Frankin bike GPZ900r rear suspension issues

Hey Jon
You will get it done and Im sure you will love it.
Reminder on bike weight. Lighter wheels are great but that raises the question is your diet working on sprung , or unsprung weight ?
Meaning has the sprung weight taken a significant loss ? Or is the majority on weight loss due to lighter wheels and other unsprung
Suspension and brakes ?
Just thinking out loud

Dave

Street Fighter LTD wrote: Hey Jon
You will get it done and Im sure you will love it.
Reminder on bike weight. Lighter wheels are great but that raises the question is your diet working on sprung , or unsprung weight ?
Meaning has the sprung weight taken a significant loss ? Or is the majority on weight loss due to lighter wheels and other unsprung
Suspension and brakes ?
Just thinking out loud

Dave

Dave, here goes -
Unsprung weight
the wheels do weight a lot less (suspect - guess 5kg for both=11lb, maybe more), discs and calipers are about the same.
Rear aluminium swingarm (I suspect is a bit less but not much with linkages)
All else is about the some.
Sprung weight is where a lot of gains were made-
I have a 530 chain setup which weights less
Lithium battery
Exhaust etc

I was curious of the weight in relation to spring rates, the GPZ900R is 228kg dry, add 5 kilos for the five litres of fuel and another 3 or so for oil and you are still lighter than the 900R in comparison, around 20kg lighter, maybe part of the problem is the spring rate is just too heavy...? Do you have any room to back the spring off to make it softer..? {sorry if you've already covered that} Check those linkages closely with the 900R still...

PS, love the weight measuring device.... :woohoo:

750 R1 wrote: I was curious of the weight in relation to spring rates, the GPZ900R is 228kg dry, add 5 kilos for the five litres of fuel and another 3 or so for oil and you are still lighter than the 900R in comparison, around 20kg lighter, maybe part of the problem is the spring rate is just too heavy...? Do you have any room to back the spring off to make it softer..? {sorry if you've already covered that} Check those linkages closely with the 900R still...

PS, love the weight measuring device....

The spring is internal, I don't think it can be removed (it has air pressure), I might have to eventually get another shock with an external spring. If anyone knows of an equivalent, let me know.
I have to admit I expected 230Kg so I was surprised when I saw 215kg.
The measuring device is from work. Just now I'm getting the fuel mixture correct, I hope tomorrow that part will be finished

Bozo wrote:

750 R1 wrote: I was curious of the weight in relation to spring rates, the GPZ900R is 228kg dry, add 5 kilos for the five litres of fuel and another 3 or so for oil and you are still lighter than the 900R in comparison, around 20kg lighter, maybe part of the problem is the spring rate is just too heavy...? Do you have any room to back the spring off to make it softer..? {sorry if you've already covered that} Check those linkages closely with the 900R still...

PS, love the weight measuring device....

The spring is internal, I don't think it can be removed (it has air pressure), I might have to eventually get another shock with an external spring. If anyone knows of an equivalent, let me know.
I have to admit I expected 230Kg so I was surprised when I saw 215kg.
The measuring device is from work. Just now I'm getting the fuel mixture correct, I hope tomorrow that part will be finished

215kg is a pretty good number for a bike this big with fluids, I'd certainly be happy with that....
Read this just now, this effects damping so that could be your problem, worth a try...

The GPZ900R rear shock damping goes off when the oil in there gets old. But it's easy to put right: just remove the shock, unscrew the air pressure hose that goes into it, and tip out the old oil into a measuring cup. Then re-introduce that same amount of fresh oil (I used a 10W viscosity) into the shock with a syringe. It will take about 200ml of oil

Check the 900 manual {or google} for air pressures, or just experiment...