Adjusting the throttle cables equally with a Uni-syn

[teebo]

I picked up a Uni-syn #4027. I get how to adjust at idle. How does one check while under throttle?

I gather it's revved to a particular point, and vacuum checked on each carb and throttle cables adjusted.

What RPM? And how do I keep it there and manage the uni-syn and adjustments. I'm short an extra long arm and hand.

[mike in idaho]

Tighten the upper cable adjuster, on the throttle, until it starts picking up revs. Do your adjustments to equalise the vacuum readings, then re-adjust the upper cable.

[LongDistanceRider]

Any rpm above idle speed where the screws aren't making contact will do.

[teebo]

So... My upper adjuster seems to do very little. It's backed almost all the way out, as is the carb side adjusters.

Fishy cable? They are new from 4into1.

[LongDistanceRider]

Adjust the bar end one all the way in, now adjust the carb ends so there's almost no freeplay. Then readjust the bar end out which lengthens the cable housing which in turn tightens the cable even more.

[teebo]

Adjust the bar end one all the way in, now adjust the carb ends so there's almost no freeplay. Then readjust the bar end out which lengthens the cable housing which in turn tightens the cable even more.

Am I overlooking some other adjustment? Carb side they are all the way out almost. Same for bar side. Even with that, there is a tad too much free play.

[LongDistanceRider]

The carb brackets probably need to be bent back to a 90 degree angle and straightened to perpendicular on the rise section.

[LongDistanceRider]

I go to the trouble of bending them to get the cable more or less centered in the end and centered on the eccentric.
RIMG0677.jpg

[teebo]

The carb brackets probably need to be bent back to a 90 degree angle and straightened to perpendicular on the rise section.

Thanks. I took the left carb and bracket off. It is definitely 90 degrees and straight. The right is ever so slightly not, which accounts for that side being adjusted slightly out compared to left. This with doing the sync by sight method.

I can't even make sense of what the correct length should be because I'm seeing different lengths.

But I suppose the amount of slack outside the sleeve also matters.

[ancientdad]

Aftermarket cables aren't always correct length, whether inner or outer portion. I've bought cables that aren't quite right in one aspect or the other, like the front brake cable for the drag bike project where the inner cable is just slightly shorter than it should be. You could re-bend the arms to create a slightly increased height to take up some of the excess inner cable length, just try to make them as close to equal as possible.

[teebo]

I'd have to make up quite a bit with the bend. As in, there is no more adjustment for tighter remaining, and there is still a little too much free play in the throttle.

Scrambler Cycles has some (what appears to be) really nice grey cables. But they are out of stock on more than one. But they list their throttle cable for the cb350 as 36". The one from 4into1 is 42". That is quite a bit of difference. No idea what the outer portion length is.

I'll figure something out. This is one of those tedious things. Like when I installed my new headlight bucket and it took over an hour to get the chrome ring to fit on correctly. Ring ang bucket were slightly different shapes.

[mike in idaho]

Do you have any of the original cables around, to compare the free length with?

[teebo]

IMG_20220330_181745.jpg

Some call it a hack. It just improvising. Rope tied to clamp, then put a weight on the rope.

Hopefully the grey ones I get won't need this.

[LongDistanceRider]

Some call it a hack. It just improvising. Rope tied to clamp, then put a weight on the rope.

Hopefully the grey ones I get won't need this.

Kudos on innovative thinking