Need help diagnosing spark plugs for proper jetting & Oil Level Question.

[86FJNJ]

Can you please look at these plugs and let me know how you think the bike is running? I would say it's running lean based on the plugs but I'm a newbie. Also, I have the fuel mixture screw at 3 1/8 turns out and it still has a slight bog right off idle which I think means it's running lean.

Current setup is below:
1986
Stock headers & collector. F1R slip-ons.
Unipod Air Filters
Carbs not sync'd (yet)
Plugs have about 50 miles on them.
40.0 Pilot Jet
155 Air Bleed
115 Main
Needle shimmed with one spacer
Air fuel mixture screw is 3 1/8 turns out.

Thoughts?

Regarding the oil level, on these bikes does the engine oil sometimes not fully drain back into the pan? I just changed the oil few weeks ago with 20w-50 VR1 (conventional) and I know it was to the top of the line on the oil sight. After a few small rides totaling about 10-15 miles after the bike was cold I noticed it was slightly less than half way up the oil sight. So I topped it back up to the top line. Then I went for a 10 mile ride and after letting the bike sit for 30 mins the oil was well above the line basically to the top of the glass. So I drained some of the oil out while it was hot and got the oil back to the top line. So that makes me think when I saw the glass about half full that the oil was somewhere else? When I topped it off I only put in a little at a time until it was at the top line. The oil was cold at that time.

Then went for 20 mile ride and afterwards oil was right at the top line, so that's good.

Then just did a 5 mile ride and now the oil is about 1/8" below the top line.

I'm pretty sure my bike is burning some oil just because of age and probably bad valve seals from it sitting 15 years but so far the oil in the glass sight doesn't seem to follow a logical pattern. I'm hoping there is a logical reason that not all the oil drains back into the pan sometimes?

Also for the spark plugs I know I torqued them in well to spec and when I went to take them out the were not tight I needed basically no pressure to loosen them which I thought was odd, do I need to use blue thread locker on the spark plug threads?

[86FJNJ]

hopefully these photos post larger so you can see better

[86FJNJ]

Forgot to mention I do get popping on deceleration when laying off throttle at higher RPM's, sounds good but that may also speak to a lean mixture?

[86FJNJ]

Here she is

[Millietant]

It's difficult to gauge fuel mixture from the FJ plugs (they run a wasted spark system, so they fire every stroke, not just every other stroke), but at 50 miles, at least we can say it doesn't look like the bike is burning oil - the plugs are still very clean.

Definitely DO NOT use thread lock on the spark plugs - they have crush/spring type washers on them. If they're a bit loose after torque'ing them and riding it a bit, just give them a little "nip up" by hand, but be careful not to overtighten them or strip the threads in the head - a lot of the bikes I work on, come into the shop with very loose spark plugs, lots are only finger tight but amazingly, it hasn't yet caused a discernable running problem on any of them (I guess I've developed a "feel" for tightening them after the first torque'ing  ) . At least on a FJ, you can get the plugs out in a couple of minutes to check them all.

With air pod filters and the F1R pipes, the bike likely is running lean, but the popping you mention could also be due to leaks at the exhaust joints/headers. I've no idea if your jet sizes are stock or not unfortunately (ours in the UK were jetted completely differently to the USA), but hopefully Randy/Robert, or someone else here can confirm that for you.

[Pat Conlon]

Along with wasted spark that Dean mentioned, US market FJ's have a closed throttle vacuum advance on the ignition timing which flash burns and left over hydrocarbons (gas) from the combustion cycle.
This is not used for performance (happens at closed throttle) but it's part of the US EPA smog system. 

It is this vacuum advance that turns your plugs white. (and clean)
You look at this and think OMG you're running lean. Not true.

Discussed here: https://fjowners.com/index.php?topic=11690.0

If you want to get an accurate plug color, disconnect the advance vacuum line off your #2 intake manifold. Don't forget to cap off the vacuum inlet port on the manifold.

Cheers. Pat

[86FJNJ]

I checked vacuum leaks at the intake by spraying starting fluid around it when running and no spike in RPM. How can I check for leaks in the exhaust? Everything looks flush and tight IMO.

I was thinking to go up to 42.5 Pilot since I'm at 3 1/8 turns out and I was also thinking to try 117.5 main.

Pat, when I disconnect that vacuum line and cap the intake do I need to also cap the vacuum line or do anything else?

[Pat Conlon]

I checked vacuum leaks at the intake by spraying starting fluid around it when running and no spike in RPM. How can I check for leaks in the exhaust? Everything looks flush and tight IMO.

I was thinking to go up to 42.5 Pilot since I'm at 3 1/8 turns out and I was also thinking to try 117.5 main.

Pat, when I disconnect that vacuum line and cap the intake do I need to also cap the vacuum line or do anything else?

You can leave the vacuum hose open, just cap the manifold port.

[86FJNJ]

Thanks Pat! I will cap the port.

 What are your thoughts on me changing from 40 to 42.5 pilot and 115 to 117.5 main?

Unipods and F1r slip one. Needles already shimmed.

[Pat Conlon]

Thanks Pat! I will cap the port.

 What are your thoughts on me changing from 40 to 42.5 pilot and 115 to 117.5 main?

Unipods and F1r slip one. Needles already shimmed.

I don't think you need to change. #40 pilots and #115 mains should be fine with your current engine mods. Just some fine tuning and you'll be there.

[86FJNJ]

thanks Pat, any thoughts on the oil level issue? Does oil sometimes not fully return to the pan? Why am I seeing varying oil levels on the sight glass?

I always have the bike on center stand when checking oil level. After 50 miles plugs don't seem to be caked with oil which I would think they would be if I were burning that much oil so quickly.

[Pat Conlon]

Yes, it takes time for the top end oil to drain back, don't worry about it.
Check your oil level cold on the center stand like the owners manual states.
Get some miles on your bike. It's common to have the valve seals shrink harden when the bike is stored, they tend to soften and expand after some fresh miles are put on the engine.

Cheers

[86FJNJ]

After all of my consultations with FJ experts and online searching I think I have either a vacuum leak by the intake ports or dirty pilot circuit or both. Although I did spray starting fluid and carb cleaner around the intake while idling and no noticeable change in RPMs. New intake gaskets from RPM shipped out today just to be safe and I'll take the carbs off and blow some carb cleaner and compressed air through the pilot circuit and go for a ride.

It seems to run really well in the midrange, I've not gone past 6k rpm and not sure I want to very much except just for testing/tuning purposes...but if I have a clogged pilot circuit that really only effects things up to 1/4 throttle correct?

Would there be any harm in me "living with" that dirty pilot circuit for a couple hundred miles in the mid range of RPM's to confirm the bike isn't burning a crazy amount of oil? Once I confirm the bike is not burning an excessive amount of oil I plan to order new tuned carbs from RPM but that's a bit of an investment so don't want to do that until I know engine doesn't need major overhaul.

[86FJNJ]

Also I'm sure you all already know this, but this has been a game changer for me while working on the FJ.

To reverse the tank, keeping it hooked up and secured into the same tank brackets so it doesn't move. Way easier than taking it on and off and using one of those small auxiliary gas cans. I put a bungie cord around it through the rear grab handles as an extra safety measure but locked into those two frame mounts it's not going anywhere.

Why has nobody mentioned this to me yet, this should be FJ 101 when joining the group.

[Pat Conlon]

That's yet another advantage the fuel pump brings to the table.