Is this normal? GSF250 front suspension

[Dare]

I've noticed recently that under moderately heavy (front) braking and occasionally on ramps, etc. my bandits suspension completely compresses. Or at least feels like it is doing so, accompanied by a 'knock knock' noise and some uncomfortable sensations in the bars. Now I know 250 suspension is meant to be quite soft although I don't quite know why... But I don't want to feel like I am damaging the bike when I'm enthusiastic on the old levers. Is this something that can be fixed easily? Or maybe it's perfectly normal... :baby:

[Robert Taylor]

I've noticed recently that under moderately heavy (front) braking and occasionally on ramps, etc. my bandits suspension completely compresses. Or at least feels like it is doing so, accompanied by a 'knock knock' noise and some uncomfortable sensations in the bars. Now I know 250 suspension is meant to be quite soft although I don't quite know why... But I don't want to feel like I am damaging the bike when I'm enthusiastic on the old levers. Is this something that can be fixed easily? Or maybe it's perfectly normal... :baby:

Yes! The suspension is very much built to a price, as it is on pretty much all 250 road bikes. The trick is to fit Race Tech emulators and appropriate linear wind springing to give it ride height control, brake pitch control, square edge bump compliance, mechanical traction, better rider feel and improved tyre life.

Anyone who says you can do it with progressive springs, longer preload spacers and heavy oil are trapped in a time warp!

[Dare]

Yes! The suspension is very much built to a price, as it is on pretty much all 250 road bikes. The trick is to fit Race Tech emulators and appropriate linear wind springing to give it ride height control, brake pitch control, square edge bump compliance, mechanical traction, better rider feel and improved tyre life.

Anyone who says you can do it with progressive springs, longer preload spacers and heavy oil are trapped in a time warp!

Thanks! Sounds well expensive though... Any guess as to the price of that mod?
Maybe worth saving the craziness for a later ride... :Police:

[James Deuce]

The knocking sound is steering head bearings.

Suspension fully compressing sounds like your fork seals gave up eons ago and you have no oil in there.

I like Robert's plan but there will be those who suggest simply sorting steering head bearings and replacing fork seals an oil. Both are right. Robert is just more right, but then that is my opinion. I'm fat so my opinion is worthless.

[Dare]

Fork seals and oil were replaced about 3 months ago at Spectrum as one of the old seals was leaking... So what does bottoming out sound like then? :)

[Badjelly]

I like Robert's plan but there will be those who suggest simply sorting steering head bearings and replacing fork seals an oil. Both are right. Robert is just more right, but then that is my opinion. I'm fat so my opinion is worthless.

<meh>I agree.</meh>

[James Deuce]

Fork seals and oil were replaced about 3 months ago at Spectrum as one of the old seals was leaking... So what does bottoming out sound like then? :)
At the risk of getting my face punched in:

1. You're fat. Lose weight. Even I don't bottom forks on a GSF250. I had one to thrash for a few days a couple of years ago when the Zed was off the road.
2. Spectrum made a genuine mistake and some other bloke with a Bandit 250 has fresh fork seals and oil that he's blissfully unaware of.

[James Deuce]

<meh>I agree.</meh>
You'll keep.

[Robert Taylor]

The knocking sound is steering head bearings.

Suspension fully compressing sounds like your fork seals gave up eons ago and you have no oil in there.

I like Robert's plan but there will be those who suggest simply sorting steering head bearings and replacing fork seals an oil. Both are right. Robert is just more right, but then that is my opinion. I'm fat so my opinion is worthless.

No, youd need suspension upgrades even more so............

[Robert Taylor]

Thanks! Sounds well expensive though... Any guess as to the price of that mod?
Maybe worth saving the craziness for a later ride... :Police:

PM me about that otherwise it will start a dutch auction from site parasites.

[NZsarge]

Yes! The suspension is very much built to a price, as it is on pretty much all 250 road bikes. The trick is to fit Race Tech emulators and appropriate linear wind springing to give it ride height control, brake pitch control, square edge bump compliance, mechanical traction, better rider feel and improved tyre life.


Wow, was about to PM you to ask that very question, might have to beef up the springs in the ZX14...:(

[FROSTY]

Before spending a single red penny dude.
Do as JD said and check steering head bearing tension.
THEN if all is well try putting a zip tie around the fork leg just above the dust cap.
Take the bike for a ride and report back on how far up the fork leg the the zip tie has been pushed.
You may simply need the CORRECT quantity and viscosity of oil for your bike to be more than happy with the front end. -It occurred to me that spectrum may have simply fixed the mechaniual issue--blown seal in one leg and not flushed n replaced the oil in both legs.
Hey if its not bearing tension and fork oil level worst case your outa pocket $50.00

[Dare]

At the risk of getting my face punched in:

1. You're fat. Lose weight. Even I don't bottom forks on a GSF250. I had one to thrash for a few days a couple of years ago when the Zed was off the road.
2. Spectrum made a genuine mistake and some other bloke with a Bandit 250 has fresh fork seals and oil that he's blissfully unaware of.

HAHAHAHA!
1. Bro. I weigh 69kg's. :rockon:
Used to be 65 but I eat well.
But then, I do throw my weight around a bit =p
+1 for the laugh though :)

2. Pretty sure seals are fresh as the leak... stopped. But hey you never know!

FROSTY Thanks for the tip! I'll do that,
Robert I'll do as FROSTY suggests and then PM

Cheers everyone =)

[fireliv]

My bandit does not do that with its front and it stock suspension.


Would do as Frosty says first.

Good Luck!

[Pussy]

Surely the forks compressing so readily is a spring issue?

[Robert Taylor]

My bandit does not do that with its front and it stock suspension.


Would do as Frosty says first.

Good Luck!

It wont if you ride very conservatively.

[Robert Taylor]

Surely the forks compressing so readily is a spring issue?

50% attributable to spring rate 50% attributable to abysmally weak low speed compression damping, part of that function being to regulate the rate of change of position. 100% attributable to way too much high speed compression damping, manifesting itself as a very solid jolt through the bars when you ride over ( or should I say hit over ) an abrupt bump.
Its amazing that in 2009 we are still riding bikes with 1950s damping technology, that is not a slight on the said brand, they are all tarred with the same brush when it comes to low cost bikes. Given the state of the world economy and all the rubbish coming out of China that situation is not going to improve anytime soon!

[fireliv]

It wont if you ride very conservatively.

True (which I do) But my partner has been a lot more aggressive with it locking the front etc and it still doesnt have issues like that.....

[motorbyclist]

Is this something that can be fixed easily? Or maybe it's perfectly normal... :baby:


....fit Race Tech emulators and appropriate linear wind springing to give it ride height control, brake pitch control, square edge bump compliance, mechanical traction, better rider feel and improved tyre life.

Anyone who says you can do it with progressive springs, longer preload spacers and heavy oil are trapped in a time warp!

by easily do we mean cheaply?

in reverse order:

fiddle with the springs, add some spacers, and/or use a heavier oil

:innocent:

(seriously, it's a 250 so don't use megabucks. shop likely stuffed up the oil so first check it has the right stuff and quantity. failing that look at the springs and how far the front is travelling - use a cable tie as suggested - but these bikes will dive a fair bit from standard. the springs/spacers should be ok unless of course a previous japanese owner may have adjusted the suspension for thier anorexic weight and dwarfism)

[motorbyclist]

True (which I do) But my partner has been a lot more aggressive with it locking the front etc and it still doesnt have issues like that.....

locking the front, while an admirably stupid display of balls and balance, does not load the suspension as much as using the front brakes properly. all those stoppies and wheelies are why the fork seals keep blowing out and all the bearings are shot

does your partner have any troubles at all? it might just be your perception of it.... use those cable ties and get back to us with a photo & measurement

[fireliv]

locking the front, while an admirably stupid display of balls and balance, does not load the suspension as much as using the front brakes properly. all those stoppies and wheelies are why the fork seals keep blowing out and all the bearings are shot

does your partner have any troubles at all? it might just be your perception of it.... use those cable ties and get back to us with a photo & measurement

Believe it or not it was part of a course that was done with Andrew Templeton (ROADSAFE). It was to prove that you can successfully lock the front end in an emergency, and how to ride it.

[Robert Taylor]

by easily do we mean cheaply?

in reverse order:

fiddle with the springs, add some spacers, and/or use a heavier oil

:innocent:

(seriously, it's a 250 so don't use megabucks. shop likely stuffed up the oil so first check it has the right stuff and quantity. failing that look at the springs and how far the front is travelling - use a cable tie as suggested - but these bikes will dive a fair bit from standard. the springs/spacers should be ok unless of course a previous japanese owner may have adjusted the suspension for thier anorexic weight and dwarfism)

Thats a ''fix'' that is not actually a fix and is best left to the mentality of the mid 20th century. But people will choose to believe what suits their pockets. The highest percentage of the problem is attributed to abysmal low speed damping, FACT.

[mitch.ww]

My GSF250 also has extremely soft front end and is not hard to bottom out! Feels a bit sketchy on some corners.. Just wondering, after everything everyone has said so far, what did you end up doing on your bike?? And did it help??

I was just gonna check/upgrade the oil in mine as the seals are mint and dont leak at all.. Is putting a higher grade oil in gonna help at all?? I'm none too keen to spend mega bucks as it is just my learner bike and its gonna be gone soon anyway!

[Robert Taylor]

My GSF250 also has extremely soft front end and is not hard to bottom out! Feels a bit sketchy on some corners.. Just wondering, after everything everyone has said so far, what did you end up doing on your bike?? And did it help??

I was just gonna check/upgrade the oil in mine as the seals are mint and dont leak at all.. Is putting a higher grade oil in gonna help at all?? I'm none too keen to spend mega bucks as it is just my learner bike and its gonna be gone soon anyway!

Thanks for your pm. Put it this way there is a cheap fix and then there is the proper way of doing it which is way way better. I subscribe to the proper way of doing it i.e emulators and springs as per my previous post in this thread.
Those who have intimated that a cheap fix works well will likely not have experienced what is possible when you actually attack the number 1 source of the problem, very weak low speed compression damping that gives little or no pitch control, especially under brakes.
Playing with oil viscosity to ''tune'' compression damping almost always has a detrimental affect on rebound damping, if the rebound damping becomes ''lazy'' through the viscosity being too heavy then the fork action will be atrocious. Similarly, adding preload is NOT a fix, you are not changing the spring rate and you still have soft springs.
In the end event its your choice between a bodge job or a proper job.