new fork springs

First topic message reminder :

Well Ive just ordered new fork springs for both my bandit and the wifes GSX650F
Went with the racetech springs and using their online calculator worked out what I needed.
Ordered the parts from Solomotoparts and gota say very easy to deal with.
They didn't have what I was after so sent em an e-mail inquiring if they could give me a price and they put what i wanted on their list.
Total with the springs and a RK chain tool ended up being ~$400 aud shipped to my door which was cheeper than springs only locally

So the front ends will be coming apart (again) shortly and getting all new springs and oil. I may end up using 7.5w or 10w oil, I haven't decided yet.

I'll let you know how things go

dhula wrote:on the 1250 it is best to pull the forks out to get all the oil out of them.
Apart from taking the wheel and brake calipers off, I recon if you have a S model, taking the whole fairing off the bike makes it a bit easier for removing and installing the fork legs. Takes about 10 mins to do.
*Take the gauges off
*undo one plug behind the gauges and thread it out of the fairing braket (there is no need to undo the indicator or headlight connectors)
*remove the 2 screws at the side of the fairing near the tank
*remove the two bolts that hold the fairing braket onto the frame
*take the hole fairing off the bike and put in on a towel on the floor, jobs done

After tipping them upside down (after getting the spring out etc) you also have to pump (stroke) them to get all the oil out.
I found that pumping the fork and leaving it for about 15 mins got heaps more out than just draining.

You will need some kind of tool to hold the damper rod end so it doesn't disappear. from memory it can sink below the level of the fork tube which can make it harder at assembly time. I used a old hollow mop handle with a plastic end cap, drilled a hole in the plastic end cap and tightened it onto the damper rod. The special tool only needs to be about a foot long.

You need to fill the fork tube without the spring fitted. Bleeding is probably the most pain in the arse bit of it all I recon.

If you're interested I'll take some pics and do a how to thingo when I get around to doing them. Probably in about 2 weeks

Dekenai wrote:I think stock is about 0.7kg/mm

Not sure what the 1250 bandit ones are but they appear to be progressive springs.

Racetech recon the standard GSX650F are 0.78kg springs and this matches with other info I have found around the traps.

Dhula,

In the pic, you can see the threaded rod with the T-handle that I made up for pumping damper rods. Not only do you want to pump the damper rod a lot to make sure you purge all of the old oil out of the cartridges, but you also need to pump the damper rod after filling the forks with oil to make sure that they completely filled, and I always use oil level rather than volume as it takes into account any oil cling you might have on the fork internals.

I also always place my forks upside down in a pan leaning against the side of my garage and let them get good and warm sitting in the sun for a few hours which really helps all the old oil to drain out.

Hi dhula,
Well finally decided I had enough spare time to swap over the fork springs in my 650F (due to the never ending rain here in BNE at present).
Followed repair manual instructions along with the RT instructions. Measurements came up within 1mm to yours BTW. The bike has just ticked over the 9K mark and the oil coming out of the forks was pretty dark. Ok so fitted 1kg/mm RT single rate springs with Motul 10W fork oil. No other changes made. There was a short period of no rain so I jumped on the bike and went for a short ride. So much smoother. Hard to single anything out but just feels a whole lot better. Looking forward to some dry roads and a trip into the twisties to really see the difference.
Well worth the money and doing it yourself is most satisfying. Time taken was approx 4 hrs - from the first bolt off to the last one back on.

Took the bike for an hours ride around Mount Cotton in Brisbane after work today. So much more confidence with the front end. Lean angles and corner speeds are up . When going over driveway entrances it is noticeably smoother - standard springs tended to be harsh and bash through the front end. Oil used was Motul Expert 10W. Damping feels right - not that I've ridden anything else to sent a benchmark. If it feels this much better with only a spring rate change imagine with a brace and GV emulators!
If you are over 70kg's I can recommend a set of Racetech springs and a oil change. It has made such a noticable positive difference in ride quality and has given me back the grin I used to get when I first learnt to ride. Bang for your buck if [b]you[/b] do the work is excellent!

Well I've come to fit the GV emulators finally (yeh I know, I'm a slack arse).
The part number for the racetech GV's is FEGV S4101 and that is what I have on the bench however there is a slight problem.
The GV's do not fit into the damper rod cup as per the racetech fitting requirements (figure one is what is in the GSX650F) as the OD of the stepped part of the GV is larger than the ID of the cup.
I've been in contact with racetech and they have been most helpful. They agree that an adaptor needs to be made up (as per figure 2 in the requirements sheet) and suggested that
1. I use PVC pipe or conduit to make a 15mm deep spacer that fits between the GV and the damper rod, or
2. have a shop turn up an adapter.
I can see no reason for either idea not to work but ATM am undecided which way I will go. Maybe I'll try the PVC pipe first and see what I think as it's cheep and easy to make at home in my shed. If I'm not happy with it I can always go to a local fab shop and have them turn up what I want so I can finish the job (or maybe buy myself a small lathe and get some aluminum or brass stock and do it myself - Hmmmmmm,.......... Oh honey)

I'll let you know how things turn out.

dhula wrote:....or maybe buy myself a small lathe and get some aluminum or brass stock and do it myself - Hmmmmmm,.......... Oh honey)

Well you'd be doing it for her really

I've finally finished (for the time being) the install of the GV into the GSX650F forks. The ride now is very good compared to what it was. For the 4wd's out there try to compare it to the difference between a 60 series toyota and a 80 series toyota. It is stiff(ish) but very compliant at the same time without the harshness the original damping had. On my ride to work there were undulations in the road that before I would know where there, now it's (almost) "what bumps"
Problem I've found is that the back is now in need of some attention. I'm guna try to see what I can do with the standard shock.
I don't think it's as good as I can get yet so a little tuning may be required once the mrs get on and has a ride.

I've gone a little away from what racetech suggested as a failing I have is I like to tinker and build up my knowledge from my own findings, not just follow whats been done before.

This is how I've set the front end up at the moment to get what I have.
*I have used a 20 (or maybe 25)mm PVC end cap that I cut down as the spacer between the damper rod top cup and the GV. This is purely to allow the GV to sit properly and work as it should. If you have a look at figure 2 as I mentioned in my last post you will see how it looks. It does effect spacer length when setting up the springs but that's all.
*The RT instructions call for enlarging the compression holes and adding 2 more on each damper rod giving a total of 6 per rod. I've only enlarged the holes that are there at the moment so have 4 on each rod. (rebound holes stay untouched)
*The RT suggestion for the GV was to use the blue spring set at 3 turns. I've used the yellow spring (it's a higher rate than the blue spring) set to 3 turns
*The RT suggestion was to use 20w fork oil. I've used 7.5w as it's what I had in the shed. (This is some of the basis for straying from the RT suggestions the way I have.)
*I've set the oil level to 130mm as suggested by RT
*I've set the front sag to 35mm to give enough downwards travel for street use given the roads we travel are sometime rough.

All in all, like Big Kev says - I'm exited

the harder fork springs and softer compression damping make a fundamental difference to the bike - you should all put this on your 'to do' list!!

I hear ya - taking my forks to Terry Hay in a couple of weeks for the Racetech springs and Goldvalve treatment.

If past experience with other bikes is any guide it should be a transformation well worth the cost.

thats what i did

The mrs has finally had the chance to take the 650F out for a spin. 200kms in all kinds of traffic and on a fair cross section of road surfaces.
She is stoked. She recons that it's such a much better bike and it's so much more comfortable and less tiring to ride now. Like me she things the back shock now needs work or replacement to match the goodness of the front.
I am considering a fork brace for the front of both bikes but I've got to do a few enquiries to see where I can find a brace for the 650F

Steve (Potatmasher) was kind & brave enough today to swap bikes for a few km.
The new forksprings certainly changed the handling immensely, the bike drops into bends much easier, and as a result twisties can be taken much faster and tracks better ... I think I'll get the same done to my bike.

Baz wrote:Steve (Potatmasher) was kind & brave enough today to swap bikes for a few km.
The new forksprings certainly changed the handling immensely, the bike drops into bends much easier, and as a result twisties can be taken much faster and tracks better ... I think I'll get the same done to my bike.

IMO there is virtually no way to waste money on a B1250's suspension, any dollar spent will reap a big return, especially on the front end!

thats right - the difference is very evident even on a short ride. its money well spent and will give you improvements in ride steering cornering and you name it.

On the way back from the Island I rode my mate's SV650 for 100kms or so - geez the front end was planted to the ground (evident also by his cornering speed on previous days). Made my Bandit feel comparitively loose. Having ridden his machine, I'm convinced the Bandit's front end can be improved. My next mod is definitely the front suspension.

PS: his front brakes were way below the Bandit's.

My partner had on of those .I loved it,unfortunately a horse truck ran it over .Total wright off and broken colarbone.