vacaum fittings

[gravelman]

hi guys joe here i have a question and i cant seem to find no info .k i have a 71 xs1 b which i recntly got anyways i was just setting it up and noticed that it has what i believe to be 2 vacaum port fittings that are joined together i think anyways.on my 72 it doesnt have that .anyways on my 72 i put barb fittings in my spigots so i coule use my vacaum carb tune however on my 71 has these huge out lets like probly half inch od anyone have any suggestions on what way to make vacaum fitting of that set up or block and put plugs with barb iam at a loss here thanks joe

 

[jayel]

pictures?

 

[MrBillohnooo]

Sounds like he's talkin about the crankcase breather tubes on the back of the head.

 

[gravelman]

kk heres a pik thanks joe

 

[jramp]

Is this what your talking about? 25 cents at Schmucks. Trash the vacuum petcocks, there no good to begin with. Good luck ....nevermind....

 

[jayel]

yes the first xs's had that cross-over supposedly it helps balance the carbs like the later YICS (YAMAHA INDUCTION CONTROL SYSTEM) add some barbs to your to your inlets like you did on the 72 for your Vacuum carb tune

 

[GreasyC]

I think both the xs1 and xs1b had this. I know what you mean, it would be nice to have a set of barb plugs that replace the hose sometimes because it makes carb tuning more difficult. If you follow the usual "run on one cylinder and adjust throttle stop until it just stalls" procedure to set the idle balance you'll find that you can completely close the butterfly on the carb for the running side but the engine never stalls, it will keep chugging along on the mixture it gets through the crossover tube from the other carb. Setting the idle mix screw is just as ineffective and baffling with the hose connected. Some guys connect the vacuum barbs together on their later model bikes though so there might be some value to it.

 

[jayel]

Some guys connect the vacuum barbs together on their later model bikes though so there might be some value to it.

I did that on my 74 model after adding barbs seems to smooth it out a bit and the XS1 does make more HP than later models

 

[gravelman]

ok guys i did a experiment to day .i unhooked the cross over and made 2 adaptors so i can hook up to my morgan carb tune which is a very accurate tool i use it on my beemers and they run sweet. anyways it didnt work worth a shit my readings where all over the map .so iam not shure if its the size of reduction .so i did the old school dead cyl with my my home made gizmos put one on each side then i capped them fired up the bike unplugged one side till idle stablized at 1thousand rpm did the other and it worked so iam at a loss with the barb thing but i w2ont quit trying lol heres some piks of my gizmo laters

 

[XSLeo]

Try using one of the home made syncing tools made from clear hose, a stick and some bright colored oil. Awsomely sensitive and accurate.
You will find it in the tech section under homemade tools, cost a couple bucks.
Leo

 

[gravelman]

i used my morgan carb tune which is same idea except it uses stainless steel rods which work ok on every other bike i have used it on iam still thinking theres something in my reduction i cant understand it lol

 

[XSLeo]

Those are a fine tool, the homemade one works great and for a few bucks,how can you loose?
The way the home made setup works is by directly comparing vaccum levels on both cylinders at the same time.
Most carb sync tools are a multiple set of tools in one unit, one tool hooks to each side then you have to compare the values of each tool. You read a value of vaccum in inches. Then you try to get that values to match.
The home made tool puts vaccum from each cylinder to each side of a liquid in a clear tube, you know instantly if the vaccum levels are off by viewing the liquid level. Now as you adjust the carbs, the reaction of the fluid is drastic, very easy to see a very minor change. You may not even realize you turned the screw and see the levels change an inch.
Leo

 

[hmusket]

Check this thread out, read down to 5twins reply, #5 http://xs650temp.proboards.com/index.cgi?action=display&board=Fuel&thread=7733&page=1

 

[GreasyC]

I use a different method than the one 5twins posted for syncing the throttle cables. I cut two small triangles of paper and stick one in each throttle stop. Slowly turn the throttle while looking down from above the carbs. When the slack in each cable is matched the papers will fall at the exact same moment as the throttles lift off the stops in sync. If one falls first increase the slack on that side a hair and try again.

Both of these methods are only a static balance, in real life slight differences between the two sides will probably mean the cables shouldn't be exactly even so a manometer balance and then fine tuning by ear are really the way to go.