Hi guys,

I'm after some vacuum guages to sync my carbs, anyone have any suggestions on a brand or a style etc etc?

I have been told i should get some with a "damper" so help reduce the needle bounce.

 

also, i have noticed in the Honda service manual that it says there should be 20mm of mecury difference in pressure

but

in the haynes manual it says the pressures should be equal. . .

whats the go?

 

All you need is a 2x4, some 3/16 clear vinyl tubing, and some ATF. They work very well, and will set you back about $5.

Homemade Manometer - XS650 Forum

 

The difference is that the Honda mechanics are a lazy bunch... If you set it 20 mm difference with mercury sticks, it's "good enough" for them...

But it's a vast improvement to get it to no difference... So get as close as you can...

Keep in mind that oil is lighter, so using that, you really want as small difference as you can possibly get...

 

How would I know of my carbs were out of sync? I re-jetted with a stage 1 kit from 6-sigma. Bike fired right up and runs smooth so I haven't gone back and screwed with anything.

 

Anytime you do carb maintenance, synching the carbs is the last step. With a good setup, it takes five minutes.

 

You can build your own carb sticks, and the end result works,,,but it's kind of an abortion looking deal, and more hassle then it's worth IMHO.

The Motion Pro Sync tool is a simple, easy to use, store and widely available for less then the full retail cost listed on Motion Pros site..

 

I've had a Motion Pro Sync tool for years, it paid for itself the first time I used it.

 

I never liked the motion pro syncing tool I ended up getting a few gauges from ebay like this:

NOSHOK 2" Dial 1/8" NPT 30 inHg Vacuum Gauge NIB | eBay

Then I mounted them up and to counter the bounce I used the brass inserts from the motion pro and it work like a charm easy to read immediate change when adjusting and you don't have to hang it anywhere it can sit flat on the seat. It seems more of a permanent tool vs the single tube method and you just add more gauges if you have bikes with more carbs.

 

This is my favorite:
http://www.carbtune.com/

A bit pricey but very accurate, easy to read, no oil or mercury. I have used it to sync carbs and throttle bodies with dead on accuracy and convenience. Worth the extra $$ as perfectly synced carbs/throttle bodies make every aspect of throttle response, horsepower, smoothness so much better. Mort

 

The Carbtune works great. Heres a great way to set it up https://www.superhawkforum.com/forum...request-23936/

 

I have the Motion Pro tool. As mentioned, it paid for itself the first time I used it.

You will need to install a tube to extend the connection to the front cylinder vacuum port, and to install a splice connection to the rear cylinder vacuum port.

The carb synch adjusting screw isn't easy to reach.

 

No matter the sync tool used you'll need to get to and add a port for the front cyl.

Best thing you can do is buy a second nipple just like the one installed in the rear cyl, and install it in front. add a short piece of line, and van line splice at the end, cap the end.

On the front, yes, add a T fitting, then a short piece of line and a vac splice fitting,, and cap it. Tuck both lines behind the frame rail when not needed.


Now you have two ready ports at your finger tips for sync'ing carbs.

The adjustment screw is easily reached with a 1/4 drive flexible extension on a 1/4 screw driver handle.

 

Nice solution and build
To each his own...

Hanging the MP tool from the service cart rolled next to the lift is easiest for me, or using the stand I made from some scrap 3/16 rod allows it to sit on a work bench, roll a away, service cart, floor or lift.

Sitting anything on the seat of a running motorcycle seems to invite having it fall. Possible damaging the tool and or the bike along the way.

I would be unhappy to see a Techs tools laying on my Bike or car in any way.

But that is just personal preference on my part. Just seen too many grease marks, scratches, dings and dents from a Tech and his tools. 25 years of watching my wife deal with techs, customers and dealership service managers has ummmm jaded me a bit on the actual "Service" one actually receives when your vehicle is in for service.

 

I've used the Twinmax (TwinMax Synchronizer) and the Motion Pro. The Twinmax is a pretty cool little tool. Not good if you're going to do 3, 4, or 6 cylinder bikes though. You can Google Twinmax for a better price than the link I provided.