Topic: On Installing XS650 Cartridge Emulators in late model CB550 Forks

[bwaller]

If you need to remove oil an easy quick way is to use a long slender turkey baster. To retrieve the emulator an extendable magnet works well. With the wheel off, 8mm bolts removed (save & re-use the oil) the fork seal resistance/or fender holds the legs in place and with a good magnet you can remove the damper rod too. Saves a load of time.

[Doctor_D]

It was too damn cold by the time I got it all back together but tomorrow I'd like to go ripping around the neighborhood, see how it feels.

Makes a lot more sense when you're in there, doesn't it?

In any case, you nailed it and I have a feeling you'll be pleased with the results. Looking forward to the ride report.

[grcamna2]

bwaller,
             I have a CB400F(33mm) and wondered if there was a company that made emulators for my bike rather than the very expensive RT "only?" option ??
I suppose MikesXS would only have them for the XS650's...I want to stay w/ my original CB400F forks.

[bwaller]

grcamna2 I wouldn't know, but check with RaceTech. You get what you pay for from these folks.

[jessezm]

I've been watching this thread with much interest, as I'm just putting single rate RT springs and RT cartridge emulators into my 400f at the moment.  Also using TTR400 adjustable preload fork caps.  I hope y'all don't mind the hijack!  My question is that the instructions for the emulators say to use 5mm spring preload, while the instructions for the springs say to go with 15-20mm.  Am I missing something here?  I've cut spacers for both 5mm and 15mm and I guess I could just try them out and see what works, but that's a pretty large difference (albeit not one that can't be compensated for with the 20mm of adjustment that the fork caps allow).  Thoughts?

[grcamna2]

Hi jessezm,
       I've ony installed 1 set of emulators w/ Racetech single rate fork springs before & that was in my 86' VFR750F in the 90's.I remember that the emulators made up for some preload & if I remember correctly I installed the smaller of the preload #'s. I think the springs may have separate instructions apart from the emulators & the emulators(along w/ some fine print) have their own recommendation;I would go w/ the emulator setting.Try measuring the height of the emulator & add 5mm to that measurement,thats what I recall from my last installation. I loved them by the way !
I am going to modify the length of the large Works dual rate springs & set mine up w/ emulators...when I can afford them.

[jessezm]

Thanks Bill!  I did just call RT though and the technician looked up my model and actually told me to set the preload at 25mm!  Since I've got the adjustable fork caps, we both agreed that 15mm would be a good place to start.  Good thing, cause that's the size I already cut today!  I also drilled out and chamfered 2 additional holes and widened the two at the bottom of the damping rods for a total of 4 X 1/4" holes.  They told me not to bother welding shut the two upper holes so we'll see...  Fluid goes in tonight!

[grcamna2]

Jess,
         How long were you on hold to find out w/ RT?....I want to get a pair of those TTR preload adjusters,can you tell me what you paid for them  ? I  think if you started w/ a smaller preload spacer you could always compensate w/ your threaded adjusters...unless you like a lot of preload, or you like it for lots of anti- dive.I like the soft initial comfort of my Works Perf. dual rate pairs of springs you sold me & will seek somebody to carefully cut & shorten the longer ones and flatten the ends correctly.I called RT today also.....and when they did get me off hold(the man told me he was speaking w/ another CB400F owner,about 4:20PM...was that you?) they told me the price was $169 for the emulators and I will have to purchase the adapters so they will fit better onto the tops of my damper rods...did you go through the same thing ?

also, what weight oil are you going with?... RT 10wt. super slick synthetic ?...w/ the more preload you have, the faster you're forks rebound...maybe you should seal up one rebound hole ??

[jessezm]

They didn't have me on hold for too long, i must have called at just the right time!  I got my TTR400 caps through his ebay listing for $50, but I was the only bidder.  Got the red ones to accent other red stuff on my bike....  I ordered my stuff from RT from the woman in sales, and she was really helpful and gave me a big discount that I didn't even ask for.  Don't remember the total but I was surprised.  I did have to use those adapters for the top of the damping rods.  They add another 3/4" if I remember correctly, so you may want to wait before having your springs cut.

As far as what I'm looking for in my ride, I really don't know yet.  I'm going for middle of the road since this is my first experience really tuning any suspension, and I don't really have a feel for what I like yet.

[Bluegreen]

Ok so here are my settings again.:

both tiny holes welded shut
6 5/16" holes drilled at bottom
15w fork oil, 175mm from the top
3 turns of pre load on emulator
5/16" of pre load on springs
progressive springs that sat flush with the tops of the forks

Went out for a quick ride around the block. Felt very different like somebody else had described. Like your tire is going over and down the bump instead of bouncing over. A little soft right now. And I think it's packing, I bottomed out after a bunch of bumps followed by a small curb into a parking lot.

I also marked my fork with tape wile bottomed out in the shop during the oil filling proccess. Then put a zip tie on the fork. After the ride zip tie was all the way to the top.

Part of me is glad it's not perfect from the get go because now I get to learn

 So set up #1
Too soft
Packing

Set up #2
15w fork oil, 175mm from the top
2 turns
5/16" of pre load on springs
Stock 550 springs 18 1/2" long

Still too soft but better
Still packing but less

Set up #3
15w fork oil, 175mm from the top
3 turns of pre load on emulator
5/8" of pre load on springs
Stock 550 springs 18 1/2" long

Didn't get to test it. Just sitting on it and pushing/bouncing it felt stiffer and packing less of a concern.

I was hoping the gurus could fill in the blanks so that I and others have a concise idea as to what changes to the following do what. I've been doing a ton of reading the last few days but am still trying to make sense of things.

Fluid Level:

Fluid Weight:

More/Less turns on emulator:

Preload on Spring:



Ie:

Fluid Weight: thicker fluid will have this affect, thinner this affect....


Sort of like the "what all jets affect what range of the throttle" list in the FAQ threads.

[grcamna2]

+1...I'm with you on this one Bluegreen,I want to learn these fine tuning techniques also;I am listening & learning to this thread for the day when I begin my own emulator
installation in my CB400F.

[bwaller]

Try more oil say 150-160mm, no more than 3 turns on the valve for now. I think you may have a spring issue though.

More oil- less air above the oil to compress. (will limit travel)

Heavier oil- more damping

Did you check for total travel? With an o-ring or zip tie on the tube measure to the underside of the lower clamp. If not do that first so you can see what changing oil levels does for you. After a ride you can re-measure the o-ring clearance.

Do go through the static sag settings too. It's best to start with the proper ride height.

Edited as I thought about it more.

[grcamna2]

Is there a standard measurement for suspension when it comes to static sag? or is it different w/ the front forks w/ emulators ? What is recommended for the rear shocks? Does 1" front & rear sound about right, generally ?

[Bluegreen]

I'd try more oil say 150mm, no more than 3 turns on the valve for now. I think you may have a spring issue though.

Make sure to answer your preload questions first by doing all the static sag tests.

I'm confused   

Wouldn't 2 turns be less dampening than 3? So the front is less likely pack with 2 rather than 3?

Sorry for all the questions, just trying to understand so I won't have to ask so much in the future 

[grcamna2]

They didn't have me on hold for too long, i must have called at just the right time!  I got my TTR400 caps through his ebay listing for $50, but I was the only bidder.  Got the red ones to accent other red stuff on my bike....  I ordered my stuff from RT from the woman in sales, and she was really helpful and gave me a big discount that I didn't even ask for.  Don't remember the total but I was surprised.  I did have to use those adapters for the top of the damping rods.  They add another 3/4" if I remember correctly, so you may want to wait before having your springs cut.

As far as what I'm looking for in my ride, I really don't know yet.  I'm going for middle of the road since this is my first experience really tuning any suspension, and I don't really have a feel for what I like yet.

Jessezm,
               Those TTR adj. preload caps, how deep do they thread into your fork tube? is it compatible w/ stock or less ??

[bwaller]

Is there a standard measurement for suspension when it comes to static sag? or is it different w/ the front forks w/ emulators ? What is recommended for the rear shocks? Does 1" front & rear sound about right, generally ?

Try to get as much total travel without bottoming and then 1.25" or 30%?? It's a matter of preference. I'm at 28% for my old guy racing.

In the rear so much depends on what shock you have. For example with my WorksPerf, total travel is 79.4mm and I set sag to 40% depending on the racetrack.

[jessezm]

I think the measurement from the cap's lip to the contact point with the spacer/washer was 13/16", and the stock caps are 12/16" by comparison, so it's pretty close.

[grcamna2]

Is there a standard measurement for suspension when it comes to static sag? or is it different w/ the front forks w/ emulators ? What is recommended for the rear shocks? Does 1" front & rear sound about right, generally ?

Try to get as much total travel without bottoming and then 1.25" or 30%?? It's a matter of preference. I'm at 28% for my old guy racing.

In the rear so much depends on what shock you have. For example with my WorksPerf, total travel is 79.4mm and I set sag to 40% depending on the racetrack.

bwaller,
     Let me ask you to define "static sag",ok? can I assume that it's the bike sitting on it's wheels w/ only the weight of the machine ? & would you consider the "sweet spot" or "being in the zone"...to be when you're racing, the suspension would be at it's best when it rides between 60-85% into it's travel when under race conditions on the track ??

[Doctor_D]

Static sag is set up with the weight of both the bike and rider, and it's an important component of suspension tuning.   That sag gives your suspension "negative travel," the capacity to follow road irregularities by extending as well as compressing.  without enough sag, the forks top out over depressions and the wheel temporarily leaves the ground.

Here's an article on the subject: http://www.sportrider.com/tech/146_0308_set_your_static_sag/index.html

[grcamna2]

So the combined cycle/rider weight...OK, I imagine the best way to measure this would be to install some zip ties on the forks & shocks and sit on the bike while a person holds the machine stable ?? I would think it would be best if the measurement would be the same for front & rear suspension? at least for "Road riding"?

[bwaller]

I see Doc has responded but seeing as I typed all this crap here it is anyway.

First, don't get the impression I'm a suspension expert, like everyone else I try to make the most of what we have to work with.

Static sag (I like the laden sag method & use a % number) is only another term for ride height, and is set with spring preload. The bike must be in "ready to ride" form, gas, oil and whatever included. Plus the rider needs to be aboard with helmet, jacket, you get the jist. When riding, you of course want available suspension both "up & downward" so starting in a postion about 30% below fully extended should give us that.

Obviously these are not modern forks, in some cases they are junk and we're trying to make a silk purse out of a sows ear (couldn't resist-sorry Pops  _  Use the best components you can, make sure the tubes are dead straight. We also have issues with stiction so lightly oil the seals. I get someone to help and first measure full travel and use an o-ring on one tube to measure from. Then I follow one of the on-line suspension tuning recs.

1) rider in place, let it settle, push down & release slowly....measure
2)                      "                   pull up & release slowly...,.measure again
3) average the two above numbers. The difference between the two is old tech fork problems, stiction, whatever. Divide this # by max travel for a percentage.

You asked about sweet spot, I'm @ 28% and for my race bike this I suppose is it. I'm using about 80% of my full travel it never really chatters in corners, doesn't get unsettled under heavy braking or my attempt to trail brake a little. These forks are better set-up than anything the same vintage I've ridden before. The Works shocks are limited in settings but I can adjust preload. I change rear setting depending on the track, heavier for fast sweepers. I use my bellypan as a guage and when it just touches I know I'm about full travel & max. lean.   

[grcamna2]

Thanks bwaller !

[Bluegreen]

So update time for anyone who was interested.

We had a few cold but sunny (sun is rare here ) days and I had some time to try and dial these forks in a bit. I'll need some warm weather and some curvy highway to really figure things out, but ripping around my test rack (four blocks of almost deserted street, 1 bumpy block and a  high speed right) I think I'm pretty close with the settings or at least have a base.

Currrent:

150mm + 30ml* of 15w fluid 
3 Turns on cartridge
Stock Springs
7/16" pre load on springs

Basically I just tried to adjust one thing at a time. Started out with adjusting the pre load on the springs until I got about 28mm of sag. Then with zip tie on a fork so I could see my travel I kept going out and riding around and coming back adding more fluid until I was about 3/8" away from bottoming out. Then back to 3 turns (from 2) on the emultors and things felt pretty nice.



*Plus 30ml because I added 15ml twice without dropping the front end completely to measure.

[grcamna2]

Bluegreen,
  With that 15wt that your using...how does it work with your outside temps?light enough w/ good compression on small bumps? how about rebound ?

[Bluegreen]

Bluegreen,
  With that 15wt that your using...how does it work with your outside temps?light enough w/ good compression on small bumps? how about rebound ?

Well that's the thing, it was about 6-7 degrees Celsius and I was only going out for about 10-15 minutes at a time and not being an expert I have no idea how much another 20 degrees in temperature and another hour of riding will affect rebound as the oil warms up. I imagine things loosen up but how much, who knows. Very new to this whole tuning of front forks.

As it was, the rebound was was good and the ride was firm over small bumps ( there is a 60ft section of pavement behind my shop perfect for testing this) but not harsh. I imagine come spring some more adjusting will have to be done, but I feel I have a good baseline. 

One of the strange things for me was after I was done testing my bike, going over to my friends cb750 who has a freshly rebuilt front end on his bike and holding the brake and pushing the front end. There was so much rebound it was nuts. The emulators change the feel of these bikes so drastically.