my Ktech 996 fork upgrade on S4

[jerry]

well finally got the Ktech 996 forks to thailand and fitted to the S4 , a lot faffing around with lower yoke shims 0.5mm and the tope yoke Capo supplied was for fat bars so i had to make shims to fit my 7/8 bars as fat bars are stupidly expensive in Thailand and would foul the stanchions anyway as the 996 SHOWASforks are 10mm longer than S4 Showas .

well been avidly testing the bike this week over 200 miles so far and things are a massive improvement on the old setup.

The New forks came from a 996 off Ebay for £120 and were sent away for Ktech revalves, overhaul and 8.5 spring set for my weight , all in i spent about £ 600.

ORIGONAL S4 SHOWAS ARE NOT WORTH SPENDING MONEY ON AS THEY HAVE A DESIGN FAULT !

first i have noticed a big improvement in stability on corners and straights ,much more precise control , i have changed a few settings on rebound and compression they are now set at 6 clocks compression and 8 clicks rebound , sag is 20mm but preload is minimal on 7 lines visible i still think the forks are a little hard and could be plusher on the bumpy bits but the airgap was set by ktech at 120mm as a starting point and i will remove some oil as i want it a bit softer maybe 130mm or even 140mm airgap using 5w oil.

i have upped the rear ohlins compression 2 clicks as well bike feels very balanced now .



was it all worth it , am i happy .....definitely ......but the quest for perfection goes on

[Thirdway]

I'm guessing the S4 are the same as the 4s internals. I had wondered where they came from. Do they have the semi cartridge design like early 80s bikes? The 996 has good internals except need re-valve and springing and then they are very good.
If the S4s are the same it is possible to improve them but it needs someone who is prepared to do the engineering work as it isn't just a straight forward valve replacement.

[jerry]

I'm guessing the S4 are the same as the 4s internals. I had wondered where they came from. Do they have the semi cartridge design like early 80s bikes? The 996 has good internals except need re-valve and springing and then they are very good.
If the S4s are the same it is possible to improve them but it needs someone who is prepared to do the engineering work as it isn't just a straight forward valve replacement.


the whole rebound rod has to be re- engineered before all other mods are considered i priced it up and decided a set off SBK forks was a better bet

[Thirdway]

the whole rebound rod has to be re- engineered before all other mods are considered i priced it up and decided a set off SBK forks was a better bet

Yes, that's what Gareth did. He was a bit miffed because he had priced the work as a 996 fork and ended up doing a lot more work without any charge. It certainly wasn't straight forward. Only cost me around £250 so I can't com pain. Night and day difference, can now brake like a demon and the fork hardly seems to dive, yet is incredibly compliant over the worst surfaces.

Took the Monster for a look and he was happy with the overall setup on the s model. Except it needed some preload taking out and a touch less rebound on the rear.

[jerry]

Thirdway what airgap in your forks ???? mine are not yet compliant enough with120mm gap not all the travel is being utilised .....

[Thirdway]

Thirdway what airgap in your forks ???? mine are not yet compliant enough with120mm gap not all the travel is being utilised .....

Actually, good point, Gareth hasn't told me which would be a bit of an issue come new oil time. Don't even know which grade of oil he used.

[jerry]

K tech set mine at 120mm with 5w oil but they said it was a starting point and that was usual for race bikes , I am using mine as road bike the 5w oil is fine so will have to find time to make the air gap 140mm

[jerry]

PROBLEM....Oh dear the forks are too hard i have now set zero preload and zero comprssion with 5 clicks rebound and removed some oil so air gap is a massive 140mmm and they are just about compliant on the local racetrack and perfect roads ...several mates have now ridden the bike around Bira track and we have come to conclusion that either springs are too hard or HM racing fitted the wrong Ktech valves ????? also static sag is ZERO !!!!!! the handling is great but comfort is zero ,,,,something not right ...I will have to bring the forks back to UK next year in meantime the bike is ridable and very accurate , i am taking corners much quicker and at greater lean angles also doing stoppies which old forks would never do but my wrist are bruised after a 150 mile ride today , my brief to HM racing was road focused forks for comfort and accuracy .

HO HUM !!!!!!!!!!!

[Funkatronic]

mighty shame :-( do you know what weight springs went in there?

[Thirdway]

Are you sure you have zero with you sat on the bike?

Is the suspension moving and if you compress tye forks does it return quickly?

It sounds like the springs are too hard but wondered if you might have twisted fork/too much stiction?

[jerry]

spring is supposed to be 8.5???,we have checked everything is straight in the yokes , the forks do move but not full travel i put tie wraps on them rebound seems fine has to be the spring ??? have now done 418 miles on them so they have bedded in too.

[jerry]

seems the spring is a 9.5 and that its the lightest made for 996 forks by k tech which is ridiculous as I specified 8.5 by my own calculations ,

HM racing and k tech now tell me they cannot supply a 8.5 or less spring for 996 forks and that 9.5 or 10 is what is used in race bikes......they said i shoild start trimming the preload spacers ?????? i am not a happy bunny about this at all.

[Thirdway]

I would be. Someone will do a set surely?

[jerry]

i will ask maxton and ohlins

[Thirdway]

i will ask maxton and ohlins

Give Reactive suspension in York a call. If Gareth doesn't know then no one does.

[Funkatronic]

mike dawson MD racing is a good bet too, in the same neck o the woods as HM Racing

[Funkatronic]

sure i have seen some 8.5 linear ohlins springs on US ebay so im sure that they make them lighter

[jerry]

I contacted all the above shops and ohlins direct and they have told me no lighter springs than 9.5 for 996 forks are available ....this is turning into a real bummer,maybe maxton or someone else has custom linear springs 8.5nm?????

[jerry]

AH HA Racetech can supply an 0.85 spring so that may be the solution??????

[Stafford]

ORIGONAL S4 SHOWAS ARE NOT WORTH SPENDING MONEY ON AS THEY HAVE A DESIGN FAULT !


Are the same internals used on the ST4S?

[Funkatronic]

i beilieve they are the same stafford

[Stafford]

i beilieve they are the same stafford

Yes just been going through the parts lists and internals do seem to be the same but what was the internal design fault?

[Dukedesmo]

I have 916 forks for my Monster with Ktech 9.5 springs, however I reckon they'll be fine for me weight-wise as they were a a tad soft on a 916 (Monster is lighter) but Ktech list both 8.5 and 9.0 springs as available for 996 on their website; http://www.k-tech.uk.com/store.php?category=1&road+value%3D=&manufacturer_id=11&model_id=516&Submit=Go

[jerry]

The design fault is that there is no rebound damping rod all the way to the cartridge unlike superbike forks and the difference is really noticable ,

I have decided to wait until i have a chance to examine the spring in my forks as it may already be 8.5 but its too hard thats for certain

[Thirdway]

Are the same internals used on the ST4S?

Yes, they are. Had mine modified by Reactive. That's the ST4s.