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Old 09-11-2010, 02:29 PM
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Default rear kicking sideways

     

01 honda cr250 , any time I am on wet grass, mud , or loose dirt. The rear kicks sideways when power band kicks in or basically whenever the rear tire breaks loose. And in fast whoops or log crossing. The rear jumps up high in the air. Rear shock has no leaks and is in fine mechanical condition. " I wiegh 215 lbs with gear. Shock is stock

---------- Post added at 11:29 AM ---------- Previous post was at 10:45 AM ----------

Also I don't ride moto. Its all woods. Lots of rocky hill climbs and log crossings.
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Old 09-11-2010, 03:13 PM
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Rear wheel bearings? An easy way to check is to grab a hold of the back tire and shake the wheel back and forth. If it has any play side to side, they are shot. I don't take chances with bearings. Or spokes not being tight? Just suggestions.
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Old 09-11-2010, 03:26 PM
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Bearings and spokes are perfect. Swingarm bushings good. I'm convinced its in the rear shock settings.
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Old 09-11-2010, 03:44 PM
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how long have you been riding this bike?
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Old 09-11-2010, 03:58 PM
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Been riding it for 2 years. Has became a problem steadily with faster riding.
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Old 09-11-2010, 05:16 PM
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What is your past experience with motorcycles?
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Old 09-11-2010, 05:26 PM
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I have a lot of experience with motors and such. But as suspension goes. Just fork seals ! No tuning experience at all !
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Old 09-11-2010, 05:51 PM
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I was more in line with riding rather than wrenching.'
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Old 09-11-2010, 06:10 PM
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Well my brother races in B class for harescrambles and he places on podium, and I keep up with him pretty easy. I wanna start racing next season.
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Old 09-11-2010, 06:28 PM
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Prior to this bike, were you riding a four stroke?
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Old 09-11-2010, 06:34 PM
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Worse ! 4 stroke sport quads. But I grew up on a cr80 and rm 100. Took about 12 years off of dirt bikes. But came back 2 years ago.
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Old 09-11-2010, 06:59 PM
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OK, with a stock shock and your weight, your problems should be in washing out, but now that I know your background, I think you need to kinda relearn your riding.
A two stroke, and especially on that is of this caliber, steers with the back wheel. To control this kickout that you are experiencing once you hit the powerband, you must remember to cover your clutch. Most of the time you can just let the rear spin a bit as the power comes on, but when it becomes a problem, gently slip the clutch with one or two fingers.
Once you get the hang, you will love the way the bike can square of a corner or flick to another line and still have the umph to keep moving forward.
The going high in the air over woops and such is probably a reult of not positioning your weight properly. Quads carry allot of weight and aren’t as nimble as a bike. You have yourself a very fine and responsive two stroke motorcross machine. It is about as far from a four stroke quad as you can get. I think what your really need is just some more seat time, and a bit of rethinking.
I hope you have a great time with the bike, I have the same one and love it. I had to relearn as well. Four stokes all my life prior, no quads but still a bit of a change.

And on a second thought. Did you adjust your race sag. With the stock spring and your weight, you might have the spring too tight. To really be able to dial the suspension in, you will need a new spring suited for your weight.

Last edited by VAL; 09-11-2010 at 07:09 PM.
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Old 09-11-2010, 07:24 PM
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That's exactly what its doin. How about the logs and big rocks /roots. The rear jumps up like a catapult.

---------- Post added at 04:24 PM ---------- Previous post was at 04:13 PM ----------

Val , my bad my blackberry didn't show the whole post. To adjust sag u loosen or tighten the spring with the locknuts correct ? Thank u for all the help . I see u post a lot on here. Its great of u to help so many. Thanks again.

Ps I even put a 14oz flywieght in it. To calm it down. LoL

---------- Post added at 04:24 PM ---------- Previous post was at 04:24 PM ----------

Val , my bad my blackberry didn't show the whole post. To adjust sag u loosen or tighten the spring with the locknuts correct ? Thank u for all the help . I see u post a lot on here. Its great of u to help so many. Thanks again.

Ps I even put a 14oz flywieght in it. To calm it down. LoL
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Old 09-12-2010, 10:45 AM
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Setting the Sag
One thing a lot of riders neglect is setting the sag on their bike. Race sag alters and controls the weight balance between the front and back of the bike. Before you can adjust your bike to the conditions of your track you should check your sag and make sure it’s consistent. To set/check the sag do the following steps.

* Put all your gear on.
* With the bike on the stand have a helper measure from a fixed point on the swing arm to a fixed point on the rear fender. For example: The center of the rear axle to the seat bolt. Write this measurement down on a piece of paper.
* Now take the bike off the stand. Get on the bike in your normal riding position with both feet on the pegs. Have your buddy measure from the same fixed points you used to get your measurement in step two. Some riders who stand a lot may want to take this measurement standing on the bike.
* Subtract the second measurement from the first. Example: 405 – 285mm = 120mm of sag. For 125’s and up you will want 95-105mm’s of sag, 80-90mm’s of sag for 85/Supermin and 60-70mm’s of sag for 65’s.
* To adjust the sag you need to either tighten or loosen the pre-load collar on the shock body.You do this by using a punch to loosen the lock collar that is tightened against the pre-load collar, then you should be able to turn the spring and it will turn the pre-load collar. If your spring turns but it doesn’t the pre-load collar you can use a penetrating lube such as wd-40 to help break the collar free. Worse case scenario is you will have to use the punch to turn the pre-load collar. If your sag is too low you will want to compress the shock spring in order to increase its stored energy so it can support your weight. If your sag is too high you want to loose the spanner nut on the shock body.
* Once you get the Race Sag set you should take your bike off the stand and measure how much your bike sags under its own weight. This is called static sag. You basically follow the same steps as setting your race sag but you just remove the rider from the equation. You also subtract the second measurement from your original measurement. Example. 405mm on the stand – 370 off the stand under the bike’s own weight = 35mm’s of static sag.


This measurement is important because it’s a good indicator if you have the proper spring for your weight. You should have between 25-35mm’s of static sag assuming you have the proper spring. Any less (ex:15mm) and your spring is too soft any more (ex: 50mm) and your spring is too stiff.




Adjusting your sag
Now that you have your sag adjusted it’s time to ride the bike. Go out on the track and pay attention to how your bike is handling. Is the front end tucking in corners? Does it have headshake? Does it drift to the outside of a high speed sweeper? Any of these symptoms can be helped by adjusting your sag.

If your bike is any of the following symptoms lower your sag (Ex: 105mm)

●The front end feels like it’s giving out underneath you in the beginning of a corner
●You have head shake while accelerating or braking
●The bike over steers on high speed sweeping corners.
●The front end feels too responsive to rider input.
●The bike wanders in whoops.


If your bike is doing any of the following symptoms raise your sag (Ex 95mm)
●The front end feels like it doesn’t turn sharp enough or your bike pops out of ruts.
●The bike under steers in sweeping corners.
●The front end doesn’t feel responsive enough to rider input.
●The bike wants to stand up in corners or hard to power slide flat corners
●It’s hard to change lines in whoops.

When adjusting the race sag you are adjusting the balance of weight between the front and rear wheel. In summary for more steering raise your sag for less steering lower your sag. You have to find the balance for your riding style. Some riders will hear this and immediately raise their sag in order to give themselves the most steering possible. This isn’t always a good thing. You may end up with a bike that is too responsive causing you to make mistakes or cut out of berms early robbing you of momentum. You want the maximum amount of steering with zero headshake.

Compression Adjustment
The compression adjustment is the most common adjustment made by riders. It unfortunately isn’t always adjusted properly.

The compression adjuster works by allowing the oil displaced by either the cartridge rod or the shock shaft. The valving in your suspension along with all damping circuits known to man are speed sensitive. They don’t apply resistance until a certain speed is reached. The higher the speed that your suspension compresses the more resistance there will be. When you adjust your clicker adjustment you are basically delaying the point that your valving provides resistance. The softer you set the suspension the higher velocity your suspension will need to compress to apply resistance.


Because of this the compression adjustment (along with rebound) is most noticeable in low speed situations. Example: Jump faces, smooth jump landings, how much your suspension settles under acceleration.

This is not to say that your suspension can’t be adjusted for all conditions. This is why you will notice that if you adjust your suspension to end harshness in braking bumps you will notice a bigger decrease in resistance to low speed situations (G-out, rolling whoops etc). What happens is you end up with overly soft suspension and you get a compromise. You can adjust for high velocity situations but there will be a trade off. The higher the velocity the less effective your adjustment will be. An example of high velocity compression would be acceleration bumps, supercross whoops, roots or rocks, severe bottoming control, and choppy braking bumps. The only way to truly adjust for any of this conditions without compromise (other than the High Speed Compression adjuster, but we’ll get to that later) is through valving changes.


Soften your compression on your forks if you experience any of the following

●Light bottoming on jump faces, jump landings, or g-outs
●Front end comes up frequently in whoops
●Harshness in braking bumps
●Headshake on acceleration bumps
●Harshness felt on slap down/Flat jump landings

Stiffen your compression on your forks if you experience any of the following

●Front end doesn’t stay on top of whoops causing an over the bars sensation
●Headshake in braking bumps
●Bottoming of any kind
● Front end dives too much on downhill braking bumps.

Stiffen your compression on your shock if you experience any of the following.
●Bottoming
●Rear of the bike kicks straight up in whoops or large braking bumps
●The bike jumps front wheel high when hitting jumps with a kicker on the top
●Riding in Sand or mud

Soften the compression on your shock if you experience any of the following
●Rear of the bike over powers the front in whoops. Rear of the bike wanders side to side.
●The bike jumps front wheel low when hitting jumps with a kicker on the face.
●Riding in hardpack, woods, or any track with choppy bumps.
●The rear of the bike wants to pop out of ruts or go side to side on braking bumps





High Speed Compression
This feature is usually only available on your bikes’ shock. This adjustment is made by turning a large nut that is usually anodized and surrounds your compression adjustment. How this works is it allows a pressure release if the pressure in your shock builds too quickly. What this means is that if you hit a series of acceleration bumps and the shock needs to pump more oil into the reservoir than the bleed passage can allow the high speed compression allows the passed to momentarily increase in size. This adjustment is basically a spring loaded series of valving. When you increase the pre load on the spring by turning the adjustment nut clockwise, you basically increase the pressure needed in order for the shock to allow the oil to pass into the reservoir and vice versa. The more pre-load you ad the stiffer the shock will be. The less pre-load the softer it will be.

Another thing people get confused about is they associate High Speed Compression with the speed of the motorcycle. The term high speed means the speed at which the suspension compresses and has little to do with the speed of the motorcycle.

Soften the High Speed when you experience any of the following
●Harshness in acceleration bumps
●Deflection or Kicking in Supercross style whoops

Stiffen the High Speed compression when you experience any of the following
●Bike seems to go in between acceleration bumps robbing you of momentum
●Bottoming or side to side kicking in Supercross style whoops

Rebound Adjustment
A lot of people get confused when it comes to this adjustment. The sole purpose of this adjustment is to control the spring and how fast it returns to its original size. The most common mistake people make when adjusting the rebound is their bike kicks and they assume it’s because the bike is rebounding too fast. The majority of the time in this situation it’s the bikes’ compression that is too stiff. Another mistake people make is that the bike is jumping nose low or nose it’s a problem with the rebound. Unless the jump in question has a really tall face the majority of rebound is done in the air.

So how should you adjust the rebound? You adjust the rebound to keep the bike level, and control the speed at which the suspension returns to full travel. For example watch someone ride when they enter a braking bump section does the fork return to almost full travel in between? If not, it should. If it doesn’t this alone could cause harshness and riders will make the mistake of backing off the compression instead of the rebound causing the sensation to get worse rather than better.





Stiffen the rebound of your shock when you experience any of the following
● Back end kicks straight up in braking bumps
● Back end isn’t bottoming but kicking straight up in whoops
● On steep jump/long jump face the bike jumps front wheel low


Soften the rebound of your shock when you experience
●Back end of the bike starts kicking in the end of braking bump section
●Bike starts to kick and the end of a whoop section
●On steep jump/long jump faces the bike jumps front wheel high

Stiffen the rebound of your forks when you experience any of the following
●Excessive up and down movement of the handlebars in braking bumps
●Bike wants to under steer in tight corners
●Front end wheelies after a slap down/flat landing

Soften the rebound of your forks when you experience any of the following
●Forks get progressively harsher in braking bumps
●Bike want to over steer in tight corners
●Fork are harsh when landing in a rough flat section

Oil Level
Adjusting the oil level can be simple depending on what you need to accomplish.
By altering the amount of oil inside of your fork you can change the speed at which the dead air space in your forks compresses. The less air volume the faster it compresses the more progressive your forks will be. The more air volume the slower it compresses the less progressive your suspension will be.

Generally speaking harescramble and enduro riders prefer a lower oil to allow the suspension to have a softer overall feel in the braking bumps and roots. They can make this trade off because they tend to not jump very much, at least not very big jumps anyway.

Motocross riders tend to need more progression and a higher oil level than an enduro rider because of the larger obstacles they encounter.

Adjusting the oil height is fairly simple you either add or remove oil by removing the fork and pouring oil out of your air bleed screw. Make small adjustments (5cc’s at a time) until you get the feel you require. If you are converting a motocross bike (that hasn’t been touched by a suspension company) to ride in the woods remove a large amount of oil (40cc’s) and then subtract or add oil 5cc’s at a time until you get the bottoming resistance you require.




Maintenance
Basic maintenance can go a long way in keeping the performance of your suspension at peak levels. Below is a list of maintenance intervals to use when it comes to taking care of your suspension

Every Ride
●Visually inspect for damage, wear or oil leaks
●Remove dust seals on fork with flat screwdriver and spray contact cleaner inside to remove dirt
●When washing your bike pry up rubber bottoming bumper on the shock shaft and wash away dirt
●Write down all changes made to your suspension, clickers, oil height, sag etc.
●Clean all adjusting screws.
●Remove the bleed screws on your forks to release air pressure.

Every Ten Hours or Once a Month
●Inspect the inner fork tubes for fine scratches from sand. Polish with chrome or aluminum polish.
●Check sag measurement.

Every 30 Hours or 4 months
●Change suspension fluid and replace oil seals
●Check Springs for proper length
●Recharge Shock with Nitrogen

Every 60 hours or 12 months
●Check and replace wear items as needed
●Change suspension fluid
●Recharge Shock
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Old 09-12-2010, 11:53 AM
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wow VAL awesome post lots of good info all in one place. I printed this out and put it in my track side binder for future reference
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Old 09-12-2010, 12:37 PM
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Quote:
Originally Posted by Duran676 View Post
wow VAL awesome post lots of good info all in one place. I printed this out and put it in my track side binder for future reference
I copied that from the internet a bit back. I wish I was that well versed.
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Old 09-12-2010, 03:34 PM
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For your weight (no gear) and riding, you need to bump up the springs.
Stock Spring Rates:
Fork: 0.40kg/mm
Shock: 4.9kg/mm
Recommended Spring Rates:
Fork: 0.45 kg/mm
Shock: 5.0 kg/mm

Until you do, you will have problems. JMO Tdub
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