Author Topic: Forks modification advice (Read 6048 times)

Triggergee · « **on:** 14 March 2018, 05:19:52 pm »

So I've been reading about Kebab19's forks mod and fancy giving it a go and have found a pair of damaged forks for £60 to use but as I've actually never taken my forks apart I'm not sure how far down the damper rods are and whether they might also be damaged, I'm guessing probably not but thought I better check with you bright lot just incase. I know I probably wouldn't be able to be 100% without getting in there. Also is the price fair for a fucked pair? Now hopefully I can actually upload the picture lol. Oh and does anyone know where to get the Debrix emulators from? Www.debrix.com doesn't seem to work

daviee · « **Reply #1 on:** 14 March 2018, 05:59:22 pm »

damper rods are at the bottom so you might get away with it the emulators can be bought from wemoto as for price damper rods are few and far between so if its worth it to you fair do's

Triggergee · « **Reply #2 on:** 14 March 2018, 06:23:41 pm »

Thanks daviee that's what I was hoping to hear. Does the tops of the damper rods still need filing or are the yss emulators a precise fit? The kit is being sold for fazers so I suppose they fit straight on.

daviee · « **Reply #3 on:** 14 March 2018, 06:51:27 pm »

should be a strait fit their is plenty of info in this forum if you search about

kebab19 · « **Reply #4 on:** 14 March 2018, 06:58:00 pm »

Nice one, the damper rods in those forks should still be 100% fine for modification. If the lowers were bent, then it'd be a different story!

As stated, Wemoto should sell 'em if you can't get the Debrix ones anymore and they will almost certainly be an exact fit for the rod.

Triggergee · « **Reply #5 on:** 14 March 2018, 07:00:36 pm »

Thanks for that, im working my way through your post Kebab19's and all the replies even if admittedly some of it is a bit beyond me. Should be able to drill some holes though... I think I better grab those forks then and start getting into it, even though I don't have much experience on bikes other than the fazer and my dad's vmax 1700 trike I can still feel that the fazers handling is a bit boat like at times.

tommyardin · « **Reply #6 on:** 14 March 2018, 10:47:31 pm »

Quote from: Triggergee on 14 March 2018, 07:00:36 pm

Thanks for that, im working my way through your post Kebab19's and all the replies even if admittedly some of it is a bit beyond me. Should be able to drill some holes though... I think I better grab those forks then and start getting into it, even though I don't have much experience on bikes other than the fazer and my dad's vmax 1700 trike I can still feel that the fazers handling is a bit boat like at times.

I have no doubt that anyone with a modicum of common sense and a little bit of skill spanner spinning and nifty with a power drill, can do this well worth while modification.

Don't rush it, take your time, think it through and work precisely and cleanly.

I did mine with a lot of help from Kebab19's post's and having dialog with him via messaging.

Keep the drilling as low as possible on the damper rods, early FZS 600 Dampers are 210mm long, the later model's Dampers are 190mm long, if you measure about 5 or 6mm from above the top of the axle hole in the bottom fork legs (Sliders) by 210mm or 190mm depending on the year of your Fazer FZS 600 you can tell where the top of the damper rods will be inside the damaged forks, before taking them apart

My FZS is a 2003, so I had the shorter 190 mm damper rods, it is paramount that you keep the holes that you drill to overcome the damping effects of the damper rods as low as you possibly can, if these holes encroach into the upper chambers of the forks on full compression your damping will be compromised at the very least.

A lot of the manufacturers of the emulators advise 3 X 8 mm holes, that in itself is a little confusing as it means 3 X pairs of 8mm holes (You are drilling through the two walls of a tube) with at least 10 mm of complete damper rod between each of the 3 sets of holes.

So starting at the original oil release hole (5 mm) in the damper rod, drill this out to 8 mm then drill another 8 mm hole at 90 degrees around the damper road leaving at least 10 mm of damper rod between these sets of holes, then repeat again for the 3rd set of 8 mm holes and you should be back directly above/inline with the first set you drilled.
Now if you add the 3 X 8 mm holes together (3 X 8 = 24) then the two times 10 mm distances between the sets of holes (2 X 10 = 20) add the two measurement together 24 + 20 = 44 that is how far you have come up the damper rods, I personally felt that it was getting very close to the point of encroachment into the upper chambers of the rods, especially with the shorter 190 mm damper rods.

Now 2 X 10 mm holes have pretty much the same area size as 3 X 8mm holes.
(Google it there are charts that will show you how to work out the area of a circle or round hole)

I lowered the original 5 mm damper holes by 3 mm by measuring accurately and marking with a permanent sharpie pen, then with a fine chain saw sharpening file I lowered the hole in both damper rods by that amount (3 mm) so I have now lowered my datum/starting point by 3 mm. I then drilled my first 10 mm holes at the lowest point of my datum hole, I then allowed 15 mm between the first and second set of holes again 90 degrees around the damper, I drilled the second set of 10 mm holes.

Now as stated earlier, my two pairs of 10 mm holes have the same value as 3 pairs of 8 mm holes.

2 X 10 mm holes = 20 mm. 1 X 15 mm space between the two sets of holes = 15 mm.
20 mm + 15 mm = 35 mm, Now minus the 3 mm that I lowered the original damper hole by filing it lower = 32 mm, as you can see I have lowered the drilling to the damper rods by the difference between 44 mm and 32, i have lowered the drilling by 12mm.

Plus I have 15 mm between the holes which must have less structural weakening impact on the damper rods, and the are only two pairs of hole as opposed to 3 pairs.

Sorry if this has been written in a laborious way but I felt it was worth and important to spell it out clearly, as you know the forks are a really important part of the motorcycles structure.
Anyone doing either of the two ways mentioned above does entirely at their own risk, none of what is written is a recommendation to anyone, but just my thoughts and practice when I did my forks.

I am not an expert or an engineer, in fact I was a brickie before retiring, but I am a very practical person that likes to think things through and work precisely.
My old dad drummed it into me and you all know the old adage 'A Job worth doing is worth .........................'

Please note that when talking about the land between the pairs of damper rod holes that you drill it means Between the top of one pair of holes to the bottom of the next pair, it does not mean a centre of hole measurement.

Triggergee · « **Reply #7 on:** 14 March 2018, 11:21:31 pm »

Thank you for posting this, no apologies needed for the thorough guide I'm very greatful for it and wouldn't undertake this work without all you foccers expertise and help. Thankfully I'm fairly good with my hands so should be ok if I'm careful but I'm definitely going to sit down for quite a long time staring at the damping rods and reading the guides over and over. I went ahead and ordered those buggered forks and just now the yss emulator valves so soon can start the staring and flapping...

Still need to work out the springs I need, I'm 75kg/ probably 80kg with gear on and have a pillion fairly often so ill work out what I need on the mad Ducati.com site linked and then hassle you all for what springs to get

Triggergee · « **Reply #8 on:** 14 March 2018, 11:30:01 pm »

Tommyyardin did you use a drill press to drill the holes or do it freehand? To be clear for the first/lowest 10mm hole you filed down the bottom of the 5mm hole by 3mm and started to drill the 10mm holes from there? Is it possible to measure the 3mm and use a centre punch to start the drilling or would this not work?

tommyardin · « **Reply #9 on:** 15 March 2018, 11:05:27 am »

Quote from: Triggergee on 14 March 2018, 11:30:01 pm

Tommyyardin did you use a drill press to drill the holes or do it freehand? To be clear for the first/lowest 10mm hole you filed down the bottom of the 5mm hole by 3mm and started to drill the 10mm holes from there? Is it possible to measure the 3mm and use a centre punch to start the drilling or would this not work?

Firstly in answer to the question about the centre punch, I think the it is very possible, quicker and could be more accurate, but I would go tap, look, tap look, tap look rather than wallop and possibly put a dent or distort the damper rod.
Start with a smaller pilot drill, say a 3mm and slowly get bigger.
I.E.: 3mm, 5mm, 6mm, 8mm, 9mm then 10mm, starting with the big drill will be really hard work and will take longer than going the multi drill route and certainly less accurate big drills can chunter and slip around until they take a bite.
I bought a set of drills from Lidle, but did not hold out much hope for them but to be honest but they are fantastic drills, much better than the De Walt set I had previously. Anyway what I am saying have a set of new or really sharp drill set handy as the damper rods are quite tough stuff.

I held my Damper rods in a carpenters wooden jawed vice and made sure it was nipped up really tight with the original oil hole top centre and went up through the drill sizes on one pair of holes at a time.

A useful tip:
After drilling out the first pair to 10mm run a piece of insulation tape around the damper rod with one edge touching the very top of the newly drilled hole, my insulation tape was exactly 15mm the distance needed between pairs of holes, it then shows you exactly where the bottom edge (not the centre) of the second pair of holes go. Make sure there is no swarf or jagged edges on the inside of the hole that could break off and possibly damage your emulator valves.
Good luck with the mod and I look forward to your thoughts on the finished results.

I started with a lighter Silkolean fork oil and fine tuned it as required by drawing thin oil out of the fork leg with a large medical syringe and a length off fish tank air pump tube, the syringe had calibration marks along its length and adding 30 grade fork oil this method gave me accuracy when drawing out the oil and also enabled me to put the exact same amount of heavier oil back, Mixing the oils to suit you our weight and riding style allows you to get between the 'off the shelf grades' my finished oil mix worked out at 17 or 18 grade, I started off with 10 grade, if I were ever to do this mod again I would start with 15 grade.

I used the YSS emulators from Wemmoto (not sure that is spelt right) and set my emulators 2.5 turns in from initial spring contact, with the slightly thickened fork oil this worked out perfect for me I am/was about 95 kilos fully garbed up with all my riding kit on. Lost a bit of weight (5 or 6 kilos) since then but bike suspension still feels right.
I used the Suzuki SV650 8.5 N/mm Linears by Ohlin, they are just a tad shorter than the original springs but adding the emulators into the stack more than makes up for that, infact I had to remove/cut about 5mm from the top spring spacers. You can always add large penny washers to the top of that spacer if you want to add more pre-load, but make sure the original solid spacer disk is on the top of the washer pile for the preload adjuster to bear down on (adjuster screw only applies to later models)
Hope this is helpful.
Tom

Triggergee · « **Reply #10 on:** 15 March 2018, 12:54:00 pm »

That's fantastic info! I think I'll go down the punch route and do it gradually as you say. Feeling quite confident now I think I know what I'm doing. I don't suppose you've got a link for the ohlin springs or a recommendation for where to get them from? Found these on eBay, right ones?

tommyardin · « **Reply #11 on:** 15 March 2018, 01:54:07 pm »

Quote from: Triggergee on 15 March 2018, 12:54:00 pm

That's fantastic info! I think I'll go down the punch route and do it gradually as you say. Feeling quite confident now I think I know what I'm doing. I don't suppose you've got a link for the ohlin springs or a recommendation for where to get them from? Found these on eBay, right ones?

Photo of the receipt from the Supplier.
Try eBay, I'm don't recall how I got this info, It could very well been from Jeff (Kebab19)

tommyardin · « **Reply #12 on:** 15 March 2018, 02:33:37 pm »

Found This link on eBay and free postage as well, bargain.
Suzuki SV650 1999-2002 and Ohlins'.

I like Ohlins' but to be honest i have never had any other makers springs.
Ohlins' To me is synonymous with suspension.

https://www.ebay.co.uk/p/OHLINS-Set-Front-Fork-Springs-Weight-85kg-for-Suzuki-Sv650-1999-2002/650021071?iid=273072093238&_trkparms=aid%3D222007%26algo%3DSIM.MBE%26ao%3D2%26asc%3D43781%26meid%3Da220411ca5cc489ea9ebe328c2842933%26pid%3D100005%26rk%3D2%26rkt%3D3%26sd%3D401494115806%26itm%3D273072093238&_trksid=p2047675.c100005.m1851

I noticed that the 'Object' number on my receipt is different than the number in the eBay link, but, that number could just be MecaData's Object number as the model and years are the same.

Triggergee · « **Reply #13 on:** 15 March 2018, 04:36:25 pm »

Those are the once I just found as well, in my last post I forgot to post the eBay link but it was a link for those but for the 2003 onward sv650. Once I saw the invoice you posted I looked for the older ones and found them at that price. I don't really have the knowledge or experience to know if they're good but I don't want to spend more than they cost really and they're the right strength - .85 for my weight plus you say they're good and you know more than me so that's good enough for me. Trouble is at least financially is im probably going to have to do the rear shock soon once I'm done with the forks, maybe I can hassle one of the foccers to help me out

vinnyb · « **Reply #14 on:** 15 March 2018, 05:14:53 pm »

Dunno if it helps but K-tech springs are £85

Triggergee · « **Reply #15 on:** 15 March 2018, 06:48:47 pm »

That could be £30 worth of help. Are they good springs?

vinnyb · « **Reply #16 on:** 15 March 2018, 07:07:46 pm »

Too early to tell from personal experience cos I haven't fitted mine yet, I've got YSS emulators to do at the same time, but the rest of their kit looks good and most of the big suspension specialists sell them so I assume they're ok. I think they're made in the UK too, if that sort of thing matters to you.
Have a look at their website, see what you think for yourself.
http://www.ktechsuspension.com/

tommyardin · « **Reply #17 on:** 15 March 2018, 07:59:59 pm »

Ohlins is a Swedish Company but have facilities in Germany at Nuremberg but their headquarters is in Upplands Väsby Sweden.
Their test centre and distribution depot is from Nürburgring Germany, home of the famous race track.
So if you are loyal and wish to buy British these is not the springs for you, I personally have no definite desire to buy British, but I do want to buy springs that are produced by one of the most famous names associated with racing and suspension. I have no doubts that K-Tech and other makes will be absolutely fine, but please do buy Linear springs and not progressives, progressives are a compromise that will always be a compromise, no spring can not work properly for a 8 stone rider and a 16 stone rider.

The YSS factory is in Thailand.

tommyardin · « **Reply #18 on:** 15 March 2018, 08:23:46 pm »

I am afraid most of the British engineering has gone, we struggle to compete on quality, price and availability.
The foundries have all but disappeared, along with our motorcycle building legacy, and the motor trade in general.
Countries like Thailand, Japan and Korea have us beaten, it's a shame to think that but it's the truth, we can not compete with them on any level.
If you really want to remain loyal to the British companies you are limiting yourself dreadfully, and to be honest you are only giving the kiss of life to a corpse.
It does make me sad to say that but I'm afraid that's the way I see it.

I always had British motorcycles built in Britain, but were they as good as the Japanese bikes of the 60's and 70's? No! British bikes were unreliable, covered your legs with oil, vibrated to the point of numb fingers, the performance of British road bikes was not at patch on the Japanese, it is no wonder the British motorcycle industry failed, along with many other industries also, we I am afraid have become a nation of paper pushes with very few youngsters having the opportunity of leaning a trade or a practical skill.

Oh Fuck! I just fell off my HIGH HORSE.

vinnyb · « **Reply #19 on:** 15 March 2018, 08:33:04 pm »

We're not quite dead yet, Triumph are selling well all over the world, Norton are niche and expensive but selling everything they can produce. Northampton is still a major player in F1 development and haven't you got a british made Nitron shock fitted Tommy?

tommyardin · « **Reply #20 on:** 15 March 2018, 09:57:18 pm »

Yeah but all that added together does not come to much, considering we were once world leaders in engineering, and as you quite rightly say we still have Triumph (Or do we) Triumph has six-world class factories around the world. Two of these factories are based in Hinckley in the UK, just a short hop from the Mallory Park race circuit. There are three other factories in Chonburi South of Bankok, Thailand, and one in Manaus, Brazil.

And Norton are still producing motorcycles for a very small market, but can not keep up with demand, people will only wait so long

But of course your right, we live in GREAT BRITAIN, and I am British and proud be be aligned with this nation, but we have to be realistic on the global front and scale.

We are a small nation with a not very loud voice anymore and I honestly believe we as the population have done this country no good with Brexit.
Of course others have differing opinions on that, time will tell.

In the mean time summer is beginning to show its head with some sunshine, so, my Fazer for one will be emerging from the darkness and brought out into the light very soon.
But having fun in the mean time jogging along on the C90, just not very quickly.

'Not quite dead yet' does not inspire much confidence, a man on an artificial respirator is 'not quite dead yet'

Triggergee · « **Reply #21 on:** 16 March 2018, 12:52:26 pm »

Well I went for the öhlin springs at £114 which should arrive from Italy in a couple of weeks and although buying British is important to me and I usually go out of my way to do so on this occasion I've gone foreign, after all the bikes japanese and the emulators are from Thailand. Speaking of emulators they've just arrived as have the damaged forks so with my new Aldi titanium drill bits I'm ready to get going.

Triggergee · « **Reply #22 on:** 16 March 2018, 02:56:47 pm »

Trying to get the Allen bolt out the bottom is a bitch! No problem on one fork leg but the other ones not budging. Tried compressing the fork and getting the missus to undo the bolt but the damper rod is still turning inside the tube. Going to try the broom handle next but because the forks bent I'm going to have to cut the stanchion at the bend otherwise I'd need a flexi broom which I've never heard of... thankfully managed to get the top nut/preload off the top with an impact gun so draining oil now and will go at it with an angle grinder later.

tommyardin · « **Reply #23 on:** 16 March 2018, 03:35:53 pm »

Quote from: Triggergee on 16 March 2018, 02:56:47 pm

Trying to get the Allen bolt out the bottom is a bitch! No problem on one fork leg but the other ones not budging. Tried compressing the fork and getting the missus to undo the bolt but the damper rod is still turning inside the tube. Going to try the broom handle next but because the forks bent I'm going to have to cut the stanchion at the bend otherwise I'd need a flexi broom which I've never heard of... thankfully managed to get the top nut/preload off the top with an impact gun so draining oil now and will go at it with an angle grinder later.

Hi,
It may seen a silly time to say this but I omitted to mention it in my posts, one of the fist things to do before loosening the top fork Stanchion cap nut is after you drop the wheel out and remove everything that is bolted onto the fork sliders try to undo the the plugs/allen screws which are accessed up through the bottom of the fork leg and through where the axle passes, if you still struggle you can some times get them out with a length of broom handle jammed down stanchion get this Mrs or a mate to bear down on it as you undo the bolts, another way is to get a powerful impact drill driver with the correct allen key in it and that may rattle it out.
I don't mean a hammer drill, but a proper impact battery driver, most builders will have one.
I struggled getting mine out and it is the most difficult part of the job, don't be discouraged and give up, they will come out, I spent the best part of a day removing mine, the fork spring pressure is your friend I put my forks back together for the spring pressure but still struggled. If you resort to the broom handle method sometimes cutting the end of the broom handle at a sharp angle help it bite into the Damper.

tommyardin · « **Reply #24 on:** 16 March 2018, 03:48:55 pm »

One other thing, when you put the damper rod back in after you have done the mod on them, is to wash the fork bottom legs/sliders out with petrol so they are completely clean with no oil where the damper rod sits, also make sure the damper rod bottom is free from oil this will help you do them back up tight, its always good practice to fit new alloy sealing washers on the fork damper fixing bolts as well, if they weep oil it would be a right pig to have to get them out again to replace those two washers.