January 26th, 2017, 11:15 AM | #1 |
One ugly son of a gun.
Name: Andrew
Location: Raleigh, NC
Join Date: Sep 2016 Motorcycle(s): 2012 250 Posts: 167
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Wobble at high speed, and carb question...
Hey guys! Got a couple quick tech questions. First, I have a slight wobble at high speeds. It's in the front bars, and it's only when I let go of the bars (I know, I know, I shouldnt be letting go of the bars, but how am i supposed to stand up on my bike at 70mph if I can't let go???). Anyway, if I am going 50mph+ and let go of the bars, the front shakes back and forth. Recently I had an absent minded motorist bump the back of my parked bike- she was pulling into a parking space and didnt see it there. It hit the curb in front of it and fell over. I was literally standing right there and saw the whole thing go down, I almost cried after I almost punched her. Not really- but I was a little upset. I noticed the wobble after that, but it could have been there before. What do you guys think I should check? I can't feel it if I'm holding the bars, it's only when I release them...
Next... what is the difference in the STOCK carbing of the 2007 and earlier (pregen) and this bike (2012)? Is it the same carb? Same jets? The reason why I ask is because I have a 2007 that's just sitting and it has a needle kit in it. I'm wondering if I can swap out the carbs (or the guts) instead of buying a whole new kit/jets/etc. Any info? Thanks guys! |
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January 26th, 2017, 11:52 AM | #2 |
Guy Who Enjoys Riding
Name: Jim
Location: North Carolina
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The first think I'd do is get the wheels off the ground and spin them to see if they're true. A wheel could have gotten bent in the hit.
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January 26th, 2017, 11:55 AM | #3 |
dirty boy
Name: Joe
Location: Johnstown, PA
Join Date: Sep 2012 Motorcycle(s): I don't even know anymore?? Posts: A lot.
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the wobble you feel could be lots of things. flat spot on the tire, bent wheel, unbalanced, loose bearings somewhere. Do you still have the bar end weights on the bike?
As far as the carb. I am pretty sure the carb itself is the same for the most part but jetting and needles are probably different. No guarantee the jets from one carb/bike would work well in another even if they are very similar. You could certainly check the jetting recommendations and or what other people are running and if those jets ect... fall into the range then give them a go but if you don't really know anything about carb tuning probably best not to mess around with it. What is wrong with your carb/jets now?
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January 26th, 2017, 11:58 AM | #4 | ||
One ugly son of a gun.
Name: Andrew
Location: Raleigh, NC
Join Date: Sep 2016 Motorcycle(s): 2012 250 Posts: 167
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Quote:
Quote:
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January 26th, 2017, 12:34 PM | #5 |
Rev Limiter
Name: Jay
Location: WI
Join Date: Jul 2013 Motorcycle(s): '06 SV650n, '00 Derbi GPR, '64 CA77 Dream 305, '70 CL450 Scrambler, numerous dirt bikes Posts: A lot.
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As TJ noted - check the rims.
Are the bars pointing straight when you are going straight? Sometimes a tip-over can tweak the front end. How old are the tires? Properly inflated? Have you checked the steering head bearings? Hold the front brake and push/pull forward/backward on the bars. Listen and feel for any clicking or clunking from the bearings. Check the rear wheel alignment carefully. Measure from the center of the axle to the center of the swingarm pivot on both sides and compare. The hash marks on the swingarm aren't always very accurate, sometimes not accurate at all. |
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January 26th, 2017, 01:02 PM | #6 | |
One ugly son of a gun.
Name: Andrew
Location: Raleigh, NC
Join Date: Sep 2016 Motorcycle(s): 2012 250 Posts: 167
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Quote:
I will check the other two things you mentioned as well, thanks for the input. |
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January 26th, 2017, 01:17 PM | #7 |
Guy Who Enjoys Riding
Name: Jim
Location: North Carolina
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If you do have a bent wheel, Woody's Wheel Works is known to do a good job straightening. I can't vouch for cost effectiveness of straightening vs. used wheel, but I'm sure you can figure that out.
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January 26th, 2017, 01:21 PM | #8 |
not an actual panda
Name: dan
Location: philadelphia
Join Date: Aug 2012 Motorcycle(s): 2008 Ninja 250, 2009 CBR600RR (Sold) Posts: A lot.
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The front end wobble is not atypical. Mine will wobble as a decelerate from 60 to 30. IIRC it starts wobbling right around 45MPH.
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January 26th, 2017, 01:24 PM | #9 | |
One ugly son of a gun.
Name: Andrew
Location: Raleigh, NC
Join Date: Sep 2016 Motorcycle(s): 2012 250 Posts: 167
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Quote:
That's what it's doing. As I said, problem could have been there all along and I only now noticed it. It's only on deceleration, but it's also not so bad that I can feel it even when I lightly hold the bars. When I let it go, though, it's a little scary. Feels like I'm about to get a tank slapper.. |
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January 26th, 2017, 01:29 PM | #10 |
Guy Who Enjoys Riding
Name: Jim
Location: North Carolina
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That problem usually shows up when the front tire starts to get worn with a triangular cross section, pointy in the middle.
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January 26th, 2017, 01:45 PM | #11 |
One ugly son of a gun.
Name: Andrew
Location: Raleigh, NC
Join Date: Sep 2016 Motorcycle(s): 2012 250 Posts: 167
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Explain please. I'm assuming you mean that it loses its "round" and has a high spot in the center? How would that even happen? I understand the logic of it- the tire doesnt want to sit on that high spot so it rocks back and forth causing the bars to wiggle and wobble... but I'm just wondering what would cause that wear other than costantly taking lefts and rights and never going straight lol.
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January 26th, 2017, 01:51 PM | #12 | |
One ugly son of a gun.
Name: Andrew
Location: Raleigh, NC
Join Date: Sep 2016 Motorcycle(s): 2012 250 Posts: 167
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Quote:
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January 26th, 2017, 01:53 PM | #13 | |
Rev Limiter
Name: Jay
Location: WI
Join Date: Jul 2013 Motorcycle(s): '06 SV650n, '00 Derbi GPR, '64 CA77 Dream 305, '70 CL450 Scrambler, numerous dirt bikes Posts: A lot.
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Quote:
Look them over closely. I have seen photos of stock tires that age that are cracking inside the tread - a sure sign the rubber is drying out. Even though you aren't planning to "drag a knee", you still want the superior traction of new tires for normal riding. In the event that you ever need to make a full-on emergency stop you are going to want that extra grip instead of a lock-up - which is what an old, dry, tire is going to give you. |
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January 26th, 2017, 01:57 PM | #14 | |
One ugly son of a gun.
Name: Andrew
Location: Raleigh, NC
Join Date: Sep 2016 Motorcycle(s): 2012 250 Posts: 167
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Quote:
You're right- I'm just cheap. I guess I didn't think of an emergency stop scenerio. Glad to be here. |
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January 26th, 2017, 02:17 PM | #15 |
Rev Limiter
Name: Jay
Location: WI
Join Date: Jul 2013 Motorcycle(s): '06 SV650n, '00 Derbi GPR, '64 CA77 Dream 305, '70 CL450 Scrambler, numerous dirt bikes Posts: A lot.
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Ha! My boys have heard that lecture many times...and it's probably saved them just as many times...
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January 26th, 2017, 02:23 PM | #16 | |
Guy Who Enjoys Riding
Name: Jim
Location: North Carolina
Join Date: Jul 2016 Motorcycle(s): Ninja 250 Posts: A lot.
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Quote:
I don't know the physics of why, but when my front tires get that way, they get noticeably squirly. One symptom is the no-hands wobble around 35 mph that you're seeing. Another I'm getting now on my Moto Guzzi is the tendency to "fall into" turns. When my front tire was new, steering was very neutral, and it felt like I could take my hands off the bar in a turn and it would just keep going around. Now on a sharp turn, the bike feels like it wants to fall over to the inside, and I have to consciously turn sharper to straighten it up. A new pair of tires for that bike is waiting for me to put them on. By the way, tire aging is quite variable. If your bike is stored indoors without any direct sunlight on the tires, and if you live away from big cities that have ozone problems, your tires may be fine. On the other hand, if you do park outside in daylight in a big city, they may be getting oxidized and hard by now. I'm in the garage parking, country air category, and six years of aging doesn't change my tire rubber much, on bikes that don't get a lot of miles on them. |
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1 out of 1 members found this post helpful. |
January 26th, 2017, 04:46 PM | #17 |
ninjette.org sage
Name: John
Location: Appleton, WI
Join Date: Apr 2015 Motorcycle(s): Ninja 300 (race), Ninja 1000 (road) Posts: 504
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People need to recognize all the interacting factors that cause head shake. It's not just one thing. Bearing wear and slop, head nut torque (and that's the nut under the top triple clamp), uneven side to side tire wear (cupping), size of the contact patch, frame flex and fork flex. If a few conditions line up just right, the head shake appears. Change one thing in this equation and the end result might not = head shake.
Putting new tires on has small chance at changing the equation enough to make the head shake go away. But for most people, replacing the head bearings has a much higher chance of doing something. I've heard a few people say new tires didn't solve the problem, but I've never heard anyone say that new head bearings didn't work. That said, people should first check the front tire visually by spinning it and looking for cupping, and checking the torque of the stem nut. These are the cheap and easy checks. BTW, I believe a front tire that is worn with a flat spot, or a sport touring style tire that has a larger upright contact patch is more likely to contribute to head shake. Pointier tires, such as true supersport, or tires that are seriously worn from track use are likely to feel "skittish" and fall into turns but actually be less likely to cause head shake. Two completely different issues not to be confused.
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January 26th, 2017, 09:01 PM | #18 | |
Daily Ninjette rider
Name: Hernan
Location: Florida
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Quote:
http://faq.ninja250.org/wiki/How_doe...ometry_help%3F http://faq.ninja250.org/wiki/Servicing_the_swingarm http://faq.ninja250.org/wiki/Uni_Tra...ge_Lubrication http://faq.ninja250.org/wiki/Steerin...ng_replacement
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January 27th, 2017, 07:32 AM | #19 | ||
One ugly son of a gun.
Name: Andrew
Location: Raleigh, NC
Join Date: Sep 2016 Motorcycle(s): 2012 250 Posts: 167
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Quote:
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January 27th, 2017, 08:40 AM | #20 | |
One ugly son of a gun.
Name: Andrew
Location: Raleigh, NC
Join Date: Sep 2016 Motorcycle(s): 2012 250 Posts: 167
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Quote:
Curiously enough, I think you have helped me with ANOTHER bike by sending me this info. According to the first post, forks that are bent *but not creased* can be straightened. I have a 2007 pregen 250 that was in a head on collision with a car (see my post in the pregen section for pics). The front forks are bent so bad that the center stand doesnt even hold the bike off the ground anymore. However, there are no creases- so apparently these forks can be straightened. Good info! |
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January 27th, 2017, 08:53 AM | #21 | |
Guy Who Enjoys Riding
Name: Jim
Location: North Carolina
Join Date: Jul 2016 Motorcycle(s): Ninja 250 Posts: A lot.
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Quote:
In my case, all bearings are properly adjusted and in good condition and my wheels are true. The head shake I'm referring to is most likely initiated by the tire being slightly out of true, combined with the peaky wear. The shake, which happens when going through about 35 mph, usually when coasting to a stop, is at wheel speed. It's not severe, and stops if the bar is gripped normally. It was not present when the tire was new. I've had it happen over the decades with some tires when they get worn, but not with other tires. The Pirelli Sport Demon I'm getting ready to replace was not made perfectly, and from the start I could see a slight side to side out of true. Your point is a good one, John. If there's any head shake, the bike should be checked for looseness in any place related to steering and wheels. But in my experience, even if everything is good, it can still be noticeable with a front tire that's approaching its end of life. |
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January 27th, 2017, 02:30 PM | #22 | |
ninjette.org sage
Name: John
Location: Appleton, WI
Join Date: Apr 2015 Motorcycle(s): Ninja 300 (race), Ninja 1000 (road) Posts: 504
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Quote:
A new set of All Balls tapered bearings solved my problem with no other work. Not only that, I could feel a difference in the bike, it felt more planted and stable in corners. In general I get the feeling that people chasing after tire or wheel issues are likely barking up the wrong tree. But nobody wants it to be the bearings because they are a huge pain in the ass to change out. Hard to DIY in your garage and expensive to bring in. But it's something I recommend every ninjette owner do, even those who don't have a head shake problem yet.
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Ninja 300 - CCS Ultralight Thunderbike Racing I want to "like" your post but I can't due to forum rules. Sorry. |
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January 27th, 2017, 02:34 PM | #23 |
Guy Who Enjoys Riding
Name: Jim
Location: North Carolina
Join Date: Jul 2016 Motorcycle(s): Ninja 250 Posts: A lot.
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Nearly 40 years ago I put a grease fitting in the head tube of my H2. The original ball bearings are still like new, not notchy, and stay adjusted. It's amazing what good lubrication and the sealing out of moisture can do. But one of my motorcycles needs new head bearings and I have the tapered rollers ready to go in. Unfortunately the previous owners didn't maintain the originals.
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February 11th, 2017, 05:43 AM | #24 |
ninjette.org newbie
Name: Steve
Location: lincoln ne
Join Date: Oct 2015 Motorcycle(s): 2012 Ninja 250, 2004 Harley FLHTPI Posts: 6
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First things first. Check your tire pressure then adjust your neck bearings. That took care of my deceleration wobble.
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February 11th, 2017, 02:21 PM | #25 |
ninjette.org certified postwhore
Name: Roger
Location: Mitchell, South Dakota
Join Date: Apr 2014 Motorcycle(s): 1978 Z1R, 1999 EX250 Posts: A lot.
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As already stated, many things can start weaves or wobbles, many times multiple things acting together. Most bikes will exhibit bar shake when slowing without hanging onto the bars at around 45 MPH, some brands or types of tires in the same brand, will damp this and others can make it worse, no way that I know of to know which type or brand works best with each bike as they all have different chassis harmonics. I've also had bikes head shake because of dented steering head bearings and also from the bearing being adjusted too tight. Here's some interesting reading on the subject.
https://books.google.com/books?id=mt...monics&f=false
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