Front End feels like it wants to snap into a washout

[fbody_mike]

Ok, this has been occurring on the GS550E lately. I go into a turn and near the apex the front feels like it wants to snap into more of a lean which make me feel like the front tire will "wash out". During a right turn, while the bars are turned to the left, all of the sudden it feels like the bars pull themselves more to the left causing the bike to lean more and over steer. When I got this bike a few years ago, the first time I took it to the mountains I had this same feeling, but that was because the forks had nearly 40 psi of air in them! I think someone thought the 4.2 psi spec was 42. Anyway after I dropped the air pressure down that problem went away. For the last few years I have been riding around with 12 psi and happy leans.
I have checked out the normal things. Steering and wheel bearings, tire pressure. The one big change has been with me, I used to weigh 225 lbs last fall and have dropped about 50 pounds so far that I am now 175 lbs (Had a health Emergency that forced a change in life). I tried lowering the fork air to 4.2 psi, but it still behaves like this. None of my other bikes are reacting like this, but they also do not have the 16" front wheel.
Any ideas guys?

Stock suspension. Pirelli Sport Demons in stock size, 28 psi front, 40 psi rear.

 

[Big T]

Where are you getting the suggested PSI?

Front is too low
Rear is too high

 

[fbody_mike]

The tire pressure I got from the factory manual and the sticker on the frame.
The front tire is listed as 28 psi and the rear is listed as 32 psi for solo and 40 for dual. I am not sure why I picked dual, maybe the frame sticker says dual or high speed riding, I will have to check.

 

[Rich82GS750TZ]

When I put new tires on last summer, I set the psi at per the manual, let’s say it was 28 front. I found that at that pressure, the front wheel felt way too squishy and eager to dive into a corner for my taste. I upped the front to something like 32, requiring more input from me, for sure, but I’m more comfortable with a bit more than the recommended pressure.

 

[Steve]

The tire pressure I got from the factory manual and the sticker on the frame.

Those pressures were the recommended pressures for tires available at the time. :-k

Tires have changed. The pressure required depends on the construction and the maximum pressure rating of the tire. As an example, an older tire might have been rated to carry 500 pounds at 36 psi. Newer tires might require 44 psi to carry the same 500 pounds, so you can't simply go by what the sticker says.

It is common practice to use the 10% rule. Check your cold tire pressure. Record it. Go for a 50-mile ride. Check your pressure again. It should go up about 10%. If it went up more than that, the initial pressure was too low, the tire flexed too much and heated the air, raising the pressure. Conversely, if it did not go up 10%, the initial pressure was too high.

Try setting both tires to 30 psi. It's pretty close to what you might find optimal, and it's easy math.

Please also note that more pressure is required in the rear tire if you carry a passenger. That means that you will have to repeat the pressure test while carrying your passenger.

The pressure you end up using in the rear tire will depend on the frequency of rear-seat occupation. If your passenger only rides occasionally, you might add a pound or two for everyday use. If the rear seat is occupied more often, run closer to what you find necessary for the additional load.

.

 

[Rob S.]

If 40, rather than 4 psi was in the forks, can't we assume those seals are shot?

 

[Agemax]

If 40, rather than 4 psi was in the forks, can't we assume those seals are shot?

If the seals held 40psi then they must be extremely good i reckon!

 

[Buffalo Bill]

From track experience, I'd say dropping 50lb was huge and you're now feeling the difference.
Your tires are not heating up like they used to because of lesser weight.
I suggest you try lowering the pressure of both front and rear by up to 15% from the manual chart. Adjust in stages as it feels better.
The lower pressures will heat the tires quicker, and have a larger contact patch.
On track this is recommended by coaches and tire reps.

The 16" front rim replaced the 18" because they steered real quick, but soon discarded for same reason. Then replaced by 17" rims for a larger contact patch and more control.

 

[fbody_mike]

Steve, I did the 10% rule test on this bike last year, but I may need to adjust due to my mass change.

Rob, actually 40 psi is not too far outside the operable range Suzuki gives. But I had to change the fork seals last year anyway because of a leak.

Bill, the problem could be when the tires are cold because I have been noticing it on on-ramps to the freeway that have tight bends, but only during the start of the commute when things are cold, and it has been in the low 40s in my area lately.

Next step is to drop air pressure and do the 10% rule test again.

 

[Guest]

The tire pressure I got from the factory manual and the sticker on the frame.
The front tire is listed as 28 psi and the rear is listed as 32 psi for solo and 40 for dual. I am not sure why I picked dual, maybe the frame sticker says dual or high speed riding, I will have to check.

The frame sticker is for the OEM tires. I go by the sidewall markings on the new tires and use the 10% method. I usually run 34 psi in the front and 36 in the back with my Dunlops. And if your front end is stock, might be a good time to do some upgrades to it, new springs (sonic springs), new bushings, fork oil, new bearings, wheels and neck, and possibly a fork brace as well.

 

[fbody_mike]

I think I've found it. Left fork had no air. When I went to add air, I could see the fork oil bubbling from the valve. Cycled it a few times and no more leak. Right side still had the 4 psi. I will have to keep an eye on it. It looks like a standard Schrader valve, I've got plenty of new cores in my box.