Where to hook up a Manometer

[STVR]

Hello

I'm getting ready to make a manometer I have the jist of it and I know what I need to get. Now this may sound like a dumb question but I have never hooked one of these up and I searched on the site but I couldn't find where to connect the clear tubing on the carb. I have a 1975 xs with original carbs. If some one could enlighten me that would be awesome!

 

[5twins]

Unfortunately, your carb set doesn't have the ports for hooking the manometer to. They didn't appear until the '76 carb set.

 

[Brian902]

That easy.

http://thexscafedotcom.wordpress.com/category/carbs/carb-boots/

But you have to remove the head to do it.

 

[XSLeo]

You can drill a hole in the carb holders easier than the head. Look at pics of carb holders to get an idea where to drill. Find some 1/8 in tubing. Steel, copper or whatever. Drill the hole slightly smaller than the tubing. You want a good snug fit. No air leaks. A good coat of sealer on the tube, press into the carb holder. Let the sealer dry.
Hook the manometer to these tubes. When not using the manometer cover with tight fitting caps.
Leo

 

[5twins]

When I replaced my carb holders several years ago, the barbed version was out of stock. I did as Leo says and transferred the barbs from my old manifolds to the new ones.

 

[STVR]

Hey thanks for all the knowledge in this thread. I actually did the dead cylinder method and im pretty close its not as acurate but its close. My bike is screaming now its never felt so good. It has great response awesome acceleration. Now i can finish the summer out riding!!! Thanks to everyone that has given me advice on this great website, this is our victory!

 

[5twins]

The dead cylinder method is about your only option at this point, until you install some means of attaching the manometer hoses. However, be aware that the dead cylinder method will only get you synced at idle. To get proper sync once you have rolled the throttle open, you have to match the amount of freeplay in the throttle cables to one another. That insures both butterfly plates begin to open at the same time and are open the same amount at any given throttle setting.

If one cable is tighter than the other, that butterfly plate will begin to open first as you roll the throttle on. This will make it open more than the other plate, and it will remain open more throughout the throttle range. The cylinders will run at different speeds and the carbs will be out of sync at anything except maybe idle.

 

[Mikey]

Unfortunately, your carb set doesn't have the ports for hooking the manometer to. They didn't appear until the '76 carb set.

so with a 75 you would use feeler gauge/ piece of paper and adjust the cables so they both open at the same time I think that's how I did with a 1974 back when I was young in 1975

 

[gggGary]

Yes and matching the exhaust volume at idle by putting your hand on the muffler outlets. I did this on an XS then did the vacuum gauge it was remarkably close. On Madness with VM34's I don't bother with the vacuum gauge anymore. Once it's close enough that you don't have hanging idle issues, it's like peeing in a dark pair of pants, it gives you warm feeling but no one notices.

 

[Mikey]

Yes and matching the exhaust volume at idle by putting your hand on the muffler outlets. I did this on an XS then did the vacuum gauge it was remarkably close. On Madness with VM34's I don't bother with the vacuum gauge anymore. Once it's close enough that you don't have hanging idle issues, it's like peeing in a dark pair of pants, it gives you warm feeling but no one notices.

That's what I thought I did back then Thanks gggGary

 

[gggGary]

hint; on 2 cable and 2 into one cable set ups if you back off the idle screws, hold an idle with throttle, (a good assistant to hold an idle with throttle is very handy here) you can synch the cables with hand on muffler exit, and cable adjusters, then set idle screws where they need to be, again with hand on muffler exit, done, no gauges or air filter removal needed Old school cool!

 

[Mikey]

hint; on 2 cable and 2 into one cable set ups if you back off the idle screws, hold an idle with throttle, (a good assistant to hold an idle with throttle is very handy here) you can synch the cables with hand on muffler exit, and cable adjusters, then set idle screws where they need to be, again with hand on muffler exit, done, no gauges or air filter removal needed Old school cool!

Once again thanks that sounds what I need to do Old school like I used to do but forgot how from back in the 70's

 

[mrtwowheel]

Way back when, pre-internet days, Chilton (not Clymer, but Chilton) published a manual more than two inches thick that covered MANY of the bikes sold back then. I tuned my TXA to that manual and used the dead cylinder method and throttle adjustment. Gotta praise them for how well written and easy to follow that manual was. Even though Yamaha DID NOT share their pictures and publications with other publishers back then. I adjusted tuned and brought a lot of bikes back to life with that manual.

Scott

 

[Brassneck]

Anyone ever try a VW carb sync tool? Like one of these: https://www.ebay.com/itm/VW-Bug-Dua...123328256997?_trksid=p2385738.m4383.l4275.c10

No idea if it would work on our carbs, but might be a viable option.