Jumping? Advanced techniques?

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#1
Ok I know this has probably been beat to death several times, but here we go. To start with I know how to jump, seat bounce, all that jazz. Im a midpack C racer and I want to go faster (dont we all? lol)

I have trouble clearing jumps that other riders easily clear in the same gear. Is it better to jump full throttle or 3/4 throttle? Obviously it depends on the jump face. Im riding a 96 125, and I notice the newer bikes jump better than mine. I dont know if its just all mental or what. But I rode an 03 kx125, bone stock, and after 5 laps I could ride it faster than mine. Given that the bike has all top end and none on bottom, i was keeping it wfo most of the time whereas my bike is usually at 3/4 and wfo on jumps that im comfortable on. My bike has some mods and runs a little better than the kx so my wfo feels like it pulls harder than the kx.

Now my question is, when jumping wfo on my bike the nose drops dramatically sometimes if there is a kicker. I thought my rebound was too fast on the rear end, on a small tabletop that i usually jump in 3rd pinned the front drops, but when jumping 4th gear 3/4 throttle required a brake tap nearly every jump. Jumping full throttle while leaning back makes me nervous, as does chopping the throttle on the lip (which works very nicely on short jumps that send you high) So is there a different technique?

I found that jumping wfo with a whip will keep me lower on smaller jumps, but i cant seem to do it on the bigger jumps for fear of my nose dropping. I always thought you were supposed to lean way forward when jumping (more throttle=more lean).

Also, gearing is a factor, and if a fast guy jumps a double in 3rd wfo on a 5 speed, am i going to need 4th on my 6 speed? My bike has similar sprockets to everyone else, but it still seems like its geared a little bit lower.

Any tips/advice, discussion would be great thanks.
 

tedkxkdx

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#2
How many bike lengths are the ramps you are speaking of? Are you topped out in those gears at WOT or is it powering on at WOT? How long are the jumps? i.e. a small ramp with one bike length and total jump length of 40ft.
The composition of the jump is important to then judge the correct advice.
Also since you are noticing a difference in your 96 to 03, I will say that when watching the old videos of 96 SX I see that bikes reacted differently than they do today. They did not seem to flow over obstacles as easy. more choppy.
 
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#3
well, when the nose drops im usually ready to shift to the next gear full throttle. so yeah almost all the way wound out. i dont jump things with the throttle wfo and the revs arent there cuz then the front goes high and it doesnt give enough power to jump the jumps.

an example of a jump im talking about are a few tables, one has about 2 bikelengths out of the corner before the jump. This is the one that i was nose diving on 3rd wfo. its about 20 ft long or so and sends ya about 8 feet or so into the air when jumped right. The ones im having trouble with are more like 50 ft. with a 2.5-3 bike length out of a corner that send you more like 12 ft in the air.
 
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#4
oops you were talking about the jump face. the face is about 1.5 bike lengths long with a pretty steep angle. and the short 20 ft one is about 2 bike lengths really steep face.

the 50 ft one out of the corner is tough to clear, but i know i could do it on a 250. I see a lot of guys that are wayyy slow in the corner and clear it like nothing on 250s. But ive never seen anyone do it without seat bouncing on a 125. I dont think ive even seen a C rider clear it on a 125, but im getting closer.
 

High Lord Gomer

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#5
Those sound tough! Got any pictures?

My guess would be one of three:

1. Backing off the throttle too early. Keep it pinned until completely in the air.

2. Possible over-rev of the motor. Power drops if you rev it out too far.

3. With short, steep faces you get abrupt transition from flat to upward. The natural tendency if to keep your body vertical as the front of the bike comes up when it hits the jump. When doing this you effectively lean forward on the bike and sometimes roll the throttle closed. I would try re-gripping the throttle in the turn prior so you have over-gripped the throttle and can maintain full throttle even when you're looking at the front fender going up the jump face.
 

tedkxkdx

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#6
If the bike is not accelerating much, like your near the rev out point then you could have a nose-drop situation. The ramp kickers or your body position affect the bike more when you have little acceleration on the ramp.
The seat bounce method is also useful since your power to ground is so much more than standing which could cause wheel spin on the high revving 125. The 250's are so much more powerful that they can do it much easier without wheel spin. Remember you make power with torque or rpm and a 125 is more with rpm in this case.
The smaller jump may require you to stay in 2nd. In 3rd you may be off the pipe enuf that as it hits the ramp you are decelerating, hence making it nose dive. If you ride this track most frequently I would suggest you play with rear sprockets to attain a better power gain for these specific jumps. I did it for my track and found that just one tooth extra was best for the overall course.
I don't agree that the faster you go the more you should lean forward on the bike. This is true when fighting the acceleration forces but not when you have already achieved the relative speed for the jump. Then the attack position, neutral, is best with of course some slight throttle up the ramp to fight decel forces.
I don't think I have seen anyone jump and actually be leaned back on the bike. The may be in an extreme attack position but not in the butt over the rear fender type of look when whooping.
In fact if you are leaned to far forward on the ramp you may be letting off the throttle when you body hits the ramp and goes more forward. So ensure that is not happening. Do you regrip the throttle a lot, I do.
 
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#8
well here's an old picture of me rolling the long jump i was talking about. They have since changed it, they pushed the corner closer and made the face steeper. The length is still about the same, the downslope starts right around the end of the picture.

I'm landing in the middle of the tabletop part right now and need a few more feet to completely clear it. I'm still getting closer though!

If the link works here it is... its kinda big sorry
www.geocities.com/kaiolink/ridepics/double.JPG
 

tedkxkdx

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#9
With their modifications they have since made to the jump I think it will be pretty tough to make it to the backside. Maybe you have to work on having more speed through the corner so you can have more pipe in 3rd.
 

KDXFreestyle

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#10
I also have a problem just like this when jumping. In the straight before the 60 or 70 foot table top... Ill get my bike maxed out in 3rd, but no matter what I do, because i think im wide open, or going really fast or something... Ill let off before the face then pin it again. If I dont do this on wide open jumps, or fast one, I think that ill nose dive. I am also comming up short on that table top, but kjnwo I can clear it. I just need to grab my balls to hit the jump in 4th, I think? I could use the help if you have any suggestions. thanks.
 

High Lord Gomer

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#11
It seems to be a significant hurdle for most people to get to the point of staying on the gas *all the way* to a jump. Many people play with the throttle just before a jump and still swear they don't. :)
 
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#12
KDX...I personally think it is easier to hit a jump in 4th 1/2 throttle than 3rd full throttle. Full throttle is twitchy and any little hand movement can have huge affects on the way a bike will take off. In 4th you can go the same speed but have more steady throttle control.

Alot of jumps right out of corners are usually good seat bouce jumps. You get more height that may compensate for a slower speed. The jump in the picture looks like a speed jump but you said they changed it. That doesn't look like a jump you would wanna come up short on...ouch!
 
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#13
hey guys, i was jsut reading through the forums to see wut i can learn, so um wuts seat bouncing?
 

High Lord Gomer

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#14
Staying on the seat all the way through the takeoff ona jump. It tends to compress the suspension more and then rebound you higher (and farther) into the air.

Dangerous to do without proper instruction...a common mistake is to not be on the gas hard enough.  The only time to use it is when you are already on the gas as hard as you can be and still need a little extra height / distance.
 
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#15
mmkay i made about a 4 foot high jump with about 3 feet wide and a little over a bikes length in length, i have a cr125, and this jump really gets warn down i only go off it like 15 times and there is a rut thats about 8 inches deep, this kinda freeks me out cuz if i dont hit the rut sometimes it swings my back end out or somethin and makes me do unentenchinable tail whips, i have triedpacking this dirt just by jumping on it alot hehe, i dont have any other ways, does neone know if this is because of the dirt or should i just wait like for a few good rainstorms to pack it down, or another way i thought was maybe lay some boards over it so it wont rip teh dirt and the bikes weight will be pressing on it, ne tips on packign will help, thanx guys