Commando Fork Cartridge Conversion

daveh · Feb 8, 2015

john robert bould said:
I suggest to my critics to design something better, not to just adapt some Jap units , i personally challenge anyone to produce a new design....from scratch ..go on get the pen and paper out . impress me :!:

Well, even though I am trying to adapt some Japanese units, I am a fan of Lansdownes and fitted a set to my Commando. It's just that I got this set for €50, so I'm a cheapskate :mrgreen:

If this doesn't work out, I may come back to you cap in hand!

Hobot · Feb 8, 2015

Ken the way I found out how much fill was too much in Roadholders was adding more till air pumped out it hydro locked after a few 100 yrd, which tosses front dramatically opposite expectations and corrections even going about 15-20 mph, so put feet down to return and let out ~25 ml to settle on 175 ml max with Norton internals. I can't use nor test any better fork action myself but will experiment with lighter system w/o any damper rods. Its total trial and error to racers as depends so much on style what works well for one - scares someone else.

lcrken · Feb 8, 2015

daveh said:
[I assume Honda specify 10wt oil in their Showa cartridge forks?

Yes, Honda specify 462 cc of their SS-8 fork oil, which is 10W.

Would you think of asking Kenny Cummings, who runs a Cosentino kit in his Seeley Norton? If he can give you some data, I would be interested as well!

I'll ask Kenny, unless he sees this post and answers.

So far I've filled one of the forks with 170 cc of oil. Close to Hobot's experimental max for stock internals. After the cartridge is pumped full, I have 2 3/4" of oil above the cartridge at full extension, with no spring, of course. I think I'll start with that, unless I get significantly different info from Kenny. My conversion is a bit different in some details than the Cosentino kit, so my optimium oil level might not be the same, but it should be close enough for a starting point. I really should see how much the spring displaces, and figure out how much air volume I have at full compression, and maybe I will. The Ninja spring displaces significantly less oil than the original Norton. If not, I'll sort it out when I can ride test it. At this point I'm pretty much done until I get the rest of the bike together.

Ken

lcrken · Feb 8, 2015

Kenny was kind enough to give me his setup info. He's also been following this thread, but smart enough not to step into the quagmire.

He uses Lightweight Redline Suspension Fluid, and sets the oil level at around 6" down from the top of the stanchions, with the spring removed and the fork fully compressed. The oil level I have after adding 170 cc of oil is an inch or so lower than that, so I have some room left to play with additional oil.

I'll report how it all works out in a couple of months, hopefully.

Ken

nickguzzi · Feb 9, 2015

I bought some Maxton rear units years ago. I went back a couple of times to change the spring to cope with extra weight.
The units still work very well, but the best part of the deal was the guidance and advice from Ron about set up in general.

Who ever you buy stuff from, the after sales can end up more valuable than the parts you buy.

Fast Eddie · Feb 9, 2015

SteveA said:
Cheesy said:

Im guessing that the only reason someone would pull out a shim cartridge and replace it with something pretty basic is that they dont know how to set it up or have someone to do it for them. Interestingly if you look on some of the mountainbike forums there is a lot of detail about fork and shock damping and re shimming etc, maybe its because they dont have engines to fiddle with!!

Click to expand...

Ease of use can make a product a better choice than another product that demands expert set up to achieve optimum results.

I have a set of Maxton cartridge forks, but in going that route I spent a lot of money and am dependent on how close Maxton were to predicting my needs. Fine tuning them is probably something I can do, making radical change probably not because my own riding/suspension analysis skills are not up to that.

What I can see is that the Lansdowne design allows fairly simple rider testing to get to something that works to where the front end is no longer an issue that limits the rider. That is a good product.

What I suspect is that a set of Maxton (or Ohlins etc.) can be set to optimum performance which may actually be 'better' but that will need to de done with access to days of track time at different tracks with an exert rider AND an expert suspension technician on hand to analyse rider inputs and make adjustment. And no doubt with a the better refinement the set up will be 'wrong' and need more adjustment to suit each particular track or tyre. This is fine if you have the resources. Most never will.

And if your application is road leisure and touring, a system that allows you to do tweeks as you go and settle for what suits your style is the choice for you.....simple to use products rule. Ken has the resources he needs to go the route he is going (knowledge, skill, time and machine tools). I don't. So I fitted something high end...unfortunately they may never get to the 'fit and forget' stage. Or I will just live with them because my riding and analytical skills wont give me good enough direction to improve things.

Steve you have nailed it there...

I firmly believe that the vast majority of modern sports bikes are actually being ridden with the set up 'wrong'. I've seen mates do it, and I've done it... we read magazine articles, concluded that we were experts and yanked on the adjusters like apes. Then declared the results as 'better' because they had to be didn't they... we had 'improved them' after all!?

There was an Ohlins trained suspension expert who used to turn up at race and track days (maybe still does) and would adjust folks settings by feel, and by them sitting on it, observing sag, asking them questions about their riding style and send them out. On their return he'd interpret their feedback and sometimes make further adjustments. I used him, and I watched others use him, and the degree of correction he usually made was staggering!

I had some Ohlins forks that had (approx) 50 compression adjustments, 50 rebound and 20 pre load ... That's 50,000 combinations isn't it? And that's before changing shims and springs and oil and etc. it's virtually impossible for a layperson to get something like that right!

Something that is simpler to use is far more likely to be optimised in use, and is therefore far more likely to perform better.

All IMHO of course.

daveh · Feb 9, 2015

lcrken said:
Kenny was kind enough to give me his setup info. He's also been following this thread, but smart enough not to step into the quagmire.

He uses Lightweight Redline Suspension Fluid, and sets the oil level at around 6" down from the top of the stanchions, with the spring removed and the fork fully compressed. The oil level I have after adding 170 cc of oil is an inch or so lower than that, so I have some room left to play with additional oil.

I'll report how it all works out in a couple of months, hopefully.

Ken

Thanks for that, Ken and thanks Kenny if you're reading this. So Kenny's setting seem to be very similar to my old Maxton settings.

By the way, you said you are using Ninja springs and they take up less volume. From which Ninja? How do they compare with the Commando spring rate?

SteveA · Feb 9, 2015

nickguzzi said:
I bought some Maxton rear units years ago. I went back a couple of times to change the spring to cope with extra weight.
The units still work very well, but the best part of the deal was the guidance and advice from Ron about set up in general.

Who ever you buy stuff from, the after sales can end up more valuable than the parts you buy.

Ron retired some years ago.....

I have a 'Ronometer' essential for basic motorcycle set up

lcrken · Feb 9, 2015

daveh said:
Thanks for that, Ken and thanks Kenny if you're reading this. So Kenny's setting seem to be very similar to my old Maxton settings.

By the way, you said you are using Ninja springs and they take up less volume. From which Ninja? How do they compare with the Commando spring rate?

I used Ninja 250 springs. I shortened them by removing coils at the "soft" end of the progressive wound spring. The remaining coils look less progressive, and closer to single rate. The stock Commando springs are 36.5 lbs/in. I can't find my notes at the moment, but I think the shortened Ninja spring came out at 37 lbs/in. Kenny is using 30 lbs/in single rate springs on his Seeley, but it is much lighter than my MK3. If the Ninja springs are still too soft, I have room to remove a few more coils before it gets short enough to coil bind. At worst, I'll just have to buy the appropriate single rate springs. I think the Ninja springs are going to work, but even if they don't, they will at least give me enough information to pick the right spring rate for replacements.

Ken

daveh · Feb 9, 2015

lcrken said:
I used Ninja 250 springs. I shortened them by removing coils at the "soft" end of the progressive wound spring. The remaining coils look less progressive, and closer to single rate. The stock Commando springs are 36.5 lbs/in. I can't find my notes at the moment, but I think the shortened Ninja spring came out at 37 lbs/in. Kenny is using 30 lbs/in single rate springs on his Seeley, but it is much lighter than my MK3. If the Ninja springs are still too soft, I have room to remove a few more coils before it gets short enough to coil bind. At worst, I'll just have to buy the appropriate single rate springs. I think the Ninja springs are going to work, but even if they don't, they will at least give me enough information to pick the right spring rate for replacements.

Ken

OK Ken, thanks for filling me in on that.

Hobot · Feb 9, 2015

Do note if unaware that shortening a spring raises its spring rate and well known benefit to those shortening forks or needing more spring rate in shorter travel more than one spring section stacked up till happy. Easier to get cut spring end flater by cutting the softer tighter coil end.

daveh · Feb 9, 2015

hobot said:
Do note if unaware that shortening a spring raises its spring rate and well known benefit to those shortening forks or needing more spring rate in shorter travel more than one spring section stacked up till happy. Easier to get cut spring end flater by cutting the softer tighter coil end.

A good point, Steve, and one which is not talked about much. As it turns out, I can use the same spring length as previously, although I am using a spring with the same rate as a Commando which I will be changing to a lighter spring.

lcrken · Feb 9, 2015

hobot said:
Do note if unaware that shortening a spring raises its spring rate and well known benefit to those shortening forks or needing more spring rate in shorter travel more than one spring section stacked up till happy. Easier to get cut spring end flater by cutting the softer tighter coil end.

I flatten the ends by heating part of the end coil, hammering it down to touch adjacent coil, and then grinding the end flat. That's a common technique for squaring up spring ends.

Just in case I wasn't clear about it, I shortened the Ninja spring to increase the spring rate up to about what the stock Commando is.

Ken

Nortiboy · Feb 10, 2015

(quote)There was an Ohlins trained suspension expert who used to turn up at race and track days (maybe still does) and would adjust folks settings by feel, and by them sitting on it, observing sag, asking them questions about their riding style and send them out. On their return he'd interpret their feedback and sometimes make further adjustments. I used him, and I watched others use him, and the degree of correction he usually made was staggering!

I had some Ohlins forks that had (approx) 50 compression adjustments, 50 rebound and 20 pre load ... That's 50,000 combinations isn't it? And that's before changing shims and springs and oil and etc. it's virtually impossible for a layperson to get something like that right! (quote)

I still ride a 4 hour Enduro each month, now at Grandpa pace. A Test rider / magazine editor once set up my gold rear Ohlins, which has about 50 clicks on compression and rebound, by feel. Once he found the sweet spot, he said a couple of clicks either way will be about the maximum useable. He was spot on. I can do most tracks with a click or two either way. I think this is probably accurate for the average rider on most shocks.

john robert bould · Feb 10, 2015

Wow, 50 adjustments!
the AJS v4 1939 lapped the IOM tt at 100mph, with webb girder forks , my old mate managed 88mph as a new comer on his Suzuki .
All the Webb forks had was side friction disc's .. with top speeds of 135 mph on a much bumper track back then . Wonder how they back then set up the front end? another 1/8 turn on the side plates with the star spring's :?:

Nortiboy said:
(quote)There was an Ohlins trained suspension expert who used to turn up at race and track days (maybe still does) and would adjust folks settings by feel, and by them sitting on it, observing sag, asking them questions about their riding style and send them out. On their return he'd interpret their feedback and sometimes make further adjustments. I used him, and I watched others use him, and the degree of correction he usually made was staggering!

I had some Ohlins forks that had (approx) 50 compression adjustments, 50 rebound and 20 pre load ... That's 50,000 combinations isn't it? And that's before changing shims and springs and oil and etc. it's virtually impossible for a layperson to get something like that right! (quote)

I still ride a 4 hour Enduro each month, now at Grandpa pace. A Test rider / magazine editor once set up my gold rear Ohlins, which has about 50 clicks on compression and rebound, by feel. Once he found the sweet spot, he said a couple of clicks either way will be about the maximum useable. He was spot on. I can do most tracks with a click or two either way. I think this is probably accurate for the average rider on most shocks.

johnm · Feb 10, 2015

" the AJS v4 1939 lapped the IOM tt at 100mph, with webb girder forks ,"

I think you meant the Ulster GP. At the IOM they didnt go so well.

johnm · Feb 10, 2015

ludwig said:
john robert bould said:

.. I personally challenge anyone to produce a new design....from scratch ..:

Click to expand...

How many do you want ? :

A system that works well on a race track , is not necessarily good for the road .
IMO , outside adjustment is overrated for a road bike .
Find the best compromise for your riding , set it up in your shop , and live with it .
This is what I have now in my Commando forks :

Ultralight , easy to service , degressive compression damping ..
I am pretty happy with it ( for now ..) .

Whoo was that going on about Ludwig not knowing that much ????

lcrken · Feb 10, 2015

I would agree with Ludwig that once you have the suspension set up properly on a street bike, you will probably not be changing it much, if ever, as long as you have the same rider and load. I'm making this conversion more for the advantage of the shim stack valves than for the external adjustments, but I think having the adjustments will make it easier to find the right setup.

But, if your riding varies from a single rider to carrying a passenger, and sometimes with luggage, the external preload adjustment is pretty convenient. I probably wouldn't change the damping adjustments for that, but then I don't very often have a passenger or much luggage.

With the basic Roadholder design, I can get the stock forks to work well on potholes or on high speed sweepers, but not both. The modern damper designs are significantly better at that.

Besides, it's a fun exercise in the shop, and another learning experience.

Ken

john robert bould · Feb 10, 2015

Ludwig..
How much for 50 sets?

john robert bould · Feb 10, 2015

Ludwig..
How much for 50 sets?

Commando Fork Cartridge Conversion

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