912S carb balance

[wannafly]

My new 912S is running great and I did the mechanical balance with the throttle arms and linkages as per the instructions and the video on there website. How many do the extra step with the vacume gauges on each carb? Does it make a big improvement of the smoothness? I think it is good now but don't have anyone here with 912 experience to compare it to. I guess it can't hurt to find some gauges and do it. Your thoughts?

[Mnflyer]

Hi Wanna, I don't have a Rotax 912 but am flying a HKS that has 2 Bing 64 carbs, and I did the mechanical syn. and ran that way for a couple hundred hrs but I then syn. with a dual aircraft manifold gauge and found that it did make a difference it smoothed out some. Don't bother with trying with a couple of single vacuum gauges they are worthless seems no two read the same, at least that was my experience. The dual manifold gauge works great but if I was to do it over I go with a instrument call a carbmate AS sell them as do other places if you google carbmate it will come up. Heres a link to AS:
http://www.aircraftspruce.com/catalo...s/carbMate.php
Another link

http://www.handsontools.com/TecMate-...771-16035.html

[hansedj]

I have the carb mate, very easy to use and works great...

[DesertFox4]

Mic, very much worth the effort to sync the carbs using the vacuum method. The mechanical method is pretty much a starting point to get the engine to run smooth enough to vacuum sync the carbs. The 912 series runs so nice and smooth after vacuum syncing. Probably a good idea to sync them a couple times a year to keep in top condition. An investment in a Carb Mate or the vacuum gauges would be well worth it.
The easiest sync tool is a twin engine manifold pres. gauge if you can find one. Just match the needles and you have it.

[Mark]

I'll also highly recommend it. My engine seemed to run just fine with the mechanical setting where it would start to get rough around 1400rpm. After the sync, it will run well below 1000rpm without a hick-up (not recommended, but it does). It's smoother at the higher rpms now also.

[catz631]

I use the "Twin Max" BMW motorcycle electronic sync gauge. I bought it off of EBAY for a good price. With the use of that instrument and the Throttle Link sold by Highwing LLC,after setup, I can do the pneumatic balance in less than one minute. It is fantastic. I have the old "bellcrank" style throttle setup vs the twin cables alowing me to use the Throttle Link.

[fly away]

Hi Wanna, www.boehm-synchrontester.de is a German producer of synchronizers. He sells its products all over the world.
I think he is the only one who can offer the tester with a Capsule pressure gauge and Zero adjustment.
Scale range from 0....600 mbar; equal 0...17.7 mercury vacuum. A dampening system will avoid vibration of the needle.

Manfred