Author Topic: Sagging front suspension  (Read 13595 times)

ST/SV

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Sagging front suspension
« on: March 19, 2015, 03:03:53 AM »
Has anyone had any problems with the front forks sagging? I don't ride the 300 daily but the other day I noticed it seemed to be very rough and almost bottoming out on the roads I normally ride. When I got home I started looking at things and noticed while sitting on it the suspension was sagging all the way down to about an inch or 2 left of travel. I've never noticed how much it use to sag before. While sitting on it and holding the front brake and working the suspension up to its limits and back down to where it settles it seems that it's settling down way to low. Has anyone done any fork work like replacing oil, springs or adding spacers?

de dee

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Re: Sagging front suspension
« Reply #1 on: March 19, 2015, 06:15:10 AM »

   let us know witch oil Wt. you  use and how much Wt does your scoot carry, you and pile on, if any,  feels like my scoot could use the same work, lots of rough roads here,.  60,000 km. and I weigh 220 after this winter,   300i DT.   

BettinANDlosing

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Re: Sagging front suspension
« Reply #2 on: March 19, 2015, 08:01:27 AM »
Changing the fork oil on my 250 made a huge difference. 10w BelRay fork oil. Easy to change, remove the shocks and drain from the lower bolt. Fill through the top. You do need large Allen bits.
2002 Kymco B&W 300; MRP 78MM "300CC", Naraku cam, Yoshimura rS3 exhaust, 17g Sliders, Yellow torque spring drilled airbox, stock carb #115 main #40 pj.

2001 "Yamaha" Zuma AKA MBK Booster; MHR OverRange, Dellorto 19mm BHBG, Polini "big" intake, RS-3 Rear shock, Stock cylinder.

ST/SV

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Re: Sagging front suspension
« Reply #3 on: March 19, 2015, 05:33:57 PM »
I weigh about 185. I'm sure it could use a fork oil change just because it moves up and down a little to easy. On the sag I'm thinking another spring but I'm sure it would be fun trying to find aftermarket springs that will fit. If I end up pulling the forks I may try a spacer on top of the spring. I have been looking thru all the threads trying to find a tupperware removal but found nothing so for. Man I hate to start breaking up the plastic.

BettinANDlosing

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Re: Sagging front suspension
« Reply #4 on: March 19, 2015, 06:05:13 PM »
The people GT unfortunately is a PITA to get the front legshield off.
2002 Kymco B&W 300; MRP 78MM "300CC", Naraku cam, Yoshimura rS3 exhaust, 17g Sliders, Yellow torque spring drilled airbox, stock carb #115 main #40 pj.

2001 "Yamaha" Zuma AKA MBK Booster; MHR OverRange, Dellorto 19mm BHBG, Polini "big" intake, RS-3 Rear shock, Stock cylinder.

agilebda

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Re: Sagging front suspension
« Reply #5 on: March 19, 2015, 10:38:54 PM »
Soft suspension

• Weak fork spring

• Insufficient fluid in fork

• Deteriorated fork fluid

• Incorrect fork fluid weight

• Low tire pressure

If you decide to dis-assemble your front forks, let me know and I will email you the service guidlines.

BettinANDlosing

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Re: Sagging front suspension
« Reply #6 on: March 19, 2015, 10:54:18 PM »
Kymco uses SS# instead of Weight rating for the oil viscosity. The recommended is SS#8 which from everything I found doing my forks is about 6.5w fork oil. I used 10w oil and it made my bike feel MUCH more stable on fast corners and takes potholes better. Before my shocks would bottom out all the time, and now I have to hit a major pothole for them to hit bottom.
2002 Kymco B&W 300; MRP 78MM "300CC", Naraku cam, Yoshimura rS3 exhaust, 17g Sliders, Yellow torque spring drilled airbox, stock carb #115 main #40 pj.

2001 "Yamaha" Zuma AKA MBK Booster; MHR OverRange, Dellorto 19mm BHBG, Polini "big" intake, RS-3 Rear shock, Stock cylinder.

agilebda

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Re: Sagging front suspension
« Reply #7 on: March 20, 2015, 01:22:39 AM »
Kymco uses SS# instead of Weight rating for the oil viscosity. The recommended is SS#8 which from everything I found doing my forks is about 6.5w fork oil. I used 10w oil and it made my bike feel MUCH more stable on fast corners and takes potholes better. Before my shocks would bottom out all the time, and now I have to hit a major pothole for them to hit bottom.

Will try this. Thanks for the info.

Budz

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Re: Sagging front suspension
« Reply #8 on: March 20, 2015, 02:10:55 AM »
after how many years and miles did the front suspension sag?

de dee

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Re: Sagging front suspension
« Reply #9 on: March 20, 2015, 03:27:01 AM »
  if you put a spacer in the front shocks, what would you use and how thick would you make it???  and would you put it top or bottem of shock,.  de dee

BettinANDlosing

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Re: Sagging front suspension
« Reply #10 on: March 20, 2015, 03:44:33 AM »
  if you put a spacer in the front shocks, what would you use and how thick would you make it???  and would you put it top or bottem of shock,.  de dee

I was also thinking about putting a spacer in to stiffen it up, but decided against it because even if it does make it feel stiffer it'll bottom out easier.
2002 Kymco B&W 300; MRP 78MM "300CC", Naraku cam, Yoshimura rS3 exhaust, 17g Sliders, Yellow torque spring drilled airbox, stock carb #115 main #40 pj.

2001 "Yamaha" Zuma AKA MBK Booster; MHR OverRange, Dellorto 19mm BHBG, Polini "big" intake, RS-3 Rear shock, Stock cylinder.

ST/SV

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Re: Sagging front suspension
« Reply #11 on: March 20, 2015, 04:26:12 AM »
agilbeda, only one I can rule out is tire pressure, checked that first thing. Let you know if I tear them down. It's been years since I have taken any forks off but it's going to bug me until I do. Replaced 4 or 5 leaking fork seals back in my dirt racing days but they were all exposed on those bikes with no plastic removal involved. The Tupperware bothers me the most. I have a Sym 125 and had to tear into the front end to get to the radiator because of a heating problem and I couldn't believe how easy it was to strip out the plastic threads on that plastic, there has to be a better way to hold that plastic on.

BettinANDlosing, you say you have a 250 and changed the fluid, does it have the same front end as the 300, if so may have to pm you when I get ready for tips on the Tupperware removal if things come to a screaming halt. I do have a large set of allen sockets I bought for my Kawasaki 1400 Concours and Honda ST 1300.

Buds, It's a '13 model, black, with 1700 miles and I just noticed it last weekend while riding after hitting a few spots in the road I usually ride but this time it hit a lot harder and jarred me, it even sounded like it bottomed out and they were not huge pot holes.

dedee, I would rather have some aftermarket springs, probably a bit stiffer, than a spacer but back in the old days we would put some washers on top of the springs to add more pressure to them which would take away some sag. I've heard some use pvc pipe also but it has to be close to the spring size. I don't know how these forks are assembled, if you just take the top cap off which compresses the spring or something different, it's been 25 plus years since I've looked in one.

BettinANDlosing

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Re: Sagging front suspension
« Reply #12 on: March 20, 2015, 04:48:05 AM »
The 250 has a similar design, let me know i can get you the fork section of the service manual when I have a little free time. You might not have to take any plastic apart, reach up / look at the top of the front shocks, if you can see the 14mm bolts at the top (two on each shock facing forward). If you think your can get a socket on them you're golden. Remove the wheel and caliper ect from the shocks and they should just drop down with some effort. You might have to turn the steering to get your ratchet on the bolts, but way better than getting the plastic off.
2002 Kymco B&W 300; MRP 78MM "300CC", Naraku cam, Yoshimura rS3 exhaust, 17g Sliders, Yellow torque spring drilled airbox, stock carb #115 main #40 pj.

2001 "Yamaha" Zuma AKA MBK Booster; MHR OverRange, Dellorto 19mm BHBG, Polini "big" intake, RS-3 Rear shock, Stock cylinder.

de dee

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Re: Sagging front suspension
« Reply #13 on: March 20, 2015, 06:39:21 AM »

  It takes me about 10 min. to remove the front clip,   last year it was raining for a couple of days,   and I striped the whole scooter for some thing to do,.  cleaned it all and put it all together again,  a real fun day for me, the look on some peoples face when they seen it,  and the next day when I was riding again ,  they asked how many pieces were left ,   only two screws,  from the tupper ware,.  de dee  300i downtown,. 

ST/SV

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Re: Sagging front suspension
« Reply #14 on: March 20, 2015, 09:04:01 PM »
The 250 has a similar design, let me know i can get you the fork section of the service manual when I have a little free time. You might not have to take any plastic apart, reach up / look at the top of the front shocks, if you can see the 14mm bolts at the top (two on each shock facing forward). If you think your can get a socket on them you're golden. Remove the wheel and caliper ect from the shocks and they should just drop down with some effort. You might have to turn the steering to get your ratchet on the bolts, but way better than getting the plastic off.
Man do I feel like and idiot.  :-[ When I read your post I thought how could you possibly reach up to a bolt to remove to take the forks out.  I've had this bike a year and a half and never realized the forks only have a single triple clamp holding them. I just thought it was like my most motorcycles with a set of triple clamps. I then ran over to the Sym to look up under it and it was basically the same thing, never noticed when I had that Tupperware off. Looks like it can be done without the Tupperware coming off like you say, hopefully this may be easier than I thought.  I'm planning on messing with it next week. I'm going to dig out the manual to see if there is anything about how much oil goes in them, if I don't see anything I may be pinging ya'll for assistance.   

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