Author Topic: Rear shock/pogo stick  (Read 4816 times)

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Offline hughes

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Rear shock/pogo stick
« on: April 17, 2005, 03:39:11 AM »
Went riding on sat. spent about 5 hoours riding trails and some moto. I noticed my bikes rear end likes to come up and hit me in the back side after hitting bumps at speed. I turned the rebound all the way in. That made it some better but still need less rebound. Sag is set at 4in. Changing my compression seem to help but acts like I need less rebound. A couple of months ago I changes the fluid in my shock and had to use 3wt. Bel-Ray shock oil. I was thinking about order a shock seal rebuild kit from rockymountainmc.com and go to a 5wt. oil. What do ya'll think.
Open Class 2-Stroke Kawasaki KX500
Yamaha 2005 YZ250
Richard Hughes
Dirt Hammers - Online Off-Road Journal
hughes@dirthammers.com
http://www.dirthammers.com

mikesmith

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Rear shock/pogo stick
« Reply #1 on: April 17, 2005, 09:38:14 PM »
10 wt.,then see how it feels.

Rick

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Rear shock/pogo stick
« Reply #2 on: April 18, 2005, 08:24:50 AM »
A few thoughts:

1. Are you sure you put "Shock" oil in your shock, or did you use fork oil?  The reason I ask is that fork oil will not work in shocks because it will not stand up to the heat generated by a shock.
2. Are you sure you got all of the air out of the shock?  When changing shock oil, air is the enemy.
3. You might have too little rebound causing a problem called "packing".  Packing is caused when your shock does not rebound completely.  Ironically, if you are experiencing packing, it will seem as though you have too much rebound.  To test this, turn your rebound clickers out instead of in and go for a ride.  You can experience the same type of problem if your compression is set too hard, so check this as well.
4. You indicate that your race sag is 4 inches, but do not provide your static sag number.  This will help determine if your spring is correct for your weight.  If not, it can feel as though you need to slow your rebound.
5. Shock seals do not go bad very often, so I doubt you need to replace this item.
6. I believe 3 wt. oil is way to light for a shock.  I recommend you change to 10 wt BelRay suspension fluid.  If you have the right spring and no internal shock problems, you might find that the heavy weight oil does the trick.

Rick

Offline hughes

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Rear shock/pogo stick
« Reply #3 on: April 19, 2005, 12:56:23 PM »
Quote from: Rick
A few thoughts:

1. Are you sure you put "Shock" oil in your shock, or did you use fork oil?  The reason I ask is that fork oil will not work in shocks because it will not stand up to the heat generated by a shock.
2. Are you sure you got all of the air out of the shock?  When changing shock oil, air is the enemy.
3. You might have too little rebound causing a problem called "packing".  Packing is caused when your shock does not rebound completely.  Ironically, if you are experiencing packing, it will seem as though you have too much rebound.  To test this, turn your rebound clickers out instead of in and go for a ride.  You can experience the same type of problem if your compression is set too hard, so check this as well.
4. You indicate that your race sag is 4 inches, but do not provide your static sag number.  This will help determine if your spring is correct for your weight.  If not, it can feel as though you need to slow your rebound.
5. Shock seals do not go bad very often, so I doubt you need to replace this item.
6. I believe 3 wt. oil is way to light for a shock.  I recommend you change to 10 wt BelRay suspension fluid.  If you have the right spring and no internal shock problems, you might find that the heavy weight oil does the trick.

Rick


Thanks Rick and Mike,

1)Yes i did use shock oil 3wt. bel ray hv1 suspension fluid.

2)I hope I got all the air out. I wasted a lot of oil during the process. I filled both sides with oil and then installed the bladder and the shock. As i installed the shock with the shock upside down in the vise I cracked open the bleed screw. First time shock rebuild so anything could have happened.

4) Will need to check static sag but I weight in at 250lbs. I am running the stock 5.4 spring with .46 up front. I have read several post here where guy's perfer the 5.4 over the heavier springs even if they wieght to much.

6)I used the 3wt. dure to last mintue repair and wanted to ride bike. I found some bel ray 10wt. I will try this weekend to replace oil and trst ride.
Open Class 2-Stroke Kawasaki KX500
Yamaha 2005 YZ250
Richard Hughes
Dirt Hammers - Online Off-Road Journal
hughes@dirthammers.com
http://www.dirthammers.com

Offline hughes

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Rear shock/pogo stick
« Reply #4 on: April 24, 2005, 05:58:36 AM »
Are you sure you got all of the air out of the shock? Rick asked.

Removed the shock today and found alot of air. With the shock upside down in the vise and the shaft fully extended I could push the shaft in about 1/2 beofore contacting any fluid. Next I open the bleed screw a the top of the shock and compressed air and some oil blew out. So started over with the refilling with 10wt. bel ray hv1. Double check this time for no air. I filled both sides of the shock with oil all the way to the top. This made a real good mess but worked. Going out of town this week so it will be next week before I can get the blader charged and test ride. Now with the shock in the vise you can push the shaft up and down and maintain fluid contact from the top to the  bottm of the stroke. Thanks Guy's.
Open Class 2-Stroke Kawasaki KX500
Yamaha 2005 YZ250
Richard Hughes
Dirt Hammers - Online Off-Road Journal
hughes@dirthammers.com
http://www.dirthammers.com

teamgreen500

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Rear shock/pogo stick
« Reply #5 on: April 26, 2005, 02:09:32 AM »
Atleast you now know exactly what a blown shock feels like....

Had one go "Real Quick" during a race at Carlsbad....a long, long time ago...in a galaxy far, far way...

Offline hughes

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Rear shock/pogo stick
« Reply #6 on: May 04, 2005, 12:34:40 PM »
Don't know what to do next. Rode the bike this evening and it's not any better. Is it possible to have to much oil in the shock. I say this because I filled both sides to the top and next installed the bladder. As the bladder was being installed oil is being pushed out of the other side(shock body). Next I pressed the shock head into the body as I released the bleed screw to allow oil to escape as the shock head was being installed. Here's my idea. I think the bladder collapsed as I installed the shock head and then I had the bladder charged to 180psi. Now I think the oil is now pressurized. I set my rider sag at 4in. but here is what is strange I have no static sag. When you remove the bike off the stand there is no compression of the rear shock. I need some help before I send this thing  to race tech.
Open Class 2-Stroke Kawasaki KX500
Yamaha 2005 YZ250
Richard Hughes
Dirt Hammers - Online Off-Road Journal
hughes@dirthammers.com
http://www.dirthammers.com

Brett

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Rear shock/pogo stick
« Reply #7 on: May 04, 2005, 09:16:17 PM »
if no static sag maybe check linkages and stuff to make sure is not binding up.

Offline hughes

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Rear shock/pogo stick
« Reply #8 on: May 22, 2005, 02:55:31 PM »
Guy's I finally got the shock figured out. It was in my assmebly process. She hooks up good a speed now. Man what a diff. Thanks for ya'll input
Open Class 2-Stroke Kawasaki KX500
Yamaha 2005 YZ250
Richard Hughes
Dirt Hammers - Online Off-Road Journal
hughes@dirthammers.com
http://www.dirthammers.com