Could it be my jets?

Hi all, I've got a rough running motor that won't idle, (but it runs now, so things are moving in the right direction) I whipped out my recently cleaned and gapped plugs to find two in a wet/ fuelly state and the other two black and sooty. I cleaned them again and ran the motor for another 10 mins. The plugs had returned to wet/ black state.

Now I have never fiddled with the jets, apart from unskrewing them and cleaning them out, when I de junked the rest of the carbs (standing for years)

I tried as best I could to return each one to the same position, but is there an easy wat to count the skrew turns back from tight? and how do I go about tweaking the black ones vs the wet ones?
(or am I barking up the wrong tree from the off?)
Basic intructions assuming only a small amount of knowledge appreciated.
Thanks

 

-What bike?

-Mileage?

-Some history, please?

-Valves in spec?

-Float levels "WET" set when you had the carbs apart?

-Have you run a compression test on this motor?

The initial position for the pilot mixture screws varies from bike to bike so without knowing the answers to the above, it's hard to give more specific advice.

 

Hi sorry for the delay, we ask questions and want answers straight away, when they are asked of us, it doesn't always appear the same.

It is a 1983 XJ 750 uk spec, off the road for some 12 years and only just into my ownership (led to beleive it went away in a working state)

I've cleaned carbs and jets carefully and tried to wet set carb ht (plastic tube method) cleaned and gapped plugs, ran, removed and re run in different cylinders and plugs still ended up in same condition (so fault with carbs / cylinders not plugs.- I guess)

Not done anything else regarding the issue.

Hope these answers go towards finding a solution.

 

You only (sort of) answered exactly half of my questions.

You missed:

-Mileage on the bike?

-Valves in spec? (Most important.)

-Have you run a compression test?

And "tried" to wet-set doesn't sound all too encouraging. YES, it's an incredible pain. However, it's also a "set it and forget it" proposition. Once you get it right.

Base pilot screw setting for your bike is 2 1/2 turns out.

 

Another basic question about the 2.5 turns, are we looking at the jets as accessed via the float chamber, or by removiing the skrewed plate from the top plate after removing diaphragm/plunger/ needle etc.

I tried the float chamber ones 2.5 times from tight and it felt loose left there but it was still attached.

Which one do I need to turn? and do you do the same to the main jet (and by how much)

Thanks as ever

Andy

 

The 2.5 turns is for the pilot jet. If you don't know what that is, then you probably haven't hit the right ones.

There is but *one* item in the FAQ Final forum. Consider it your bible for carbs.

If you search for Rickcomatic's post to tune by ear/tune the old fashioned way, it will walk you through everything you need to know and do about setting the carb pilot jets.

http://xjbikes.com/Forums/viewtopic/t=1640.html
http://xjbikes.com/Forums/viewtopic/t=1640.html

For the life of me, I can't find the "tuning the old fashioned way" thread.