Throttle synch

[Greybeard]

In the "How To" section in the TPS/Throttle synch topic it mentions "backing off the right throttle idle screw", but then I can find no further reference to re-establishing a setting of that adjuster.

 

If one is to "back off" that setting it would reason that it was set in the first place, but subsequent idle screw adjustment only refers to the left side.

 

I question this because I must admit I did a stupid thing.

 

Had it idling on the stand one day and I just wanted to bring the revs up a tad.

 

Not even thinking, I twisted the knob on the synchronization rod!

 

When I initially twisted it, the knob itself turned on the threads. When I twisted it back, the rod turned on the other end!

 

Since it was running fine before I zoned out I'm following the synch instructions from where one "Closes the air bypass screws"

I'll thread the synch rod rod into the swivel end, maybe with some red Loctite.

Then put on my synch tool and turn the white knob until all is back to snuff.

Don't think I even need to upset the air bypass screws.

 

I am a tired old git.

[Guest ratchethack]

Most (including Yours Truly) find it preferable to keep the RHS idle screw backed well off at all times.

 

Since the ball joint on the RHS is "self centering", as long as the pin on the LHS at the synch adjuster knob hasn't worn to the point where its got sloppy, it seems to be perfectly fine to use the LHS idle stop screw solo.

 

Not sure I understand what you're referring to by the "swivel end", but please DO NOT use Loctite (let alone red stud and bearing mount!) on the sync rod at the RHS end! You may fully understand this, but just in case -- you want the rod to thread freely in and out of the plastic ball joint piece at the RHS end when the locknut is backed off. If the knob has come even partially loose on the synch rod (as would be expected if you forced it without having first backed off the locknut), to be "sure" about re-securing it, I b'lieve I'd prefer a dab of JB Weld on the outside to Loctite. Since Loctite is anaerobic, it depends on a lack of oxygen to cure. This means you'd have to thread the knob off to apply it to the internal threads for it to help.

 

But o'course, that's just me.

 

Good luck.

[Greybeard]

Thanks, RH, that clears up a LOT!

 

Prior wrench had dabbed yellow assembly paint on the white knob/rod thread mating area and I noticed a crack in the paint so I surmised I had turned the knob on the shaft.

I certainly didn't force anything so maybe it was just cracked or maybe it did actually move.

 

But, as you explained, if the adjustment is made by the knob staying in position on the shaft and the shaft threading in and out of the swivel end on the right, then I'll belay the Loctite!

 

Ok, just went out and checked things closer.

 

The RHS is still tight in the ball swivel.

The left side needed a 1/2 turn back for the crack in the assembly paint to line up.

 

Since the deities are smiling on me and I didn't screw around with anything else, then it should be back to where I started!

 

The tech who fettled this bike had some attention to detail anyway.

Assembly paint on all the adjusters, etc. AND he'd installed bullet ends under the seat for the TPS.

 

I read the mv and it's 154.9.

Doesn't seem worth it to try to get the xx4.9 out of it, does it?

 

I still need to light it off with the balance stick on just to say I looked.

[Guest ratchethack]

EGADS, GB!

 

A remembery is a terrible thing to lose.

 

I just went out and took a gander at my Guzzi, and now I think I may've got this wrong.

 

I recall the factory paint marks as you described. I took them off long ago, but IIRC, the paint mark on the knob doesn't line up with wot I posted above.

 

I haven't needed a synch in quite awhile, so maybe someone will correct me if I'm wrong about wot's properly fixed to wot here?

 

There's usually a dedicated short list just a-chompin' at the bit to catch me out. A few will go so far as to dream stuff up if they can't find anything solid. . . All sincerely motivated corrections more'n welcome, but let's see who might jump on this first. Shouldn't be long now.

 

My apologies in advance if need be.

[Greybeard]

Well, the RHS does have a lock nut that is still tight and no lock nut on the left .....and the tuners marks on the right were not disturbed.

 

Don't screw with me now RH!

[Guest ratchethack]

Don't screw with me now RH!

OK, GB. Here's the deal. You got me goin' on this with your mention of the adjustment assembly paint, which got me thinkin' (always dangerous). Since I've got valve adjustment and a TB synch comin' up in awhile anyway, I figured might as well get this settled now. So I took the synch rod out entirely and gave it a careful inspection and lubed the joints with BTWBG. Now it doesn't emit that tiny squeak anymore.

 

It operates just as I had originally posted above: The knob is fixed securely to the rod. Adjustment is properly performed by loosening the locknut before turning the knob, and the rod should freely thread in and out of the plastic fitting at the RHS ball joint. The LHS throttle pin is set in a small block that's fixed on the rod so that the rod can rotate in the block, but the rod isn't threaded into the block, and the block cannot move axially on the rod. Got the picture?

 

NOTE: This one came back to me once I got the rod out: In case of a stubborn locknut, flats are machined into the middle of the rod, so you can get an open-end wrench on it if need be. (BTDT)

 

Yes, a remembery is still a terrible thing to lose, but (at least in this case) I ain't completely lost mine yet, after all.

 

Oh yeah - If my adjustment knob ever got loose on the rod, I'd still put a dab of JB Weld on it to secure it.

[Greybeard]

Mechanically, something is not jiving there, RH.

 

Why would the end that you apply a locknut to and would want secured (the RHS, because of not being certain of depth of engagement in the swivel end fitting) be the end that you look to revolve for adjustment?

 

Conversely, the left end with the 4 lobe adjustment wheel, passes through a block that's not threaded (on the bell crank of the left throttle body) and the white 4 lobe wheel is not staked but turns in & out freely on the threaded shaft end?

 

No, the shaft is stationary while you turn the white knob.

[Dan M]

The threaded rod is stationary. The white knob turns on the rod. At least on a 2002.

[docc]

My yellow Anti-tamper paint is long gone. And, still, I can't imagine the value of using any kind of permanent adhesive (JB Weld or Red Loctite) on the throttle rod. It's adjustable, after all.

 

Best advice, so far is the pinned TPS procedure. It's not the only way, but worth a good fettle, eh?

[Greybeard]

Thanks gents.

 

Now back to one of the original questions.

 

If you back off the idle screw on the right side as the instructions say, when in the sequence do you re-adjust?

 

I quote;

 

("Disconnect the synchronization rod at the ball joint on the right side (the side with the TPS sensor), back off the right throttle idle screw using a 2.5mm hex key, and back off the "choke" cam (make sure the choke cable permits full retraction of the cam (it didn't on my bike). )

 

Would seem to me if you have a solid throttle shaft between the 2 throttle bodies, one of those idle set screws has to be redundant.

[raz]

You leave it backed off. Maybe the How-To should state this more clearly as this comes up several times a year.

 

Ratchethack: I don't understand a word of your description of the rod adjustment. Either I just misread it, or your gear is completely different than the ones I've seen. It could also be that you misunderstand the construction completely but that would surprise me.

 

I just turn the LH white knob. There is no lock nut. I actually put one on (a wing nut, how cool is that) for a while, until I noticed the sync went out as I tightened it.

[Guest ratchethack]

Would seem to me if you have a solid throttle shaft between the 2 throttle bodies, one of those idle set screws has to be redundant.

Multi-carb and multi-TB motors always provide a way to set idle at each instrument. Many procedures call for measuring the height of the throttle slides or butterfly opening to the bore with a feeler gauge, and setting each idle screw accordingly. One of the Guzzi procedures calls for this. On many motors, this is more of a necessity for accuracy. On twins, the synch task is greatly simplified over multi's, and it's not so necessary -- as long as there's not too much slop in the linkage.

 

WRT the synch knob, the object of adjusting it is to shorten or lengthen the synch rod. My adjustment knob is fixed solidly to the synch shaft. If mine's the only one, maybe it's got frozen up where it's not intended to be. In any case, I've found it easy enough to back off the locknut on the RHS, make the adjustment by turning the knob, and lock the rod in place when it's synched. Works exactly the same either way. This is just me, but I like the idea of being able to lock it in place with the locknut, just assumed this is the way it was designed and intended.

 

My apologies for any confusion, but I won't be attempting to "fix" wot I figure ain't broken on mine.

[Greybeard]

You leave it backed off. Maybe the How-To should state this more clearly as this comes up several times a year.

 

 

THANK YOU!

[Greybeard]

Multi-carb and multi-TB motors always provide a way to set idle at each instrument. Many procedures call for measuring the height of the throttle slides or butterfly opening to the bore with a feeler gauge, and setting each idle screw accordingly. One of the Guzzi procedures calls for this. On many motors, this is more of a necessity for accuracy. On twins, the synch task is greatly simplified over multi's, and it's not so necessary -- as long as there's not too much slop in the linkage.

 

But, again, in this application it's redundant as Raz pointed out?

Only the factory uses it?

[Guest ratchethack]

But, again, in this application it's redundant as Raz pointed out?

Only the factory uses it?

GB, are you looking for consensus opinion here? Back in post #2 you got mine:

Most (including Yours Truly) find it preferable to keep the RHS idle screw backed well off at all times.

 

Since the ball joint on the RHS is "self centering", as long as the pin on the LHS at the synch adjuster knob hasn't worn to the point where its got sloppy, it seems to be perfectly fine to use the LHS idle stop screw solo.

Is it WRONG to use both idle stops? NO. Is it WRONG to use only the LHS stop? NO, (part II). As with any trade-off, you weigh your options against your objectives, take your pick, and live with the consequences.