Jerking

[Mekkakat]

So I'm in the middle of shimming my needles (as soon as I fight the right freaking washers), and I was thinking about something that also kinda worried me.

The main reason I wanted to shim was to fix how chuggy the bike was in 1st and 2nd gear (and sometimes 3rd too), because it's jerking me all around in turns and rush hour traffic.

However, when I am in neutral and shift to first to begin riding, the bike jutts forward. Equally, if not worse, if I start the bike in first, it tries to pop forward a bit.

Is that normal? Should I be worried or is this all stuff I need to stop being paranoid about?

[greg737]

The "chuggy" feeling you're describing is excessive play in the drivetrain.

The number 1 worst offender in EX-250 drivetrain play is the Cush-Drive assembly in the rear wheel hub. You can correct this by "shimming the cush drive" as directed in this proceedure: http://faq.ninja250.org/wiki/How_to_shim_the_cush_drive

The second biggest contributor to EX-250 drivetrain play is a poorly adjusted chain. If you shim the cush drive then you'll have to re-adjust the chain after you're finished, so that will take care of itself.

Now, about the "bike jutts forward when I shift out of neutral," that is completely normal. It's just a characteristic of bike's clutch system. Don't worry about it at all. Relax and read this: http://faq.ninja250.org/wiki/Why_is_...27clunky%27%3F

When you're at a standstill, preparing to put it in first and ride away, if you pull in and release the clutch lever a couple of times while you're still in neutral, then pull it in again and shift into first you'll find that the "jutt" is reduced substantially.

[CZroe]

Originally Posted by greg737

The "chuggy" feeling you're describing is excessive play in the drivetrain.

The number 1 worst offender in EX-250 drivetrain play is the Cush-Drive assembly in the rear wheel hub. You can correct this by "shimming the cush drive" as directed in this proceedure: http://faq.ninja250.org/wiki/How_to_shim_the_cush_drive

The second biggest contributor to EX-250 drivetrain play is a poorly adjusted chain. If you shim the cush drive then you'll have to re-adjust the chain after you're finished, so that will take care of itself.

Now, about the "bike jutts forward when I shift out of neutral," that is completely normal. It's just a characteristic of bike's clutch system. Don't worry about it at all. Relax and read this: http://faq.ninja250.org/wiki/Why_is_...27clunky%27%3F

When you're at a standstill, preparing to put it in first and ride away, if you pull in and release the clutch lever a couple of times while you're still in neutral, then pull it in again and shift into first you'll find that the "jutt" is reduced substantially.

Actually, he may want to check his clutch cable adjustment. Yes, there is some movement with the clutch lever pulled in as you downshift (enough to turn the rear at idle speed if up on a stand), but it isn't supposed to be enough to pull you or jerk you.

[DaBlue1]

Originally Posted by Mekkakat

...The main reason I wanted to shim was to fix how chuggy the bike was in 1st and 2nd gear (and sometimes 3rd too), because it's jerking me all around in turns and rush hour traffic.

What rpms are you chugging around at in those gears?
What do you mean by jerking around turns and rush hour traffic?
What is the condition of your chain? An old chain with binding links can cause a jerking feel.
Also check to make sure that your oil is at the proper level. Too much oil can also cause a slight jerk or clunk when shifting from neutral to 1st.

[Live2ride]

I have the same issues with my new gen but I always though it was normal . The jerking from the neutral to first shift is especially noticeable, it is a slight jerk (not like dropping the clutch in first by accident) but it still lurches forward an inch or two. As far as the jerking in lower gears goes, I get that a lot. I try to feather the clutch to ease the jerks but it only helps so much. If I let off the throttle in first there is a really hard jerk that engine brakes very roughly and abruptly. Apparently shimming the carb needles is supposed to help with the jerkiness but I'm not willing to suffer gas mileage considering it can apparently make a rather large difference in mpg; maybe 10-15 mpg, I've heard of people getting as low as 42mpg after shimming the needles.

[CZroe]

Originally Posted by Live2ride

I have the same issues with my new gen but I always though it was normal . The jerking from the neutral to first shift is especially noticeable, it is a slight jerk (not like dropping the clutch in first by accident) but it still lurches forward an inch or two. As far as the jerking in lower gears goes, I get that a lot. I try to feather the clutch to ease the jerks but it only helps so much. If I let off the throttle in first there is a really hard jerk that engine brakes very roughly and abruptly. Apparently shimming the carb needles is supposed to help with the jerkiness but I'm not willing to suffer gas mileage considering it can apparently make a rather large difference in mpg; maybe 10-15 mpg, I've heard of people getting as low as 42mpg after shimming the needles.

I've gotten worse without shimming anything and with 15:41 sprockets (should increase economy).

[Live2ride]

Originally Posted by CZroe

I've gotten worse without shimming anything and with 15:41 sprockets (should increase economy).

Hmm, I was thinking of shimming the needles, removing the snorkel and getting a 15t front sprocket to keep the mpg roughly the same as stock and have 1st gear actually be somewhat useful. I may try it for 1 tank and see the difference in mpg / jerkiness to see if the pro's outweigh the con's. If it does work well (if I do it) then I'll definitely chime back in on this thread to let you know .

[setasai]

As greg737 said, check the cush drive. I have the same jerking issue and posted about that in another thread. It's a free "mod" (I guess you'd call it) that doesnt affect MPG but should remove the throttle jerking issue.

If you can wait, i'll be doing it tomorrow and I'll let you know if it works for me.

[kkim]

http://www.ninjette.org/forums/showthread.php?t=70898