Article [13] ST1300 - Throttle Body Synchronization

Re: ST1300 - Starter Valve Synchronization

Sorry to revisit the starter valve sync thread but this is my first time at this and I have a couple of questions.
1. In smallville's first post it looks like one pair valve tube and the crank case breather tube are clamped off, leaving one pair valve tube unclamped. Do I need to clamp the crankcase breather tube?
2. Once I have disconnected the four tubes from the 5-way do I just leave the 5- way alone or do I have to clamp the 5th tube to the 5-way?
3. Having warmed the bike up I attached the carbtune and then had to leave the garage for some time. The bike is now cold. Can I carry on from this point by starting with the carbtune attached and waiting for the bike to warm up or do I have to reconnect everything up to warm the bike up before re-attaching the carbtune?
4. When I lifted the tank the biggest fuel link pipe split. I have ordered another one, along with the clamps but am struggling to remove the split pipe. Is there a knack or do I have to remove the whole tank to get access?

Many thanks in anticipation.
 
Re: ST1300 - Starter Valve Synchronization

Another view Howard:
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1. Both valve tubes should be blinded, whether at the tail end (like I did above) or at their source. The one in Scott's first post may have been blinded off at the source.
2. No need to clamp the 5th hose off at the 5 way tee.
3. Rewarm the bike--no harm in doing it with the hoses attached to the vac gage and the pair recycling hoses blinded. I do find it interesting how much difference there is in vacuum cold vs. hot. When cold, the wax valve assembly (buried between the #1 and #3 throttle bodies, below the fuel rail) pulls on the linkage, so vacuum then is different and is moot--balance the vacuum at idle with a warm engine.
4. The large hose grips well, and fits over a couple ribs on the lower tank and upper tank nipples. The hose is stiff enough that you'll likely need to pull the tank off (or sufficiently forward. If you pull with the tank in place, be prepared for jamming the tank forward into your handlebars, potentially denting it as the hose finally and suddenly unseats.
 
Re: ST1300 - Starter Valve Synchronization

Wow, thank you so much for the quick and informative reply Bakerboy. Really appreciated. Back out to the garage it is ;0)
 
Re: ST1300 - Starter Valve Synchronization

Thanks to everyone who contributed to this thread. I performed this procedure today for the first time. (2005 bike with 104,000 km) I used my old mercury sticks that I've had for 40 years. They still work just fine and are accurate enough for this adjustment. (You just have to be careful not to handle the mercury) There was a slight difference between throttle bodies, but not much and it was very easy to equalize. Way easier than synching the carbs on my old Venture Royale. I replaced the vacuum hoses while I as in there as I've had a blockage a couple of times in the last few years.

Thanks again, Wayne
 
Re: ST1300 - Starter Valve Synchronization

I just finished synchronizing the startervalves on my bike usinbg this write-up. Works like a charm! Bike runs smoother now. Thanks!
 
This was very helpful, educational, but now I'm stuck. I have disassembled everything down to the 5-way and vacuum hoses, have my manometer ready...and for the life of me I cannot figure out how to get vacuum hoses off when I can't get my hands anywhere near them. My hands are not huge, but no way I can get fingers onto hoses to have leverage to pull them off. The thought of trying to replace them is even more daunting. Do you use needle nose pliers? Is there another tool?
Seriously, I'm not sure how to proceed, but loathe to just give up and just reassemble everything.
 
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I was in the habit of using a dull flat screwdriver tip to gently push the end of the hose 'off' the nipple. Move the screwdriver tip to different spots around the nipple to help unseat the hose, and to work the hose off evenly. But even if damaged, that hose is cheap at parts stores.
 
BakerBoy said:
I was in the habit of using a dull flat screwdriver tip to gently push the end of the hose 'off' the nipple. Move the screwdriver tip to different spots around the nipple to help unseat the hose, and to work the hose off evenly. But even if damaged, that hose is cheap at parts stores.
Click to expand...

Squirt some lubricant around the hose the night before you start and the hose can be pushed (not pulled) off very easily. Also you should replace that hose anyway. It will cost a couple of bucks at the local auto parts store or you can buy it off of Amazon. You will need 4mm or 5/32". They are exactly the same diameter.
 
^Petroleum-based (hydrocarbon) lubricants can degrade the hose, so if you use lubricant on the hose, be sure it is silicone based.

The easy-as-you-go dull flat screwdriver technique never resulted in a damaged a hose on mine. But I did install longer hoses after ~5 years on mine for easier 5-way tee access during starter valve synchronizations. A picture of that is in post #10 here: https://www.st-owners.com/forums/th...t-thermostat-starter-valve-synch-other.38212/
 
Smallville said:
This is my first attempt at a How to article so bear with me.
Starter Valve synch for ST1300. Special thanks to Blrfl for letting me borrow his Carbtune manometer.

Remove seat. Move seat bracket to maintenance position. Loosen 10mm bolt holding rear of tank down.
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Remove two 8mm bolts holding down front of tank.
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Locate prop rod located under where the rear seat would be. Raise tank by pulling backwards first and then lift front up. Install prop rod as shown. You can remove one of the chrome caps if you wish, and place end of prop rod in bolt head.
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Now you should be looking at the top of the air box.
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I like to go ahead and unclip the IAT sesor (white connection on rear of air box). Then proceed to remove all screws holding down top of air box. nine in all. A good magnetic tip screw driver works well as if you drop a screw, it may be gone for good. However usually the wind up on the rubber mat under the Throttle bodies. DAMHIK.

Once the air box lid is removed you should see this.
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Remove air filter. Remove snorkles and bases. Two screws hold each snorkle on. Each has a metal tab bent over it to prevent it from backing out. Use a flat blade screwdriver to gently pry them open. Once the snorkle is removed two screws hold the base on. Some people have had trouble getting these loose. This is where a good screw driver comes in handy. Although some have found a impact driver was needed. I was lucky and all mine broke free easily. Remember where each snorkle came from as it will make reassembly easier.
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Once you remove the last base, you will gently pull up on the air box base and find that there are two rubber hoses attached. The back on is easiest to remove first. They are held on with a spring clamp. You can squeeze them by hand to remove. I find it better to remove the clamp untill reassembly as they tend to slide on the hose.

Once the air box base is out of the way you want to look for this.
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This is the T that you will disconnect each hose from to obtain your readings.

Before we can remove the vacuum hoses first remove the IAT sensor from the air box lid and plug it back into the connector. Now start the bike and allow to warm up to operating temp. Shut bike off. Remove each vacuum hose that leads to each cylinder. One will remain as it runs to the map sensor. Block off each PAIR suction hoses. In the picture you can see the green things I use to pinch off the hoses. Start bike (you may have to give it a little throttle) and hold engine speed above 2000 rpm for 5 seconds or more untill FI light blinks. The bike should idle now. Attach your vacuum hoses to your guage and adjust each cylinder to match cylinder number 1.

Adjusment screw.
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Once all are adjusted correctly it should look like this.
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When finished. Reassembly is in the opposite order. To reset the ECM. Find the ECM connector located under where the rear seat would be.
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With the engine stop switch in RUN and the iginition off. Jump the brown and Green/pink wires. Turn the ignition on. Remove jumper wire. The FI lights for about 5 seconds. During this time short the wires again. The Fi light should start blinking. Shut off ignition.

During reassembly if you forget how a snorkle was aimed, there are indicators on the snorkle and air box base that you can line up.
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Reassemble and start. Check idle and adjust if needed.

Overall not a bad job. I would reccomend placing some anti-seize on the screws that hold the snorkle base down to the throttle bodies. Also remember that snug is tight enough for the snorkle, base and air box cover.
Click to expand...
Thanks for this post. I am getting ready to attempt this, and the description and pictures are great!
 
I'm hoping everyone that read the first post will read this one as well.

There are a couple of thing I learned this week that should be addressed. First and foremost, if your Carbtune is dirty or even lacking perfect condition you're wasting your time and probably messing up your bike.

**** I highly recommend disassembling your Carbtune and not only clean it up but polish the rods with a magic eraser. This important step made mine work silky smooth, and better than new. They should bounce on your finger with no resistance.

**** Your bike won't trip the Fi code unless your kickstand is down

**** There's two 5-way connectors under the airbox. You want the smaller one, connect your nice and clean Carbtune in it's place.

**** Answer to #3 in post #22, according to Larry is incorrect. If you have to come back the next day you should start over.

**** I believe the picture of the pair hose clamped off in post #1 is incorrect. That's the crankcase breather.

**** Do not adjust your idle at 1200, 1500 or above even that as stated on some other ST sites. 1000 -+100 per the manual

**** There's an easier and better way to clear the codes as follows:

Per Larry on a different site:

Side stand down and gear in neutral
1 turn the engine kill switch to RUN
2 turn the ignition switch to ON
3 DO NOT TOUCH THE THROTTLE (if you do, start over)
4 start the engine
5 if you touched the throttle start over
6 let the bike run for 2 min (don't touch anything while its running)
7 turn the kill switch to OFF
8 Turn the key to OFF
9 You have now cleared all the error codes

Disassembly link:


F3197AB8-BA83-4023-A6C4-739617052829.jpeg
 
Great article!

It looks like the embedded photos were lost, though. (I think when the website moved to a new server maybe.) Instead of being embedded in the text, they appear as a separate list of photos at the bottom of the article. I was having trouble following the text so I attempted to re-create the original document, just going by what looked right. See attached PDF .

I think I got all the photos in the right place but on page 8 of the PDF file, there's text that just says "adjustment screw." Can someone verify that the arrow in the photo is in fact pointing to the adjustment screw? If not, I'll delete this one and re-do it. Thanks.
 

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alanm123 said:
Great article!

It looks like the embedded photos were lost, though. (I think when the website moved to a new server maybe.) Instead of being embedded in the text, they appear as a separate list of photos at the bottom of the article. I was having trouble following the text so I attempted to re-create the original document, just going by what looked right. See attached PDF .

I think I got all the photos in the right place but on page 8 of the PDF file, there's text that just says "adjustment screw." Can someone verify that the arrow in the photo is in fact pointing to the adjustment screw? If not, I'll delete this one and re-do it. Thanks.
Click to expand...

Yeah, it's the adjustment "nut" actually. You turn those nuts with a 1/4" 7mm deep socket to match the setting on the number one cylinder.
 
Are you sure you want to plug the crank case breather tube? wouldn't that build detrimental pressure and potentially cause a seal or gasket to fail?

If this is undesired maybe the instructions that folks are referencing can be updated? Nice write- up!
 
For anyone who may be interested, I found the OEM replacement JT3L Throttle Position Sensors (TPS) online at AliExpress. This is not a part that Honda offer separately and only supply with complete throttle body assy at around £2400GBP!!!

Around £16GBP including delivery to UK. I have one on order, will se any good when it arrives.
 
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