Something seems unbalanced... Tach needle bouncing

Avaholic88 · June 28th, 2010, 11:35 AM

First a disclaimer: Being very new to riding, and owning this first bike for less than a year, I'm a bit of a drama queen, making a fuss over things that sometimes are really nothing. BUT:

I've recently noticed a slight repetitive jerking while riding. My fuel economy hasn't suffered (this dummy's gauge for engine problems) so I don't think efficiency is lost, but it's worst between 6500-7500 rpm in each gear. I notice the tach needle is bouncing slightly, I feel a light bounce in the bike, and I can definitely hear the engine speed "wavering" at a constant rate that increases and decreases with engine speed, not road speed.

It disappears when I am applying more throttle and accelerating, returning when I ease off a bit and want to maintain speed or decelerate slightly.

I first noticed this a couple hundred miles after my 7500 mile service, and though I doubt it's a big deal (see disclaimer) I want to make sure and mention it in case it's a red flag that I should investigate before it becomes a safety or expense risk.

Thanks everyone. I love this site.

kkim · June 28th, 2010, 11:43 AM

Is your jetting/intake/exhaust stock?

Avaholic88 · June 28th, 2010, 11:45 AM

Quote:

Originally Posted by kkim

Is your jetting/intake/exhaust stock?

Yep everything is stock.

kkim · June 28th, 2010, 11:49 AM

would you characterize it as a stutter during light, steady throttle applications while at higher cruising speeds with the throttle just barely cracked open?

do you know what all they "adjusted" during your service?

Avaholic88 · June 28th, 2010, 12:02 PM

Quote:

Originally Posted by kkim

would you characterize it as a stutter during light, steady throttle applications while at higher cruising speeds with the throttle just barely cracked open?

do you know what all they "adjusted" during your service?

Yeah that describes it pretty well...

I do have what seems to be a low-detail list of the work they did, but it's at home (currently slacking on the job). I can post it up when I get it if that will help.

kkim · June 28th, 2010, 12:10 PM

what you are experiencing seems very similar to a lean jetting condition in the pilot circuit usually experienced by those rejetting their carbs and having the mixture screws set a bit too lean.

I doubt the dealer adjusted the mixture screws, so it might be something else related to making the bike running a little leaner. If you could check what you have related to work done, it might help track down the possible problem quicker w/o having to guess.

Avaholic88 · June 28th, 2010, 12:14 PM

Quote:

Originally Posted by kkim

what you are experiencing seems very similar to a lean jetting condition in the pilot circuit usually experienced by those rejetting their carbs and having the mixture screws set a bit too lean.

I doubt the dealer adjusted the mixture screws, so it might be something else related to making the bike running a little leaner. If you could check what you have related to work done, it might help track down the possible problem quicker w/o having to guess.

Ok thanks very much for the help. I'll grab the paperwork tonight and maybe contact them to ask about it. I'll post up about the work done if I'm still clueless.

kkim · June 28th, 2010, 12:15 PM

thanks, that would help.

one last thought... is you chain adjusted to specs??? at least 1" of free play? perhaps they overtightened it?

Avaholic88 · June 28th, 2010, 12:25 PM

Quote:

Originally Posted by kkim

thanks, that would help.

one last thought... is you chain adjusted to specs??? at least 1" of free play? perhaps they overtightened it?

I believe it is adjusted properly since I remember it being one of their work items, but I haven't checked it myself. I'll do that as well. Thanks

Alex · June 28th, 2010, 12:58 PM

I don't want to jump immediately to the CDI issue, but one of the symptoms is the tach bouncing a bit in the 7500 rpm range, here's a thread with all of the gory details:

http://www.ninjette.org/forums/showthread.php?t=21043

Might have nothing to do with it, but if you can duplicate the tach reading differently when warm, that might be an explanation for what you're seeing.

kkim · June 28th, 2010, 01:12 PM

yeah, I purposely avoided mentioning the CDI issue until we eliminated possible service related (simple fix) causes.... didn't want to send him into a panic.

Avaholic88 · June 28th, 2010, 01:37 PM

Quote:

Originally Posted by Alex

I don't want to jump immediately to the CDI issue, but one of the symptoms is the tach bouncing a bit in the 7500 rpm range, here's a thread with all of the gory details:

http://www.ninjette.org/forums/showthread.php?t=21043

Might have nothing to do with it, but if you can duplicate the tach reading differently when warm, that might be an explanation for what you're seeing.

It's definitely possible, because the symptoms are less noticeable on my morning commute, while more pronounced in the hotter afternoon commute home. That tach reading jump in hot weather has happened, but only once. It was definitely the hottest temp I've ridden in, and I was surprised to see the tach up around 10.5k instead of 9k at 75 mph...

Avaholic88 · June 29th, 2010, 09:39 PM

Proving that my rightful place as king of the noobs is still all mine, I checked my chain and realized it is way, way loose. Either it wasn't adjusted properly during the service or I've just been paying far too little attention to it. Either way, I fail as an owner.

It's got more than 2 inches of slack, which I imagine is approaching unsafe riding conditions. The physics involved in causing the symptoms I've described make sense in my head, so I'll bet I've found the primary issue. I'm quite surprised that my fuel economy hasn't suffered because of it, and hopefully my idiocy hasn't led to damage, though I didn't notice any unusual wear.

So, because I'm still too much of a bum to invest in the necessary tools (though I will very soon), I've got a message in with the shop asking for the soonest 20 minutes of their time for a quick adjustment and inspection. I've also located the nearest torque wrench and cotter pins.

If I had a tail, it would be between my legs in shame

Alex · June 29th, 2010, 10:03 PM

I hadn't seen this here, I would have just answered here first instead of SBR. Sorry about that!

kkim · June 29th, 2010, 10:46 PM

Glad you found a possible fix for the problem, Nate.

Adjust the chain yourself and be free of having to take it to a shop.

Speaking of newbs

here's an interesting thread to help you with chain adjustment.

http://www.ninjette.org/forums/showthread.php?t=13833&

Daeldren · June 30th, 2010, 03:21 AM

Something simple you may want to check before jumping to the cdi issue is to double check your battery terminals. I had a similar problem but mine was more pronounced and it was caused by a loose connection on the battery, when I hit bumps the connection would come loose causing the tach to jump and the engine to rev.

Avaholic88 · July 7th, 2010, 04:04 PM

I adjusted my chain and during the process found a real mean tight spot. It's pretty long and there's a big difference in slack between the tightest part of that tight spot and the rest of the chain. I adjusted the slack to spec at that tightest spot, which left other sections seeming way too loose. I think I found the REAL problem.

Additionally, when I hopped on after the adjustment, those symptoms I've been telling you about were WORSE, which I guess I should have expected I suppose since I had just tightened a chain that had a tight spot. It was so bad initially that I felt (and heard) an intermittent grinding/rubbing vibration (which I'm pretty sure was the tight spot going over a sprocket, and which I also assume is very, very bad).

I loosened the chain a little, scared to loosen it so much as to run the risk of it jumping off, but also scared of the wear it was putting on my sprockets. I can still feel a little of that rub each time the tight spot goes 'round, and wouldn't you know it, it occurs at the exact same frequency as the engine wavering, tach needle dance, and jerky motion I originally complained about.

I think I'm finally ready to solve the true problem, and since I can't seem to find any solutions for a tight spot on the interweb, it looks like I better fork over for a new chain. I plan to keep riding the 34 miles a day until then, though, so yell at me if I'm being an idiot. Thanks guys

kkim · July 7th, 2010, 04:29 PM

Nate,

can you tell what's causing the tight spot? rust, damaged chain, dirty????

you might be able to loosen up the stiff section with some penetrating oil (PB Blaster, Liquid Wrench or something similar) if the tightness is not being caused by a damaged chain.

An overly tight chain is bad for the sprockets, but even worse for the rear wheel bearings and engine bearings on the output shaft.

Avaholic88 · July 7th, 2010, 05:26 PM

Quote:

Originally Posted by kkim

Nate,

can you tell what's causing the tight spot? rust, damaged chain, dirty????

you might be able to loosen up the stiff section with some penetrating oil (PB Blaster, Liquid Wrench or something similar) if the tightness is not being caused by a damaged chain.

An overly tight chain is bad for the sprockets, but even worse for the rear wheel bearings and engine bearings on the output shaft.

I honestly can't see anything that would make me think it's causing a tight spot. I've kept it well cleaned and lubed (just not well adjusted

) so no rust or dirt... All the links look to be fine, but I may not be able to recognize damage.

kkim · July 7th, 2010, 05:36 PM

try the penetrant and see if it helps to loosen up the tight spot.

so, if you adjust the chain slack for one inch when the chain is at its tightest, how much slack do you have if you rotate the chain to the loosest spot?

Avaholic88 · July 12th, 2010, 09:28 AM

Quote:

Originally Posted by kkim

try the penetrant and see if it helps to loosen up the tight spot.

so, if you adjust the chain slack for one inch when the chain is at its tightest, how much slack do you have if you rotate the chain to the loosest spot?

The loosest section has about 2.25 inches of slack when the the tight section has about 1 inch. I'm gonna pick up some penetrant on the way home tonight, and I spose I'll order a new chain and sprockets if that doesn't help even the chain out...

kkim · July 12th, 2010, 10:54 AM

do you store/park your bike outdoors?

Avaholic88 · July 12th, 2010, 11:40 AM

Quote:

Originally Posted by kkim

do you store/park your bike outdoors?

It's stored in a covered carport, so technically outdoors, yes. I thought I did a pretty good job of keeping the chain clean and lubed, but I might have slipped up at some point.

Avaholic88 · July 12th, 2010, 11:43 AM

About to order a set of AFAM chain and sprockets, so hopefully that'll work out. And yeah I'll do a better job maintaining them this time.

kkim · July 12th, 2010, 12:03 PM

yes, a 1.25" difference from tight to loose is quite a difference. Only thing I can think of is that the chain is rusty in one section and binds up a bit to make it "tight".

since you're ordering a new chain/sprockets, I'd try the penetrant trick to see if you can loosen up the chain, just to see what's up with the chain and to prevent this from happening again in the future.

GL

Avaholic88 · July 12th, 2010, 12:19 PM

Quote:

Originally Posted by kkim

yes, a 1.25" difference from tight to loose is quite a difference. Only thing I can think of is that the chain is rusty in one section and binds up a bit to make it "tight".

since you're ordering a new chain/sprockets, I'd try the penetrant trick to see if you can loosen up the chain, just to see what's up with the chain and to prevent this from happening again in the future.

GL

Yeah I've read in many places now that penetrants can be very damaging to o-ring chains when the dissolving abilities intended for rust go after the o-rings also. But, as you mentioned, I'll be replacing the chain anyway, so I'll give the penetrant a shot to confirm our theories.

kkim · July 12th, 2010, 12:27 PM

yes, there is always a small possibility of any chemical interacting with rubber parts, though it largely depends on the exact composition of the rubber. I've used penetrant many times near rubber parts and never had problems, then recently used it on some levers and the rubber mud shield swelled up and deformed.

you could try something like wd40 first, though it doesn't work nearly as well as penetrant to loosen up rusted up parts.

June 28th, 2010, 11:35 AM	#1
Avaholic88 ninjette.org member Name: Nate Location: Palo Alto Join Date: Aug 2009 Motorcycle(s): 2009 Ninja 250R Posts: 26	Something seems unbalanced... Tach needle bouncing First a disclaimer: Being very new to riding, and owning this first bike for less than a year, I'm a bit of a drama queen, making a fuss over things that sometimes are really nothing. BUT: I've recently noticed a slight repetitive jerking while riding. My fuel economy hasn't suffered (this dummy's gauge for engine problems) so I don't think efficiency is lost, but it's worst between 6500-7500 rpm in each gear. I notice the tach needle is bouncing slightly, I feel a light bounce in the bike, and I can definitely hear the engine speed "wavering" at a constant rate that increases and decreases with engine speed, not road speed. It disappears when I am applying more throttle and accelerating, returning when I ease off a bit and want to maintain speed or decelerate slightly. I first noticed this a couple hundred miles after my 7500 mile service, and though I doubt it's a big deal (see disclaimer) I want to make sure and mention it in case it's a red flag that I should investigate before it becomes a safety or expense risk. Thanks everyone. I love this site.

June 28th, 2010, 12:58 PM	#10
Alex ninjette.org dude Name: 1 guess :-) Location: SF Bay Area Join Date: Jun 2008 Motorcycle(s): '13 Ninja 300 (white, the fastest color!), '13 R1200RT, '14 CRF250L, '12 TT-R125LE Posts: Too much. Blog Entries: 7	I don't want to jump immediately to the CDI issue, but one of the symptoms is the tach bouncing a bit in the 7500 rpm range, here's a thread with all of the gory details: http://www.ninjette.org/forums/showthread.php?t=21043 Might have nothing to do with it, but if you can duplicate the tach reading differently when warm, that might be an explanation for what you're seeing. __________________________________________________ Montgomery Street Motorcycle Club / cal24.com / crf250l.org / ninjette.org ninjette.org Terms of Service Shopping for motorcycle parts or equipment? Come here first. The friendliest Ninja 250R/300/400 forum on the internet! (especially Unregistered)

June 29th, 2010, 10:03 PM	#14
Alex ninjette.org dude Name: 1 guess :-) Location: SF Bay Area Join Date: Jun 2008 Motorcycle(s): '13 Ninja 300 (white, the fastest color!), '13 R1200RT, '14 CRF250L, '12 TT-R125LE Posts: Too much. Blog Entries: 7	I hadn't seen this here, I would have just answered here first instead of SBR. Sorry about that! __________________________________________________ Montgomery Street Motorcycle Club / cal24.com / crf250l.org / ninjette.org ninjette.org Terms of Service Shopping for motorcycle parts or equipment? Come here first. The friendliest Ninja 250R/300/400 forum on the internet! (especially Unregistered)

June 30th, 2010, 03:21 AM	#16
Daeldren two wheel addict Name: Kenneth Location: Simpsonville, SC Join Date: Apr 2009 Motorcycle(s): 94 xlh 883, 1984 kawi gpz money pit Posts: 556	Something simple you may want to check before jumping to the cdi issue is to double check your battery terminals. I had a similar problem but mine was more pronounced and it was caused by a loose connection on the battery, when I hit bumps the connection would come loose causing the tach to jump and the engine to rev. __________________________________________________ The M endorsement on my license stands for mental.

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June 28th, 2010, 11:43 AM	#2
kkim Join Date: Nov 2008 Posts: Too much.	Is your jetting/intake/exhaust stock?

June 28th, 2010, 11:49 AM	#4
kkim Join Date: Nov 2008 Posts: Too much.	would you characterize it as a stutter during light, steady throttle applications while at higher cruising speeds with the throttle just barely cracked open? do you know what all they "adjusted" during your service?

June 28th, 2010, 12:10 PM	#6
kkim Join Date: Nov 2008 Posts: Too much.	what you are experiencing seems very similar to a lean jetting condition in the pilot circuit usually experienced by those rejetting their carbs and having the mixture screws set a bit too lean. I doubt the dealer adjusted the mixture screws, so it might be something else related to making the bike running a little leaner. If you could check what you have related to work done, it might help track down the possible problem quicker w/o having to guess.

June 28th, 2010, 12:15 PM	#8
kkim Join Date: Nov 2008 Posts: Too much.	thanks, that would help. one last thought... is you chain adjusted to specs??? at least 1" of free play? perhaps they overtightened it?

June 28th, 2010, 01:12 PM	#11
kkim Join Date: Nov 2008 Posts: Too much.	yeah, I purposely avoided mentioning the CDI issue until we eliminated possible service related (simple fix) causes.... didn't want to send him into a panic.

June 29th, 2010, 09:39 PM	#13
Avaholic88 ninjette.org member Name: Nate Location: Palo Alto Join Date: Aug 2009 Motorcycle(s): 2009 Ninja 250R Posts: 26	Proving that my rightful place as king of the noobs is still all mine, I checked my chain and realized it is way, way loose. Either it wasn't adjusted properly during the service or I've just been paying far too little attention to it. Either way, I fail as an owner. It's got more than 2 inches of slack, which I imagine is approaching unsafe riding conditions. The physics involved in causing the symptoms I've described make sense in my head, so I'll bet I've found the primary issue. I'm quite surprised that my fuel economy hasn't suffered because of it, and hopefully my idiocy hasn't led to damage, though I didn't notice any unusual wear. So, because I'm still too much of a bum to invest in the necessary tools (though I will very soon), I've got a message in with the shop asking for the soonest 20 minutes of their time for a quick adjustment and inspection. I've also located the nearest torque wrench and cotter pins. If I had a tail, it would be between my legs in shame

June 29th, 2010, 10:46 PM	#15
kkim Join Date: Nov 2008 Posts: Too much.	Glad you found a possible fix for the problem, Nate. Adjust the chain yourself and be free of having to take it to a shop. Speaking of newbs here's an interesting thread to help you with chain adjustment. http://www.ninjette.org/forums/showthread.php?t=13833&

July 7th, 2010, 04:04 PM	#17
Avaholic88 ninjette.org member Name: Nate Location: Palo Alto Join Date: Aug 2009 Motorcycle(s): 2009 Ninja 250R Posts: 26	I adjusted my chain and during the process found a real mean tight spot. It's pretty long and there's a big difference in slack between the tightest part of that tight spot and the rest of the chain. I adjusted the slack to spec at that tightest spot, which left other sections seeming way too loose. I think I found the REAL problem. Additionally, when I hopped on after the adjustment, those symptoms I've been telling you about were WORSE, which I guess I should have expected I suppose since I had just tightened a chain that had a tight spot. It was so bad initially that I felt (and heard) an intermittent grinding/rubbing vibration (which I'm pretty sure was the tight spot going over a sprocket, and which I also assume is very, very bad). I loosened the chain a little, scared to loosen it so much as to run the risk of it jumping off, but also scared of the wear it was putting on my sprockets. I can still feel a little of that rub each time the tight spot goes 'round, and wouldn't you know it, it occurs at the exact same frequency as the engine wavering, tach needle dance, and jerky motion I originally complained about. I think I'm finally ready to solve the true problem, and since I can't seem to find any solutions for a tight spot on the interweb, it looks like I better fork over for a new chain. I plan to keep riding the 34 miles a day until then, though, so yell at me if I'm being an idiot. Thanks guys

July 7th, 2010, 04:29 PM	#18
kkim Join Date: Nov 2008 Posts: Too much.	Nate, can you tell what's causing the tight spot? rust, damaged chain, dirty???? you might be able to loosen up the stiff section with some penetrating oil (PB Blaster, Liquid Wrench or something similar) if the tightness is not being caused by a damaged chain. An overly tight chain is bad for the sprockets, but even worse for the rear wheel bearings and engine bearings on the output shaft.

July 7th, 2010, 05:36 PM	#20
kkim Join Date: Nov 2008 Posts: Too much.	try the penetrant and see if it helps to loosen up the tight spot. so, if you adjust the chain slack for one inch when the chain is at its tightest, how much slack do you have if you rotate the chain to the loosest spot?

July 12th, 2010, 10:54 AM	#22
kkim Join Date: Nov 2008 Posts: Too much.	do you store/park your bike outdoors?

July 12th, 2010, 11:43 AM	#24
Avaholic88 ninjette.org member Name: Nate Location: Palo Alto Join Date: Aug 2009 Motorcycle(s): 2009 Ninja 250R Posts: 26	About to order a set of AFAM chain and sprockets, so hopefully that'll work out. And yeah I'll do a better job maintaining them this time.

July 12th, 2010, 12:03 PM	#25
kkim Join Date: Nov 2008 Posts: Too much.	yes, a 1.25" difference from tight to loose is quite a difference. Only thing I can think of is that the chain is rusty in one section and binds up a bit to make it "tight". since you're ordering a new chain/sprockets, I'd try the penetrant trick to see if you can loosen up the chain, just to see what's up with the chain and to prevent this from happening again in the future. GL

July 12th, 2010, 12:27 PM	#27
kkim Join Date: Nov 2008 Posts: Too much.	yes, there is always a small possibility of any chemical interacting with rubber parts, though it largely depends on the exact composition of the rubber. I've used penetrant many times near rubber parts and never had problems, then recently used it on some levers and the rubber mud shield swelled up and deformed. you could try something like wd40 first, though it doesn't work nearly as well as penetrant to loosen up rusted up parts.