How to Use EMPI Carb Synch Tools

RainyRider · Post by **RainyRider** » Fri Nov 06, 2009 10:55 pm

I used just the smaller one, inserted directly into the meter - yes, the holes are covered when you do this.

I removed the chrome tubes and inserted the small rubber directly over the carb body opening. Then opened the throttle just slightly (slight increase in rpm, the carb slides are now just up from the closed position), then adjusted the throttle cables until I had equal reading on both carbs. Equal reading means the slides are positioned to allow the same air flow through both carbs as you are opening up the throttle. Also checked at higher RPM just to see if they were still drawing air equally.

At least, that's the way I do it on my R-50 - also the four carbs on my ST1100.

Note: I wouldn't try to adjust the throttle cables when the slides are in the closed position at idle - your readings can be way off when you actually start to open the throttle. DAHIK. Also, if you try to take a "test ride" with the tubes and air filter disconnected, you may get some VERY interesting reactions going down the road, such as the bike just "quitting" when you open the throttle - I guess it just leans out too much and stops running for a few seconds - of course, YMMV.

fred

'91 Honda ST1100 (Gets a lot of waves from sport and touring riders.)
'05 Yamaha Road Star (Gets a lot of waves from the cruiser crowd.)
'57 BMW R-50 (Gets a lot of waves from EVERYBODY!!)

808Airhead · Post by **808Airhead** » Sat Nov 07, 2009 12:13 am

Good stuff,I am waiting to get mine in,I cannot wait to synch these babies up!!! I used the old style Uni-syn,but the little red ball jsut bounces to much to get a good reading.IIRC the holes in the side are there to adjust the vacuum level on the meter to smooth out the pulsations of the intake stroke.Atleast on my Uni-syn it works that way.

schrader7032 · Post by **schrader7032** » Sat Nov 07, 2009 8:35 am

Fred -

Thanks. I can't seem to get just the smaller one to fit insde the meter opening . The OD and IDs are just too different. Looks like I'll fit the smaller into the larger one, then fit them both onto the meter while covering the two holes in the meter.

I've done my /7 carbs with the TwinMax, so I'm somewhat familiar with using devices like this. I've balanced the /2 carbs by ear and using the plug shorting methods, but I'm not sure I've got them spot on.

The thing that I'll have to deal with is handling the carbs and getting the air tubes off after a ride. I'll need to warm the engine/carbs up before I start this process. So after the short ride (~30 miles), I'll have to quickly loosen the carbs so I can separate the tubes then reconnected the carbs to the head. I want to do this so that I can restart the bike while it is still reasonably warm to get the best synch.

Kurt in S.A.

schrader7032 · Post by **schrader7032** » Sat Nov 07, 2009 8:40 am

Oh, and what about the plastic screen that inside the meter opening? It's loose but doesn't look like it could come out and be sucked into the carb. What's its purpose? Should I just yank it out of there and throw it away??

Kurt in S.A.

schrader7032 · Post by **schrader7032** » Sat Nov 07, 2009 12:04 pm

Jeff -

Thanks...that's exactly the setup I finally ended up using. I went for a short warm-up ride and then installed the two meters.

And I'll have to say it made quite a difference. The idle speed wasn't the same between the carbs, so I adjust them both for a good balance and RPM. I then pulled partial throttle, say around 1500-2000 RPM and could see that the left cable was pulling stronger. I took some of the tension out of the left cable and got a good balance.

Went for a ride. It's like a different bike! Idles better, no rocking back and forth. And the bike felt much smoother at speed and at the shift points as well as seemed to pull a little stronger under throttle acceleration. That might be more of a "desired" perception, but the bike was definitely smoother.

Kurt in S.A.

808Airhead · Post by **808Airhead** » Sat Nov 07, 2009 12:55 pm

Nice!That is the result I am expecting as well!

jeff dean · Post by **jeff dean** » Wed Nov 25, 2009 10:28 am

BTW, I learned about the EMPI gauges from Tim Stafford and through this excellent manual here:

http://www.barringtonmotorworks.com/gal ... =14&gid=97

VBMWMO · Post by **VBMWMO** » Mon Feb 15, 2010 2:53 pm

I took the plunge and bought these. Jeff Dean provided the following link:

http://www.dealparts.com/mm5/merchant.m ... COMPONENTS

I'm anxious to give them a try but I can't figure out the rubber bits that come with them. As you can see in the link, there's a smaller conical shaped adapater which probably is what goes into the opening of the carb. The larger rubber adapter seems to fit on the end of the measuring device. But after that, I'm clueless.

Edit -- OK, I was able to get the one small piece to fit inside the larger adapter. That seems to be right. Notice the two holes in the larger adapter and the two holes in the synch tool. Do these need to line up or not?

Has anybody used them already and can you provide a few tips on their use? I have the stock 26mm carbs on my R69S.

Kurt in S.A.

jeff dean · Post by **jeff dean** » Sat Aug 07, 2010 12:05 pm

Perhaps a photo will help?

Tim Stafford and I used it to synch carbs at 5, 10, and 20 kg/h (kilograms per hour). Works like a champ.

We left the pivoting plastic screens in place. Have no idea what they do.

http://www.dealparts.com/product/43-5712-0.html

Vintage BMW Motorcycle Owners