Suspension Mods Gen1

omc1984

omc1984

Registered
Alright....my barn find gen1 has to get a lot of updrades and this for the start regards to the forks:
My Plan is an complete overhaul and improvement. I have all the tools...so this is no topic.

1. New Seals from SKF

2. Remove Compression adjuster and fit k-tech flow control valves

3. fit SC59A fork springs + custom preload spacer
-> rated at 1.07kg/mm and with 8mm installed preload should be perfect for me (and my riding, luggage)
4. Modify Bottom out -> make it softer by drilling bleed holes into the cartridge head

5. fit racetech gold valve on compression

6. change adjuster pin for rebound in the fork cap
-> change to R1 2002-2008 to achieve "1click" every 1/8 of a turn instead of 1/4turn

7. polish rebound needles

8. brushhone cartridge inner diameter

9. polish inner assembly

10. Flat the hydraulic pistons for better sealing


The Tricky part is the rebound assembly/piston. I guess Tl1000R, ZX12R, GSXR1100 are using the same hydraulic pistons, right? As Racetech doesn't offer a piston for the rebound I might have to revalve it. Do you have any specs or suggestions which stack ?
 
Sounds like you know what you are doing and I have no input on which stack to use, but whenever I pull the trigger on some rear shock upgrade, it will be the Penske shock that others swear by on the forum. Have you considered just doing that? (I know they are not cheap though)
 
Certainly does sound like you are fully on top of your suspension components and what's needed for your requirements . I on the other hand am not ... but I do appreciate what investing good money into your suspension can give you in return . I am very interested in this rebuild , as I am sure will be others .
 
yeah...i know what i am doing.

But some advices on the rebound stack of the fork is necessary. I've found these informations:
http://norwestsuspension.com/9907-hayabusa-fork-stock-valving-valving-images

The Rebound Stack is a bad design. the check valve is bad and the way the stack is build also. Hopefully a solution is on the way.

In Regards to the rear. We are not allowed to ride a penske in public traffic. And honestly I hate rebuilding them. I rather prefer ohlins, k-tech or OEM in terms of a rebuild.

So I was thinking about a Gen2-Shock + gold valve. But honestly I would like to see a TTX in the busa. Does any one have an idea whether the Gen2-TTX would fit the Gen1-Busa?
 
Well , I do not know for certain , but I gave my mate my Gen 2 shock to fit up to his Gen 1 , and I will confirm next call to him how that went (soon) .
But I was running the old top of the range SU046 Ohlins on my Gen 2 , which was the premium Ohlins shock for the Gen 1 , and it fitted perfect .
The TTX36 I run now has the same end fittings as the older shock . I will just have another look at the length of SU046 Gen 1 and TTX36 Gen 2 .
DSCF1275.JPG
 
Last edited:
Are U sure about the SU046. This S46-Shock is for the GSR600.

Could anybody confirm, that Gen2-TTX fits into the Gen1? @ROADTOAD1340 could you test this anyway? I guess I can pay that back sooner or later!

Anyway...the Gen1-Ohlins fits into the Gen2-Frame. Interesting! And for the people looking around this is the confirmation!
 
They are the same length , with the TTX36 using the ride height to add 5mm in height . This TTX was actually aged to be affected by the recall , it had been sent in then qualified fixed and now , only within a week or so , was resprung for my weight , and stored for next project Busa . The new build TTX36 that is fitted to my bike , is fitted with a slightly different bottom mount , in that the ride height thread starts a bit higher up the shaft .
 
Interesting thread. Seems like you are using a lot of different pieces for the forks (Racetech, K-tech, etc.) why not one manufacturer? I'm not saying this is wrong or bad, just curious why you didn't let one manufacturer set the fork up? I've worked with Racetech, they are very good. I have heard good things about K-tech too. Good information in this thread though.
 
ROADTOAD1340 said:
I am pretty sure it is called the SU046 ,thats the shock in the picture with the TTX36 . This shock I call SU046 was the top Busa shock for Gen 1 , there were 2 types , and this one had more adjustment and was the premier Ohlins of the 2 for Gen 1 . This is the real spec name , I have got it wrong OHLINS S46PR1C2LS .
Click to expand...

AHHH!!! you are talking about SU406...there was the mistake! how ever...i gonna send you a PM soon

fallenarch said:
Interesting thread. Seems like you are using a lot of different pieces for the forks (Racetech, K-tech, etc.) why not one manufacturer? I'm not saying this is wrong or bad, just curious why you didn't let one manufacturer set the fork up? I've worked with Racetech, they are very good. I have heard good things about K-tech too. Good information in this thread though.
Click to expand...

You are right...somehow. Let me explain it a bit more in detail. The K-Tech Flow Control Valve only controls the bypass flow over the adjuster needle. it is like a tap. you close it and you reduce the flow over the bypass. If you look and analize the behavior of the original compression needle/assembly you will realize that as soon as you are opening the klickers more then 7clicks you will not reduce the flow. thats why the orifice at the needle is more open then the other orifices in the bypass. So effectively you have 7 clicks availabel to play with. if you insert a K-tech FCV you still have these "7 klick opening range" but transfered to a finer adjustment of 24klicks or so...
This still has nothing to do with the compression piston or stack. As soon as you close the adjuster you are limiting the orifice flow and more work is done on the compression piston.
That beeing said: the style k-Tech builds their compression pistons is not perfect for me. The flexibility you get with a gold valve (huge ports) is what I want.
But sadly racetech doesn't offer a rebound piston :-(

However. The OEM style of the checkvalve side is a real dilemma. Racetech wants to reuse the OEM checkvalve with their gold valve.
A few years ago I made several custom assemblies for the checkvalve side. Problem fixed!
 
ROADTOAD1340 said:
They are the same length , with the TTX36 using the ride height to add 5mm in height . This TTX was actually aged to be affected by the recall , it had been sent in then qualified fixed and now , only within a week or so , was resprung for my weight , and stored for next project Busa . The new build TTX36 that is fitted to my bike , is fitted with a slightly different bottom mount , in that the ride height thread starts a bit higher up the shaft .
Click to expand...
Toad, sure you don’t need me to “test” that shock out while you wait to build you next busa? Actually, I would be more than happy to test all your spare parts for you. :hide:
 
...thinks getting started now. A friend send me his 99 Busa Forks because they are leaking.
Some things were coming into my mind at the Moment. I will inspect the valving assembly and take some detailed measurements on the fork and cartridge. Analysing the oem Rebound shim stack is simple and in Addition to some calculations i should figure out how to rebuild the Rebound stack in a more performant way.

How ever: the fun part starts here. I still have a KYB 24mm Cartridge from an 07-08 Yamaha R1. The cartridge is a full rebuild including an andreani Piston kit and some more mods to the hydraulic. I will check whether this cartridge would fit into the busa-fork. The cartridge doesn't have the right spring rate at the Moment. But this isn't a big deal.
I'll try to make a lot of pics....so stay tuned
 
I got a set of Gen 2 fork , fitted up with 30mm Ohlins cartridges that were originally for Gixxer 1K . I am not certain , but I think some machining was necessary for fitment . I had our cities only qualified Ohlins tech set it up for my old weight , they were a great fork before the FGRT208 changeover . Enjoying your methodical approach and component knowledge , man I love good suspension hardware .
 
me too...well a set of ohlins forks would be very nice. honestly i am not sure how much Money i have to spend on the bike. so in Terms of the Suspension I am more focussed on improving with some elbow grease (and because i have the Tools).

in regards to ohlins...there is an other Option as well. Ohlins has the SBK-Valvings 03200-25 and -27 for 25mm cartridges. This might also be an Option for the gen1
Only Thing that complicates the Situation is that the busa has a 12.5mm rod instead of a 12mm (ohlins) rod
 
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