Carb synching

[Shotgun]

Has anyone used a Twinmax for synching their carbs?

[donaldb10]

I used one on a Royal Star, havent had to do the Valk yet.  Also used it on Yamahoe's V Star and made big improvement on the V Star.

[Thunderbolt]

I like it.  Fast and simple.  There are several people on the board that have made their own multi tube units and they seem to work.  Most of the ones I have done or assisted with have been close on 4 or 5 cylinders.  Usually there will be one that will be off enough that when corrected will improve the idle.

[Shotgun]

How do you do it?  Just hook it up to #1 (I think #1 is fixed) and then adjust all the others against it one at a time?

[Patrick]

How do you use it,, you ask??? No matter which method you use its all the same.. #3 is the non-adjustable carburetor[ middle, right side].. You adjust all to match readings from #3.. Engine should be warm and idling at a constant speed[ speed may change as you do this]..If the fan turns on, wait until it stops to continue[or place an electric fan in front of the radiator]..Generally this job is completed so quickly that the fan may not come on..

[Thunderbolt]

couple more things.  Take the choke mechanism covers off, they are the long chrome covers that are held on with three screws.  When you remove them, you will see the adjustment screws, usually have paint, light blue or yellow on them.  As he said you are adjusting all others to #3, it is the center cylinder on the right side sitting on the bike.  It has no adjustment screw.  Doesn't matter which port on the Twinmax you use, but I put "A" on #3 and move "B" to the others in succesion.  I usually do #4 first, then #2, then #6, then #1 and last #5.  Cylinders are 1,3,5 front to rear on right and 2,4,6 front to rear on left.  The adjustments are very touchy, you turn it and take the screwdriver off each time or when you do remove it, it will change.  I usually zero the Twinmax and turn the sensitivity up all the way.  What you are looking for is for the needle to swing either side of zero the same amount.  The service manual indicates that you should pinch off the vacuum line on #6 when you do that cylinder, but I have found that not to be necessary, as this is so quick.  One more thing, get a golf tee or similar item and stick in the vacuum hose that you remove from the back side of the intake of #3 cylinder.  If you fail to do this, when you put the hose back on #4, it will make the bike run bad as it will pull air into the hose removed from #3 through the "T" on the pair valve system.

[Shotgun]

Thanks a lot for the help, I'm going to do it this week.  They have never been done in 35K so I'm sure they need it