Throttle control for jumps

[jim7411]

Okay, I am new to the two stroke world. I just bought an '05 YZ250 and I still have an '02 YZ250F. On the thumper I always stated steady throttle off a jump so that it would not nose dive excessively from engine braking. I have read that the YZ250 has a tendency to jump nose-high. So I took a jump and sure enough, it went straight up. I talked to another guy at the track who told me to soften my suspension way up and let the suspension break in. I did this and it helped a lot but I am leary of the way it is going to sail if I hit it harder and with the new power and learning curve, I am nervous to launch it. I also talked to them about throttle control and one told me to run up to the base of the jump then ease of the gas and let it go from there. He said this helps bring the nose down. I know if I keep the gas on steady up the jump face it's going to go nose-high. So how do you control the throttle for a two stroke when approaching a jump all the way through take off? Right now with the new bike I am not even jumping the small 30 -35 foot tables that I was before because of the unknown flight path.
This is a fantastic bike and I am gong to really love it when I get it in the air a bit more but right now I am just trying to stay out of everybody's way because I am riding so slow on this thing.
I am thinking that on small jump faces like 3-4 feet high I should race up to it then ease of the throttle right before the jump and let it "coast" off the jump. Then on larger jumps with a 10 to 12 foot ramp I should run it up about half way to three quarters way up the face before easing up and coasting off. What do you suggest?
At last practice I left the thumper home until I get myself comfortable on this bike. Then I will bring them both out to the track and race the 125 and 250. Right now there is no use even trying to race the 250 because I just feel that I can't even ride it smooth enough yet on the track. Our track is all sand and I also had the stock tires on when I went to practice which also made me feel un-easy. But the 773's are here and I am itching to get back out when there are not as many people to contend with while I try to work the bugs (butterflies) out. :laugh:

 

[Studboy]

Jim,

I've jumped almost everything from big doubles and tables to freestyle ramps with my YZ, and I've had quite a few of those really nose high experiences.

What is usually happening is that I'll hit the power hard on the jump/ramp, and it will throw my body back on the bike, making me go nose high. I couldn't really feel this happening when I was on the bike, but from watching videos of myself when I've done it I've figured it out.

To prevent this, either jump a gear higher to smooth out the power a bit (not recommended on super steep jumps), or everytime you are going to jump, contiously think to yourself about rolling on the throttle smooth instead of hitting it, all the time making sure that you keep your body pulled forward on the bike.

 

[jim7411]

Thanks for the reply. I may be doing what you said but I was thinking about how I needed to stay way forward on this bike and when I took the jump I had my head over the front number plate and it still went high. But I did take the jump before I adjusted the suspension so maybe that had alot to do with the inital nose high. I will have my son video tape me and see what I may be doing wrong and If I loop out then I will have a nice video to post here. So it's a win/win situation.

 

[Studboy]

I will have my son video tape me and see what I may be doing wrong and If I loop out then I will have a nice video to post here. So it's a win/win situation.

Agreed. :p I should post the one of me doing a near loop out off of an FMX ramp... not a good feeling! :yikes:

 

[lwsmithjr]

I think the dynamics are actually caused by the Gyroscopic effect of the rear tire rotating. Because a two stroke accelerates so easily and quickly, if the gas is still on as you leave the face of the jump, the rear wheel accelerates RAPIDLY and shoots the nose up in the air. If you chop the throttle right as you leave the face, the effect would be greatly reduced even if you accelerated hard up the face. If you back off on the approach then the deceleration will cause the nose to drop.

Having said all of that, after only riding a four stroke for a year, after 18 months back on a two stroke, I STILL struggle. Especially on jumps out of turns....A four stroke takes some of the thinking out of the equation. Of course for me, knowing HOW to do something and actually being ABLE to do it are two different things!!

 

[SpectraSVT]

Do you know how to use rear brake? If so I would be ready to use it every jump til you get used to a 2 stroke. I actually had a similar experience but reversed. I rode a 4stroke on a big jump track and the nose kept dropping all the time by itself. I personally would rather loop out then endo. You can break wrists landing nose first. The YZ, for me anyways, requires alot of different body positions for jumping. Sometimes I'm way back, other times I'm way forward. Keep practicing and taking it slow like your doing it now.

 

[the_monk]

I know nothing about jumping. That being said, I just read an article in some dirtbike rag that mentioned something about "chopping the throttle just before take off will unload the rear spring, causing the front to drop on take off".

Makes sense to me. Rear shock is compressed on acceleration to the jump, chopping (or letting off quite a bit) near the lip should cause the rear to unload and transfer the bike (and probably some of your) weight to the front tire with very little effort on your part.

Again, the only jumps I've ever done are by accident. The grain of salt is a 10lb salt lick.

 

[pace]

My advice is to shortshift and carry a taller gear on the face of the jump, while holding a light throttle to maintain velocity. Once you're in the air, you have a few options. You can use body english to modestly raise or lower the nose, and get the bike to follow your intended arc. Pushing on the bars and optionally closing the throttle (in the air) is going to pitch the bike down. Secondly, you should learn how to brake tap as it's really the only way to abruptly pull the nose down in a panic situation. However, you can also routinely use the technique immediately after leaving the ramp to preemptively correct a nose-high flight path. Make sure you grab a little clutch before hitting the rear binder!

Once you're comfortable with jumping the two stroke, I think you'll find that you can adjust the pitch of the bike pretty much on-demand in a more responsive manner than a four. The key to learning to jump however is mastering throttle control on the jump face. I see a surprising number of riders - even intermediates - going nose high followed with scary rear-wheel landings because they have never learned the fundamentals of setting up body position and throttle for the takeoff ramp.

-pace

 

[i_955]

Keep the throttle neutral. If you gas it the front will be high. If you chop the throttle you better be ready to have the seat kick you hard in the a$$ and over the bars you'll go.

Baby steps, you'll get it in no time. They fly great.

 

[High Lord Gomer]

Merely letting off the gas while in the air on a 4 stroke drops the front end (due to the engine braking slowing the rear tire rather dramatically). Letting off on a 2 stroke doesn't do this. To get the same effect, you'll need to pull the clutch and hit the rear brake.

Or, as mentioned early, it is better to get the proper body positioning to match your takeoff acceleration.

 

[crazy_man]

be sure to pull the clutch in when you hit the rear brake in air, i saw this guy try to hit his brake in air and locked up the rear wheel and you could hear the clutch slip big time, sure nuff the clutch quit on him on the straightaway(the jump was right before the straight)it was pretty funny but the guy was :pissed: cause he was in 2nd place

 

[High Lord Gomer]

Are you sure that was the clutch and not the flywheel shearing off the woodruff key?

Almost every time I've seen someone (or done it myself) hit the brake without pulling the clutch, it kills the motor in the air. (...and it gets *real* quiet in the air without the motor running)

For the clutch to be bad enough to slip and let the motor continue running, I don't think it would have been working well enough to move the bike, anyway.

Shearing a woodruff key on the flywheel would result in the bike missing, sputtering, and even backfiring.

 

[crazy_man]

i think it was the clutch cause the motor was running fine it made a nasty sound and he lost acceleration, i think it was in 2nd gear with the motor revving high and he still had the gas on when he hit the brakes, he was a beginner so i dont think that he knew how to do it properly

 

[Studboy]

I'm pretty sure that hitting the brake in the air wouldn't break the clutch.
Something else happened.

 

[crazy_man]

de diddnt "break" the clutch, when he hit the brakes the clutch slipped, it sounded nasty, not like a wooddruff key sheared off, it was a slipping sound, he was using the clutch to keep the revs up the whole race, so the clutch was prabably worn a bit, the jump was a small table top then a sharp u turn, he was slipping the clutch a lot to keep the revs up around the u turn (it was a 2stroke), who knows what kind of maintainence he did to the bike? im almost positive it was the clutch

 

[Redcrasher]

If you learn to blip the throtel to bring the front wheel up, or tap the rear brake to bring it down you can hit a jump anyway you want and adjust in the air. When you pull in the clutch to tap the brake it help rev it a little to keep the engine running, somtimes the clutch still has enough drag to kill it

 

[ellandoh]

You should keep a steady acceleration through the ramp and then let off the throttle as soon as your rear tire leaves the ramp. so ive been told .unless its a kicker style....obviously.

2 strokes dont have near the engine braking as 4 strokes . i dont know if i even keep on throttle till the rear tire leaves, i believe i let off somewhere between when the front tire is on the lip and when rear is on lip its subconcious but you stated this track is sandy and i know i keep an even throttle longer when riding sand due to the extra drag. i hit every jump as if i want to land level then english it in the air to match the attitude of the down ramp if hit perfect or nose high for unexpecteds. however i love the feeling of leaning over the plate and yanking my legs up to get the downramp smooooooooooth