FJ1100 Needle Jet Assembly Order

[Miker]

Sorry if this question has been answered already.  I know carbs are a big topic and have a lot of posts, but I couldn't find the answer anywhere.

I bought the FJ1100 with stock 155 air bleed, 37.5 pilot, and 112.5 main jets.  Stock ignition coils/TDI.  Correct NGK DPR8EA9 plugs torqued down tight.  The needle jet circlip position was two notches down.  The bike also came with a 4 into 1 Supertrapp exhaust and K&N air filter in the stock airbox.  The mixture screws were like six turns out.  My plugs were always bright white.  Slide operation smooth, no holes in diaphragms, and no leaks at boots.  Maybe a slight leak at the headers, but who doesn't have that. 

I corrected any valve clearance issues, completely dismantled the carbs, cleaned everything, replaced all the rubber/brass/needle jet with complete rebuild kits, moved the circlip on the needle jet to the third spot down, threw in a washer, bumped the pilots to 40 and main to 122.5 main jets, left the float height and air bleeds stock, verified each bowl held the same amount of fuel, replaced all fuel lines (including a brass T barb) with 10mm and routed them correctly per OEM requirement, replaced the stock airbox with individual pod filters.  My Gunson colortune told me I was still a bit lean at 4.25 turns out mixture screws up to quarter throttle and really lean at half/full throttle.  So, I threw in 47.5 pilots, removed the washer, and moved the needle to the fourth spot down.  The mixture screw setting went to 3.75 turns out and still not bunson blue for all other throttle positions. 

I now have 52.5 pilots and 132.5 main with the needle jet circlip still at four spots down.  The idle is a bunson blue at 1.25 turns out, but over quarter throttle still looks lean and my plugs have heavy carbon around the base with white insulators with burn marks. So what the hell....

I never thought the assembly of the parts of the needle jet looked right, but I found pics online that suggested it was correct, so I never questioned it.  Then I questioned it again when I saw page 63 of this Mikuni BS Series rebuild tutorial: https://thexscafedotcom.files.wordpress.com/2014/06/mikuni_bs-cv_carburetor_rebuild_tutorial.pdf. 

Maybe I just need to raise the floats, but not sure how much to raise them and I wanted to verify the needle jet assembly first.  I attached a pic of the needle jet assembly I found online, a screen shot of page 63, a couple plugs from my bike, and my needle jet assembly in the order it has always been installed on my bike. 

As always, thanks very much for all your help.

[Miker]

I also took the high vacuum petcock failure rate out of the equation by installing a 10mm inline shut off valve in the fuel line while maintaining proper length and routing. I just leave the petcock on prime.  The original fuel filter is in the petcock and in good shape. I don't know how to check the valve at the gas cap.

[Pat Conlon]

......I now have 52.5 pilots and 132.5 main with the needle jet circlip still at four spots down.  The idle is a bunson blue at 1.25 turns out, but over quarter throttle still looks lean and my plugs have heavy carbon around the base with white insulators with burn marks. So what the hell....

So.... running 52.5 pilot jets, 132.5 mains and needles raised all the way up, I bet you have heavy carbon around the base of your plugs. Try disconnecting (and plugging) the vacuum advance line to your igniter box and take another plug reading. That should darken things up a tad bit.....
You can read about how and why the vacuum advance works here:
http://www.fjowners.com/index.php?topic=11690.0

Just for a reference point, I have a 1380cc kit and for jetting I'm running only 42.5 pilots, 127.5 mains and needles set all the way up. This combination was arrived at on a Dyno with accurate fuel air readings from a wideband O2 sensor.

[Miker]

Try disconnecting (and plugging) the vacuum advance line to your igniter box and take another plug reading.

Just for a reference point, I have a 1380cc kit and for jetting I'm running only 42.5 pilots, 127.5 mains and needles set all the way up. This combination was arrived at on a Dyno with accurate fuel air readings from a wideband O2 sensor.

I attached pics of the plugs above. Sorry, forgot to mention I'm running a Dyna 2000 with Dyna 3.0 ohm green coils as of a couple days ago. However, the situation and plugs read the same when I was running the Chinese DIY ignitor with stock ignition coils.

Yea I figured I was way heavy on the jets...

[Miker]

I also removed the California evap system and plugged the single gas tank and two carb ports.

[Pat Conlon]

....Yea I figured I was way heavy on the jets...

Yes ^^^ I think so.... I've never heard of a FJ running 52.5 pilot jets....perhaps a drag bike.
After you installed the 40 pilots 122.5 mains and needle shimmed at middle clip, other than reading the color tune, what made you think you were running lean? Any symptoms?

What are the advance settings on the Dyna?

[FJ_Hooligan]

So you have a stock motor with a performance exhaust and a K&N filter.

And you think the jetting needs to increase 20% on the main jet and 40% on the idle jet? 

If that's true then you have something seriously wrong with the carbs.

I take it you're judging the mixture settings by holding the throttle open a certain amount and not while the bike is moving and under load?

[Miker]

I really appreciate the help with my carb jetting as I don't exactly know what I'm doing, but my main question was whether or not I assembled the needle jet to the slide with the components in the correct position/order.  I know my post was long winded, so I am sorry if I wasn't clear. 

I could be wrong, but I read the plugs as a rich mixture in the low end and lean mid to full throttle.  I ride enthusiastically and am heavy on the throttle most of the time. 

Another thing I maybe should've mentioned is that all the jets are EBC, which I read run smaller than Mikiuni. 

Pat
The Dyna is on the position 1 advance setting.  However, this condition existed before the installation of the Dyna a couple days ago when I was running the Chinese DIY system.

David
I threw in the giant jets because I wanted to see if I could make the bike rich as I was still over four turns out on the idle screws with 47.5 pilots.  Those plugs aren't completely black and I still have the

No.  I have four pod filters.  Stock motor and performance exhaust is correct.  I listed everything in my initial post.  I know it's long. 

My assumption the bike is still running lean at some point during the combustion cycle is due to the very pale / white color of the color tune flame beyond quarter throttle with no load (should be slightly lightened bunson blue with hints of pink), the color of the plugs - bright white insulators with burn marks and heavy carbon around the plug bases (normal plugs should look like the 'ok' to 'good' pics in the attached image; mine more resemble the hot or lean plug), the bad fuel consumption estimated at probably 20 miles per gallon, some backfiring (mostly before the Dyna swap; completely gone after the Dyna install). 

[FJ_Hooligan]

I'll ask again.  Are you riding down the road and watching the colortune or is this all stationary in your garage?

If you're sitting still and trying to use the colortune for ANYTHING BUT idle mixture assessment, you're fooling yourself and wasting effort.

[FJ_Hooligan]

The thick plastic washer belongs under the E-clip (thus raising it).  This is shown correctly in the first picture.  The second picture appears to show it on top of the clip which would be wrong.

[Miker]

I'll ask again.  Are you riding down the road and watching the colortune or is this all stationary in your garage?

If you're sitting still and trying to use the colortune for ANYTHING BUT idle mixture assessment, you're fooling yourself and wasting effort.

I answered your question above.  No load.  Ok Colortune can't relay accurate mixture information beyond 3k rpms... Fair enough. 

The reason I listed all my bike's specs was so that no one had to ask.  Since I now know for sure the plastic spacer was never an issue, I need to find out what is causing the assumed lean mixture due to the other evidence I mentioned.  As Pat stated, my jetting is way overboard for my machine, so there must be a fuel restriction somewhere, otherwise those plugs would be completely black. 

[FJ_Hooligan]

How many miles are you putting on the plugs prior to "reading" them?

What kind of riding are you doing?  Hard or normal?

The poor fuel consumption is verification that you're over-jetted.  Try going back to a 40 or 42.5 idle jet and set the mixture screws using the "blip the throttle test" then go for a long ride and reexamine the plugs.

[Firehawk068]

I also removed the California evap system and plugged the single gas tank and two carb ports.

I have a question about this comment.................Which two carb ports did you plug? 
It is my understanding that the "Vent" hoses should be open to the atmosphere on the "Non-Evap system" Bikes? They are normally run down behind the engine with the other hoses.


Also, I could be wrong on this topic, but it is also my understanding that people have run into confusion using the "Colortune" to tune a "Wasted-Spark" ignition system.
This is also the case when trying to use a spark-plug color-guide, as this system typically causes the spark plugs to appear "cleaner/leaner" than the fuel/air mixture would dictate?
The spark plugs fire both during the compression event AND again during the exhaust event......................
Using a Hotter ignition system such as the Dyna-2000 and Coils may make these appear even leaner?

Granted, I have no experience with the Dyna ignition systems, as I have never used one, so I don't really know if the system still uses the "Wasted-Spark" like the factory FJ system uses.

Exhaust Gas analyzer would be the proper way to tune, especially with mods.

Also, David R is probably the most knowledgeable guy on this forum when it comes to tuning these carbs..............
Tons of experience here! His advice is priceless............

[Miker]

I have a question about this comment.................Which two carb ports did you plug? 
It is my understanding that the "Vent" hoses should be open to the atmosphere on the "Non-Evap system" Bikes? They are normally run down behind the engine with the other hoses.

Also, I could be wrong on this topic, but it is also my understanding that people have run into confusion using the "Colortune" to tune a "Wasted-Spark" ignition system.
This is also the case when trying to use a spark-plug color-guide, as this system typically causes the spark plugs to appear "cleaner/leaner" than the fuel/air mixture would dictate?
The spark plugs fire both during the compression event AND again during the exhaust event......................
Using a Hotter ignition system such as the Dyna-2000 and Coils may make these appear even leaner?

[/quote]

I definitely appreciate any and all input I get from you guys... thanks very much.  This is the most knowledgeable forum I've ever come across on any topic. 

I am going to swap out the jets as soon as I get the time. 

Good points on both the plugged evap ports and the wasted spark.  I attached some pics of the ports attached to the removed evap system that I plugged.  Two on the carbs on the intake manifold side and one port on the gas tank.  Although the evap canisters, carbs, and gas tank were connected in a closed system (carbs to evap canisters and evap canisters to gas tank), the evap canisters did have open lines connected to the bottom of the units.  I don't necessarily think that means the ports on the carbs should be open though.  I attached the parts diagram. 

I don't know whether the Dyna 2000 or ND boxes use a wasted spark system or whether that would affect a colortune reading.   

[FJ_Hooligan]

You have capped off the correct ports on the carbs.  Those go directly into the intake and must be capped off, so you're good there.

The Dyna ignition also works as wasted spark.  This is a product of a 2-coil shared ignition layout. 

How does the exhaust smell at idle?  With the large idle jets it should smell very rich.