Less yoke offset increases the trail. If the trail is slightly increased, that would be safer than if it is reduced. If you are using the Commando fork yokes, you would be safer. But I think most Japanese bikes have a non-taper fit in the top yokes - most Nortons have a taper fit in the top yoke. Less yoke offset decreases the trail and makes the machine more stable as you brake, but too much stability can suddenly cause the machine to stand-up and turn the wrong way. I laugh if I change something and the result scares me - you might not. I was lucky - when I had the wrong yoke offset , it caught my mate first, so for me - I was ready for it when it happened as I braked - I still almost ended-up on the deck.
Click to expand...

which is it ?? one of you is wrong, but the good news is one of you is right....
 
I really don't want to highjack this thread but I ran across it as I'm working on this front end. I'm wondering if it looks like it's all there? This was on one of Hobot's bikes, really looks like over kill but I may use it if it makes a difference? From the front view it looks like a Mac truck and must add weight to the front end. Could someone tell me who made it? RGM made the brace.
 

Attachments

  • Commando with VFR750 Fork/brake Conversion
    IMG_6386.jpeg
    454.9 KB · Views: 126
Racetech shim stack emulators and norton damper bodies. If you want only compression damping that will work as long as you have an O ring on the OD of the racetech to stop the oil flowing past the OD. Sit them on a 26mm OD garter seal and with them held in position by the mainspring that will also work for a time but the garter seal will get torn up if the stanchions have not been finished on the ID.
 
acotrel said:
You say the trail and the fork length match, but you might be comparing the two machines. If the donor machine has a different rake or front wheel size, the yoke offset from it might give a different result to the one which you might expect. Less yoke offset increases the trail. If the trail is slightly increased, that would be safer than if it is reduced. If you are using the Commando fork yokes, you would be safer. But I think most Japanese bikes have a non-taper fit in the top yokes - most Nortons have a taper fit in the top yoke. Less yoke offset decreases the trail and makes the machine more stable as you brake, but too much stability can suddenly cause the machine to stand-up and turn the wrong way. I laugh if I change something and the result scares me - you might not. I was lucky - when I had the wrong yoke offset , it caught my mate first, so for me - I was ready for it when it happened as I braked - I still almost ended-up on the deck.
Click to expand...
The AI indicated no work would need to be done to the angle of the steering stem for the VFR fork and triple clamp. I would need to verify that before proceeding.
 
NYC Norton is doing the cartridge replacements for Commandos now. They want $1,250 for a set.

I can buy a set of Honda fork legs for $125 + postage and them machine the parts as long as I know what to do. The photos provided help a lot and I would like to benefit as much as possible from the work done in the past by others before me.
 
o0norton0o said:
No,.. the honda years are 99- 2004 so you can turn and thread the existing fork cap to fit the commando forks.. In 2005 the forks cap change it's shape so it's got a big void instead of material that needs to be machined.

Here's an early fork cap and a 2006. The later one has a big hollow, rather than solid aluminum that could be adapted to fit a norton fork tube.

View attachment 124683

I'll warn you now, that I just made my last modification a month ago to get a home made pair to work exactly right that I have been working on and testing for what is now the third year. There's a lot to learn to get it right.... I could write a book on it, or you could just read the book that I read. It's not Norton specific, but it's the book to read if you want to make your own fork suspension cartridge and develop an idea of what things you need to prioritize...



You should also visit this site: https://www.peterverdone.com/archive/highspeed.htm

Peter shows the different brands of showa 20mm dampers. The valves are different (6 ports) on the suzuki versions rather than the honda (8 port version) There are also versions with internal top out springs.
Click to expand...
I have that book. I don't have a clue where it is, but I have it somewhere.

Did you document your mod? Where there any threads that helped you along the way?
 
baz said:
The twin disk triumph RH fork leg upgrade is still available
I don't think any production triples came with twin discs?
Click to expand...
I haven't heard of this. Are you saying there is a fork leg out there that I can use on my Commando to add a second brake? Tell me more.
 
I notice that you are new to the forum, Rick. If you haven't already seen these threads, you might find them interesting. At least if you are considering modifying the stock forks instead of fitting alternative designs from other manufacturers.

o0norton0o (Frank) has done a lot of research and experimentation with the Honda internals to Norton forks, but I don't know if he has posted much of it. If you should go that route, I'd suggest you contact him directly for advice and questions.

http://www.accessnorton.com/threads/commando-fork-cartridge-conversion.18452/

https://www.accessnorton.com/NortonCommando/ohlins-cartridge-conversion-to-commando-forks.31255/

lcrken

Thread '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...
  • Like

Ken
 
richlandrick said:
I haven't heard of this. Are you saying there is a fork leg out there that I can use on my Commando to add a second brake? Tell me more.
Click to expand...
You can still get the Commando Production Racer dual disk conversion from Andover Norton

andover-norton.co.uk

Andover Norton Parts Drawings - Andover Norton Factory Parts - Commando Parts

Andover Norton Parts are the only Norton spare parts in the market manufactured to original drawings, within the factory-approved tolerances, from the correct materials, and with the correct finish.
andover-norton.co.uk andover-norton.co.uk

I used this setup on my PR back in the mid '80s, and it worked quite well. I don't have a good picture of it, just this one from 1986.

Commando with VFR750 Fork/brake Conversion


This is a picture of the original PR single disk setup. The other side is just a mirror image in the dual setup.

Commando with VFR750 Fork/brake Conversion


Ken
 
Hey Ken, Glad to see you post.

Rick, I don't think I posted a dedicated thread for my project, although I might have, because I know that I have posted some info on the site about my modification. I wrote an article for the PNW norton owners magazine last year, but that was over a year ago while I was still experimenting with different things. Ultimately, it took 2 years of testing before I got it right. I probably spent $2000. on parts, springs and tooling, so it's cheaper to buy it from Kenny if you are going to develop it all yourself. I spent untold hours on the lathe, on my knees draining fluids, and knuckle busting parts together then back apart until I could do it in my sleep. All told I made 6 pair. My friend Don has a set in his commando, and John, who saved my ass when my brand new AN exhaust pipe broke on the Vashon ride 2 years ago also has a set. The rest are my prototype and test sets.

The links that Ken posted are the links that I used to copy Ken's project. There's a ton of shit to learn before you get everything right... The chart below gives you an idea of how much testing I've done with various springs. Add to that a number of different viscosities of top notch, most thermally stable fork fluid for the best results.. I think I changed fluid, parts, or both over a dozen times in back to back months more than once...

damper specs5a.jpg
 
Last edited:
o0norton0o said:
Hey Ken, Glad to see you post.

Rick, I don't think I posted a dedicated thread for my project, although I might have, because I know that I have posted some info on the site about my modification. I wrote an article for the PNW norton owners magazine last year, but that was over a year ago while I was still experimenting with different things. Ultimately, it took 2 years of testing before I got it right. I probably spent $2000. on parts, springs and tooling, so it's cheaper to buy it from Kenny if you are going to develop it all yourself. I spent untold hours on the lathe, on my knees draining fluids, and knuckle busting parts together then back apart until I could do it in my sleep. All told I made 6 pair. My friend Don has a set in his commando, and John, who saved my ass when my brand new AN exhaust pipe broke on the Vashon ride 2 years ago also has a set. The rest are my prototype and test sets.

The links that Ken posted are the links that I used to copy Ken's project. There's a ton of shit to learn before you get everything right... The chart below gives you an idea of how much testing I've done with various springs. Add to that a number of different viscosities of top notch, most thermally stable fork fluid for the best results.. I think I changed fluid, parts, or both over a dozen times in back to back months more than once...

View attachment 124726
Click to expand...
I greatly appreciate you sharing the information and understand the work that can go on for years developing a good solution. If I go down this route, I will try to produce a YouTube video showing how it was done and give credit to everyone who pioneered the modification.

I suspect that all the details are known now and just need to be gathered in one place. With your work and specs posted by others elsewhere the optimum spring rate seems to be a known for various body weights. Fork oil weight is probably a known as well. That leaves physical changes.
 
o0norton0o said:
No,.. the honda years are 99- 2004 so you can turn and thread the existing fork cap to fit the commando forks.. In 2005 the forks cap change it's shape so it's got a big void instead of material that needs to be machined.

Here's an early fork cap and a 2006. The later one has a big hollow, rather than solid aluminum that could be adapted to fit a norton fork tube.

View attachment 124683

I'll warn you now, that I just made my last modification a month ago to get a home made pair to work exactly right that I have been working on and testing for what is now the third year. There's a lot to learn to get it right.... I could write a book on it, or you could just read the book that I read. It's not Norton specific, but it's the book to read if you want to make your own fork suspension cartridge and develop an idea of what things you need to prioritize...



You should also visit this site: https://www.peterverdone.com/archive/highspeed.htm

Peter shows the different brands of showa 20mm dampers. The valves are different (6 ports) on the suzuki versions rather than the honda (8 port version) There are also versions with internal top out springs.
Click to expand...

o0norton0o said:
No,.. the honda years are 99- 2004 so you can turn and thread the existing fork cap to fit the commando forks.. In 2005 the forks cap change it's shape so it's got a big void instead of material that needs to be machined.

Here's an early fork cap and a 2006. The later one has a big hollow, rather than solid aluminum that could be adapted to fit a norton fork tube.

View attachment 124683

I'll warn you now, that I just made my last modification a month ago to get a home made pair to work exactly right that I have been working on and testing for what is now the third year. There's a lot to learn to get it right.... I could write a book on it, or you could just read the book that I read. It's not Norton specific, but it's the book to read if you want to make your own fork suspension cartridge and develop an idea of what things you need to prioritize...



You should also visit this site: https://www.peterverdone.com/archive/highspeed.htm

Peter shows the different brands of showa 20mm dampers. The valves are different (6 ports) on the suzuki versions rather than the honda (8 port version) There are also versions with internal top out springs.
Click to expand...
What is being shown in the first photo. Is the blue cap an unmodified Honda part and the silver cap the same cap having been machined to fit the Commando?
 
richlandrick said:
What is being shown in the first photo. Is the blue cap an unmodified Honda part and the silver cap the same cap having been machined to fit the Commando?
Click to expand...
Almost right... The blue cap is an 06 model cap and it's useless. (it's actually one of Ken's photos from his modification thread) and the silver cap IS a modified '03 fork cap. Suzuki from those same years uses the same basic Showa 20mm cartridge, but has a 6 port valve instead of the honda's 8 valve... The problem with buying used suzuki forks for the damper was that the fork length was short, so you need to buy and thread a new 10mm damper rod and an adjuster rod for rebound control to make it work. The honda cartridge was long enough to work with just the modification parts.

Here's a valve body comparison from Peter Verdone's site... Notice how closely the suzuki valve looks like the Racetech gold valve (which are expensive)... IMO, just use the honda damper because road bikes run mostly on the low speed valve, not the shim stack. Most riders steer around the bumps on public roads, but it's nice to have a secondary valve for rough spots... Offroad bikes use a lot move secondary, so maybe some high quality secondary valve transforms a dirt bike performance noticeably. I think on a road bike, it's just nice to have a secondary for the occasional rough patch and the joints on the highway pavement. Plenty of people just run the landsdowne on the public roads and they have no secondary shim stack valves...

Commando with VFR750 Fork/brake Conversion
 
richlandrick said:
I greatly appreciate you sharing the information and understand the work that can go on for years developing a good solution. If I go down this route, I will try to produce a YouTube video showing how it was done and give credit to everyone who pioneered the modification.

I suspect that all the details are known now and just need to be gathered in one place. With your work and specs posted by others elsewhere the optimum spring rate seems to be a known for various body weights. Fork oil weight is probably a known as well. That leaves physical changes.
Click to expand...
I copied Ken's modification. Ken copied Chris Cosentino's design, which is the commercially available set sold by Kenny at NYCnorton. I wanted to make my own set like Ken did, so I spent twice what the Cosentino set costs. I'm not selling any of my sets out of respect for Chris, Ken, and Kenny who all helped me. Nor am I going to contribute to undermining their work... Cool on you if you want to take on this project like the rest of us... It's much more satisfying if you learn it all by your own trial, error and testing. Then if you feel like making dampers and selling them at least you did your own development...
 
I will not be making and selling. Just making and using. I'm retired and just enjoy working on motorcycles. And I seem to be falling in love with my Commando all over again.
 
At $360 + postage, the Landsdowne kit seems like a no-brainer. Rebound and compression adjustability, and you get to use Commando springs. I can't see making my own when these are available.

I think I'll add a 13 mm master cylinder, have my rear rotor resurfaced, and add the Landsdowne kit.

BTW I took the rotor the previous owner removed from the bike to O'Riley's Auto Parts. They turned it on the brake rotor lathe for what would have been $14. However, due to a warp, there was not enough material left after turning the first side. They stopped the process and didn't charge me. My rear isn't warped, and after seeing them work, I'm convinced they can resurface the rotor. Eventually, I'll take the rear rotor in and try again.
 
M

Post in thread '1971 Single sided swingarm fastback (2011)'

Hello, I have had some time to put a few hundred miles on my "special" The bike is fast, CR carbs stock engine with a few internal lightening mods.
Handling is still not quite there, the front end I think ive sorted after about 4 different oil viscountcies tried. The rear end i had shock rebuilt with new charge and fluid and a very heavy spring. But mostly The bike has become just a bike that get compliments. The idea I had 20 years ago to make a super norton have fizzled
1971 Single sided swingarm fastback (2011)


1971 Single sided swingarm fastback (2011)


1971 Single sided swingarm fastback (2011)
  • Like
 
I just found out the Landsdowne damper does not eliminate "the fork clunk." So I'm back to researching.
 
Last edited:

Similar threads

TeddyG
Disk brake conversion
Replies
16
Views
4,060
acotrel
acotrel
D
Trident conical hub drum brake converted to disc
Replies
9
Views
1,991
daveh
D
baz
  • Locked
Rear disc brake conversion
Replies
7
Views
1,997
Danno
Danno
ThatZip
  • Locked
Norvil front disk brake conversions.
Replies
13
Views
4,401
kommando
kommando
B
  • Locked
Commando with air ride assist on front forks
Replies
15
Views
2,497
74ok
74ok
Back
Top