home made Verses carbtune

[dray]

this is what happened last fall I used a friends carbtune to set my carbs ever sense bike runs but runs like crud stalls when stopping or going slow. this all started after the carbtune tune up.

 

so today what i did is a bit of parts buying i picked up 14 foot of 3/16 clear tubing and a pair of line restricters and some lite weight oil now on Wednesday I'm going to put it together and have a home made Man-O-Meter

 

and then I'm going to find out just how good the carbtune really is or not at this point i have 9 bucks into my manometer and it should work just fine

 

ill let you all know how it worked out next week when i get a chance to work on the bike with some luck ill get a day when it will hit the 40 deg. mark

 

dray

[Red Ryder]

Hey Dray, I made one of those. My Carbs were so out of balance that the fluid Instantly sucked all the way up the tube and into the carb. I had to quickly hit the Kill Switch. After several attempts at this with the homemade one I decided to purchased a Carbtune. Hope it works for you bud. Later-

[sleadhed]

Dray

you will need to use 4 tubes at least 3/4 inch I.D. to hold the light weight oil. (I used ATF) the result I a meeter 16X more sensitive than a mercury gauge.

This makes the adjusting tricky due to the sensitivity. but It will work well.

I'll take a photo of the one I made and post it tomorrow

Ken C.

[RPG]

this is what happened last fall I used a friends carbtune to set my carbs ever sense bike runs but runs like crud stalls when stopping or going slow. this all started after the carbtune tune up.

 

so today what i did is a bit of parts buying i picked up 14 foot of 3/16 clear tubing and a pair of line restricters and some lite weight oil now on Wednesday I'm going to put it together and have a home made Man-O-Meter

 

and then I'm going to find out just how good the carbtune really is or not at this point i have 9 bucks into my manometer and it should work just fine

 

ill let you all know how it worked out next week when i get a chance to work on the bike with some luck ill get a day when it will hit the 40 deg. mark

 

dray

 

Used correctly and providing the carbtune is clean you will get excellent results using the CarbTune. I suspect you did not meet at least one of those conditions judging by your results.

[KiteSquid]

Do you have a URL to some plans for this sensitive manometer?

[dray]

Do you have a URL to some plans for this sensitive manometer?

 

 

ill try to get it ready to use for this weekend ill take a pic and get it to you with a list of parts i used

 

dray

[Captainkirk]

I purchased a set of Motion Pro Professional series Carb Sticks (mercury manometer) and have excellent luck with them. The down-side is, of course, the mercury; EPA hates it and is trying to ban it. Fortunately it is still available.

Another device you might try in conjunction with the carb sticks is the Gunson Colortune, which is essentially a replacement spark plug with a clear glass window that actually allows you to view the color of the flame burning within the combustion chamber as you adjust the needle. It works, too! One ColorTune plug will do all four cylinders (one at a time, naturally) and is fairly reasonably priced.

[KiteSquid]

I found Motion Pro web site, but I cannot find the carb tuner that uses mercury.

 

They have a replacement tool for $100 that does not use mercury.

 

Click HERE to go there...

[dray]

ok its mostly done but I'm not happy yet the restrictors didn't do what i wanted them to so i have a better idea I'm going to try i went looking for parts today and no one had what i wanted so later this weekend I'm going to run to Saginaw to see if i can find one more part I'm going to try a air adjuster for an aquarium so i can set it so how much air is allowed to flow through the line

[hipshot]

ok its mostly done but I'm not happy yet the restrictors didn't do what i wanted them to so i have a better idea I'm going to try i went looking for parts today and no one had what i wanted so later this weekend I'm going to run to Saginaw to see if i can find one more part I'm going to try a air adjuster for an aquarium so i can set it so how much air is allowed to flow through the line

 

if you are going to try the "aquarium valves", don't make the mistake of buying the plastic models!

go with the higher priced brass ones.

the plastic ones leak, bad!

just jt

[Captainkirk]

Apparently Kitesquid is correct! I bought my carb sticks a few years ago, but have seen them on the M/P website recently. They have been replaced by the next generation "mercury-free" carb sticks...

 

http://www.motionpro.com/motorcycle/tools/syncpro%3Csup%3Eandtrade;%3C-sup%3E/

 

Looks like the EPA got'em after all!

 

Any way you look at it, that's not a lot of money spent for a tool you should use every 90 days.......very few things are as important to a multi-carb bike as well-synched carbs.

[hillrider]

For the uninitiated, do the carbtune and colortune use the same adjusting screw, or are you adjusting two different things?

[dray]

if you are going to try the "aquarium valves", don't make the mistake of buying the plastic models!

go with the higher priced brass ones.

the plastic ones leak, bad!

just jt

 

thats what im looking for every one seems to have the plastic ones the old brass ones must not be as cheap as they used to be as i cant find any yet and years ago i had hundreds of them LOL

 

most of it is finished even have oil in it getting close now

 

Dray

[KiteSquid]

 

Looks like the EPA got'em after all!

 

EPA or lawyers chasing liability suits????

[Neil86]

Yes water/oil is more sensitive than mercury.....the problem is the Venture idles at about 10 inches of mercury.....to use water or oil (lighter than water) you need columns 13.5 times higher than mercury filled ones....(10 in Merc. X 13.5 = 135 inches or ~11 feet). Thats idling...as the throttles close while synching it can go much higher.

[JPM]

Yes water/oil is more sensitive than mercury.....the problem is the Venture idles at about 10 inches of mercury.....to use water or oil (lighter than water) you need columns 13.5 times higher than mercury filled ones....(10 in Merc. X 13.5 = 135 inches or ~11 feet). Thats idling...as the throttles close while synching it can go much higher.

 

But if you have a V twin, a U tube with a carb connected to each end could give you a comparison for the two. That is all you need for a twin. Now, for a V 4 and a separate column for each cylinder, that's a different story.

 

Joe

[Neil86]

I think you'll find the U-tube pretty erratic as both cylinders try to lift the fluid...interested to see how it works out.

[wizard]

I used a self made man o meter for years on my Triumphs. I was very happy with it. I still have it mounted in my garage. Never did like the results with my Harleys . I used it for awhile on the Venture, but having to plug and move the tubes was irritating. I now have the Carb-tune. So much easier to use with 4 carbs.

[Captainkirk]

For the uninitiated, do the carbtune and colortune use the same adjusting screw, or are you adjusting two different things?

 

You are adjusting two different things.

The adjustments you do with the carb sticks alters the amount of throttle butterfly valve (not the main slide opening!) opening from fully closed. This setting is altered via the throttle plate synch screws on the throttle shaft (see your Venture manual for an extremely well-detailed description). In theory, a properly synched bank of carbs will have all four butterflies open the same amount at the same time and flowing the exact amount of air through the venturis, creating (again, in theory) equal vacuum readings on your carb sticks. Naturally, these readings are affected by the "pumping ability" of each cylinder (which is why it's so frustrating to set up a motor with low compression on one or more) and the oscillation caused from the (for lack of a better description) suck-and-blow of the piston (now you know why those restrictors become so important-they dampen out the dancing mercury (or other media) columns so you can actually read them!)

The idle mixture screws, on the other hand, affect fuel/air mixture settings through the pilot jet (or "slow jet") a.k.a. your idle circuit. This is what we adjust using the ColorTune. Typically, initial settings are made around 1-1/2 to 2 turns out from closed, and each screw adjusted for highest RPM (lean peak) setting at the optimum vacuum reading. This "tuning by ear" process is vague and difficult for the inexperienced tuner. The ColorTune gives a visual cue that is easy to follow. If you have ever viewed a gas dryer or furnace burner, properly adjusted, you know a properly adjust burner flame is a nice cobalt blue, with lean going from light blue down to orange in extreme-lean cases.

So, in essence, the procedure is to synch the carbs and stabilize idle speed at the correct vacuum range, then fine tune the pilot circuit via the pilot screws. Did any of this make sense?