Colortune problems / Mixture screw?

I put my 12mm colortune in my Maxim X yesterday, and I was having a really hard time with it. It was sparking to the head so much that I could never get a good idle. I didn't have the viewerscope on, so I am going to try that to see if the extra plastic will stop the arching.

The other thing was that I could never really get a yellow flame. I understand that the screw on the Mikuni's is a mixture of air and fuel. So does screwing out mean more air? Or does it just mean more mixture? If so, how do you set the mixture?

Anyway, I am really discouraged about the whole Colortune thing, and the whole tuning thing!

I am now more than ever seriously considering buying a gas tester.

 

Sparking to the head? How so? It should screw into the spark plug thread and spark inside. You see a bright ring while it is firing. The plastic shouldn't really be required if you see the coloured ring. Are you sure you have the proper sized colourtune? Also, don't forget the copper seal with it.

The mixture screw adds more fuel if you screw it out (counterclockwise) because the screw is obstructing the flow of gas. Turn it in and it is leaned by restricting fuel through that passage. You set the mixture by the colour of the light from the colourtune. You want a bright "bunsen" blue colour for optimal mixture.

I kept turning mine out until the flame turned yellow then turned it in until I got the blue colour desired.

 

Does your colotune have an insulator around the center electrode? Auto versions like mine don't have one and are known for sparking across the base. To stop this on mine I put heatshrink around the center electrode below where the plug lead screws on and then a plastic straw over that. Did the trick.

 

One last thing, if you get too frustrated call Rex or send him an email before you part with the bucks for a pocket analyzer. Rex is a great guy and truly knows how to tune a bike. He is known on this forum as ShadowHawk.

 

richard03 I tried using the one I bought and also got frustrated with it!
I solved my sparking problems with electrical tape on the connector end that screws onto the colortune plug.
I couldn't really see much of a color change and blamed it on the bright sunny day. Plan on trying it again one evening or when it's a cloudy day!
I haven't given up yet, as many people do use them, so it must work!

 

If you get rid of the colortune send it my way! I need one bad.

PS.. whats the part number for the new model colortune?

 

Here is the link for ordering the colortune. Note that you can just buy the plug with no ht lead, scope or mirrow. You would have to make a ht lead and it will work without the scopetube but only in a dark room or at night. That would cost you 18 gpb. That would be $33.2856 usd in todays market.

 

sorry... but theres no link... lol

 

http://www.ekmpowershop.com/ekmps/shops ... AT&catid=8

Ok, I'm having one of those days I guess. I went to the doctor yesterday but can't remember if I have alzheimers or not. O rwas it last week I saw him ....or was he a she.... or ...... 8O

 

XJ plugs are 14mm thread FYI. I found the kit stateside from Northern Tool. Link:

http://www.northerntool.com/webapp/wcs/ ... allpartial

I'll probably order one from them as I have used them before.

 

Thanks for the reply Bluemaxim! Yes it was sparking from the metal connector on the wire. I will try to insulate like you said.

Fraps - I think the reason I may be having trouble is that the X's spark plug is recessed like most cars. It is about 3-4" down inside the head. This leaves a lot of metal around the spark plug!

The problem with my carbs, is that the mixture screw doesn't control just air or fuel, it controls a mixture. In other words, one passageway from the air meets up with a fuel passageway, and then they go through the mixture screw.

So - my question is - how do I control the mixture? It seems to me that turning the mixture screw out will just allow more air and fuel at the same time. So, it is not really controlling the fuel/air ratio. Or is it?

 

Richard you are misunderstanding what I did at first about CV carbs. Unlike auto carbs these have no internal fuel pump. When you open the throttle it only allows more air to flow. These carbs are 100% dependent on air or vacuum produced by it's movement to suck the fuel into the air stream. All the fuel passages must meet up with an air passage to pull the fuel.
I promise you that turning the screw out will indeed increase the amount of fuel present in mixture as long as the float bowl is at the proper level, there are no restrictions in the passages and the intake valves are seating and doing their jobs.

 

Quick question about colortune units: everyone seems to be out of the 14mm MOTORCYCLE colortune (#G4170) but they have the 10mm MOTROCYCLE colortune with the 14mm adapter.....is this a better way to go as opposed to ordering the automotive-designed 14mm colortune #4074? Isn't the motorcycle colortune plug smaller than the automotive one, so as to not alter the compression ratio of the small volume motorcycle cylinders?

Any help or advice would be appreciated, as "it is time" for me to get one.......

 

You know guys ... there was a time before COLORTUNE ... that we had to set the PILOT JETS ... "By ear!" The idea is to get your idle mixture NOT lean. Lean is BAD. Rich is GOOD.

Sinc the carbs. Tweak the Pilot Screw. Initial set: 2.75 Out -- 1/4 turn MORE than Factory. If it idles good right there ... leave it! If if don't ... turn the screw IN until the engine stumbles ... tweak-it.

A tiny bit ... like you're working on a fine watch ... not a lawn mower! When the idle begins to stumble from being too lean ... tweak it OUT ... (Tweak ... don't rush it) ... eventually, you will arrive at the "Sweet Spot" ... where the idle STARTS to get nice ... continue the tweak!

Listen to your engine. If the idle climbs ... let it ... tweak ... when you arrive AT THE SPOT ... that further tweaking DOES NOTHING to improve the IDLE ... Go BACK to where you had achieved MAX idle before the additional OUT tweaking didn't improve the Max rpm!

Do 'em all like that!

Sure ... it might be a single-digit percent rich ... so what??? Rich is Good.
Rich means you are not going to be at risk of a lean mixture overheating valves, seats, burning away oil sheen on cylinder walls ... and causing you to have to hit the starter button -- time and again -- because you stalled it and need to put another needless hit on your starter clutch.

So, ... you want to run a skootch rich -- or, split the cases to overhaul a starter clutch???

You pick it ...

I like being able to put my hands on my hips at the light ... showing-off some fine-tuning on magnificent engineering!!!

 

Rick seems to be the kinda guy that went to the old school where you really knew how to be a mechanic!!!
That's the way I learned too.
But yes I broke down and bought a colortune, it's a 14 mm motorcycle type. Got it on e-bay new for 60.00 usd from the UK.
It works great! I never use the tube and I do use the extension on the center electrode... mine does have an insulstor on it.
Yes, when you turn the mixture screw out (counterclockwise) the fuel mixture does get richer!

There is a lot to these carbs and if you have a good teacher to assist you you will be able to sit at the light just like Rick!

 

I have colortuned several bikes that were set by ear. They ran right after I colortuned them. There is guess work and there is precision.

 

Hvnbnd, could you tell me where you bought a 14mm motorcycle plug from? All I can find is the standard automotive colortune plugs in 14mm. Do you recall the name of the eBay seller? All I seem to find on eBay is the "Colortune 500" which is listed as a motorcycle unit, but I don't think they are.......

 

Mine is the 500 model. Some don't like it but it will work for tuning. It most certainly got my bike running. Someone just posted a link to Northern tool where they are selling the colortunes. Other than that I would order from Gunson's. I will admit that the true motorcycle version is better insulated and less likely to spark across the plug.

 

Mine doesnt say it's a color tune 500 but here is one just like mine..... only about $30.00 cheaper!!!
Darn!!!
Oh well I've got about that much use out of mine!

http://cgi.ebay.com/ebaymotors/GUNSONS- ... enameZWDVW

 

That auction isn't over yet...

 

If anyone gets a Colortune without the ceramic insulator over the center contact you can write or call Colortune and they will send you one. Mine wouldn't work without it because of the arcing.

 

http://www.carbtune.com/colortune.html
This is the link for ordering from Morgan. Click on "order shoping cart" and then click on the colortune pic on that page and you will see that you can order just a plug for about 18lbs. or $35 USD. So if you guys don't like the auto 500 model you don't have to buy everything just the plug.