Suspension upgrades advice! - Wrist Twisters
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post #1 of 82 Old 05-06-2019, 08:13 PM Thread Starter
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Suspension upgrades advice!

Hi folks,

My 2005 919, as far as I know, has never had the suspension adjusted, the fork oil changed and is fully stock. With 65k on the clock now and the likelihood that I will be using the bike as my commuter for a fair few years to come I am pondering if I can get the suspension upgraded without huge cost. I have peeked at the work required to change the fork oil and springs, and it does seem a little beyond me, or a long way beyond me...and that is after considering I have nowhere to hoist and raise the thing. The huge fear there is that yes yes! I could likely get the forks off, but then what eh? Disaster!

research suggests that simply changing the fork oil will make a great difference. Yet changing the springs also will further improve handling. And then the rear shock not will need, but will be begging (somehow) also to be worked on.

The Racetech springs seem around $200AU.
I have seen a F3 shock 98-00 model for around the same price. So that would be $400 on parts alone...already have the front fork seals.

Assume the work would take 2-3 hours at a half decent grease merchant (or am I hugely off target there?) and so all up...perhaps around $6-700.

If I am close to the quotes in the minds of others more experienced than me in such matters, the real question is would such measures make a very noticeable difference in handling, as in major improvements?

I am fine with the bike as it is, but have seen so many reports of how different the suspension upgrades feel and am thinking that this would be a better investment than for example, upgrading the danmoto cans. For handling (and maybe my back and shoulders!) should be improved by the former...

Kindly advise, and please, fel free to point me to any good deals accessible for an englishman long marooned through repeated amorous adventure here in Melbourne...

Cheers,
Daniel
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post #2 of 82 Old 05-06-2019, 11:57 PM
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Just for starters get your mechanic to just service the forks. Fork oil, seals and bushes.
I can almost guarantee that will improve your front end when you consider yours has never been done. Imagine the state the oil is in, probably filthy.
Do the rest, fork springs, rear shock, in stages. As specials come up and you've got money to spend.
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post #3 of 82 Old 05-07-2019, 05:46 PM
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Quote:
Originally Posted by thegutterpoet View Post
Hi folks,

My 2005 919, as far as I know, has never had the suspension adjusted, the fork oil changed and is fully stock. With 65k on the clock now and the likelihood that I will be using the bike as my commuter for a fair few years to come I am pondering if I can get the suspension upgraded without huge cost. I have peeked at the work required to change the fork oil and springs, and it does seem a little beyond me, or a long way beyond me...and that is after considering I have nowhere to hoist and raise the thing. The huge fear there is that yes yes! I could likely get the forks off, but then what eh? Disaster!

research suggests that simply changing the fork oil will make a great difference. Yet changing the springs also will further improve handling. And then the rear shock not will need, but will be begging (somehow) also to be worked on.

The Racetech springs seem around $200AU.
I have seen a F3 shock 98-00 model for around the same price. So that would be $400 on parts alone...already have the front fork seals.

Assume the work would take 2-3 hours at a half decent grease merchant (or am I hugely off target there?) and so all up...perhaps around $6-700.

If I am close to the quotes in the minds of others more experienced than me in such matters, the real question is would such measures make a very noticeable difference in handling, as in major improvements?

I am fine with the bike as it is, but have seen so many reports of how different the suspension upgrades feel and am thinking that this would be a better investment than for example, upgrading the danmoto cans. For handling (and maybe my back and shoulders!) should be improved by the former...

Kindly advise, and please, fel free to point me to any good deals accessible for an englishman long marooned through repeated amorous adventure here in Melbourne...

Cheers,
Daniel
"repeated amorous adventure"
Now that line is a keeper, even if I can't at all honestly claim it.

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post #4 of 82 Old 05-07-2019, 06:54 PM Thread Starter
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Ah, mcromo...I was typing in such a flurry that I neglected to add the 'mis' to adventure...which is far more accurate, unfortunately!

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post #5 of 82 Old 05-08-2019, 04:18 PM
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I just finished installing Race Tech Gold Valves in my 2007 Hornet 900 forks, as well as replacing all bushes, seals and O-rings. I can hardly explain how much better it is - just so plush. I used to feel every bump on the road surface, and hard-edged bumps would simply lock up the forks. Now I just float over the bumps, and the hard-edged stuff has become very soft and controlled.

It seems as though the Showa forks have very bad compression damping from the factory - far too much compression damping. I would 100% recommend doing the same - new seals, bushes, compression Gold Valves. It's not very difficult, but if you lack the tools and a decent, clean workspace, just have it done by a suspension specialist. It's a pretty standard job for a suspension shop, so call around and ask for quotes.

If you're anything over around 70kg, you would also benefit from replacing the fork springs with heavier ones. This is also routine work for a suspension shop. You can find the appropriate spring rate using Race Tech's product search on their website.

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post #6 of 82 Old 07-09-2019, 08:53 PM Thread Starter
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I think, with the tax return anticipated, that I can stretch to get some new springs with the seals and oil change. I will already be paying the grease merchant for the labour to get them off and change the oil, so will assume that it won't be that much more labour to get the springs replaced as part of the same job? And this is what I am seeking:

https://www.solomotoparts.com/Race-T...s-CB919-02-07/

yet what type>?

Advice welcome and appreciated as always!

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post #7 of 82 Old 07-09-2019, 09:55 PM
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Quote:
Originally Posted by thegutterpoet View Post
I think, with the tax return anticipated, that I can stretch to get some new springs with the seals and oil change. I will already be paying the grease merchant for the labour to get them off and change the oil, so will assume that it won't be that much more labour to get the springs replaced as part of the same job? And this is what I am seeking:

https://www.solomotoparts.com/Race-T...s-CB919-02-07/

yet what type>?

Advice welcome and appreciated as always!
IDK if it matters but those are for the 2002~2004 forks. Might want to double check things. IIRC, someone suggested non-progressive springs for the 919, I'm sure someone will chime in. Last thing you want to do is buy the wrong ones.

I'm looking forward to doing the same upgrades, maybe this year.

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post #8 of 82 Old 07-09-2019, 10:18 PM Thread Starter
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IDK if it matters but those are for the 2002~2004 forks. Might want to double check things. IIRC, someone suggested non-progressive springs for the 919, I'm sure someone will chime in. Last thing you want to do is buy the wrong ones.

I'm looking forward to doing the same upgrades, maybe this year.
I have an 05 model...and the description and 'fits' section include the 05 model on that page...?

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post #9 of 82 Old 07-10-2019, 01:48 AM
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Gutter those springs will fit your forks. No worries.
I've got the exact springs, weight and brand, fitted to my forks.
Along with new oil don't forget seals and bushes.

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post #10 of 82 Old 07-10-2019, 03:24 AM
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Quote:
Originally Posted by thegutterpoet View Post
I have an 05 model...and the description and 'fits' section include the 05 model on that page...?
Oooops... there was a "more" button on that page that I didn't see. It listed 3 years, then had "more" and then it lists the other years.

Good to be sure.

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post #11 of 82 Old 07-10-2019, 03:32 AM
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Just wondering, which gold valve kit did you get. I noticed they have 3 different setups, 1 rebound and 2 others. I didn't know there were different gold valve kits.

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post #12 of 82 Old 07-10-2019, 12:03 PM
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Quote:
Originally Posted by KarlJay View Post
Just wondering, which gold valve kit did you get. I noticed they have 3 different setups, 1 rebound and 2 others. I didn't know there were different gold valve kits.
The more expensive Compression Kit is a later development, and designed for more complex shimming arrangements oriented to track use.

The HFR Rebound kit used to be sold as "do not use on street, for racing only".
I see they now say OK to use on street.
Again, a later development, and designed for more complex shimming arrangements oriented to track use.

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post #13 of 82 Old 07-10-2019, 04:28 PM
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KarlJay, I have the "Race Tech Type 1 Gold Valve Fork Kit # FMGV S2040". This is the basic Gold Valve compression kit, which comes with a one-time access code for Race Tech's online shim stack calculator. The calculator seems to have been spot-on, in my case. The forks feel amazing now, and I feel no need to mess with them any further. Perfect for the rough public roads in my area.

The other compression kit, G2R valves, is for advanced users, as mcromo44 said. I believe they come with a differently shaped piston that allows you to set preload on the shims, so you can create a digressive damping curve.
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post #14 of 82 Old 07-10-2019, 04:51 PM Thread Starter
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Gutter those springs will fit your forks. No worries.
I've got the exact springs, weight and brand, fitted to my forks.
Along with new oil don't forget seals and bushes.
Already have the seals, comrade...will get the springs. Assume the mechanic will have the right oil. Should I also get the bushes before hand? I will peek now...

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post #15 of 82 Old 07-10-2019, 05:09 PM
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The bushings you might get away with but only if intend on servicing your forks again and regular. Bushes are an item that wear and have an allowance of wear.
When I replaced the springs in my forks I also replaced the bushings. I could've reused them since they didn't show too much wear but I figured I wouldn't break the forks down again for a while.
They are cheap enough to replace while the forks are being worked on.
Might pay to ask your mechanic exactly what fork oil he intends on using. Just so you know.

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post #16 of 82 Old 07-10-2019, 05:29 PM Thread Starter
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I'll have a chat with the Balkan beast...though I have more instinctive trust in him that anywhere else I have been in Melbourne. Plenty are true swine.
Peter Stevens...installed rear brake pads the wrong way round, metal on metal.
Gassit motorcycles...carb sync led to horrid revving on idle. took it back to get checked again, the mechanic didnt realise his pal had worked on it the week before and told me 'whoever did this was a cowboy...' then suggested it was the carb manifold. No improvement. Left those pricks telling me I was lucky it was still running at all. pure scum.
Yamaha City...one of their chum insurance assessors deemed by bike a write-off with only damage to one fairing, then called me 'as a mate' to offer me a dirt cheap price for another friend to buy the bike from me.
recently tried a new chap in Coburg, who was a little pricier than expected for the PC III install and left the wires hanging out the front after removing the heated throttle grips.
Bike Dock seemed decent enough, but have moved away now.
felt skanked by a local crowd who gave the 919 a sound check, including valve check, all fluids, general condition, then ripped the thing apart when I took it for a RWC.

best chaps I have come across were a comrade from the motherland Pete...Everything2wheels. To the point, up front, superb work.

Also found this brilliant fiend in Sunshine - WestSide Motorcycles - straight talking, loves his craft, well priced, feels like I am talking to noble spirit with magic greasy hands. Its just a little out the way...worth the trip though.

My luck with mechanics in Melbourne has been appalling. In 15 years riding back home in England, never had any issues whatsoever...probably more checks in place.

This what I need, mate?:>
https://www.ebay.com/itm/ALL-BALLS-F...IAAOSwRLZUIuYS

And...what oil should I ask for, or should be seeking! With my normal riding rather rugged and all urban?

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post #17 of 82 Old 07-10-2019, 06:31 PM
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Personally I would only use OEM seals and bushes. Usually order them from Partzilla. I just wouldn't trust All Balls stuff as I've read it's shit.
The fork oil I used was Maxima 10w.
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post #18 of 82 Old 07-10-2019, 06:49 PM
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Damn... Makes me glad I have the means to do my own mechanical work.

Pro Honda SS-8 (10W) is the original spec oil in the Hornet 900 workshop manual. If you can't find that, Motul's Expert 'Medium' 10W Fork Oil is almost exactly the same viscosity. Motul stuff is pretty widely available here in Aus, too.

However, unless you're very heavy, I think it might be better to go with a lighter oil, as the consensus online seems to be that the 900's forks are over-damped and under-sprung from factory. Motul's Factory Line Light/Medium 7.5W looks like a good choice if you want to try softening up the damping for a more plush ride. Interested to hear the views of others on this.

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post #19 of 82 Old 07-10-2019, 07:00 PM
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I'd be down for giving that Motul 7.5W a go next time I service my forks.

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post #20 of 82 Old 07-10-2019, 09:50 PM
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So when you setup the shim stack, do you get a bunch of shims to pick from and then use their software to determine which ones to use or do they send you a stack based on what you input into the software?

Seems like your stack should work for anyone else that is riding on the street and similar body weight. Is there any reason others here wouldn't just use all the same shim stack?

On the bushings, are those pressed in or is this an "at home" job someone can do?

I didn't do mine last time, but I was planning on doing the seals/oil again, maybe this year.

I wonder if going from 10wt to 7.5wt would change the effect of the stack by much.

[EDIT] one other thought, if the valve kit that is more advanced can be setup for street use, wouldn't that be the best overall choice because it would offer the most options for fine tuning the forks?

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post #21 of 82 Old 07-10-2019, 10:45 PM
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Quote:
So when you setup the shim stack, do you get a bunch of shims to pick from and then use their software to determine which ones to use or do they send you a stack based on what you input into the software?
You just get a big bag of shims with the kit, and only use whatever the calculator says.

Quote:
Seems like your stack should work for anyone else that is riding on the street and similar body weight. Is there any reason others here wouldn't just use all the same shim stack?
The kit comes with a new, higher flow piston, which has larger ports than the stock item. The piston ports are obviously a fixed size orifice, so they can't be tuned, unlike the shim stack, which is highly configurable with different combinations of shims. One of the selling points of the kit is that the new piston's ports, being larger, play a lesser role in producing your damping force, and the shim stack plays a relatively larger role, compared to the stock config. So it has a broader scope for tuning. I guess the G2R kit has a wider tuning scope on top of that. So yeah, it's really just the piston that's different.

I had a look at the factory Showa piston and it does indeed have pretty small ports. However, I'd be interested to see what happens if someone used a similar shim stack on a factory piston. I would guess that it would be better with some shims removed, to compensate for the more restrictive piston. Or maybe you could just drill the ports out to get a similar flow rate?

I have also heard of people using factory pistons from other forks which have larger ports, like the Bandit 1200, from memory. It's just a 20mm diameter piston. I can measure the stock piston, and/or post the shim stack configurations, if anyone is interested.

Quote:
On the bushings, are those pressed in or is this an "at home" job someone can do?
The slide bushings are split down the side, so you just expand them with a screwdriver (or preferably something that wont scratch your fork tubes) and slide them off the tube. Easiest part of the job.

Quote:
one other thought, if the valve kit that is more advanced can be setup for street use, wouldn't that be the best overall choice because it would offer the most options for fine tuning the forks?
I'm not sure if you get any help with the configuration of the advanced kit. They might expect you to be an expert with a shock dyno and all the other means of tuning them yourself. Maybe you would just use the exact same stack, I'm not sure. You would have to ask Race Tech themselves. But I can fully recommend the standard kit. I've never done any sort of revalving before, but I was able to get the result I wanted.

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post #22 of 82 Old 07-11-2019, 12:00 AM
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You just get a big bag of shims with the kit, and only use whatever the calculator says.



The kit comes with a new, higher flow piston, which has larger ports than the stock item. The piston ports are obviously a fixed size orifice, so they can't be tuned, unlike the shim stack, which is highly configurable with different combinations of shims. One of the selling points of the kit is that the new piston's ports, being larger, play a lesser role in producing your damping force, and the shim stack plays a relatively larger role, compared to the stock config. So it has a broader scope for tuning. I guess the G2R kit has a wider tuning scope on top of that. So yeah, it's really just the piston that's different.

I had a look at the factory Showa piston and it does indeed have pretty small ports. However, I'd be interested to see what happens if someone used a similar shim stack on a factory piston. I would guess that it would be better with some shims removed, to compensate for the more restrictive piston. Or maybe you could just drill the ports out to get a similar flow rate?

I have also heard of people using factory pistons from other forks which have larger ports, like the Bandit 1200, from memory. It's just a 20mm diameter piston. I can measure the stock piston, and/or post the shim stack configurations, if anyone is interested.



The slide bushings are split down the side, so you just expand them with a screwdriver (or preferably something that wont scratch your fork tubes) and slide them off the tube. Easiest part of the job.



I'm not sure if you get any help with the configuration of the advanced kit. They might expect you to be an expert with a shock dyno and all the other means of tuning them yourself. Maybe you would just use the exact same stack, I'm not sure. You would have to ask Race Tech themselves. But I can fully recommend the standard kit. I've never done any sort of revalving before, but I was able to get the result I wanted.
I remember some time back when someone said they drilled the piston and reworked the stack. I don't remember if it was the 919 or the old 700S that I was into before, but it was a cheap way to improve the performance.

Overall, the kit doesn't seem very expensive.

BTW, what's the difference between these kits and the cartridge emulator kits?

IIRC, someone mentioned the lack of low speed rebound as a key thing missing in our forks, is this covered in either of these kits?

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post #23 of 82 Old 07-11-2019, 12:38 AM
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I remember some time back when someone said they drilled the piston and reworked the stack. I don't remember if it was the 919 or the old 700S that I was into before, but it was a cheap way to improve the performance.
That's interesting, I can't see why it wouldn't work.

Quote:
BTW, what's the difference between these kits and the cartridge emulator kits?
I was confused about that too but it turns out they're both very different products. The cartridge emulators are made for damping rod type forks, which are totally different internally. Cheaper bikes like the SV650 and Ninja 250 have damping rod forks, and they are pretty average. Damping rod forks produce their damping force from simple fixed-size orifices, so they are not really tunable. You can change the damping oil viscosity, but then you are changing both compression and rebound at once. The cartridge emulators are added into the forks to add control of compression damping, and to make it more plush, in a way that wasn't previously possible.

The 919 and most higher-spec road bikes have cartridge type forks, i.e. with a shim stack for compression, and another shim stack for rebound. So the "Gold Valve" kits for these bikes just replace the existing pistons and shims in the forks with new items with slightly different dimensions, and in a configuration specific to your weight and riding style.

I think Race Tech were silly to give them both the same name.

Quote:
IIRC, someone mentioned the lack of low speed rebound as a key thing missing in our forks, is this covered in either of these kits?
There is a "Rebound Gold Valve" kit available, but I'm not sure what difference it would make. My rebound damping is stock and I have no issue with it. The main problem I had was with excessive high-speed compression damping, making the forks really harsh on hard bumps.

Btw, there's a cheap method of tuning that is popular with the VTR1000 crowd, called "Rogering" the forks. I believe the VTR1000F forks are nearly the same as the 919's. Part of that mod is to change the profile of the rebound adjustment needle, which comes with a step. Grinding the step off the needle supposedly adds more fine control of rebound damping.

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post #24 of 82 Old 07-11-2019, 07:36 AM
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I remember some time back when someone said they drilled the piston and reworked the stack. I don't remember if it was the 919 or the old 700S that I was into before, but it was a cheap way to improve the performance.

Overall, the kit doesn't seem very expensive.

BTW, what's the difference between these kits and the cartridge emulator kits?

IIRC, someone mentioned the lack of low speed rebound as a key thing missing in our forks, is this covered in either of these kits?
2004 and later forks have low speed rebound adjustment by virtue of the screw up at the top of the forks.

All 919 forks have relatively poor low speed compression characteristics, and no adjustment capability.
The solution for that is to drill a bleed port into the side of the piston.
This provides a non adjustable low speed compression effect.
Too small a hole results in little to no improvement.
Too big a hole means losing all low speed compression damping effect.

Years ago, zach123 brought this all to the table, and posted a diagram using reference material from Racetech.
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post #25 of 82 Old 07-11-2019, 07:51 AM
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KarlJay,

See the last post in Rebuilt F3 Shock.

Also see the Drop Box using path 919/Suspension & Chassis/ Front Ends/Racetech re zach123's work of many years ago as later updated with some newer info I found on the Racetech website.
Re low speed compression bleed port drilling.

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post #26 of 82 Old 07-15-2019, 08:36 PM Thread Starter
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Found my bushings...have the seals and so now the racetech springs...what Type seems for the best?

I am 5ft9 and around 10 stone - 66kg-ish I believe - can weight myself this evening on the fancy glass gadget my new housemate has delivered to the bathroom. I wear a heavy-ish Dririder adventure jacket during the winter and boots always, and lightweight dririder air jacket in the spring/ summer/ autumn. My riding is mainly fairly aggressive street riding, with some trips out afar, hopefully more in the future...

The type of spring ranges from .8 to 1.2 kg/mm. Any advice?

Cheers,

D

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post #27 of 82 Old 07-15-2019, 09:05 PM
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Racetech spring rate calculator.
https://racetech.com/ProductSearch/1...CB900F/2004-07
Put in your weight.
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post #28 of 82 Old 07-15-2019, 09:39 PM
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Any advice?
Don't go too high. Forks are already harsh enough without adding "oversprung" into the bargain.
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post #29 of 82 Old 07-15-2019, 09:50 PM Thread Starter
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Racetech spring rate calculator.
https://racetech.com/ProductSearch/1...CB900F/2004-07
Put in your weight.
0.87 kg/mm

better to go for the .9 or .85!???

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post #30 of 82 Old 07-15-2019, 10:10 PM
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Go low.

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post #31 of 82 Old 07-16-2019, 01:11 AM
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I went with .95's and they were too much, no compliance over bumps at speed, very harsh feeling, even though they "bounced" well when held stationary with the front brake. And I weigh 20kg more than you...

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post #32 of 82 Old 07-16-2019, 02:23 AM
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I'm around 90kg and went with .85. Very happy.

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post #33 of 82 Old 07-16-2019, 03:46 AM
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Originally Posted by Islandboy View Post
I'm around 90kg and went with .85. Very happy.
Yeah, I should have done the same..

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post #34 of 82 Old 07-16-2019, 07:49 AM
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I went with .95's and they were too much, no compliance over bumps at speed, very harsh feeling, even though they "bounced" well when held stationary with the front brake. And I weigh 20kg more than you...
I'm curious as to how much installed preload you went with.
Do you still have that info handy?

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post #35 of 82 Old 07-16-2019, 07:59 AM
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Originally Posted by thegutterpoet View Post
0.87 kg/mm

better to go for the .9 or .85!???
Paying attention to both Islandboy's and K1w1Boy's posts, the fact you are on a mush rear spring 04+, allowing for you are relatively light, keeping in mind the assumed road qualities you encounter, and you are not a track day rider at pace, then I suggest .085s or 0.875s and no higher.
Plus make sure the installed preload determination is done correctly and it's no more than 15 mm.
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post #36 of 82 Old 07-16-2019, 11:21 AM
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I'm curious as to how much installed preload you went with.
Do you still have that info handy?
I don't, sorry, and the forks are gone now.

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post #37 of 82 Old 07-16-2019, 12:14 PM
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I don't, sorry, and the forks are gone now.
Thanks for answering.

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post #38 of 82 Old 07-16-2019, 03:41 PM Thread Starter
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A little heavier than I thought...at 69kg...which comes out the mincer as .88!

Still, the advice here seems to aim for the .85?...my riding is mainly urban, the style of which I would call...spirited!

Never really been too bothered by the bumpiness yet eager to treat myself to an upgrade and with 15 years absent of fork oil and spring change (seals and bushings also) I hope that as many say, I will feel the difference...

Keen to order!

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post #39 of 82 Old 07-16-2019, 05:46 PM Thread Starter
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And I will ask for 10W fork oil, from what I gather above, this seems for the best? $20 for some Motul expert 10W medium just up the road.

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post #40 of 82 Old 07-16-2019, 06:52 PM
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And I will ask for 10W fork oil, from what I gather above, this seems for the best? $20 for some Motul expert 10W medium just up the road.
Go for it.

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