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Posted (edited)

I am trying to calibrate my new SyncPro Carburetor Tuner. I checked the idle, it is at 1000rpm. I attached the short hose to Cylinder 1 -- which I believe is the rear cylinder on the left side, and normally wears the cap instead of the tube. See picture.

 

When I start the bike to calibrate, the leftmost column rises all the way up and past the scale. The other tubes are also very high, but don't get sucked into the engine.

 

It seems the engine has too much vacuum. What should I do? Should all the other vacuum tubes and caps still be attached? Should I reduce idle?

 

I'm getting frusty,

 

Dave

Edited by Dave77459
fergot picture. oops.
Posted

I have one of those from Motion Pro...calibrate it will all the tubes connected together with the supplied T. I used it a few times and it seemed to work pretty good, then it got to where it would not calibrate.

One of the screws that you used to calibrate it would not turn enough to get the tubes all at the same level.

I hung it up in the back of my shop (should have thrown it away) and bought a Morgan Carb Tune.

I should have done that in the first place but decided it was to expensive with shipping.

http://www.carbtune.com/

Morgan Carb tune seems to work pretty good, but If I had it to do the third time I would probably find 4 analog gauges to use.

Posted
I have one of those from Motion Pro...calibrate it will all the tubes connected together with the supplied T. I used it a few times and it seemed to work pretty good, then it got to where it would not calibrate.

One of the screws that you used to calibrate it would not turn enough to get the tubes all at the same level.

I hung it up in the back of my shop (should have thrown it away) and bought a Morgan Carb Tune.

I should have done that in the first place but decided it was to expensive with shipping.

http://www.carbtune.com/

Morgan Carb tune seems to work pretty good, but If I had it to do the third time I would probably find 4 analog gauges to use.

I liked the notion that you could calibrate the SyncPro, which you can in theory. But my RSTD just seems to throw out too much vacuum. I'm hoping that I am doing something wrong and that someone can tell me "oh, you are connected to the wrong port" or something.

 

The other issue I have with the SyncPro is the separation of the fluid (see photo). "Shake it down like a thermometer?" Seriously? Does not work here.

 

If I don't get help here, I am writing MotionPro for advice, then I am sending it back to the store. Right now, the SyncPro appears to be defective.

 

Dave

Posted

I have the same issue with mine. Talked to Tech support at Motion Pro and they said something about putting grease on the adjustment screws. Seems the new units are coming with direction that have you do this before using.

Havent tired it myself as I am await replacement fluid for mine. Try contact the tech support at Motion Pro and they should fix you up.

Rick F.

Posted

I also liked the idea of the calibration...

If you let it sit for a few days...all that separation will go away. It does not seem to like to be moved around much. Hang it up when you store it and it will be ready to use when you need it.

I do not think it matters which port you connect for calibration. They all should be fairly close.

I had trouble checking the sync at higher RMPS also...had to be real careful or it would try to suck the fluid in...

If I were you I would see if I could exchange it for some gauges or get your money back.

I just did not have good luck with those.

Posted

I contacted MotionPro tech support, who responded thus:

Hello Dave,

 

Thank you for your inquiry.

 

There are possibly two reasons for the problem you are having. One is, yes the V-Star may have a higher vacuum pressure than the Sync Pro’s maximum vacuum rating. However, the latest version Sync Pro is rated up to 44 cm hg pressure.

 

The second possible cause is insufficient fluid volume in the tool itself. The less fluid there is, the lower the vacuum capacity.

 

Initially I suspect the latter. What I would like to do is send you a refill kit at no charge so you can raise the fluid level (volume) in the tool.

 

Increasing the fluid volume will also put the fluid measurement at the lower to mid range of the scale.

 

If you provide a mailing address I would be more than happy to send you a Sync Pro refill kit.

 

If you have any questions, please do not hesitate to contact me.

 

Regards,

I am cautiously optimistic that this will work. I'll report back. I asked why this would work, and if I am answered, I'll report that as well.

 

Dave

Posted

Here is the explanation offered of why the new fluid will work better:

The Sync Pro uses vacuum against vacuum to determine both resolution and the position of the fluid in the range of the scale. When you look at the reservoir, you will see that each column has an air gap between the calibration screw and the fluid. It is this air gap that gives the functional range of the tool. A larger air gap (or a low fluid level) in any given channel, will cause the vacuum pressure capacity to diminish. Visa versa when there is less of an air gap, the fluid will not rise high enough in the tubes. With no air gap the fluid will incur a hydraulic lock and will not move at all. A channel failure will happen if air leaks past the calibration screw o-ring and increases the air gap thus fluid is sucked up into the engine or vacuum pressure exceeds the limits of the tool. In any case, it is failure of the o-ring.

 

Perhaps when I used the word “may”, the intent was not to imply the tool might or might not work. I used that word on the premise that since I have no idea what the vacuum rating is on your Yamaha and the engine rpm the tool is being used at it is hard for me to give an exact answer.

 

I believe the Sync Pro will perform much better for your application with a reduced air gap between the calibration screw and the blue fluid.

I just love the back-peddling about using the word "may". I don't a non-lawyerly reading of the word may creates an implication of "will". :-(

 

Anyways, I sorta understand that the refill kit "may" work for me, I guess because it replaces the O-rings more than it changes the fluid volume. Or something.:think:

 

Dave

Posted (edited)

Edit:

BTW, does anyone know what the vacuum rating of a second gen/RSTD is at 1000 rpm?

 

Dave

 

I think I answered my own question. Page 2-9 of the service manual indicates it is 37 kPa (280 mmHg), or 28 cmHg. This is much less than the 44 cmHg MotionPro indicates is the maximum of the SyncPro.

Edited by Dave77459
Answered my own question.
  • 2 weeks later...
Posted

I got the fluid kit (for free) on Monday, and did the repair to the SyncPro yesterday. I sync'd today.

 

I think the new kit forms a better seal around the adjustment screws. The gaskets are sent packed in grease, and I think this helps with the seal.

 

Anyways, with the repair, the SyncPro functioned well. It is quite sensitive to the throttle, so high revs during syncing is not wise.

 

Full disclosure: I mistakenly re-installed the two right side tubes backwards, with the flow restrictors on the gauge side instead of the bike side. The right two columns were very flaky, jumping a lot. I didn't see the cause for this until I was re-reading the instructions to find the storage settings, and when I checked I found that they were backwards. The left two channels were installed correctly, and were very stable. I didn't go back to check that it solved the flakiness, but I am confident that it will.

 

In the end, after repair the SyncPro did the job, and I like the calibration feature. I'd like the motion to be more damped, but I am satisfied.

 

Dave

Posted

Sounds like a lo of Micky Mousing around to me. I'll stick to the mechanical vacuum gauges - they work perfectly, are pretty much impervious to rough handling, are easily calibrated (and only need it once every 40 years), and are generally available for around $70.

 

I guess I'm just stuck in the past, but it works for me!

Goose

Posted
Sounds like a lo of Micky Mousing around to me. I'll stick to the mechanical vacuum gauges - they work perfectly, are pretty much impervious to rough handling, are easily calibrated (and only need it once every 40 years), and are generally available for around $70.

 

I guess I'm just stuck in the past, but it works for me!

Goose

 

I'm bringing them with me so we can compare. I don't think they have the same benefits as yours. They seem flimsy, need to be calibrated every use, and are more expensive. Other than that, they are wonderful. :(

 

Dave

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