Number 4 spark plug oily

[cl1ve2004]

Rebuilt carbs, new o rings, mixture screws etc..bench set butterflies and mixture screws.


Put the carbs back on, starts ok with no choke, did carb balance, all good...sounds a lot better,and goes better now, but stuttery at low end.


Took plugs out and 1,2,3 nice colour, but 4 has oil (not petrol) on electrode..


Checked the coils, coil leads and caps,swapped with some spares still the same result, oil on number 4 plug.


Any ideas, carbs again, or am I looking at valve seals ??


Cheers

[kebab19]

Was it doing this before your carb rebuild, or was this why you took 'em apart?
Is it oiling up quite fast and quite badly?Are there big miles up on her?
Did you use a new spark plug each time?
Coil was my first thought but you've ruled it out 
Compression test for cylinder #4?

[cl1ve2004]

Tha rebuild was because she was stuttering badly across the rev range.


It's loads better accelerating now since rebuild, but not 100% as I explained.


Tried 3 different plugs and they all came out slightly oily after about a 10 minute ride.


The oil isn't dripping, more like a mist on the end, I'm gonna buy a compression tester to try, she's only glt 34K miles on the clock.


Cheers

[Gnasher]

It's not oil if it's a mist, it's fuel.


There's something a miss with your rebuild.

[cl1ve2004]

Cheers Gnasher I'll take  the carbs off, check everything out, and take a good [size=78%]look at the needle valve seats..[/size]

[Gnasher]

If the plug is getting wet, the fuel is getting into the cylinder, in which case you need to check for a spark at the plug.  If there's none, put the plug into another cap and check it again, if there's a spark it's not the plug, check the cap, do the same as with the plug.  Go backwards up the high tension circuit, if all ok check the low tension.


Now it's also still possible it's the carb but it will be the pilot circuit, or the enricher circuit is stuck open. 


 

[cl1ve2004]

Hi Gnasher thanks for that info, I've checked the spark and it's powerful at HT plug, even swopped coils with different plug caps and it was fine..


I ain't going anywhere so I'll check it again for spark and then whip the carbs out, and check the items you said..

[Gnasher]

All the info is based on the assumption there's nothing else wrong with the bike?  What prompted you to rebuild the carbs in the first place?

[cl1ve2004]

It was crap through the rev range, I reckon I may have had a dodgy tank of petrol as it was ok before I filled her up,tried STP and put some Isopropyl in but no good,so as it was winter,thought I'd do the whole fuel system once the weather was better..
Had to get one mixture screw removed professionally on number 1 carb the rest I replaced as a matter of course.
I've been meaning to sort it for ages, now seemed a good time
Can I just swap the LT leads into 1 and 4 coil, as the HT leads won't stretch to swap on plugs to see if that is the problem?
Thanks

[Gnasher]

It was crap through the rev range, I reckon I may have had a dodgy tank of petrol as it was ok before I filled her up,tried STP and put some Isopropyl in but no good,so as it was winter,thought I'd do the whole fuel system once the weather was better..
Had to get one mixture screw removed professionally on number 1 carb the rest I replaced as a matter of course.
I've been meaning to sort it for ages, now seemed a good time
Can I just swap the LT leads into 1 and 4 coil, as the HT leads won't stretch to swap on plugs to see if that is the problem?
Thanks

Sounds like classic pilot circuit issues.   

[cl1ve2004]

Carbs off then.. I'll crack that tomorrow...


Cheers Gnasher, I'll keep the notice board up to speed..

[cl1ve2004]

Took carbs off, removed all pilot jets,were all clean from rebuild could see through them,..took mixture screws out on all 4 and blasted carb cleaner through with my finger over mixture hole until cleaner came out of pilot jet holes. Checked everything in bowls,Reset mixture screws cleaned everything up.
Swapped number 4 jet for number 2 , carbs back on,new plugs fitted
 still number 4 plug black other 3 grey...
and downpipe not getting as hot as the other 3..
Depressed now !! but not beaten.What else to do/look for guys!!
Done coil swap, caps ,now plugs also

[BBROWN1664]

Get a compression tester and see what you get from that.

[Gnasher]

Did you clean out the bleed hole in the main carb body and the idle mixture jet?

[cl1ve2004]

Ah, not done the bleed hole,    did all the other jets..got them off again now, I'll start with the bleed hole, then try choke plungers as well as blasting everthing else again..Thanks for info guys, I will get there !!!

[cl1ve2004]

Gnasher I'm going to look well dumb here, but where is the bleed hole on the carb body ??

[Gnasher]

Gnasher I'm going to look well dumb here, but where is the bleed hole on the carb body ??

Look in the carb main body there's a tiny hole engine either side of the butterfly, the hole goes down and over the idle air mixture screw.  This/these block end result no idle mixture, the cylinder won't run below 2k - 2.5k ish. 

[cl1ve2004]

  Thanks Gnasher I'll check it out..

[cl1ve2004]

Finally got all 4 plugs the same colour, nice tan electrode !!!


A quick dash up the road,runs well through the rev range, idles fine,just need to balance carbs tomorrow..


Did as advised by Gnasher and cleaned bleed screws, also changed new mixture screw back to the old one.


Got a Pipercross air filter coming next week so may hold off on the balance until that's fitted.


Thanks for all the help and advice from you guys, just convinces me this forum is the best.