Tuners & Tweakers ~~ Ride Report ~~ Post ColorTuned XJ750

Clean Carbs
YICS Synced
YICS Colortuned

Even though the Colortune Plug was showing me a very pretty solid BLUE on all four holes ... my bike is running LEAN.

Not too much air and backfiring.
Not too much air and hesitating and performing poorly.
Seemingly ~~> Running G-R-E-A-T!!!
But, after examining the Spark Plugs after today's outing: ...
"Too-clean Lean"

Today was neighborhood bikers play follow the leader day.
99.9% youngsters on late model or new bikes and one Senior Citizen on an Old XJ-Bike, older than most of the other riders, following each other all over the place.

The ride was a mixed bag of performance demands.
Town, main drag, back roads, deserted road, highway and wrapped-up with some real high rpm time on ramps and Interstate.

I started the day on a brand new set of Champion RN9YC Sparklers.
When I peeked at the plugs after getting it home and letting it cool-off ...
the plugs looked like I didn't even start the bike today.

Not like they just been over a hundred miles.

This is why I'm going to Bump-up my bike to the "Non-USA" Jetting and see what happens ... next week!

 

Which bike is this on Rick? What main jets are in there now? Usually when this occurs the mixture should be set just back from rich or with a little bit of orange showing. If it is lean at WTO then rejetting is needed or the airfilter is a K&N with stockjets!

 

1983 XJ-750 Maxim.

This bike is Stock ... well, mostly stock ... really. I added a Cooler off a 900 and a aftermarket Windscreen ... that's it.

I even had to drill-out the manhole covers to get-in to the screws.

The first thing I'm going to do is run a colder Plug and Bump-up the Main Jets. I'm big and I could feel from the way the bike was pulling ... that a bump or a bump-and-a-half won't hurt. When I go visit my sister; it's a straight shot over the Mass Pike into New York State. Big trucks are doing 75 - 80. The outside lane is moving like people are engaged in qualifying for a Gran Prix.

My Idle is rock steady.
Absolutely NO problem going from stopped to 80mph+ with complete command of power when a nuance of throttle is needed for gear changes or WOT put on to pass.

It's nice to have to do THIS kind of tweaking.
This bike's only got 15,000 on it.
This is the kind of needin'-to-play-with-it you like to do!

But ... it's Lean.
And, ... Lean ain't good!

 

I had to go and be sure.

It's NOT a K&N Filter.
Stock.
Looks like its mostly paper.

 

My sources at the bike shop swear that the stock paper elements are best for performance. They told me to chuck my Uni.

 

Bumping up the jets to 122 should do the trick. I did this with my K&N filter and it helped a lot. I ahve heard about the stock filters vs after market versions and I know the higher flow of the after market ones demand rejetting. Plus the K&N needs to be cleaned and reoiled at least once a year minimum, twice is better and four times is best. That is a lot of time to maintain a filter so they may be right.

 

Very, very interesting.
Still doing: "Micro-tweaking"

The endless pursuit of perfection.

The tweaks are OUT to Enrich the Mixture.
Each time a daily alteration is made from the previous days setting ... the Pilot Mixture Screw(s) is only moved about 1-Degree. A genuine micro-tweak.

Although I'm still too lean to leave it like this; the bike is running fabulous.
Starts ~~ Instantly!
Idles ~~ Smooth and steady.

20 Miles for tuning.

Full response without a glitch from 980 ~> Redline.
Instant power on.
Excellent deceleration although with LESS severe engine braking due to the additional Pilot Mixture burn.
The ... "Whoppity, whoppity, whoppity ... throaty deceleration note is now more of a low, low "Whoa-oh-oh-oooooooo"

The Power-on note changed too:
It's the same Growl you know the 750 likes to make ...
But, now it sounds like somebody reduced the Treble and added a little Bass.

That the bike has not been "Running Hot" these past couple of day ... I can only attribute having the Oversized 900 Oil Cooler on it to help regulate engine temperature.

I'm sure the work I did working out the geometry to hang the 900 Cooler on the front is paying-off HUGE!

 

Re: Tuners & Tweakers ~~ Ride Report ~~ Post ColorTuned XJ75

Haunted by "Running Lean" ... I have scrubbed the idea of tweaking it OUT.

Returned to SQUARE ONE.
YICS Tool Inserted.
ColorTuning initiated.

Opposite approach from "1st Blue" employed.

Ran bike.
Ran Pilot Mixture Screw OUT until obvious Too Rich condition evident in performance and the Visual Inspection allowed by the Colortune.

Yellow / Yellow Orange / Backfire
Tweaked IN until the Visual Inspection showed traces of Yellow.
Obvious improvement in performance.
You see it ... and, you definitely HEAR it.
Went beyond "The Spot" ... to see how wide the window is for BLUE until Performance and Visual indicate the Mixture is too Lean.

Tewaked OUT for "The Spot" where the Visual Inspection showed the Mixture to just begin becoming TOO RICH.

Micro-tweaked IN until the Performance and the Visual Inspection allowed by the Colortune Plug showed the last traces of Yellow and Orange in the Mixture being TOO RICH.

During the time that the Mixtures were being set ... WATER was expelled from the drainage ports near the exhaust flanges attaching them to the collector box. Enough to puddle beneath each silencer.
....................

The bike ran Great.
The distance of the test ride, today, not far enough to inspect the Spark Plugs.

 

So a K&N Stock style (not pods, but K&N nonetheless) requires re-jetting? Really? I was told otherwise and am running one. I don't see much indication of running lean when I pull the plugs, but now I am paranoid. My plugs are light brown...so I think I am ok on my 550. Well except for cylinder #3 which is more on the blacker side of brown. Carbs are nicely synced, so I might turn in the pilot screw a bit on #3 as it seems a bit rich.

 

I don't understand why the K&N filter would be cause for having to re-Jet.

I think there is just so much air that's going-in the bike through the Airbox Inlet Port.
I think the filter ... filters air.
I don't know if foam or paper makes any difference at all ... I am sure that there are some who buy into the Ad-Copy and think K&N Filters "are a guicker picker-upper."

Not me.

 

Re: Tuners & Tweakers ~~ Ride Report ~~ Post ColorTuned XJ75

Agreed. I got the K&N because I didn't want to replace the filter every year, and because I got a steal on eBay where the K&N was cheaper than the stock one.

 

K&N recommends a jet increase of one size on their website. The air filter is a restriction also and installing a K&N on a Harley ElectraGlide will net a 6HP increase. So the fiter makes a difference in air mass flow. More fuel is therefore needed to compensate. I believe this was one of the contributing factors to my cylinder head warping. I ran the K&N for two summers without rejetting and the second summer is when the head warped. Running hot at speed could do this, and a lean mixture is a hotter burn.

 

really. hmmmm... Perhaps maybe I should go back to the stock paper element.

I couldn't find the required jet increase on the K&N website, but I'll believe you.

 

I couldn't find it either. Maybe I read it somewhere else. I will look for it and post what I find.

 

Re: Tuners & Tweakers ~~ Ride Report ~~ Post ColorTuned XJ75

I think I am ~~> Dialed IN !!!

I didn't get to do a legitimate High-Speed Run / Kill / Check ... like I wanted to do, today ... because the Highway looked like a Parking Lot due to an accident.

The Bike is running sooooooo freakin' good!
I spent most of the limited time checking-out -- 0 - to - 80+
NO hesitations.
NO burps, backfire or feathering-out.

Power.
Control of power.
Sweet mother of acceleration!
With the Pilot Mixture tuned at the hairy edge of RICH ... The ride was smooth, cruiser-style quick, not as crisp on the engine braking as I would like ... but, the pull and power-on immediacy of the way she's cookin' right now ...

I'm probably done.
Sum-buddy-hep-meh!
I done tuned dizz bike rite-hup to da harry edge huf giddy-yapp!
Dam shore did!

 

Saturday Rode Test Commencing at 17:15 Hrs EDT
Findings to folo upon return.
If I return!

 

Good news Rick! I have been searching for the jetting guide concerning K&N air filters and aftermarket exhausts but to no avail. I am certain that it is not on the K&N webs site as I stated so I apologize for that. Chaulk that up to old farts with faulty memories. I will contact K&N for an official answer.

 

Re: Tuners & Tweakers ~~ Ride Report ~~ Post ColorTuned XJ75

Oooooh ...
Boy's and Girls ...

I ... am ... Dialed ... IN!

Synced ... dinked, and doinked.

Cleaned carbs and clean-tuned.
YICS Synced.
ColorTuned Pilot Mixtures

I made the mistake of thinking that the ColorTune Plug would find the right mixture by inserting The Plug and bottoming-out the Pilot Screw and Tweaking it OUT until I got the ColorTune Plug showing me BLUE.

Remember: I have ALWAYS said ~~> LEAN is BAD!

Why then ... did I ColorTune and get tuned to a LEAN condition.

Answer:

There is a window ... an area, where the Air-Fuel Ratio will be such ... that the ColorTune Plug will show you BLUE ... when you have found an Air-Fuel Mixture that is correct to have the burn be BLUE.

This "On the LEAN side" Mixture is the wrong place to be!!!
Although the engine will have ~~> Excellent ALL-Around Performance -- Including a rock solid Idle @ 900 - 1050rpm's ... the Over-all condition is entirely too LEAN.

The CORRECT Mixture is found at the other side of that BLUE Window.

To find the correct mixture where the Air-Fuel Ratio is the best for running the XJ-Engine ... continue to turn the Pilot Mixture Screw OUT ... making the Mixture RICH ... observing the COLOR of the burn and listening to the performance to the engine.

Rpm's will rise.
The Color will be BLUE as the rev's are added-on.
The Color will change away from BLUE and become YELLOW or ORANGE-YELLOW.
The performance will deteriorate, miss and/or backfire.

This condition has insufficient Air. Too much fuel in the Ratio with not enough Air, prevents combustion and the misfiring and plug fouling will begin.

From this Overly Rich Condition ... the Pilot Mixture Screw is adjusted IN.
Micro-tweak the Pilot Mixture Screw IN.
Slowly.
The PLUG will once again show BLUE.
The performance will return to a steady Idle.

The Pilot Mixture is adjusted to an optimum Air-Fuel Ratio which is "ON the RICH Side."
Do 'em all that way!

I did and I'm DIALED IN!
Tuned.
Playground slide effect of OEM overabundance of foam rubber -- REMOVED!
New Tires.
New Brakes.
SilverStar Headlight Bulb.


And ... just for good measure:
Some fresh Golden Spectro 20W/20 added to the Front Forks tonight!

Greased and ready to whip-ass!

"RickCo Seven Five Zee-row is ready for take-off!"

 

(Control Tower): Affirmative Rickco, seven, fife, zero. Cleared to depart runway 32, climb to 5000 (RPM) maintain 5000 till clear outer marker and expect 9000 (RPM) when clear of class B airspace.

 

I got a reply from K&N today. It is vague so I suppose he doesn't know bikes or carbs. But the link has some good info. Seems a jet increase is called for with CV carbs. Here is the answer:


Thank you for your interest in K&N products. As
for replacing the jets,
if they are worn when you install our air filter,
you can run into a
lean condition with the increase in air flow,
Because each bike is
different in wear and maintenance I cannot say
for sure that every bike
will need new jets. Here is some information from
the installation
sheet, please click the following link for more
information:
http://www.kandn.com/instructions/17077.pdf

If you have additional questions, please contact
our Customer Support
department at (800) 858-3333

Thank you for writing,



James Johnston
Customer Support Representative,
K&N Engineering, Inc.
jamesj@knfilters.com
Phone: (800) 858-3333

 

Re: Tuners & Tweakers ~~ Ride Report ~~ Post ColorTuned XJ75

So Rick? Are the screws still turned out about the same (3 to 3 1/2 out)? Or did you find that you had to go out a little more?

 

"WATER was expelled from the drainage ports near the exhaust flanges attaching them to the collector box." (Quoted from Rick)

Hey Rick,
Silly question here...what does the water from the exhaust tell you? I haven't had a chance to check the lean condition of #4, but will know to look for the water, if it exists.
Thanks!!

 

It tells you that you filled-up at a place that is serving-up Ethanol in the gas they sell.

I'm seeing more and more stickers on the gas pumps informing you that the fuel has the Ethanol included.

I quit buying regular as a result ... and, I'm shellin'-out the extra dime for Premium.

 

Thanks for the info, Rick. It sounds like I might benefit from dialing the screws out a bit on my ride (seems I should do this to all 4). If you can hear the difference between "just right blue" and "just a bit rich yellow/orange," do you think I can find this spot without the Colortune? I'm in a class all weekend coming up, but should be able to set aside some time to finally get this bike back on the road again. It's killing me not being able to ride right now. (But, I love reading everyone's ride posts!!)

 

Yep ...
You can "Find" it.

Tweak the Mixture Screw OUT ... Tweak - tiny tweak.
The Idle will INCREASE as the Mixture becomes more RICH.
Control the rpm's with the Idle Adjustment Rod between 2 & 3

There will come a point when further Tweaking OUT does NOT cause the Idle to Increase any further.

This is a plateau where the Mixture is RICH enough provide Good Burn and steady Idle as the Fuel Percentage is still being raised approaching the point where it will become too RICH.

Eventually, you will hear the Cylinder begin to react to where the FUEL Percentage in the Air-Fuel Mixture becomes TOO RICH to ignite.
The Cylinder will misfire, cough, pop, sputter and die-out because there is TOO MUCH FUEL in the Pilot Mixture.

Tweak back IN at that point ... until the Cylinder is firing steadily with the Mixture ~~> Corrected for a sufficiently RICH Mixture that will:

Support a steady IDLE ...

Do all four like that.

At this point ... the bike is tuned to have the Pilot Mixture set "ON THE RICH SIDE"
Rich is GOOD.
However ... you won't know until you test ride and see how the engine is performing ~~> "Coming off Idle and transitioning to the MAIN Jetting.

If there is a momentary delay ... a hesitation ... happening before the bike puts the power on ... the Idle Mixture is still a little too RICH and will need further ~~> Microscopically adjusted tweaking IN.