odd surging

jschorr · August 8th, 2014, 09:32 PM

so i noticed something today on the highway. it is an surging, it doesnt have to do with rpm but with speed, it happens around 60, 65 when i am just cruising. meaning if i get on it it doesnt happen but if a put it in 6th and just roll along ( around 7-8 rpm) i can feel it pulse.

i will start knocking down the list here in the next few days, but so far i have lube chain, grease bearings, and clean airbox filter..

anything i missed?

jkv45 · August 9th, 2014, 06:28 AM

I would say it's most likely a carb adjustment issue.

Definitely check your air filter, but most commonly surging is a sign of a lean mixture.

Have you had the carbs off at any time? Have you made any adjustments to the idle mixture screws?

If the carbs haven't been synced recently, that would also be something to do.

Old gas or gas with moisture in it can give you odd running issues also.

rubber side down · August 9th, 2014, 07:05 AM

Sounds lean. Put a shim under the needles in the carbs. You can get a 6 pack of them at menards for 50 cents. The 3mm washers they have are the same washers I received from jetsrus.com

jschorr · August 9th, 2014, 09:10 AM

So I am hearing carbs and lean running.

Carbs are shimmed with 2 washers with the idle mixture screws about 2 3/4 turns out. Running a bit rich at idle.

But if it was carbs wouldn't it be doing it every time I ran at 7/8 rpm? Not just at a set speed?

I will try different gas next time I fill it. I use the same place every time.

jkv45 · August 9th, 2014, 09:01 PM

Quote:

Originally Posted by jschorr

So I am hearing carbs and lean running.

Carbs are shimmed with 2 washers with the idle mixture screws about 2 3/4 turns out. Running a bit rich at idle.

But if it was carbs wouldn't it be doing it every time I ran at 7/8 rpm? Not just at a set speed?

I will try different gas next time I fill it. I use the same place every time.

I'd look at the plugs to see how they are burning overall.

I'd lean the idle mixture by turning the screws in if you think it's rich.

If it's still doing it and you don't have any answers, I would add some choke the next time it does it to see if it gets better or worse.

jschorr · August 9th, 2014, 09:36 PM

Well it is good news bad news time!!!! Good news is I found the pulsing and don't have to rip my carbs down.

Bad news is I found the pulsing when I lost a rear brake caliper bolt on the way home. Maybe I forgot to lock tight the top one?

I lived so I guess all wells that ends well.

jkv45 · August 11th, 2014, 08:55 AM

So it was a loose rear caliper that was causing it?

Ninjinsky · August 11th, 2014, 09:14 AM

Quote:

Originally Posted by jschorr

Bad news is I found the pulsing when I lost a rear brake caliper bolt on the way home.

As I recall someone else had the same thing a month or so back. Perhaps we should incorporate a brake bolt check into our monthly maintenance checks.

jschorr · August 11th, 2014, 05:53 PM

as far as i can tell yes, it was the speed of the brake disc causing the caliber to move and bind slightly.

i cannibalized a fix in till thurs when i get new bolts, it is at 89% good to go right now so no pleasure cruising just work and back.

my bikes checks have become much more extensive since i found that. i look at everything every day now.

i think what happened is i got paint in the threads when i painted the swing arm and that made the lock tight not hold. i am upping to green locktight for the new bolts just in case.

August 8th, 2014, 09:32 PM	#1
jschorr ninjette.org member Name: todd Location: pittsburgh Join Date: Apr 2014 Motorcycle(s): 1995 ninja 250r Posts: 130	odd surging so i noticed something today on the highway. it is an surging, it doesnt have to do with rpm but with speed, it happens around 60, 65 when i am just cruising. meaning if i get on it it doesnt happen but if a put it in 6th and just roll along ( around 7-8 rpm) i can feel it pulse. i will start knocking down the list here in the next few days, but so far i have lube chain, grease bearings, and clean airbox filter.. anything i missed?

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August 9th, 2014, 06:28 AM	#2
jkv45 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. MOTM - Jun '18, Oct '16	I would say it's most likely a carb adjustment issue. Definitely check your air filter, but most commonly surging is a sign of a lean mixture. Have you had the carbs off at any time? Have you made any adjustments to the idle mixture screws? If the carbs haven't been synced recently, that would also be something to do. Old gas or gas with moisture in it can give you odd running issues also.

August 9th, 2014, 07:05 AM	#3
rubber side down ninjette.org member Name: Travis Location: so dak Join Date: Nov 2013 Motorcycle(s): 01 gixxer 1k, 02 gixxer 600, 02 ninja 250, a slew of dirt bikes Posts: 52	Sounds lean. Put a shim under the needles in the carbs. You can get a 6 pack of them at menards for 50 cents. The 3mm washers they have are the same washers I received from jetsrus.com

August 9th, 2014, 09:10 AM	#4
jschorr ninjette.org member Name: todd Location: pittsburgh Join Date: Apr 2014 Motorcycle(s): 1995 ninja 250r Posts: 130	So I am hearing carbs and lean running. Carbs are shimmed with 2 washers with the idle mixture screws about 2 3/4 turns out. Running a bit rich at idle. But if it was carbs wouldn't it be doing it every time I ran at 7/8 rpm? Not just at a set speed? I will try different gas next time I fill it. I use the same place every time.

August 9th, 2014, 09:36 PM	#6
jschorr ninjette.org member Name: todd Location: pittsburgh Join Date: Apr 2014 Motorcycle(s): 1995 ninja 250r Posts: 130	Well it is good news bad news time!!!! Good news is I found the pulsing and don't have to rip my carbs down. Bad news is I found the pulsing when I lost a rear brake caliper bolt on the way home. Maybe I forgot to lock tight the top one? I lived so I guess all wells that ends well.

August 11th, 2014, 08:55 AM	#7
jkv45 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. MOTM - Jun '18, Oct '16	So it was a loose rear caliper that was causing it?

August 11th, 2014, 05:53 PM	#9
jschorr ninjette.org member Name: todd Location: pittsburgh Join Date: Apr 2014 Motorcycle(s): 1995 ninja 250r Posts: 130	as far as i can tell yes, it was the speed of the brake disc causing the caliber to move and bind slightly. i cannibalized a fix in till thurs when i get new bolts, it is at 89% good to go right now so no pleasure cruising just work and back. my bikes checks have become much more extensive since i found that. i look at everything every day now. i think what happened is i got paint in the threads when i painted the swing arm and that made the lock tight not hold. i am upping to green locktight for the new bolts just in case.