Starter valve sync

I read the tutorial on doing the sync and I feel comfortable doing it on my own. My question is about resetting the ECM after syncing the throttle bodies. Is this necessary and what is it accomplishing? This is the only thing in the tutorial that seemed a bit unclear to me so I would greatly appreciate any comments regarding the subject.

My ST is experiencing a bit of a rough idle on a cold start when the air temperature is warm (75+), it wanders a bit right away then eventually settles down. When at full operating temp the bike idles smooth at 1000 RPM and on a cold start at a lower air temp it goes to the normal high idle until it heats up to one bar then drops to idle smoothly at the correct RPM. If anyone has any suggestions based on these symptoms I would also appreciate them as I am just assuming it just needs a sync at 75,000 miles.

Thanks,

kflan

It's just resetting any codes thrown from running the bike with the intake apart.

https://www.st-owners.com/forums/showthread.php?146755-Starter-valve-sync
http://stwiki.notonthe.net/twiki/bin/view/ST13/ECMQuickGuide

It could be the sync dirty air filter plugs etc.
When warm the idle wax isn't opening the butterflies for air so the starter valves would have an effect.
(note there is no butterfly sync and don't clean them or the molly coating will come off)

I was a bit anxious about doing this operation- it seemed a bit tougher than doing a carb balance, which I used to do after every oil chance on my Airheads. ( I adjusted the valves at every oil change, so had to re-sync, if I adjusted valves). However, it took all of 5 minutes, including RE-DOING it, since I figured it went way too easy! I used a Twin-Max and did one at a time. Worked like a charm.

Not a lot of difference, but am glad it is done.

Typically the air cleaner will be removed and the IAT sensor unplugged which will set an error code. To avoid that, and the need to clear the FI code, I set the air cleaner cover off to the side of the bike with the IAT sensor remaining attached.

Thanks for the info everyone. Will tackle this when my carb sync tool arrives.

I have one more question for you guys. My Haynes manual says adjust the nut on the starter valve but other information references a screw. Is there a slot in the screw for a flat screwdriver or am I turning the nut to sync the valve? It looks to me like the nut is there to lock the screw in position but I don't see a screwdriver slot in any illustration. Thanks, all.

kflan

kflan22 said:

I have one more question for you guys. My Haynes manual says adjust the nut on the starter valve but other information references a screw. Is there a slot in the screw for a flat screwdriver or am I turning the nut to sync the valve? It looks to me like the nut is there to lock the screw in position but I don't see a screwdriver slot in any illustration. Thanks, all.

kflan

Click to expand...

A 1/4 inch drive 7mm deep well socket works perfect. It allows you to use it like a thumb screw between you thumb and Index finger.

I used a 7mm open end wrench, but i like Igofar's idea better.

Thank you all for the help. I did the sync last night and did notice a smoother idle and transition when getting on the throttle. I used the Motion Pro Sync tool and it worked well. I hooked the lines directly to the throttle bodies which was a pain in the butt. Next time around I will get some adapters to hook up the hoses where the 5 way connects. I took a gamble on the Motion Pro tool but I would actually recommend it if you don't have access to a Morgan Carbtune. With the mini jets in the tubes it was quite easy to calibrate and dial in the valves.