Racetech goldvavles freek wanted

[pyromaniac]

Originally posted by KTM-Lew
I agree with Russ that with no mid-valve and the very light stack you are probably riding too low in the stroke......that's what i was trying to say in my last post. :silly:

They probably ARE refering to changing the bottoming cone. :thumb:

Why would they change the bottoming cone? And does that really cost $70?

Its been this way all the time even when i was superhard compression. I have gone from all stock and superharsh to supersoft and still harsh on small bumps.

Even when i ride in the pits in first gear on idle speed i feel a stone smaller than my fist. So i dont think its because its riding low in the stroke.

 

[marcusgunby]

If different valving is not fixing it, it must be something else.Did you disable the mid in the end?

 

[russ17]

pyro
one thing you might take a look at is a bent fork tube I have had seen a few of theseas of late you can pull the springs out and work the tubes and see if you are getting a hitch. the ones I have seen were in the lower leg
Russ

 

[georgieboy]

KTM-lew, i read that you said: see if it is using 7" on 4" bumps.
Is that the way of telling whether yr suspension has enough damping?
I mean, if i roll over those 4'' bumps i may be using only 2'' of travel, right?
If i hit them with high speed, i cld bottom it on those same bumps?

 

[terry hay]

Pyro
The valving you are using appears way too light as the other guys have mentioned. Also as previously mentioned I believe you may have binding or stiction occurring. This is a common problem with the dual chamber forks. It would seem your are little confused about the function of these particular forks as well. First I would recommend you run a single stage stack. For your weight I would start with a CH5. Unless you have already removed the midvalve I would keep it in place. The midvalve provides an excellent means of controlling the height of the stroke and I don't believe it is responsible for all of the so called "mid stroke harshness". If you choose to you can alter the stiffness of the midvalve to achieve different effects pertaining to steering and comfort. Firstly we should be clear on your assembly. After procuring the correct springs and assembling the compression valving assemble the forks in the following manner. Fill the inner chamber with 2.5wt oil. Motorex if you can get it. Pump the damper rod to ensure you expel any air trapped in the cartridge. Fully extend the damper rod. Top the oil up so that the level is appr. 10mm above the shoulder and insert the compression assembly. You will feel quite a bit of resistance at first. You should then hear excess oil and air being exhuasted and the pressure will reduce. Tighten the cap. The level inside the cartridge is self regulating and is not to be altered. Set the level by fully compressing the damper rod. excess oil will be expelled and the level is now set. Tip the cartridge up to let the excess oil run out of the holes just below the cap. If you fail to do this it will affect the volume in the outer chamber. Install the cartridge into the outer chamber and fill with 387ml of oil. As this oil merely lubricates and determines the air volume, oil weight is not so critical. To ensure greater accuracy with the outer chamber volume you should make sure that there is no oil in the void between the tubes. If you have completely disassembled the tubes this won't be a problem. If not you can express the oil from between the tubes by full extending them until you feel the bushings touch. This should be done prior to installing the cartridge. Now complete the assembly and install the forks in your bike. Now lets look at possible problems creating stiction or binding. We'll start with the basics. Whilst apart you should have checked the tubes for straightness and the bushings for wear. If this is fine check for any wear in the anodising on the inside of the alloy stanchion. This usually occurs where the tube is held by the lower triple clamp. If there is a wear patch, have the tubes HARD anodised. Next lets review the installation. This is one of the main cause of stiction when there is no apparrent fault with the forks. The lower triple clamp should not be overtightened as this will compress the alloy tube and impede the sliding action of the chrome tube creating harshness. Also pay particular attention to your axle alignment. As the axle is passed through the fork, sometimes the clamping area binds on the axle and it is pulled towards the other fork as the axle nut is tightened. This reduces the required distance between the two legs and the forks will bind as they're compressed. Also creating harshness. I'm going to presume you Know how to check this. If not let me know and I will instruct you.

 

[marcusgunby]

Terry im interested in your choice of oil weight for the inner chamber-do you find it makes any difference to the rebound clickers position? i ask as on my 04 rm im only 6 clicks from full in, using the std oil.I have heard many use a 7.5 wt in the inner chamber to slow the rebound.Im a bit worried this may stiffen my compression more than i would like.

 

[pyromaniac]

When reading the Racetech papers they recommend me to use low and highspeed stack. Also recommends 5wt oil if i remember but i can try 2.5wt. I have checked that the forks arnt bent but not very good but i boubt they are since i know what this bike have been through. I have already removed the midvavle as recommended by RT. I have also make sure the forks arnt binding. My friend think my suspension is good but he is a bit heavier and faster, could be that.

I will try a single stack and 2.5wt oil just to se if it gets better. All changes i have made have been to make it softer and its been for the better but still im not happy with it.

 

[marcusgunby]

Also you need to make sure the passages for the compression adjuster(the hole in the centre) is clear and the Inner Chamber Spring is not binding in any way.

 

[terry hay]

Marcus
The earlier Hondas are benefitted by the thinner oil for both front end grip and improved feel. I haven't worked on the latest RM250s as yet. I presume they will be similar to the latest CRs, CRFs. In the current CRFs we are increasing the rebound damping as it is inadequate and deflection is common. Do you know if they are using the 34mm piston or the 23 in the RM? You seem pretty sharp and obviously keen to try things. Keep us posted on your developments.

 

[bclapham]

terry: whats the scoop on the motorex oils- ive got a good line on some- will the 5wt synthetic fork oil they sell work in a shock?

btw- the RM forks changed for 04- the 01-03 had the pistons with the ~22mm (going from memory) shims and i assume the 23mm piston but the 04 rm forks (125 and 250) look like last years cr forks- longer springs and a 19mm flats on the top adjuster

 

[marcusgunby]

Terry i have the 125 but the fork is i guess the same as the 250 bar the valving,springs etc-it does look like the Cr fork but i havnt really looked hard, as all i have done is a passive side revalve.Once i get them apart i will give a full rundown.Im thinking it has the 23mm piston but dont quote me on it.

 

[marcusgunby]

Pyro i forgot to say- i have a set of 03 RM showas for service-guess what, they have lots of stiction at the top of the stroke-this is when they are off the bike, i will let you know what i find.

 

[marcusgunby]

Well i didnt find much, the oil was very bad after around 20 hours use, the fork seals were very dry and causing drag.I found his rebound was at 3 clicks from full slow and that didnt help.

Rebuilt and they feel good when worked by hand.

Does yours have that shim stack below the main shim stack?? its called a bleed shim stack?

 

[pyromaniac]

Originally posted by marcusgunby
Does yours have that shim stack below the main shim stack?? its called a bleed shim stack?

You mean stock? Cant remember but it had quite many shims. I didnt change the stack but rode anyway this weekend but i did turn the clickers in alot on the compression and it did help overall but its still harsh. Its worst when im going fast over bumps like 10-30cm high, it will bounce the fontwheel and cause alot of headshake. I have to slow down or i will loose controll and crash hard :( On bigger bumps at slower speed it works better but i also think my shock is too hard cause it wants to throw me off if i attack too hard. I simply cant ride as fast as i want or the bike will throw me off or make me lose controll, i know i should be able to ride faster if the suspension is right.

Well i have taken the forks and shock off the bike and plan to drive to the suspension company tomorrow. It looks like it was the bottoming cone they change after all, i found little info on their homepage. Here what it looks like http://www.springzz.com/pris_ren_mod.html its the picture beside "Modifiering Showa Twin Chamber".