Oil on spark plugs.

Forum rules
Please can you post items for sale or wanted in the correct For Sale section. Items / bikes for sale here will be removed without warning. Reasons for this are in the FAQ. Thanks
User avatar
AyzenShiro
Settled in member
Reactions:
Posts: 6
Joined: Mon Sep 02, 2019 8:12 am
Bike owned: NC30, RC390
Oil on spark plugs.

Post by AyzenShiro » Mon Sep 02, 2019 7:11 pm

Hi guys,
recently i bought nc30 in decent condition, it was sitting in garage for about 6-8 months so first step was fresh oil, fresh fuel, charge battery etc. but when i get to spark plugs ...wel there was huge suprise waiting for me, spark plugs ware bearly screw in, i was able to unscrew it with my bare fingers, and everything was covered in black oil:
Image

any idea whats going on, or what went wrong?

cheers

magg
Senior Member
Reactions:
Posts: 1910
Joined: Mon Sep 20, 2010 11:55 pm
Bike owned: VFR400
Location: Blue Mountain NSW Australia
Re: Oil on spark plugs.

Post by magg » Tue Sep 03, 2019 2:01 am

Wasn't running when you bought it? May have been decent appearance but engine could be another story. Two cylinders oily, what about the others. You could simply make should all plugs are clean and try starting. No run or poorly running with much exhaust smoke suggests engine needs rebuilding.

richyrd5
Senior Member
Reactions:
Posts: 1351
Joined: Fri Feb 21, 2014 1:31 pm
Re: Oil on spark plugs.

Post by richyrd5 » Tue Sep 03, 2019 8:25 am

Doesnt look good.....only thing to do is take them all out,clean them and put them back in,fire it up and hope for the best...you will soon find out if it's a worn engine!!..but also if the plugs were loose it could be spark plug hole gaskets leaking into the recessed and fouling them,but looks to me as if engine is burning oil.....good luck and let us know what happens.....

User avatar
AyzenShiro
Settled in member
Reactions:
Posts: 6
Joined: Mon Sep 02, 2019 8:12 am
Bike owned: NC30, RC390
Re: Oil on spark plugs.

Post by AyzenShiro » Tue Sep 03, 2019 3:38 pm

magg wrote:
Tue Sep 03, 2019 2:01 am
Wasn't running when you bought it? May have been decent appearance but engine could be another story. Two cylinders oily, what about the others. You could simply make should all plugs are clean and try starting. No run or poorly running with much exhaust smoke suggests engine needs rebuilding.
All plugs are like that, bike was running fine, i did test run and it was fine, just had to stay on choke for a while.

magg
Senior Member
Reactions:
Posts: 1910
Joined: Mon Sep 20, 2010 11:55 pm
Bike owned: VFR400
Location: Blue Mountain NSW Australia
Re: Oil on spark plugs.

Post by magg » Tue Sep 03, 2019 9:57 pm

Maybe plugs came from another bike and owner failed to tighten them correctly, who knows. You could ask or just clean them and keep riding if the engine sounds good and goes well. No need to create work unless there is an issue. Choke to start but once running just a fast idle 2000-3000 rpm for 30 seconds or so and then ride away, depending on ambient temperature.

ArizonaRVF
Settled in member
Reactions:
Posts: 33
Joined: Sat Jan 26, 2019 1:09 pm
Bike owned: 1994 RVF400R
Location: Desert Southwest USA
Re: Oil on spark plugs.

Post by ArizonaRVF » Sat Sep 07, 2019 3:26 pm

Based upon the color of those plugs and the amount of oil, I would have to believe the rings are questionable. I would recommend a leak down test.

Ozzibiker
Settled in member
Reactions:
Posts: 35
Joined: Tue May 20, 2014 5:33 am
Bike owned: VTR250 / VFR400
Location: Tokyo, Japan
Re: Oil on spark plugs.

Post by Ozzibiker » Fri Nov 15, 2019 2:50 am

Any news?

Which country are you in?

Foxy400
Regular Member
Reactions:
Posts: 793
Joined: Mon Sep 02, 2013 7:31 pm
Bike owned: NC35 NC29 Bonneville CBR600F4i
Location: Cheshire
Re: Oil on spark plugs.

Post by Foxy400 » Sun Nov 24, 2019 11:07 am

Yes, I'd like to know how this one turned out as well.

User avatar
NGneer
Site Supporter
Site Supporter
Reactions:
Posts: 1349
Joined: Wed Jan 21, 2009 7:37 am
Bike owned: x3 NC30,Matchless G80s AJS16ms
Location: Köln
Re: Oil on spark plugs.

Post by NGneer » Thu Nov 28, 2019 11:12 am

Another possibility is that your rocker cover gasket(s) leaking a bit. I had this once and it allowed oil to pool in the plug recces giving me a VERY oily plug - on the outside anyway. That coupled with the finger tight plugs would possibly allow the oil it to seep down the threads into the combustion chamber and foul up the plugs. Just a thought.


I would either give the plus a very good clean or just bit the bullet and get some (Quality) new ones, make sure they a re-fitted correctly and then go for a decent run on the bike. Have a look at the plugs when you get back and that shoould let you know if you have solved the problem or if there is something more you need to chase down.

User avatar
AyzenShiro
Settled in member
Reactions:
Posts: 6
Joined: Mon Sep 02, 2019 8:12 am
Bike owned: NC30, RC390
Re: Oil on spark plugs.

Post by AyzenShiro » Thu Dec 19, 2019 12:34 pm

Hi guys, so for past months i had couple of more issues with bike, i end up rebuilding carbs, front forks, exchanging spark plugs, some wires, jets, seals, orings and recently carb intake rubbers as well and i did some painting as well. It was a bloody mess, yesterday i manage to run it for first time after rebuild and it start and runs quite alright, carbs was balanced on desk. I'm gonna ride it/test it on weekend.
I was never work on bike before, and i found it really satisfying.

Cheers.

Image Image Image


Post Reply