Just finished synching!!!

That was MUCH easier than my father and I had anticipated! We got off to a rough start, finding that my O-rings for my carb transfer pipes were not replaced after 32 years and started leaking immediately However, once we got the gas situation taken care of and the vacuum gauge that our good friend lent to us taken care of, it was all downhill from there! Thanks to BigFitz52 and RickCoMatic, synching was easy as pie with the right directions! I would highly reccommend synching your own carbs if you are even remotely mechanically inclined and on a budget! A vacuum gauge costs less than one hour's labor at a mechanic's shop!

Soon to be out riding!

 

Nice job!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! What is the bike?

 

It is a 1980 XJ650 Maxim. I just checked and repaired the valve clearances, installed new gaskets, cleaned and re-jetted my carbs with a Dynojet Stage III kit, installed new parts inside the carburetor, installed K & N pod filters, and installed a MAC 4-1 exhaust. So far, so good!

 

Adjusting mixture with the colortune always seemed tricky. I'm never sure I have it right.

 

Please report results of a road test -- let us know how she feels and is running please.

 

IMHO, I am discovering that "right" is any point between yellow and white that provides best low-end pull (2k to 4.5k) while maintaining mid range

 

Also, Please note that (at least this is what I am learning) the true nature of the engine's "state of tune" does not reveal itself until it is well warmed up -- my engine runs lean(er) for the first 10 to 15 miles until well warmed up when it finally begins revealing what is going on... So, take it out for a spirited run, try to feel what's going on (or chop plugs, but only after it is well warmed up) -- then come back and color tune or make adjustments

...before...

Repeating the same procedure again including the thorough warm up.

Hope this helps

 

THIS is probably one of the most important factors in getting a good solid sync with a smooth idle and crisp throttle response. Adjust on it when it's not fully warmed up and you'll be revisiting.

 

We let it warm up plenty and the further we got into the synching, the warmer it was. If you do a google search, you will find that colortuning may be some kind of a gimmick, as you are not actually using YOUR spark plug DIRECTLY. It could be completely different once you get your everyday spark plug in there.

 

The ColorTune works too well, and in the manner described, for it to be just a "gimmick."

Granted, it's nowhere near as precise as the method it replaces (using an EGA) since it's a "visual" assessment rather than a precision electronic instrument; but it helps you get much closer than "by ear." More importantly, it helps detect ISSUES that you might not have been aware of otherwise (like an inability to actually adjust mixture via the pilot screws.)

 

That reminds me, when we synced the carbs, we didn't even need to touch the pilot screws. What is the purpose of those?

 

Those screws are for setting the idle mixture via the Colortune.

 

Well, they're for adjusting the idle mixtures anyway. The ColorTune is just one way.

Where are they currently set?

 

They are currently set at about 2.5 turns out each.

 

Cool.

Now is when you would use the ColorTune to determine how lean or rich the mixture is at idle.

You need to start regularly reading your plugs to be sure you're not running lean; and it wouldn't hurt to re-adjust the idle mixtures using the "idle drop" method (by ear) as a start.

How accurate was your wet-set of the floats?

How is throttle response? Any stumble or bog?

What you need to remember about these motors is that if run too lean, they're absolute screamers right up until they hole a piston or two. Just be very vigilant of your mixtures (do some plug chops at 5K as well) so you don't melt something.

 

If you don't have a Colortune len has them. Its worth the money.

 

Due to starter issues and Iowa weather and waiting for more parts to come in from Chacal, I haven't gotten to ride it yet. I've read these forums over and over again and I understand that I definitely DO NOT want to run lean. I just gained access to a colortune today too, so I will be doing that soon.

 

Your lucky to find one. Good luck

 

I am wondering what everyone's experience with a colortune is. I just got one and used it today. I had my adjustment screws out about 4 turns and was expecting it to be rich, so i thought I would see yellow flame. I saw basically nothing except spark. For each cylinder, as I turned the screw out (counterclockwise) I started seeing more and more blue until yellow, so i backed it back in until the yellow went away, just searching for that pretty blue. I never saw it until I revved it up and the engine spun down. then i just saw dull-blue flame.

I figured this was as good I was going to get and moved onto the next one. same thing--no visible flame--just spark. The exhaust pipe on this cyl was a bit cooler than the rest (by about 100deg F) so i pulled it out and started seeing intermittent blue until it got pretty constant like the previous one. The idle lifted too, which is good, because I always have to put a little pressure on the throttle to keep it from dying. I don't think i bothered revving it up after this one.

Thinking i was doing pretty well, i started on the 3rd one (which is actually cylinder 2) and saw the same thing. except this time once i saw any flame in the viewer i started getting mad backfiring. Strangely enough, it would happen in both exhaust pipes at the same time so i screwed the screws for cyls 2 and 3 back in a little until the backfiring stopped, but that means there's no flame visible in the viewer again.

This doesn't really correspond to what the colortune manual said would happen, so i just want to know if this is what others are experiencing.

Any tips?

 

Mine works pretty much like the book said.

You may have float level and/or primary circuit issues, betcha. What do your plugs look like?

One more point-- ALWAYS 'blip' the throttle -GENTLY when using the ColorTune- between adjustments and let the motor settle back down.

 

A backfire while colortuning can leave a residue on the plug that obscures the glass window with combustion deposits. The spark will still be visible but the flame colour will not be readable. If the plug is sparking and there are no cracks in the glass section the plug is ok and working as it should, it's just coated with a thin film that needs to be cleaned off.

I've been experimenting with various solvents to get this deposit off and so far methylated spirits or paint thinner seem to work but are not ideal. MEK is better but is horrible stuff to work with. The glass window will appear frosted if held to the light ... that's the combustion deposit. Try cleaning starting with methylated spirit and a good rub with a cotton tip.

 

I finally took my bike out for about a 7 min ride. When I got home, I pulled my spark plugs. Here's what they looked like:
#1: Black - RICH
#2: Light brown - LEAN
#3: Dark brown - rich
#4: White - REALLY LEAN

Did I just not ride it long enough to get the right results? Or at least consistent results? The bike idles GREAT, and pulls through the RPMs very smoothly and gracefully. I haven't colortuned yet; could this be of any cause to the different spark plug colors?

 

I am not sure you can tell what's going on by pulling old plugs -- the colors reflect the last few minutes of their use -- and if they are old and loaded up w/gunk from bad running...or if you were idleing for an extended period they can be darker or black. Not much use... you want to pull 'em under controlled circumstances.

Now, leave those old junk plugs in and put into your pocket your 8 new plugs (2 sets) and your socket wrench and go for a 20 minute or so ride, some of it hard...

Then pull over in your selected safe stretch shut her down and put in the new plugs -- Then using same safe stretch, make several runs and chops starting with "top end" if you safely can (wot, 3rd ok, then chop) -- if not, then do 5.5k chops and do several -- to inspect color -- you will likely see a decent off-white with a hint of brown -- that's good... If not, well you'll have to figure out what to do... here's one to help:

http://www.factorypro.com/tech/carbtune ... gines.html

This article good too -- note nothing new here -- these have been posted before:

http://www.johnsmotorcycleparts.com/Kei ... g_tips.htm


Then pull those plugs out and put in the second new set and do several 3k chops... see color... do a 4k chop -- see color -- leave that set in -- go home pull in to garage and do not allow extended idel - shut her down and pull plugs -- inspect -- how do they compare to you chops on the road ? This last will give an indication of very lowest end...

Go from there... the more you "chop and look" the more you learn (in a controlled manner) --


Hope this helps

 

What's that? I hear recent experience speaking, from a guy tuning on a fresh resto with some perfomance mods no less. Good going, Coach.

WHAT HE SAID, and then some. Gotta start with new plugs.

If #1 keeps coming back black no matter what you do, you may have a bad valve stem seal. (Which CAN be replaced without pulling the head, but your valves have to be in good shape and you have to be UBER careful or you will end up pulling the head.)

 

Unsolicitated, I know, but, IMHO, These are good-color, new-plug, 6K chop examples:


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Fitz is right! On a scale of 1-10, I am at about a 13 on the jealousy scale over your (dmcccoach) bike! If I only would spend the time and money that you have on your bike! Well, one day I'll buy a brand new Harley and hopefully spend the time to polish that one...

 

Ummm -- thanks... listen my good friend this isn't a contest... I am lucky, yes, but a little maniacal too. FWIW my project wasn't that expensive, as I said I know I am lucky and grateful

I will say it does take time.

Keep us posted man, on your results...

p.s. I usually become all philosophical or poetic and cite a few favorite lines, but I am resisting... serioulsy I want to know what you do and how it works... thanks

 

What do you mean what I do and how it works?

 

I thought we were ultimately trying to help you with this question?

 

From this, I clicked on your build. NICE!