"Wax" Idle control unit.

[The Dark Shadow]

Andrew put some really good comments out there.
Your not going to find anything wrong with the idle wax assembly, other than the damage you caused by changing the adjustment on the factory preset nut, that the service manual clearly indicates NEVER to change the settings.
Many of the folks who listened to videos or forums, tried all kinds of jury rigged attempts, often damaging stuff worse than before.
The folks that “fixed” the idle issues by what they thought they did actually unfouled the bind in the linkage (black barrel) and the threads in the rod were stuck or sticking on the edge of the hole etc.
After having many hundreds of these come through and having to repair “YouTube mechanics” solutions, I bet if you followed Andrew’s advice and checked the linkage instead of doing what the manual warns you against, you may find the solution.
And yes, thinner oil moves heat away faster than thicker oil, and dino oil can change the idle speed versus synthetic oil sometimes.

Tell ya what Larry...

Please ignore any of my posts and don't bother to reply.

If you reread what was written in this thread, then reread your reply, you might realize that your comment is out of line and something that only a prick would write.

You've made insulting comments directed to me before.

I don't need you. You might think everyone who drives a Honda does, but I don't...

Sayōnara.

 

[Al st1100]

Andrew put some really good comments out there.
Your not going to find anything wrong with the idle wax assembly, other than the damage you caused by changing the adjustment on the factory preset nut, that the service manual clearly indicates NEVER to change the settings.
Many of the folks who listened to videos or forums, tried all kinds of jury rigged attempts, often damaging stuff worse than before.
The folks that “fixed” the idle issues by what they thought they did actually unfouled the bind in the linkage (black barrel) and the threads in the rod were stuck or sticking on the edge of the hole etc.
After having many hundreds of these come through and having to repair “YouTube mechanics” solutions, I bet if you followed Andrew’s advice and checked the linkage instead of doing what the manual warns you against, you may find the solution.
And yes, thinner oil moves heat away faster than thicker oil, and dino oil can change the idle speed versus synthetic oil sometimes.

I can't wait to lower my idle speed and get a 15 - 20% mpg increase. I wish the Honda engineers would of thought of that.

 

[Igofar]

Tell ya what Larry...

Please ignore any of my posts and don't bother to reply.

If you reread what was written in this thread, then reread your reply, you might realize that your comment is out of line and something that only a prick would write.

You've made insulting comments directed to me before.

I don't need you. You might think everyone who drives a Honda does, but I don't...

Sayōnara.

Sounds like you think you own the forum
But when you post advice or comments that could mislead some poor person into trying some foolish attempt to correct something by not following the correct procedure, just because you think it’s correct because you watch videos, it’s only fair to post information on the thread where folks have all the information to pick from.
Andrew’s post #3 was right on the mark.
And watch your language, this is a family forum.

 

[The Dark Shadow]

Sounds like you think you own the forum
But when you post advice or comments that could mislead some poor person into trying some foolish attempt to correct something by not following the correct procedure, just because you think it’s correct because you watch videos, it’s only fair to post information on the thread where folks have all the information to pick from.
Andrew’s post #3 was right on the mark.
And watch your language, this is a family forum.

Again, you are arrogant, condescending and insulting.

No, I do not think I own the forum. But perhaps you are projecting... Is your accusation a confession...?? Sure seems like that to me, and I'm sure there are silent watchers who agree with me but who won't chime in to avoid becoming a target of your arrogance, and I very much understand their position and do not fault them for this. In fact, I can confirm I have conversed privately with other forum members who have confirmed this.

When you accuse me of doing things I haven't done, well sir, that shows ignorance and arrogance I don't need people like that in my life.

Lakum deenikum waliya deen.

You have your way and I have mine.

Live your life, buddy, and I'll live mine. There's no need to interject yourself into my activities by intersecting on this forum.

I expect you'll likely make a response, because your arrogance suggests you are not satisfied without having the last word. I bid you adieu. Sayōnara. You do not need to reply. In fact, please don't.

 

[wjbertrand]

Yes, it's funny... So many people say that Honda's are virtually maintenance free, but this bike has several idiosyncrasies that make maintenance a PITA.

My thermostat is verified working properly but that's a good point. Thanks.

I would not agree with the statement that the Honda ST or any motorcycle is “maintenance free”. That’s not a realistic scenario.
I would however argue that the bike is relatively low maintenance compared to other models, especially European bikes.
I also would differentiate maintenance from unscheduled repairs.

 

[TerryS]

The fast idle system on the 1300 and my 09 VFR800 are similar and surprisingly complex for a dumb "100% mechanical" system. With my 800 I was faced with seized starter valves that defied my attempts to synchronise until I spotted the stuck parts. In unsticking them, I managed (unwittingly) to change the factory "unadjustable" nut on the reference starter valve which then set me off down a rabbit hole of settings. I learned the hard way that the factory settings are "set and forget" for a reason.

There is a real interrelationship between the starter valves, the wax unit nut and the idle stop screw, and anyhing other than the factory setting can lead to undesirable behaviour. For example, you can have the reference starter valve screwed a bit too closed, synchronise the others to it and then set the idle stop screw to give the correct hot idle, but the cold start revs will be too slow and the engine may bog/stall when part warmed.

Conversely you can have the starter valves a bit more open that required, and that will give a faster cold idle that may not settle back to the hot idle speed before you ride off, and that will lead to the idle speed hanging up no matter what you do with the idle stop screw. In that situation you could back off the wax unit nut but now you have changed two factory settings.

The whole idle speed control in these bikes assumes that there are no air leaks around the throttle butterflies when the throttle is closed, and that all air entering the cylinders passes through the starter valves; any leak e.g. from a damaged throttle bore, tight throttle cable or a split in a vacuum hose can lead to unexpected behaviour that you could possibly mask with synchonisation but will probably manifest elsewhere. Likewise the system parts need to be free to move; there's no mention of lubricating any of the linkages but it doesn't seem like a bad idea, and you need to be able to see some slack between the wax nut and the SV linkage when everything is warmed up, otherwise the idle stop screw won't be doing much. Lastly the wax unit needs to be fed with a clean stream of coolant; any blockage means it will be less responsive to engine heat and will not track the warmup properly.

 

[Igofar]

The fast idle system on the 1300 and my 09 VFR800 are similar and surprisingly complex for a dumb "100% mechanical" system. With my 800 I was faced with seized starter valves that defied my attempts to synchronise until I spotted the stuck parts. In unsticking them, I managed (unwittingly) to change the factory "unadjustable" nut on the reference starter valve which then set me off down a rabbit hole of settings. I learned the hard way that the factory settings are "set and forget" for a reason.

There is a real interrelationship between the starter valves, the wax unit nut and the idle stop screw, and anyhing other than the factory setting can lead to undesirable behaviour. For example, you can have the reference starter valve screwed a bit too closed, synchronise the others to it and then set the idle stop screw to give the correct hot idle, but the cold start revs will be too slow and the engine may bog/stall when part warmed.

Conversely you can have the starter valves a bit more open that required, and that will give a faster cold idle that may not settle back to the hot idle speed before you ride off, and that will lead to the idle speed hanging up no matter what you do with the idle stop screw. In that situation you could back off the wax unit nut but now you have changed two factory settings.

The whole idle speed control in these bikes assumes that there are no air leaks around the throttle butterflies when the throttle is closed, and that all air entering the cylinders passes through the starter valves; any leak e.g. from a damaged throttle bore, tight throttle cable or a split in a vacuum hose can lead to unexpected behaviour that you could possibly mask with synchonisation but will probably manifest elsewhere. Likewise the system parts need to be free to move; there's no mention of lubricating any of the linkages but it doesn't seem like a bad idea, and you need to be able to see some slack between the wax nut and the SV linkage when everything is warmed up, otherwise the idle stop screw won't be doing much. Lastly the wax unit needs to be fed with a clean stream of coolant; any blockage means it will be less responsive to engine heat and will not track the warmup properly.

Thanks for posting such a well explained explanation of why the factory settings should not be changed.
Too many Facebook and YouTube videos out there nowadays that can lead folks in the wrong direction, and end up really causing problems elsewhere while trying to jury rig a fix somewhere else.
You probably saved a few folks a lot of frustration by your post.
Thanks for sharing.

 

[The Dark Shadow]

So I got frustrated with the bike and I rigged it up by drilling some holes in the fairing and detaching the wax unit, replacing it with a manual lever that I can operate just like a manual choke!

Wow! It is such an improvement over this temperamental thermo mechanical unit.

 

[Willsmotorcycle]

Pictures or it didn’t happen.

 

[The Dark Shadow]

The fast idle system on the 1300 and my 09 VFR800 are similar and surprisingly complex for a dumb "100% mechanical" system. With my 800 I was faced with seized starter valves that defied my attempts to synchronise until I spotted the stuck parts. In unsticking them, I managed (unwittingly) to change the factory "unadjustable" nut on the reference starter valve which then set me off down a rabbit hole of settings. I learned the hard way that the factory settings are "set and forget" for a reason.

There is a real interrelationship between the starter valves, the wax unit nut and the idle stop screw, and anyhing other than the factory setting can lead to undesirable behaviour. For example, you can have the reference starter valve screwed a bit too closed, synchronise the others to it and then set the idle stop screw to give the correct hot idle, but the cold start revs will be too slow and the engine may bog/stall when part warmed.

Conversely you can have the starter valves a bit more open that required, and that will give a faster cold idle that may not settle back to the hot idle speed before you ride off, and that will lead to the idle speed hanging up no matter what you do with the idle stop screw. In that situation you could back off the wax unit nut but now you have changed two factory settings.

The whole idle speed control in these bikes assumes that there are no air leaks around the throttle butterflies when the throttle is closed, and that all air entering the cylinders passes through the starter valves; any leak e.g. from a damaged throttle bore, tight throttle cable or a split in a vacuum hose can lead to unexpected behaviour that you could possibly mask with synchonisation but will probably manifest elsewhere. Likewise the system parts need to be free to move; there's no mention of lubricating any of the linkages but it doesn't seem like a bad idea, and you need to be able to see some slack between the wax nut and the SV linkage when everything is warmed up, otherwise the idle stop screw won't be doing much. Lastly the wax unit needs to be fed with a clean stream of coolant; any blockage means it will be less responsive to engine heat and will not track the warmup properly.

Finicky interrelated micro adjustments is certainly part of my life. That said, the lack of easy access and abundance of tools necessary for certain procedures on this bike is daunting at times. I would have preferred to take it to a pro and have them do the work, but the "pros" here screwed up on my bike in various ways... So, I had to start learning for myself. I have a great full socket set now, a torque wrench, brake bleeder, and lots of other stuff. End of last season I took off my wheels and brought them to a trustworthy guy to change tires. (The previous guy put a scratch in my wheel and took my bike for a hot ride, and didn't tighten the oil pan but tight enough and it kept dripping... When I called him, he said that's normal to do that for a few weeks after an oil change... Smh) This is the type of "pros" who exist here.

BTW, have you ever adjusted an RC helicopter swash plate...? Finicky and interrelated, just as you described the starter valve adjustments. And the physical adjustments need a subsequent electronic adjustment... It's a PITA for sure... That's why helis need so much maintenance time compared to flight time...

 

[wjbertrand]

So I got frustrated with the bike and I rigged it up by drilling some holes in the fairing and detaching the wax unit, replacing it with a manual lever that I can operate just like a manual choke!

Wow! It is such an improvement over this temperamental thermo mechanical unit.

Interesting solution. Did you get any photos of your set up?

Setting up the starter valve mechanism is a bit tedious and it takes a couple iterations to get it right, but with understanding and a little patience over 2-3 days (to allow for enough fresh cold start trials) it can be done. It’s actually a pretty simple system in concept and not some voodoo magic never to be touched as some would have you believe. After all, it was just a human being in a factory that initially set up and installed it in the first place, not some magical wizard!

After setting mine up, the bike started, cold idled and warmed up normally for years.

 

[TerryS]

So I got frustrated with the bike and I rigged it up by drilling some holes in the fairing and detaching the wax unit, replacing it with a manual lever that I can operate just like a manual choke!

Wow! It is such an improvement over this temperamental thermo mechanical unit.

Just the way that Honda set up the original 5th gen VFR800; these bikes have a traditional left bar choke lever that actuates the starter valve linkage via a cable; as you say, it works really well and allows direct control.

 

[dduelin]

Just the way that Honda set up the original 5th gen VFR800; these bikes have a traditional left bar choke lever that actuates the starter valve linkage via a cable; as you say, it works really well and allows direct control.

I had a 5th generation 1999 or 2000 (WTH I forgot the year!) VFR800FI. It was the first generation VFR to be fuel injected and it did not have a manual choke but used a similar water temperature actuated mixture enrichener as the ST1300. The automatic enricher is an added complication but it the system is maintained it has proven reliable in Honda and other brand vehicles. It must have been the 4th generation carbureted VFR750F that had a manual choke.

 

[MidLife]

I had a 5th generation .....and it did not have a manual choke

Looks like some were converting back to manual.

5th gen manual choke conversion

Hi,is it possible to have a manual starter valves lever to operate.??

www.vfrdiscussion.com

 

[Igofar]

While it is possible to adapt, modify, fabricate, and change adjustments that should not be changed, to achieve different results, or at least think that you achieved different or better results, a lot of the time these modifications, adjustments, or changes really did not have anything to do with the wax valve high idle problems, but merely appeared to do so because you moved something.
If you look at the threaded rod, and the factory set nut, you will see that it runs through a black plastic barrel that has a couple flats on it that allow it to roll, or move around as the rod passes back and forth through it.
The setting on the nut is more or less a stopping point when the nut bottoms out on the barrel.
To prove that it can be corrected without even touching it with hands or tools, providing it’s not a clogged coolant line, dying t-stat, or fouling of the linkage, I have often corrected the idle issue with nothing more than a short spray burst with some plastic friendly contact cleaner on the barrel contact points.
What happened? The barrel became free again and the idle dropped in front of the owners eyes.
What happens is the threads on the rod get dirty, or the support arms of the barrel get dirty and the rod no longer moves smoothly through the barrel, sticking, often causing the high idle issue.
The barrel can turn just enough to catch the threads on the sharp edge of the barrel causing it to stick or bind.
So for the folks that think their adjustments may have solved the issues, it’s often a case of whatever they touched or moved is really what freed things up and dropped the idle.
I will try and attach a close up picture of the rod and the hole it goes though and see if any of you have a light bulb moment.

 

[MidLife]

The automatic enricher .......

Isn't it more like an automatic de-enricher?

A cold ST is by default in full choke (rich) mode when cold and then the was assembly automatically "push the choke" back (de-enrich) when the bike warms up?

Or maybe you mean that the Wax assembly automatically goes in "enrich" position when the bike cools down?

 

[dduelin]

Isn't it more like an automatic de-enricher?

A cold ST is by default in full choke (rich) mode when cold and then the was assembly automatically "push the choke" back (de-enrich) when the bike warms up?

Or maybe you mean that the Wax assembly automatically goes in "enrich" position when the bike cools down?

Whatever.

An automatic device for easy cold starts vs a manual system. Call it what you like best.

 

[tnbill]

I would say the wax control is no more than an idle rpm control that is temperature operated. The fuel injection system will (IE) ECU will control the mixture based on coolant temperature to name one perameter. But i don’t have any experience with 1300.

 

[TerryS]

I had a 5th generation 1999 or 2000 (WTH I forgot the year!) VFR800FI. It was the first generation VFR to be fuel injected and it did not have a manual choke but used a similar water temperature actuated mixture enrichener as the ST1300. The automatic enricher is an added complication but it the system is maintained it has proven reliable in Honda and other brand vehicles. It must have been the 4th generation carbureted VFR750F that had a manual choke.

Honda made a few changes to the 2000 and 2001 5th gen, and added the wax unit and a catalytic converter among other changes, but the 1998 and 1999 (which I currently own) have the manual "choke" lever.

 

[TerryS]

I would say the wax control is no more than an idle rpm control that is temperature operated. The fuel injection system will (IE) ECU will control the mixture based on coolant temperature to name one perameter.

The idle speed is completely set by the starter valves and the airflow they allow. The wax unit just holds the starter valves open further when cold, and then progressively releases them until they rest on the idle stop screw. You are correct that the FI system is varying the volume of fuel injected based on a whole lot of parameters including coolant temperature, but also inlet air temperature, barometric pressure and throttle position, and also the signal coming back from the O2 sensors.