Basic Suspension Tech

Wondering if this has been addressed yet.

I have not messed with mine and have not looked at what the PO has it set at. I plan to fiddle some tonight after I get the VFR running to possibly sell.

All I know is it rides ROUGH. I am 6', 175 pounds and on trips load my bike with 40# of junk I'd guess. Any passenger on there will be my girl and she's all of 115#. Mainly concerned with day to day riding. Anyone know where theirs is set up F/R?

For now, let's leave it with stock components. I may add Progressive front springs as it helped my KLR out a lot. For now I just want to adjust what is there. I don't feel this bike is worthy of emulators and high dollar shocks.

First thing you need to do is count how many clicks you are now from softest to hardest. Write it down then start making adjustments.

IIRC the front is set up in the middle and the rear looked to be on the stiffest, and I can feel it. I was loaded down and didn't want to unload to get to the spanner wrench.

I found the front too harsh - it was kicking off bumps too hard. Reducing the preload from line 3 (factory ssetting) to line 4 sorted this completely under all load conditions. I weigh about 150lbs plus kit.

At the back I have preload on 6 (out of 7) with the rebound a half to a quarter turn off max for two-up touring with luggage (panniers and top box, all heavily loaded). This works so well I can hardly tell I've got all the extra weight.

With pillion but no luggage I have preload set to 5 and rebound a turn and a half off max.

Ridden solo I'd ideally have preload on 4 (factory setting) but as I ride two-up most of the time I just keep it on 5 when I ride solo because it's not the easiest thing to adjust. Pity Suzuki didn't think to fit a remote-adjust preload knob.

Thanks Sproggy, I have yet to mess with this yet. Been doing house work and getting the VFR sold and riding it for the last time

I think the rear is maxed out. It doesn't move a bit when I sit on it. I will try 4 and 4 and the preload a turn out from max since it's just me and when loaded I travel pretty light.

set the front at 4 and the rear at 2 with the preload out 2 turns!! I have yet to ride....more snow and I have a new Shinko 009 rear to put on. Burn out in the garage tonight.

Sounds like you are making some progress. If you haven't asked or checked on this board http://www.vfrdiscussion.com/forum/index.php?act=idx
you should.

bones said:

set the front at 4 and the rear at 2 with the preload out 2 turns!!

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Errr...... it's the rebound adjustment that's measured in turns in/out (the screw at the bottom of the shock), not preload.

Unless you weigh as much as an 8 year old (or the average Japanese rider....) you'll likely find a preload setting of 2 at the back is far too soft, unless you're quoting clicks off maximum in which your 2 is everyone else's 5 Factory setting is 3 for the 1250 and 4 for the 1250S and I reckon few people would want to go lower than this - it would make the back of the bike sit low and slow the steering.

I settled the preload at the front to the most soft and at the rear in position 2.

I weigh 74 kg and I ride alone.
With the values of preload advised by Suzuki, with high speed, the motorcycle jump too much on the roads that I use.

These roads are very damaged and with a suspension setting too hard there is a significant risk of loss the grip.

RDKR 350

RDKR 350 said:

I settled the preload at the front to the most soft and at the rear in position 2.

I weigh 74 kg and I ride alone.
With the values of preload advised by Suzuki, with high speed, the motorcycle jump too much on the roads that I use.

These roads are very damaged and with a suspension setting too hard there is a significant risk of loss the grip.

RDKR 350

Click to expand...

Sounds like we are at similar setups and weight. Not to mention the road conditions seem identical.

RDKR 350 said:

With the values of preload advised by Suzuki, with high speed, the motorcycle jump too much on the roads that I use.

These roads are very damaged and with a suspension setting too hard there is a significant risk of loss the grip.

Click to expand...

I think it's probably safe to say that Suzuki didn't intend the Bandit for high speed riding on badly damaged roads. Reduce the preload too much under those conditions and keep riding fast and there's a chance you'll bottom out the suspension and then you can talk about significant risk of loss of grip!

I probably shouldn't say this here, but maybe you should either slow down or buy something with more suspension travel designed for the kind of roads you're riding (BMW GS, for example).........

Bumpy roads don't always mean dual sport roads. Our roads here are riddled with pot holes and massive expansion gaps from freeze/thaw. Anything too stiff and it is hard on your body.

OK Bones and Sproggy
On this subject, there was no single way.

I believe that the choice of a suspentions setting is a matter of personal feelings.

We must feel good for ride with the greatest possible security.

My previous bike was a 1000 Yamaha FZ1 and suspentions were very flexible.
This gave, in my view, excellent sensations on the roads in our hills.



The BMW 1200 GS is actually a very good machine on the roads.
But I prefer the 12.5 Suzuki.
So I have to adapt it to better depending on the purpose and my driving style.

RDKR 350

Suspension will work correctly and safely only within its design parameters. Preload should be set to give the correct amount of static sag and, although there is some leeway to allow for the personal feelings that you mention, since we're all around 75kg we should have our preload set about the same.

If the preload is set too soft/low then too much of the suspension's travel will be 'used up' by the weight of the bike and rider, leaving less available travel to deal with road conditions. So low preload may make the bike ride more comfortably but you should be careful that on the badly damaged roads you ride on you don't run out of travel becasue that's far worse than having a choppy ride.

I'm not saying you shouldn't run with low preload because ultimately it is down to personal choice - just pointing out that suspension isn't just about comfort and suggesting that you consider the consequences of running considerably more static sag than is generally recommended by suspension designers and experts.

Incidentally the Fazer 1000 is well known for having soft suspension as standard but it was designed that way (for reasons best known to Yamaha....) - the Bandit 1250 is designed to run stiffer so it's bound to be harsher on damaged surfaces than the Fazer.

Thank you for your response Sproggy.

To determine the adjustment of suspensions, I made three steps at the front and rear.
Step 1: wheel off from the ground, fulltravel .
Step 2: wheel on the ground with the weight of the motorcycle single.
Step 3: wheel on the ground with the weight of the bike and my weight with my motorcycle clothes.

At the front, for a travel of 130 mm, measuring 1 must be equal to 33/38 mm and measuring 2 equal to 43/48mm.

At the rear, for a travel of 136 mm, measuring 1 must be equal to 12/17 mm and measuring 2 equal to 32/37 mm.

Compared to the theory (German magasine "Motorrad" 16.02.2007), at the front the spring is right. But the rear spring is a little too hard.

RDKR 350

The reason for the Bandit's harsh ride is because the suspension has too much compression damping. The only way to improve it is to alter the valving in the suspension. Since the rear shock is not servicable then it must be replaced. The front fork can be modified by installing a product such as Racetech's Goldvalve. I recently added one to mine, along with heavier fork springs and now have a much smoother ride.

What's involved in installing Racetechs? I am thinking progressing front springs will be a purchase in the very near future.

For the sake of completeness, the temperature in winter and in the beginning of spring requires soft suspentions and lower pressure in the tires.

But it is true that I will probably buy an more flexible and adjustable rear shock.

RDKR 350

bones said:

What's involved in installing Racetechs? I am thinking progressing front springs will be a purchase in the very near future.

Click to expand...

It requires complete disassembly of the fork. If you've never had forks or shocks apart it can be quite a job. Racetech's instructions are somewhat lacking and even incorrect regarding oil weight. I suggest contacting Cogent Dynamics Motorsport www.motocd.com . They have several options for the Bandit suspension and are getting rave reviews from owners. They also have excellent customer service. If you're determined to do it yourself, buy the kit and I'll be happy to answer specific questions.

AXEL said:

It requires complete disassembly of the fork. If you've never had forks or shocks apart it can be quite a job. Racetech's instructions are somewhat lacking and even incorrect regarding oil weight. I suggest contacting Cogent Dynamics Motorsport www.motocd.com . They have several options for the Bandit suspension and are getting rave reviews from owners. They also have excellent customer service. If you're determined to do it yourself, buy the kit and I'll be happy to answer specific questions.

Click to expand...

Thanks, I think my $$ will get spent on a few other items first, but maybe the next winter down time I will consider these if I am still lacking what I think it should ride like.

I pretty much left everything stock for the first 1000 miles to get a good feel for the bike. I also felt it was just a little harsh on the ride. I moved both the front and rear preloads 1 click softer. In the owner's manual it's on page 3-22. I weigh 185 and ride solo, generally w/o much strapped to the back. Moving the adjustments 1 click made a very small, but noticable change for the better. One tip, put the bike on the center stand and have someone on the back to raise the front wheel when you do the front. The screw is soft and will bugger if adjusted under load. However, doing a full set up measuring static and laden sag is the best method to do it right for each bike and rider.