Can old plugs cause a rich condition?

jjmaine · July 21st, 2016, 10:13 AM

The previous owner had just had the bike serviced and the carbs clean before I bought it from him and they forgot to hook the choke cable back up when they put the carbs back on. So today I took the tank off to hook the choke back up and decided to check and change the plugs while I had the tank off (it's cheap peace of mind) even though they were probably just changed recently. The plug in the left cylinder was a perfect tan color but the right plug was black. I had noticed a slight gassy smell from the exhaust before I changed the plugs and now after swapping them the exhaust smells like exhaust. I also checked the float height in each carb using the clear tube method and they were both spot on and even with the top of the bowl. My question is can a weak/old plug cause the bike to run rich? It runs great now there is no bogging or hesitation on the throttle after its good and warmed up. According to the PO the jets should be all stock.

Just run the bike as long as it runs great? No need to go mucking with the carbs?

jjmaine · July 21st, 2016, 10:15 AM

Picture of the old plugs.

RacinNinja · July 21st, 2016, 10:25 AM

To me, that looks oil fouled, not necessarily rich. Oil fouling can cause a rich condition since all of the fuel may not be burned. A worn plug can make a weak spark causing some of the fuel to be unburned.

I would ride it for a thousand miles or so and check the plugs again to see the condition.

jjmaine · July 21st, 2016, 10:37 AM

Okay I will do that, thanks RacinNinja. Just curious though, what causes oil fouling? Is it something I should be worried about?

RacinNinja · July 21st, 2016, 10:41 AM

Quote:

Originally Posted by jjmaine

Okay I will do that, thanks RacinNinja. Just curious though, what causes oil fouling? Is it something I should be worried about?

Could be piston rings, could be valve stem seals, could just be some oil getting sucked in through the air box because someone over filled it with oil. Could be any number of things, really.

Give it some time and check again. Don't worry about it unless you've got blue smoke out an exhaust pipe.

jjmaine · July 21st, 2016, 10:43 AM

No smoke so I guess I'll ride the hell out of it. Thanks!

RacinNinja · July 21st, 2016, 10:46 AM

Quote:

Originally Posted by jjmaine

No smoke so I guess I'll ride the hell out of it. Thanks!

Flog her till she chokes!!

jjmaine · July 21st, 2016, 11:12 AM

Quote:

Originally Posted by RacinNinja

Flog her till she chokes!!

That I will surely do or at least try...

July 21st, 2016, 10:13 AM	#1
jjmaine ninjette.org member Name: Justin Location: Maine Join Date: Jul 2016 Motorcycle(s): '05 Ninja 250, '16 Ninja 300 Posts: 113	Can old plugs cause a rich condition? The previous owner had just had the bike serviced and the carbs clean before I bought it from him and they forgot to hook the choke cable back up when they put the carbs back on. So today I took the tank off to hook the choke back up and decided to check and change the plugs while I had the tank off (it's cheap peace of mind) even though they were probably just changed recently. The plug in the left cylinder was a perfect tan color but the right plug was black. I had noticed a slight gassy smell from the exhaust before I changed the plugs and now after swapping them the exhaust smells like exhaust. I also checked the float height in each carb using the clear tube method and they were both spot on and even with the top of the bowl. My question is can a weak/old plug cause the bike to run rich? It runs great now there is no bogging or hesitation on the throttle after its good and warmed up. According to the PO the jets should be all stock. Just run the bike as long as it runs great? No need to go mucking with the carbs?

July 21st, 2016, 10:25 AM	#3
RacinNinja Vintage Screwball Name: B Location: Washington Join Date: Feb 2016 Motorcycle(s): 2011 Ninja 250, 2008 Ninja 250, 2019 KTM 1290SDR, 2017 FZ10 Posts: A lot. MOTM - Mar '16	To me, that looks oil fouled, not necessarily rich. Oil fouling can cause a rich condition since all of the fuel may not be burned. A worn plug can make a weak spark causing some of the fuel to be unburned. I would ride it for a thousand miles or so and check the plugs again to see the condition. __________________________________________________ Goin' fast on slow bikes!

July 21st, 2016, 10:43 AM	#6
jjmaine ninjette.org member Name: Justin Location: Maine Join Date: Jul 2016 Motorcycle(s): '05 Ninja 250, '16 Ninja 300 Posts: 113	No smoke so I guess I'll ride the hell out of it. Thanks!
	1 out of 1 members found this post helpful.

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July 21st, 2016, 10:37 AM	#4
jjmaine ninjette.org member Name: Justin Location: Maine Join Date: Jul 2016 Motorcycle(s): '05 Ninja 250, '16 Ninja 300 Posts: 113	Okay I will do that, thanks RacinNinja. Just curious though, what causes oil fouling? Is it something I should be worried about?