Measured Front Fork Travel

[Firefight911]

I was looking to source a spring and revalve the front end this winter, so I did some digging around. I know Traxxion was mentioned above, but I have also used RIch at Sonic Springs in the past. I have a phone meeting scheduled with Rich for tomorrow. In the meantime, I called Race Tech and after 3 days of trying to get the person I wanted, I got his secretary who supposedly butted him during a meeting and wast told....they have developed a "kit" for the Super Tenere, but is is not available for sale at this time. I was told it will be available in 30 days. That is all I have on that piece of info.

You got a lot more out of them than I did. No response to phone or email! None, nada, zip, zilch! Please, let them know that!

I'm thrilled working with James at Super Plush so far. The springs did come from Traxxion but, as those who know suspension, even a little, the parts is the easy part. The tuning is the fun part! Note, I never said hard part!! Once my back strain, work schedule, doctor's appointments, business meetings settle in a day or two, I'll update my suspension thread with more data on what I have found/done so far.

 

[YamaPA]

For shits and giggles, I decided to calculate the overall rate of the OEM progressive spring.

0-75 mm is the soft srping at .85 kg/mm
75-190 mm is the stiffer spring at 1.22kg/mm

So .85 x 75 mm = 63.75
and
(190-75) or 115mm x 1.22 =140

140 + 63.75 = 204.05

204.05 divided by 190 mm = 1.07 kg/mm as the rate.

Now I was asking how you guys weighing in at 185 lbs got to using .95 kg/mm springs because you were saying with the new springs full travel was being achieved. Do you guys have have replaced your springs like your the spring rate (please restate your weight and spring rate)?

BTW, V-Strom springs are the correct length 425 mm (Yamaha specs 427 mm) but the ID of the V-strom springs springs may be a wee bit too small. Most of the V-strom springs are 24.5 to 25 mm ID springs and this may NOT (I DONT KNOW FOR SURE AS I HAVE NOT HAD MY FORKS APART YET) slide over whatever it has to slide over in the Tenere forks. I got this info from Rich at www.sonicsprings. com . He has V-Strom springs at .95, 1.0 and 1.1 kg/mm available for $80 plus $12 shipping. If someone has the desire to pull forks apart and measure the diameter of the parts the springs sit over, we would know if the V-Strom springs would fit. Until that happens, its a crapshoot. Springs from Sonic are however returnable/exchangeable or you could get custom springs done.

Rich did make one point regarding full travel that I forgot about....the top out spring. Chances are that last 1.0" or less of travel that we are not getting is part of the manufactuers claim of 7.48 inches of travel and would be accessible if you pull on the front forks to extended them beyond what you get when the front wheel is simply just elevated.

Comments regarding Race Tech....yeah, they dont return calls very well and so far neither has Traxxion. WTF is with these businesses? I'd highly doubt Race Tech gets their shit together to release a kit in 30days....I'd bet against it personally.

 

[3putt]

Traxxion recommended 1 kg/mm, I requested .95. I am 185 lbs, really like the spring. If I change anything I may go to 5 wt oil on next change (OEM is 0 wt).

I just miked the spring, 27mm ID, 38mm OD. I stated that above also, but I gave the measurement in inches.

My advice, the spring may be the correct length but may require a different preload length, in other words the OEM spacer may be wrong length. If it is too short then you can fab a longer one, but if it is too long, no fix for that as there is no enough clearance on the adjuster to allow a shorter spacer. Just a heads up, probably will not be a problem. If too short you have room to add a couple or three washers also at the top.

P.S. I checked RaceTech website this morning, they do have XT1200Z page, but nothing works and they have no actual numbers, i.e. stock spring rates.

 

[YamaPA]

I did talk to Race Tech yesterday.....again. There will be a kit coming out. Right now, they have all the specs, testing was completed Nov. 15, 2011, and well, the XTZ1200 is just about 20 bikes down on the list before things get finalized. I pushed them hard for the kit. At this point, the kit will be springs, compression valve and stack, and rebound valve and stack. Rest of the OEM stuff is used. The spring they are planning on using will NOT be a newly fabbed spring, it is a model no. 3755 spring which will be cut a wee bit shorter, heated, bent and then ground ....I think this is part of the delay. So, if YOU are capable of shortening a spring CORRECTLY you may be able to get the parts sooner...but not the kit. But it is NOT ready now and wont be any sooner than 2/24/12. I'm on and will post more when I find out. BTW, they will also have a rear shock for the bike as well....I did not inquire about that timing.

Other factoids...the OEM preload on the OEM spring is 7 mm minmum and 25 mm maximum......data from Race Tech

 

[3putt]

I am happy with my fork springs now, but will keep their valve kit in mind. Just need to test my setup on some rough off road to be sure, not sure when I will get the chance for that. I suspect the damping will be fine with adjustability we have.

I am happy with the damping on the shock, so ordered a spring from HyperCoil for $85 free shipping. They have a 8" (stock is 8.39") rated for 800 lbs/in (stock is 755) and also sell a spring divider with .38" flange, I will machine to make up the difference in length. I am shooting for race sag of 30% or about 57mm, I have 77mm with the OEM set to 1 mark firm on preload.

8" x 2.25" ID 800 lb/in Spring
http://www.tntperformance.net/8-Long-225-Inside-Diameter-Hypercoil-HCSP8A.htm

Spring divider
http://www.tntperformance.net/25-Spring-Divider-MRP2SLDR.htm

 

[mcrider007]

Traxxion recommended 1 kg/mm, I requested .95. I am 185 lbs, really like the spring. If I change anything I may go to 5 wt oil on next change (OEM is 0 wt).

I will not attempt to guess how Yamaha numbers their fork oil but Yamaha Suspension Oil 01 has a viscosity of 15.6 cST@40C and that viscosity range is considered to be a 5wt (same oil they put in the FJR).

 

[3putt]

Recommended oil = Suspension oil type 01 (from some research this is 0 wt and produced by Ohlins for Yamaha)
This info is from Amsoil tech: Actually, According to Yamaha's Specs, their fork oil is a "0" wgt.... Barely, at 3.58 cSt..
AMSOIL's 5 wgt is 4.38 cSt. Only 8 tenths higher cSt... Virtually impossible to tell the difference and would be used as a direct replacement for the Yamaha Fluid

I have the Amsoil 5 wgt, but have not installed.

 

[mcrider007]

Recommended oil = Suspension oil type 01 (from some research this is 0 wt and produced by Ohlins for Yamaha)
This info is from Amsoil tech: Actually, According to Yamaha's Specs, their fork oil is a "0" wgt.... Barely, at 3.58 cSt..
AMSOIL's 5 wgt is 4.38 cSt. Only 8 tenths higher cSt... Virtually impossible to tell the difference and would be used as a direct replacement for the Yamaha Fluid

I think you are looking at the wrong temperature viscosity, the numbers you are quoting appear to be the viscosity at 100C, fork oil will never get that hot in street bikes. Take a look at:

http://www.peterverdone.com/archive/lowspeed.htm

and then go to the viscosity chart at the bottom of the page. Yamaha 01 is pretty consistent with most of the other listed 5wt oils.

 

[3putt]

The quotes I made are from Amsoil, I claim no knowledge of this stuff, just trying to get a number to deal with on my level. It all started when I was trying do determine what weight was in there so as how to adjust it if needed. We are sorta out there alone on this bike, no big history base to go by unless the FJR is a help.

It was common knowledge with the 99 FXDX, if the forks were bottoming then go to 10 wt. Think that was my first mod to forks.

Anyways, I have the Amsoil 5wt which is pretty similar to OEM, and I will adjust from there if need be. Until I get rough and rowdy on some proper off road sections I will not be able to tell for sure what I need with the new springs. Since I am able to hit the bottom gently on some severe ditches at speed, I suspect that I may need to go up on the oil weight a tad. Time will tell.

 

[mcrider007]

Anyways, I have the Amsoil 5wt which is pretty similar to OEM, and I will adjust from there if need be. Until I get rough and rowdy on some proper off road sections I will not be able to tell for sure what I need with the new springs. Since I am able to hit the bottom gently on some severe ditches at speed, I suspect that I may need to go up on the oil weight a tad. Time will tell.

If you find you are bottoming, your first adjustment should be to increase the amount of oil in the forks which will increase the total resistance at the end of the fork's compression stroke.

http://www.peterverdone.com/archive/oilheight.htm

I appreciate all the work you are doing to sort out the suspension, it will make it very easy for the rest of us when we come out of our caves after the long winter.

 

[Firefight911]

Anyways, I have the Amsoil 5wt which is pretty similar to OEM, and I will adjust from there if need be. Until I get rough and rowdy on some proper off road sections I will not be able to tell for sure what I need with the new springs. Since I am able to hit the bottom gently on some severe ditches at speed, I suspect that I may need to go up on the oil weight a tad. Time will tell.

When I swapped the springs out, the fluid was flushed and spec'd to the book's level. I have Maxima Racing 5 wt. on board. I'm in the same boat as you David in that I haven't had a chance to get out and get "rough and rowdy" with it.

 

[3putt]

I measured the oil to book spec at 150mm so will be simple to add 5mm or 10mm without pulling the forks, just remove caps and add.
485ml = 150mm so to add 10mm = (485/150=3.23ml) x 10 = 32.33 ml.

Phil, I'm thinking you may have slightly heavier weight than stock, but getting really good ride. I have only hit bottom twice, once was driving down in a deep ditch, the other was when I saw a sharp depression and slammed on my brakes just before hitting it at about 30mph, so due to braking I was already compressed. That was in a down hill gravel/dirt section, I felt if I had to run that way again, I could have hit it with the throttle on and got a much better result, the suspension really surprised me to take it that well.

 

[Firefight911]

the suspension really surprised me to take it that well.

Said that so many times since changing things up there myself!!

I'm going to try to do some dirty riding tomorrow if the stars align. I am liking the fork action with the current set up in terms of linear compression/return of the fork in travel and controlled action in terms of damping with my current set up compared to stock. It is in the more extremes of travel and continual hits that remain the unknown with the current state of tune. It has certainly allowed me to ride with much more confidence and faith in what the front is telling me. It has definitely exposed the weakness and off balance nature I created with the rear as well.

 

[mcrider007]

I measured the oil to book spec at 150mm so will be simple to add 5mm or 10mm without pulling the forks, just remove caps and add.
485ml = 150mm so to add 10mm = (485/150=3.23ml) x 10 = 32.33 ml.

I think you need to rethink your formula (although the final result is probably pretty close). The amount of oil that it takes to get to a 150mm oil height will vary greatly from fork to fork and is not relevant to how much oil is required to change the oil height by any desired amount. The 150mm oil height is actually the amount of air volume that is left between the top of the oil level and the top of the forks when the forks are fully compressed and without springs. To change the air space (oil height) from 150mm to 140mm you need to measure the inside diameter of the fork tube and then calculate the volume of oil required to raise the oil level 10mm.

 

[3putt]

You are correct, I jumped the gun there, figured the air gap not the actual volume of the oil. Sh$t. I was hoping for an easy way without pulling the forks again. Wish I had measured the depth of the fork fully compressed, then I could have figured the volume.

I could just bring the level where it sits with everything in, while on the bike up another 10mm using the syringe cut tube method. That would be pretty close since it such a small percentage of the total already in there.

 

[3putt]

Okay, what about, the upper fork is 21.5" (546.1mm) long from seal to top. When you compress the lower fork tube bottoms at the seal. The ID of the lower fork tube is 40mm (estimate). 485 ml makes a level 150mm from top. Volume of 40mm tube at 15.15" (385mm) height is 485 ml. which leaves about 150mm of air gap.

485 / 385 = 1.259 ml per mm
10mm = 12.59ml

 

[YamaPA]

Wow, you guys go the hard route when increasing fluid levels...I take a syringe and add 10 ccs per leg, try that for a while, then add 10 ccs more. When I found my "spot", I simply take the factory measurement and then add so many ccs per leg in the future...measure that distance...and I have my new air gap measurment.

 

[mcrider007]

Okay, what about, the upper fork is 21.5" (546.1mm) long from seal to top. When you compress the lower fork tube bottoms at the seal. The ID of the lower fork tube is 40mm (estimate). 485 ml makes a level 150mm from top. Volume of 40mm tube at 15.15" (385mm) height is 485 ml. which leaves about 150mm of air gap.

485 / 385 = 1.259 ml per mm
10mm = 12.59ml

I think you have a very good estimate, I calculated 12.56 ml with a 40mm inside diameter.

 

[~TABASCO~]

A little off topic, maybe I need to start another post... Anyone looking at maybe having the stanchion tubes Nitrated coated... Like the super-cross and GP bikes... Almost zero sticktion ?

 

[3putt]

LOL Tabasco, you are looking for the high dollar thread, this is the low dollar one. I'm the one always trying to get the most for my buck, with as little work as possible. ::013::

YamaPa, that is just way too simple. ::012::

mcrider007, thanks.