Author Topic: How Soft is Soft  (Read 13230 times)

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Marrtyn

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on: September 05, 2010, 03:40:42 pm
I have noticed that my front suspension on my G5 is quite soft, wether or not it is too soft, I don't know.
Are there any figures for the ammount of compressinon on the fork springs for a given load.  i.e by hanging weights onto the ends of the bars, the suspension lowers by "X" ammount.
Sometimes I feel as though the bike can fold under me if I inadvertantly grab too much front brake, especialy if i am doing a turn, at slow speed. (I do try to balance out the braking, between front and rear)


Ducati Scotty

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Reply #1 on: September 05, 2010, 05:32:33 pm
The front suspension is soft.  Not terribly so like some bikes I've had but it is, especially for a 230# guy like me.  I've noticed the same brake dive as you.  I have loosened up the preload a bit on the rear so they match the front better and the bike feels better overall even though it's softer.

Here is the best site I've found on how to set your suspension:
http://www.ohlins.com/Checkpoint-Ohlins/Setting-Up-Your-Bike/Underrubrik_1/

This is technically for a high performance bike and we don't have all the fancy damping settings mentioned BUT getting the right spring rate and sag settings is the majority of getting your suspension tuned properly.  I think the front springs are probably too soft for many people.  You might be able to get by with just adding some preload with longer spacers, but you do have to do some disassembly to do that.  Many people will tell you that you can just add more fork oil or use heavier weght fork oil and you can but they're both kind of a bad cheats.  If you add more oil it's still just as soft at the start of compression but effectively makes the fork more progressive so you're less likely to bottom.  Heavier oil makes the fork slower to dive but does not provide any additional support or spring rate for something like a sustained hard stop on the front brake.  The advantage of these techniques is that they require very little dissasembly.

I don't know the dimensions or spring rate of the front forks but I'll be working on mine this winter and will post what I find.  There are some progressive rate springs available for the RE that many people like.  Progressive rate springs are often great for non-sport bikes and provide better handling and comfort.  On a performance bike they are usually a nightmare if not impossible to get set right.  I prefer regular straight rate springs and if a little preload increase doesn't do it I'll be looking for some this winter.  Also, I should note that I like my bikes set up like many race bikes: stiff springs, little preload, and little damping.  That won't suit everyone.

Hope this helps.

Scott


prof_stack

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Reply #2 on: September 05, 2010, 06:23:04 pm
My new C5 soaks up pavement irregularities very nicely and seems fine on spirited (but not yet peg grinding) riding.  One of the stretches I ride used to be a washboard nightmare on the Moto Guzzi and Buell Blast and XB9S.  On the C5 it is not so noticeable. 

So for me the suspension is a positive, at least right now.  Also, my weight is purposely down to 175# (from over 190#) since mid-July.  That helps, too.  (Also helps the blood pressure, but that is for a different forum...   :D)
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Maturin

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Reply #3 on: September 05, 2010, 07:51:37 pm
In my opinion the fork is not only too soft but also not very responsible to smaler bumps in the road. I already tried to unload the pressure that could occure while assemlbing it by loosen and tighten all bolts, but the outcome was only little. Any experience with fork oil additives like MoS?
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Ducati Scotty

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Reply #4 on: September 06, 2010, 12:28:19 am
If you feel it's soft and not responsive to smaller bumps you may want to try lighter oil and stiffer springs.  I think they put in engine oil at the factory but I intend to replace it with synthetic fork oil, not sure what weight to use.

I've never used additives in fork oil before.

Scott


gashousegorilla

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Reply #5 on: September 06, 2010, 12:38:43 am
 IMHO, I would start with the basic's,fork oil. The correct amount and the correct wieght for the rider, you may be able to achieve what you are looking for there. The C-5 comes with 10 w 30, thin motor oil. Thats old technology. Try a 15 or a 20 wieght specific fork oil, and you will feel the difference right away. That being said, there ain't nothing wrong with experimenting with that front end either.I'm looking foward to scotty's front end work. I'm sure he's gonna find something that will make it better.
  Also motor oils get bubbley , It  gets foamy. A good quality fork oil will not do that.Can you imagine all that foamy oil being forced through the little holes inside you fork?
« Last Edit: September 06, 2010, 12:56:44 am by gashousegorilla »
An thaibhsí atá rattling ag an doras agus tá sé an diabhal sa chathaoir.


2bikebill

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Reply #6 on: September 06, 2010, 10:27:38 am
"......The correct amount and the correct wieght for the rider......"

Do you have any specific reccomendations? I'm feeling it's time to change my fork oil and haven't a clue what's best. Solo rider, 160 pounds. Several bikers I've mentioned changing - even checking - fork oil to have looked at me with amusement and asked "why?"    :-\
2009 Royal Enfield Electra (G5)


Ducati Scotty

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Reply #7 on: September 06, 2010, 04:05:13 pm
Fork oil wears down over time and needs to be replaced.  I was also amused when I saw that it's supposed to be 'checked' at regular intervals in the manual.  If it's not obviously leaking out or past the mileage to change what's to check?

Scott


gashousegorilla

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Reply #8 on: September 06, 2010, 04:59:41 pm
"......The correct amount and the correct wieght for the rider......"

Do you have any specific reccomendations? I'm feeling it's time to change my fork oil and haven't a clue what's best. Solo rider, 160 pounds. Several bikers I've mentioned changing - even checking - fork oil to have looked at me with amusement and asked "why?"    :-\
Will, you can't just check the fork oil on these bikes.The fork legs must be removed .Then you might as well change it. It's a time consuming and tricky job. If you have no experience with front ends, this is probably not the one to learn on.But if you have, then go for it. Those guys who rolled there eye's at you don't know what there missing. The correct suspention set up makes a big  difference. Unless you think the front end feels too soft, or your past 7.5 k miles, I would not sweat it. I would think at your weight, that no more then a 15w oil would do. The higher the viscosity, the stiffer it's going to feel. The book states 265 cc each leg. Thats what i put in, and it's fine. I put in 20w, I'm 175 US lbs. and its a little stiff, but I don't get front end dive. I like my bikes to feel a little tighter then the stock set up.Same with the rear.
They will handle better, but at the expence of comfort. And like scotty said,if it has not leaked,and you would know it, your level is probably OK.
Dan.
An thaibhsí atá rattling ag an doras agus tá sé an diabhal sa chathaoir.


2bikebill

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Reply #9 on: September 06, 2010, 06:02:42 pm
Thanks - I was just unsure what oil I actually need to put in there when it comes time to change. I'm at around 6000 miles so no hurry.
I checked the level once, just because I was familiarising myself with the bike and checking everything. I used a straightened out wire hanger as a dipstick. I noticed one side was half an inch lower than the other, but plenty in both so didn't give it another thought.
2009 Royal Enfield Electra (G5)


Ducati Scotty

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Reply #10 on: September 06, 2010, 10:03:55 pm
Half an inch different isn't that bad.  It's quite common for bikes of all makes to be fairly different heights and also common to have very low quality oil.  Changing it out is one of the best low price mods to do.

Scott


Marrtyn

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Reply #11 on: September 07, 2010, 05:39:55 pm
Thanks for all the interesting responces.
The manual just states "fork oil" 200m/leg. I suppose they mean 200ml/leg.(no viscosity quoted) and to check every 1000 kms., and replace at 12000 kms.(7500 mls.)
Is the oil just topped up thro the 2 slotted screws at the top of the forks?


gashousegorilla

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Reply #12 on: September 07, 2010, 06:18:59 pm
Thanks for all the interesting responces.
The manual just states "fork oil" 200m/leg. I suppose they mean 200ml/leg.(no viscosity quoted) and to check every 1000 kms., and replace at 12000 kms.(7500 mls.)
Is the oil just topped up thro the 2 slotted screws at the top of the forks?
No, you must remove the fork leg to check. I guess it feels too soft for you? How much do you weigh? ( I'll be nice, ::)). The bikes are made for the average customer, You may have to set things to your liking. I would go to the dealer and talk it over with him. He should be able to set it up the way you like it. I would start by going to a 15 w FORK Oil.
An thaibhsí atá rattling ag an doras agus tá sé an diabhal sa chathaoir.


gashousegorilla

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Reply #13 on: September 07, 2010, 07:57:18 pm
 I'm pretty sure the service book says 265 cc's.
An thaibhsí atá rattling ag an doras agus tá sé an diabhal sa chathaoir.


Marrtyn

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Reply #14 on: September 07, 2010, 08:18:24 pm
No, you must remove the fork leg to check. I guess it feels too soft for you? How much do you weigh? ( I'll be nice, ::)). The bikes are made for the average customer, You may have to set things to your liking. I would go to the dealer and talk it over with him. He should be able to set it up the way you like it. I would start by going to a 15 w FORK Oil.
Thanks gahousegorilla. My weights 175lb.
Does this mean then, that, by rights , according to the book, I have to remove the forks every 1000kms., to check the oil.Surely this can't be right Can it?