Starter valve sync.

Can I use normal mercury carb styx for the starter valve sync. on my ST1300?
I've had the carb styx for years.

Yes you can - That is what I use on mine. But I modified the circuit to make the connections easier. I lengthened the circuits and ran them to the front of the frame. The yellow tygon tubing is what was added.

Interesting. I haven't done it yet (of course) are the hoses that hard to get to that you put on the yellow extensions?

Or do you have to do it THAT often that you wanted it as easy as possible?

They're a mild pain in the butt, especially if you have big fingers.

--Mark

Dave O / HighRider shows a great fix to make the job easier..

That 5-way connnector at the heart of his yellow tygon tubing is very small and its difficult to pull off the factory vacuum lines when because they're buried down within all the throttle body hardware / wiring. When I did mine the first time I thought I was going to break that 5-way connector--and with my bike's new high altitude stutter at low RPM I'm wondering now if it's cracked.

Pete, the balancing is easy--but if you've a mercury stick you probably already know that. Accessing the vacuum lines is the hardest part. Make sure your upper fuel tank is empty before starting.
-John

So what is at the end of those yellow hoses, are they connected to the 5-way joint?

That`s a dam good idea "Highrider", I would have done the same thing if I had some extra hose.

When I carried out my "sync" I found the "5way" connector and all 5 hoses right at the bottom under the fuel injector wiring. There was no way that I was going to reach the hoses where they were attached to the throttle bodies, not with my fingers! I disconnected some of the hoses from the "5way" and smoothly rerouted the whole assembly to a position above the wiring. The "5way" is now much easier to access and with some inline adaptors I could extend the Honda hoses without removing them from the throttle`s.

I did my "sync" the same way as "TT" does. I left No 1 cylinder connected to the "5way" and hence connected to the M.A.P. sensor, then took one of the spare lines to the "Carbtune" blanking off the remaining two. I didn`t have any blanking rubbers but my BMW R1100S has and they fitted perfectly. No`s 2, 3 and 4 were connected to the "Carbtune". I removed the I.A.T. sensor from the airbox and re-connected it to the wiring harness. This procedure prevented any fault codes.

My idle was only slightly out on No`s 3 and 4 so I reset the idle to 750RPM. I don`t know if anyone else has noticed but the idle will only remain "in-sync" at the idle speed you set. If I increased or decreased the idle the sync would always be marginally out. Just out of interest, my local dealer has "NEVER" done a "sync" on any ST1300 and they have sold quite a few!

Regards to all,

Mike

Houses of Parliament earlyish last centuary. I`ve set the scene:-

Lady ASTOR :- Mr. CHURCHILL, you are DRUNK !!

Winston CHURCHILL:- Yes madam and you are ugly, however, I shall be sober in the morning!!

Houses of Parliament earlyish last centuary. I`ve set the scene:-

Lady ASTOR :- Mr. CHURCHILL, you are DRUNK !!

Winston CHURCHILL:- Yes madam and you are ugly, however, I shall be sober in the morning!![/QUOTE]

Lady Astor to Churchill: Sir, If you were my husband I would poison you.
Churchill?s answer: Madam, if you were my wife I would take it.

REDMIKE or Highrider do either of you have a write-up on how to sync. I understand the princaple, did it to my old Datsun 240Z SU carbs. What/where is the adjustment. Extra kodos to Highrider I wish more people would post pictures, in this digital age ther is no reason not to. Thanks from a newbie

note: removed invalid link.

A throttle body sync is really simple, the majority of the work is getting to the components.
The service manual spells it out very well, if you don't have a manual, plan to get one. It is an excellent investment for your bike.

Thanks I will be ordering a manual soon. PS link does not work

Just filling my head with some more useful info:

Dave,
Did you simply install couplers and then add additional length hoses to re-locate the 5pnt Tee to a more user friendly location?

Do you know what size the hose was? ID and OD? And did you use polypropylene tubing?

Thanks,
Andrew

Highrider said:

Yes you can - That is what I use on mine. But I modified the circuit to make the connections easier. I lengthened the circuits and ran them to the front of the frame. The yellow tygon tubing is what was added.

Click to expand...

The tubing I use is called Tygon and I get it from my local hobby shop, it was designed to be used with nitromethane based fuels. I think the size is either 5/32" or 3.5mm ID, it is very flexible and easy to use. Polypropylene tubing would be too stiff for this application. You will need about 6 feet to do what I show in the pic. Connectors can be found at an auto parts store, or I made mine from brass tubing.
A word of caution if you're going to do this mod - the factory 5 way connector is delicate and needs to be removed from the factory hoses with care. If that connector is broken, you're done until the dealer can get you a new one.

Dave,

But the intent here is to replace the 5 way connector with a new one, in the new location, right? Along with relocating all hoses to a more convenient location.

Thanks for the info

Andrew

islandstar said:

Dave,

But the intent here is to replace the 5 way connector with a new one, in the new location, right? Along with relocating all hoses to a more convenient location.

Thanks for the info

Andrew

Click to expand...

No, the intent is to relocate the existing 5 way connector to allow easy access for syncing.

my bad, that's what I meant.

Thanks for the help

Im struggling to rewire harness after overhaul, do you know/remember where long wire white connector at bottom left of picture goes?

davidagnew12009 said:

Im struggling to rewire harness after overhaul, do you know/remember where long wire white connector at bottom left of picture goes?

Click to expand...

That's the IAT sensor. It connects to a socket on the top of the air box after you've installed it.

--Mark

• How does a person know if they should have their starter valves synched?
  
• Is there some type of indication from the engine or throttle response that indicates a synch is necessary?
  

I am over 90K and have never had my starter valves synched.

motofisch said:

• How does a person know if they should have their starter valves synched?
  
• Is there some type of indication from the engine or throttle response that indicates a synch is necessary?
  

I am over 90K and have never had my starter valves synched.

Click to expand...

98k for me, never even had the air box off the bike. No need.