Topic: MotionPro Syncpro fix

[cmouta]

I was able to get my Syncpro to work properly and I figured I'd document the process and the problem/fix that I think everyone has with the unit.  So you put your restrictors in, turn your screws all the way out per the manual, hook all the lines up to one carb, start the bike and it sucks out all your sync juice like such:
http://youtu.be/BYN67dIHohg

Is the unit a piece of crap?  No, but the instructions are.  When you turn the screws counterclockwise to achieve maximum vacuum or whatever, it's really easy to go too far


Once you back the screw out so much that the O-Rings are in the threads you're totally screwed and that side is basically exposed to atmosphere making even the slightest vacuum on the other side enough to screw things up.

The problem with the directions is that they tell you to back out the screw counterclockwise all the way.  Lets say you went right to the threads but were still good.  Once the bike is running they tell you to lower it to the bottom 1/3rd, you'd have to back it out some more but you're completely out of room to do so.  Not cool.

A vacuum gauge with a restrictor would be handy to see what kind of vacuum your bike is pulling.  Then you could simulate it with a mityvac brake pump if you wanted to play around with it, which is exactly what I did.  If you pull the unit apart and remove the tubes in the back, you can set the adjustment screws to wherever you want without changing the fluid height. pop the tubes in, and go from there.

Chances are it's set up fine from the beginning so just look in the window and make sure your O-Rings arent in the threads and you should be fine!


Also if you've got bubbles or anything in the tubes, swinging the unit in a windmill motion absolutely works to clear it all out.

[MRieck]

This is why I have an old mercury unit and a Morgan.

[bwaller]

Or a beauty old set of gauges/dampers! 

[Duke McDukiedook]

Read the fine print, these were never designed for engines at 500cc or greater. There is usually too much vacuum for the light fluid to resist being sucked out. Either get dial gauges or plunk the money on a morgan if you have a 500cc or greater engine.

[cmouta]

Read the fine print, these were never designed for engines at 500cc or greater. There is usually too much vacuum for the light fluid to resist being sucked out. Either get dial gauges or plunk the money on a morgan if you have a 500cc or greater engine.

Well I put a fluke calibrator with Druck pressure module on my engine and it was bouncing around(forgot the restrictor) -2 to -10 inHG around 1100rpm.  10inHG = 24.5cmHG and the syncpro has a maximum vacuum limit of 40cmHG so I think its well within the limits of the device.

[tlbranth]

This is why I have an old mercury unit and a Morgan.

Yo

[cmouta]

Also the fluid they provide is/has propylene glycol so it sounds like you could probably get away with using propylene glycol antifreeze as a replacement. 

I didn't know any better when I bought my syncpro last year but there's nothing in the fine print that says "not for 500cc+ bikes." and unfortunately in my 650 manual it didn't list a typical vacuum readout of the engine to compare to it's "fine print" 40cmHG limit. Just a differential limit between cylinders. From searching on these forums it seems like alot of people have purchased this unit and had problems with it.  I don't think the immediate solution should be "spend another 100 bucks on something else" but rather "take a little time to understand how the device works and make the 100 bucks you already spent work for you"

[Duke McDukiedook]

40cmHG = 7.7psi and the 750 manual calls for 8-10psi vacuum on the carbs.
A 750 draws too much vacuum for these meters.
I don't know what the manual calls for on other bikes, I just know about mine and the fact that it sucked the fluid out on mine.
The tech at motion pro said he wished they had a disclaimer about not using it on bikes above XXXcc's- I don't remember what the exact number was.
He has had to field a lot of calls on that subject and just offers another blue vial of fluid for you to suck in your carbs.

[cmouta]

40cmHG = 7.7psi and the 750 manual calls for 8-10psi vacuum on the carbs.
A 750 draws too much vacuum for these meters.
I don't know what the manual calls for on other bikes, I just know about mine and the fact that it sucked the fluid out on mine.
The tech at motion pro said he wished they had a disclaimer about not using it on bikes above XXXcc's- I don't remember what the exact number was.
He has had to field a lot of calls on that subject and just offers another blue vial of fluid for you to suck in your carbs.

Ah well that certainly makes sense then.  I too don't know what other manuals typically call for but measuring mine out put me at around 5psi vacuum max at idle.  I wonder why the 750 draws so much more?

[Vinhead1957]

I used that unit and read the directions and did not have a problem.

[Steve_K]

I have one and it worked well the first season.   I stored it vertically and lost fluid.  I needed to get a refill bottle.  This spring same thing, fluid low.   I have used it on a 750 GIXXER and on a 550, but I could not keep the fluid in the thing,  I kept it at lower rpm (3000) when blipping the throttle.
I have used vacuum gauges and mercury sync tools and never have problems.

I can not recommend this product.  I think a Morgan Carbtune is in my future.

Anyone want to buy mine?

Steve