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onvert Mid-Valve to Standard Check Valve?
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Posted by: DJPdesign---------------------

Convert Mid-Valve to Standard Check Valve?

Honda CRF450R 2003.
The front is to harsh on the initial stoke, and not very plush.
89KG / 195.5lbs. Mainly MotoX racing.

I plan to do the following modifications, and was after advise.
Has any body got any experience on a 50mm Showa on the CRF450R ’03?

Friction reduction.
Titanium Nitride the fork legs. (reduce friction, and tolerances around bushes)
It will probably be Titanium Aluminium Nitriding ($150)(bit harder and even less friction.
Anodizing the fork legs and clamps (black) while there apart.($50)

Valveing options, (these are a little limited in the UK) Most people treat the suspension as a scary black box).

1 Send it away and get the stack changed, by a local guy. ( I wont know what he’s done but a few racing mates who say that its better. Cost $100

2 Send it to a race guy further a field, he will re-valve, compression, mid and rebound, at a cost of $400. It will be a new shim stack. But I will still not know what is going on.

3 Race Tech. Get there gold vale set and sit down with the video and work it all out. Settings have already been obtained from the web site.
The problem with this is that they specify removal of the mid valve?
Convert Mid-Valve to Standard Check Valve. Check reservoir piston rod for wear.

What effect will loosing by Mid Vale have?

4 Get a shim pack and have a go, any body know where I get them from in the UK?
I would need some base settings to start with.

5 Tumic Raceing. http://www.tumic.com/01c37392fb14e6303/index.htm
This is the money no object GP spec route. They use the Race tech vales, and I can get the coating done my self, can I get there cheaper than $1000

I have spoken to many people about the fork setup and am getting lots of different advise. Many people say that a revalve will do the job, and that their revalve is the best!

I would very much like to have a go my self and remove the “myth” that suspension is a scary black art, and we just have to pay to get the best.

Thanks for your help,

Dan

NB marcusgunby? Can you recommend any one in the UK?
Can you help with the re-valve?

Posted by: marcusgunby---------------------

Firstly i would drop the idea of coatings unless you like the looks of them -they wont make the bike perform any better-i had some done and it actually ruined the suspension.Also i dont like the idea of removing the midvalve as its a bit of a backwards step.

What area do you live in? i can reccomend some people?

Posted by: Vic---------------------

Marcus- How did the coatings ruin the suspension?

Posted by: marcusgunby---------------------

They took up all the tolerance in the forks and shock.If you apply the coatings you need to ensure the extra thickness is removed from all areas like where the bushes ride.Basically it ended up really sticky instead of nice a slick.The std parts are not made to a high enough quality to ensure they work properly after the coatings have been applied.Think of if we add coatings, and they have a certain thickness how can the fork/shock work correctly.Ive know others to have it done and it work ok, but i wouldnt advise it.

Posted by: DJPdesign---------------------

Marcus, Thanks for your reply, thought that I had drawn a blank there for a while.

Coatings, Yep you have guessed it I do like the idea of gold forklegs, and black fork tubes! The bike is all black and I have had the frame polished! Its important to feel confident and assured on the start line….

The coatings although thin should help reduce tolerances and reduce friction.
Here is a link on the coatings. http://www.ttigroup.co.uk/ptc030_pvd.htm. I have spoken to these guys and they do a lot of fork legs. I appreciate that the bushes could wear out faster, but the idea is to drop friction.

How did they “ruin” the suspension, are you talking about the suspension setup or suspension parts?

The Race Tech Gold valves, actually change the compression and rebound valves.
I believe that the “mid valve” is the rebound valve right?
After speaking to them in the USA; they say that you can leave the mid valve if you like, it will not make so much difference, although there optimum set up would change this valve.
They also mentioned that they probably have the most data for the Honda CRF 450, and that presently they have not had any problems with the recommended setup.

The compression stack is modified to a more “suitable” two stage set-up as have been discussed else where in the forum. They give you the shims and a start point for the installation.

I am keen to try doing this myself as I can imagine that I would be able to tune the suspension better once I have a better understanding of how it works.

I would be great if you could recommend someone, for me to talk to, I just need to be convinced that my money is well spent, and that it a good way forwards. Mail me direct if you want, dan@djpdesign.co.uk

Thanks

NB anyone tried any aftermarket forks / shocks?

Posted by: DJPdesign---------------------

Sorry,
I'm in South Wales, but will travel / post for a better job.
I am interested in getting the suspension as good as possible with the Showa units. I believe that more time can be saved with the suspension than any where else.

Posted by: marcusgunby---------------------

It sounds like the best plan is to get some gold valves as these are the best way to learn.I dont know anyone to reccomend other than MH racing in horsham -not sure how far that is???

On the coatings the problem is they do have a certain thickness and forks shocks are designed to have certain gaps between the bushes/piston rings etc.Once you add the coatings those gaps dissappear.So you get more stiction than a normal setup.The factory forks are designed to have the coatings as so have the correct tolerances.Im not saying they will all be as bad as mine.However i dont believe even a good coating setup really will reduce friction to the point of feeling a difference.If you like the looks thats a good enough reason.

The midvalve is on the back of the rebound piston.

Posted by: DJPdesign---------------------

Thanks for you advise, I was just very interested in the Tumic suspension conversion, seemed like they had put some though into it. (Well about $1000+ worth actually). It looks and sounds like they “know” what there doing. They’re going to open a “race tech” shop in the UK in about 3 months.
Good point on the coatings. I spoke to the coaters and you can specify the thickness, Typically Coating Thickness 1-4 (µm)! They don’t recommend less than 2. It’s all to do with the time in the bath and the substrate. I am sure that the tolerances on these production parts are way outside of this. I’d do some measuring! Worst comes to the worst I’ll machine (hone) the bits to fit. (Should be fun!)
I have spoken to Mark at MH racing, they were the second option in the original mail, and are not too far away. I am trying to get the best suspension possible without going aftermarket.
He does change the stack, I believe, so it should be a similar set up to the Race Tech setup.
I hear that the piston whole diameter on the standard pistons is a little too small and so with the larger wholes in the race tech valves allow the stack to do more of the work? Make any sense?
Thanks for the info on the mid stack; it appears that the shim is changed just to make the stroke plusher.
I think that I will go for the Race Tech bits and see if they are any good. (At £109 its a OK gamble). If this does not work they shall be straight off to MH, with the original guts back in and the Race Tech bits on Ebay!
Thanks.

Posted by: bclapham---------------------

DJP. i rode a crf450 with racetech susp and the owner had it set for around my weight. Although it was a great bike,in hindsight i realise that the susp wasnt that good since it seemed to ride quite high in the stroke and there wasnt enough travel left and it would blow throught the stroke on the bigger stuff. just my opinion. unfortunately the website search function isnt working, but i would say the general consensus i have learned over the last year is that fork performance has a lot to do with the midvalve and running the GV's is a step back, but unfortunately, this is all we have for the mechanically inclined that does not have access to shim stacks

Posted by: DJPdesign---------------------

Interesting, perhaps Race Tech is not the way to go. Damn!
Anybody know where I can get a set of shim stacks?
And a rough start setup for the CRF?
I have heard of people just modifying the standard stacks on CRF ‘02’s. I don’t know if they just remove a shim or two, or change the order.

Q is the compression stack a two stage setup as standard?

Posted by: marcusgunby---------------------

I wouldnt go down the gold valve route for the valves as such-its more the system where they give you shim stacks to try out.They are agood learning system of shims and how they work.Your pistons are not really in need of replacing but no one i know of sells stacks for a reasonable price.

Revalving can be reducing the number of shims-the thickess, the size and the amount of stages-or all three.Thats why its is a bit of a art form to get it really good.I think the Cr has a single stage stack.

Posted by: dbrace---------------------

The 03 cr450 has a two stage fork comp. stack.

Posted by: motometal---------------------

do they use heat when applying the coatings you speak of? And the TiN coating will work on chrome plated steel?

Posted by: DJPdesign---------------------

I don’t think that heat is used. Its more akin to anodising. The just put the part in a bath. Saw some forks done with TiN, on the weekend, they were very plush. Probably the best I have ever felt.

You will need to apply heat to get the fork legs (chrome bits off the clamps) there glued and pinned. My local suspension guy is doing this for me. (you need a special tool to hold the chrome part when you undo them

I am going to go for TiAlN Titanium Aluminium Nitride, its even harder and only a few pounds more.

Posted by: marcusgunby---------------------

One of the biggest places of stiction is the fork seals-some factory(works) seals are very loose and super slick, but they dont last long.

Posted by: JTT---------------------

Quote:

Originally posted by marcusgunby
-some factory(works) seals are very loose and super slick, but they dont last long.

...like some suspension builders....

Posted by: bclapham---------------------

Dan:

i think most of your problems are in the valving, i expect it doesnt matter how much cash you throw at a fork, unless the valving is good then you wont like them. you said you felt a bike with plush coated forks, was it the coating that made them good or the valving? probably the latter.

if i were you i would look to the valving first, there is no point having cool looking forks that dont work as well as the next blokes well setup stockers

Posted by: Vic---------------------

Posted by: svi---------------------

Quote:

Originally posted by DJPdesign
Convert Mid-Valve to Standard Check Valve?

Friction reduction.
Titanium Nitride the fork legs. (reduce friction, and tolerances around bushes)
It will probably be Titanium Aluminium Nitriding ($150)(bit harder and even less friction.

Are you sure thats the right price? It looks amazingly cheap, is that the price per leg or for both?

Posted by: DJPdesign---------------------

The price is 42UKP £ for TIN, 62UKP £ for TiAlN. That’s each leg. ($210 at1.7ex rate).
This does not include disassembly etc. add 100UKP?
It’s a place in North Wales, labour is not expensive there I guess?
They knew the price on the phone, and do a lot of these coatings for bikes.
Here is the link to the coatings, just for interest.
http://www.ttigroup.co.uk/ptc030_pvd.htm

I Agree with you BClapham, the valveing is a must. I’ll have found a bloke who used to be GB champion, still rides, he is going to help. He has some base settings for the CV, and Mid stack. He also has a workshop and is familiar with the peeing on the mid valve etc.

This will all happen next week now as my motor is having a new piston this week. Arhh. Pretty poor as its only done about 7 hours hard work. (CRF2003)

Happy racing, I’ll let you know how we get on!

Posted by: svi---------------------

Do you have a number for those guy's thats well under half the price I paid for the last set of forks I had done.

Posted by: DJPdesign---------------------

This is the address and phone number, see previous post for web data.
They are used to doing parts by post.
They have a TiN process run every day, and about 2 TiAlN per week.
If you let them know when parts are arriving, they mentioned that they can change schedules to suit a fast turn around! how’s that for service!

NITRIDING SERVICES
HORTONWOOD 40
TELFORD
SHROPSHIRE
TF1 4EY

TEL:01952 677372

NB anybody know where I can get “works” seals in the UK.
I know they don’t last long, but it would be nice to try them.
Thanks

Posted by: motometal---------------------

Is polishing required or recommended after these treatments, and if so how is it done?

Are there any acids used or any potential for hydrogen embrittlement?

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onvert Mid-Valve to Standard Check Valve?

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