Bouncy ride - would new springs help?

[bat-kam]

I know that this has been discussed several time but I am struggling to find it on the forum.

Recently I have noticed that when going around the corner or a roundabout the front end of the bike jumps when going over an uneven surface. This is very unsettling as it makes the bike to stand upright or jump and unsettle me enough to slow right down.
So I was thinking of upgrading the springs front and back to Hyperpro. Would this cure the issue? Are those springs any good? What oil should I use for the forks? 5 or 10 or 15W?

Thanks for the advise in advance
Kam


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[Sid Squid]

The standard SV springs aren't known for being heavy, whether they're right for you depends on, primarily, your weight. If the suspension is 'bouncy' this usually signifies a lack of damping - how many miles has the fork oil done?

[21QUEST]

The standard SV springs aren't known for being heavy, whether they're right for you depends on, primarily, your weight. If the suspension is 'bouncy' this usually signifies a lack of damping - how many miles has the fork oil done?
Glad you answered before someone weighed in with "springs on the SV are utter rubbish....you need the latest titanium springs matched to a GSXR front end and brembo brakes..." :p ;)

[Sid Squid]

Glad you answered before someone weighed in with "springs on the SV are utter rubbish....you need the latest titanium springs matched to a GSXR front end and brembo brakes..." :p ;)
Well, all I can say in my defence is that I actually do know a little bit about them there motorbicycles :D.

[bat-kam]

The bike has done 25k miles and I wouldn't think that the fork oil have been changed. I am 14stone including gear.


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[Biker Biggles]

You dont say how old the oil is but if its a few years then you will benefit from new oil.The stuff in there is probably like water with some smelly emulsion.

[bat-kam]

Oh, sorry. The bike is 4 years old.
Any recommendations regarding oil?
Maybe rookie question but while changing oil should I replace the seals too? If so what make should i go for? My budget is limited as the newborn has joined our family ;)


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[yorkie_chris]

I wouldn't bother with hyperpro springs, get some Ktech linears instead. Not much in it price wise. Get 0.9 springs and some silkolene RSF10.

If the seals are still sealed, leave them alone.

Don't bother with the rear spring, the damper can't handle the stock spring so putting a heavier one on will make it worse.

[bat-kam]

I am not sure that I have found springs that you were talking about. On their website the one I could find were 9.0N rather than 0.9.
http://www.k-tech.uk.com/product_detail.php?id=2228
Are those the right ones?


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[MJC-DEV]

Yes, there the right ones, same number different units 0.9Kg = 9N. I also use the Silkolene RSF Pro 10W. Very good oil.

[bat-kam]

That's good. I will make the buy and report once new springs will be in.

How much oil did you put in in each leg?


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[wideguy]

Oil capacity depends on the year and model. Somewhere just over a pint per side.
I've been using synthetic multi-viscosity motor oil in all my forks for over 20 years. It works great, is very slippery, extremely durable and resists fade with hard use. Also cheaper than motorcycle fork specific oil.
What viscosity depends on how you want the damping. More viscous will give more damping. Stock for my '00 is 10w. Don't know if the newer models are the same. Probably.

[yorkie_chris]

I am not sure that I have found springs that you were talking about. On their website the one I could find were 9.0N rather than 0.9.
http://www.k-tech.uk.com/product_detail.php?id=2228
Are those the right ones?


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0.9kg/mm = 0.917N/mm

For oil level you don't measure volume, measure oil height with leg fully compressed without spring fitted.

Stock is 110 or so, usually I like a bit less oil, gap of 120mm or so. Personal preference to an extent and millimeter precision is not going to cause you to die in a fireball here!

[wideguy]

I pour in the recommended volume, then check the height.
Suspension guys sometimes recommend adding more oil, for instance where you like the damping action, but are having bottoming problems, or less, if you like the damping action but aren't using all the travel.
Well, I see you ARE a suspension guy Chris...

[bat-kam]

Springs and oil bought. Once received I will give it a go in changing them on my own. Will I be able to do it without proper work bench and vice?


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[yorkie_chris]

Yes just think ahead before you plow in ;)

Crack the caps off before undoing bottom yoke bolts.

[dkid]

Springs and oil bought. Once received I will give it a go in changing them on my own. Will I be able to do it without proper work bench and vice?


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This video will give you the rough idea link (http://www.youtube.com/watch?v=Cj-cb12BCRw)
How are you going to support the front end?

[bat-kam]

Thanks, that is very nice video.

I haven't think of the way of supporting the bike yet. I have the front and rear paddock stands but the front will be in no use as the forks would be resting on it.
Any home grown ideas?


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[dkid]

There are a few methods. Headstock stand is a good investment as is an abba stand. You could sell your paddock stands...
http://forums.sv650.org/picture.php?albumid=921&pictureid=7048

Otherwise, Ratchet straps over a strong roof timber and under the top yoke works ok when a rear paddock stand is also used. Some have used a car jack under the engine but I can't testify to the effectivness of that one.

I now have a front headstock stand but before I had it I opted for the ratchet strap method with a jack just to help steady
http://forums.sv650.org/picture.php?albumid=934&pictureid=6374

[MJC-DEV]

Folded Black and Decker work mate and a bit of wood under the engine also works well but you'll need two people. One to lift rear, one to shove wood under.

[bat-kam]

Was just thinking if it would be a good idea to change the seals at the same time?
The issues that I can see are undoing the bolts at the bottom of the forks that hold the insides in place and the 'PCV tube' or something else to use to push the oil seal in place
Again, i have no vice to hand :(


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[dkid]

I

If the seals are still sealed, leave them alone.



This

[TamSV]

Was just thinking if it would be a good idea to change the seals at the same time?

As has been said, if they're not leaking then there's no point in changing the seals.

It's worth mentioning that you'll be compressing the fork fully so make sure there's no rust spots etc on the top part of the fork. Otherwise you could damage the seals when you compress the fork and then you will need to change them.

The issues that I can see are undoing the bolts at the bottom of the forks that hold the insides in place and the 'PCV tube' or something else to use to push the oil seal in place
Again, i have no vice to hand :(

You don't need to undo the damper rod bolt at the bottom of the forks unless you're fully dismantling them to change bushes or seals - as discussed you don't need to do that. :)

You don't need a vice either.

Basically, get the bike supported on your rear stand and get the front end in the air - either with a headstock stand, jack under the motor, or one of the range of heath robinson lash ups that'll do the same job.

Remove brake calipers and tie them up out the way. Remove front wheel and mudguard. Loosen top yoke pinch bolts (the ones on the sides of the yoke). Crack the top nuts on each fork leg - just to loosen them off rather than remove them.

Then loosen the bottom yoke pinch bolts and slide out the forks.

Take the top cap off each fork, remove the spacer, washer and spring, and tip out the old oil. Pump the forks and leave them upside down for a bit to make sure it all comes out.

Turn the fork up the right way and fully compress it. Fill with oil, stroke the fork in and out a couple dozen times or so to remove air, top up oil to the specified height, extend the fork and put the spring/washer/spacer back in. Pop the top cap back on and tighten it by hand.

Put the forks back on the bike, nip up the bottom yoke pinch bolts. This holds the fork while you torque up the top cap properly. Then refit wheel/tighten everything up properly etc.

Get yourself a manual and follow it. The manual has to include everything so it will show full disassembly of the forks but, as described above, you can ignore that. It'll also tell you how to take apart the top cap/preload adjuster. You don't need to do that either.

HTH.

[bat-kam]

And I was able to do the change last weekend. It took me just under 4 hours, so not bad.
I had few issues:
I was missing alan key no 12 - quick trip to b&q
The dome bolt on left hand side holding the mud guard was totally locked. So i had to drill it out.

The rest went OK

I was surprised when I saw the colour of the fork oil. The left leg had white/clear water and the right one had white/salmon pink slush.

Another surprise were the springs. They didn't look like the standard suzuki ones. They were progressive but didn't look like the Hyperpro and they were in the forks with tighter coils at the bottom of the forks. Was that correct? Does anyone know what make they are? On the inside of the bottom forks there were Showa stickers.

http://img.tapatalk.com/d/13/07/10/tuquhy4e.jpg

I put the new springs and added oil up to the 120mm from the top of the forks. The difference in ride is very noticeable. Lest bouncy and more feel from the front. Now I started to feel that the rear of the bike jumps ;)

The way I secured the bike was the rear paddock stand and ratchet straps over the roof beam and under the tope yoke

http://img.tapatalk.com/d/13/07/10/pa9u3ydy.jpg
http://img.tapatalk.com/d/13/07/10/bega9yva.jpg

Like most of you said it would be easy job and it was

Many thanks for all the advise

Kam