High idle question rpm question. I'm

Cloud_master said:

Only "coating" I saw, was carbon.

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If what you removed looks anything like what's in this picture, what you saw was the molybdenum sealant. It's easy to mistake that for carbon buildup, but one of the other things the coating does is prevent that stuff from sticking so it doesn't build up in the first place.

--Mark

I speculate that the coating on the trailing edge of the butterflies creates a little turbulence for the intake charge just upstream of the fuel injectors to smooth off-idle response. When the ST1300 was in design in the early 2000s engineers were wrestling with meeting upcoming EC Category 3 emissions standards which were the first standard for motorcycles and also make the bike able to meet even more stringent Category 4 standards that were coming during the life cycle of the platform. Fuel injection was deemed necessary to meet emissions and the ST was a first generation fuel injected motorcycle for Honda and many first gen FI motorcycles suffered abrupt dry/wet injector response when the fuel comes in.

Cars and trucks have the luxury of a large amount of inertia that can mask coarse fueling at low rpms. Motorcycles cannot hide it as well or at all.

The fact that the bike started and ran OK albeit with the original complaint shows that throttle body and FI system still operates OK but probably the bike without the molybdenum coating on the butterflies and throttle bores will have throttle response a little less smooth.

Yep, looks like I took that coating off. I have taken the bike for a ride since. Actually ran better than it did before the spark plu change and my "throttle body cleaning". Just my high cold idle problem remains. My opinion, the coating is to prohibit the sticking of the butterflies to the bores at idle. But what do I know, I just took the coating off since I thought it was carbon. My 01 Monte Carlo throttle body needs to be cleaned every 3 years or so since it will stick at idle due to carbon build up. Maybe that had a moly coating at one point too.

Blrfl said:

It might mean that, but it doesn't. The owner of a bike without the coating has a set of throttle bodies which will no longer seal properly when the throttle plates close. The rest of what Larry said is spot on.



That's a very broad statement, and it's wrong. Off the top of my head, Ford, Mazda, Nissan and Subaru all sell or have sold sold cars with coatings.

--Mark

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Service Manual NOTE:
....damage to this may cause incorrect throttle and idle valve synchronization.
....idle wax valve assembly - loosening or tightening this can cause throttle and idle valve synchronization failure.
Page 5-132 - Do not apply commercially available carburetor cleaners to the inside of the throttle bore, which is coated with molybdenum.

Igofar said:

Service Manual NOTE:
....damage to this may cause incorrect throttle and idle valve synchronization.
....idle wax valve assembly - loosening or tightening this can cause throttle and idle valve synchronization failure.
Page 5-132 - Do not apply commercially available carburetor cleaners to the inside of the throttle bore, which is coated with molybdenum.

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yes, I got it. Thank you for pointing this out multiple times. I had cold high idle problems long before I even decided to lift the tank. Btw, I'll repeat myself, the coating has no bearing on the idle. I've put on 100 miles since. Idles like normal. My wax valve and or coolant passages to the valve are the problem. Not lack of coating. I don't give a crap about the coating.

Cloud_master said:

yes, I got it. Thank you for pointing this out multiple times. I had cold high idle problems long before I even decided to lift the tank. Btw, I'll repeat myself, the coating has no bearing on the idle. I've put on 100 miles since. Idles like normal. My wax valve and or coolant passages to the valve are the problem. Not lack of coating. I don't give a crap about the coating.

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I was not pointing it out to you multiple times, I simply put that out there because of questions other people asked within this thread.
Sorry for you thinking I was directing it to you alone.

klaproth said:

Actually, most cars DO have that coating.

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Blrfl said:

That's a very broad statement, and it's wrong.--Mark

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Thank you. I did not know that - but then, my truck is a year 2000, and our SUV is a 2005, and the last is an '89. So, I'm not up to date technologically on cars' throttle bodies.

OK troops, what's the next move.
opcorn

Al Gully said:

OK troops, what's the next move.
opcorn

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Make sure that coolant is getting through the coolant lines to heat the wax valve in an unrestricted flow as intended. If so, and there are no other mechanical deficiencies, replace the wax valve.

Blocked passage not letting water get to the wax module. Honda has a bulletin out on this problem. Remove the coolant line to verify that its not blocked/obstructed with crap or black paint.
Another member corrected this problem with a blast of air if I recall, I just can't find the thread at this time, maybe he'll chime in.

Igofar said:

Blocked passage not letting water get to the wax module. Honda has a bulletin out on this problem. Remove the coolant line to verify that its not blocked/obstructed with crap or black paint.
Another member corrected this problem with a blast of air if I recall, I just can't find the thread at this time, maybe he'll chime in.

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I saw that post somewhere as well.

I already ordered the wax valve. I figured if I'm going through the notions to dump the coolant, pull the tank, airbox, throttle body, etc, I'm changing the $42 wax valve even if I only find a blocked line.

May I suggest that when you do the coolant flush, you take a scotch bright pad and remove the paint from the INSIDE of the radiator pipes (both sides) as this is often found inside the coolant system and is often a cause of what your experiencing.
Edit: Depending on the tools you have, you may not need to remove the throttle body to swap out the wax valve.

I found the link to the thread that solved the obstruction problem: https://www.st-owners.com/forums/show...ed-help!/page2
It is also discussed on the thread titled: SE Thermal Switch ???
Hope this helps. And when you get your new part, instead of trying to adjust the setting, just make sure the crap is removed from the lines.

Here is my post from a long time ago. It work for me. I hope it works for you:

https://www.st-owners.com/forums/showthread.php?31374-Cold-idle-at-4-000-rpm-s!-Need-help!/page2

See thread #12.

Dale

Igofar said:

May I suggest that when you do the coolant flush, you take a scotch bright pad and remove the paint from the INSIDE of the radiator pipes (both sides) as this is often found inside the coolant system and is often a cause of what your experiencing.
You also do not need to remove the throttle body to swap out the wax valve.

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When you say "pipes", are you referring to the hose attach points on the radiator, that are maybe 2-3"? Or something else?

Igofar said:

You also do not need to remove the throttle body to swap out the wax valve.

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Yes! I was dreading that.... Having this same issue and researching before I posted.

Cloud_master said:

When you say "pipes", are you referring to the hose attach points on the radiator, that are maybe 2-3"? Or something else?

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I was referring to the two elbows where the large radiator hoses attach to the radiator. For some stupid reason they decided to paint them both inside and outside on these elbows, after a while the paint blisters up, peels off, and makes its way into the coolant system. I often find large pieces of paint stuck inside the T-stat housing, and all the way to the overflow coolant tank. Once the paint is removed, and the system cleaned out, you will no longer have any issues with your Wax Valve unit. Again, despite what others have done on this or any other forum, the service manual states that you should NOT attempt to alter or adjust the the new SE Thermal switch once installed.
Good luck.
If you have any other questions, feel free to PM me a contact number and I would be glad to call you and discuss it with you further.
Igofar

I would like to add one other warning that may save you a roadside breakdown with a major coolant leak....
The 3-way plastic tee is held up against the frame with a metal loop strap, this keeps it from vibrating, and stops the hose from kinking at this point. Make sure you secure it back into the retainer when your finished. Also, these tee's have a nasty habit of cracking, and snapping off the tubes due to being over tightened by the worm clamps (hose clamps) Do not over tighten these clamps or you will find yourself riding along, then all of a sudden, your coolant will not be leaking out, but, pumped out of your motor before you realize it etc. This type of failure under the side panel that you won't be able to see right away (while riding) could cause you to toast your motor!
Always check this 3-way tee, and only gently snug the clamps down. Or do what I do, and purchase another spring clamp (like the one that attaches to the radiator on this line) then two smaller spring clamps from the auto parts store and be done with the hose clamp issues.
Good luck.

Igofar said:

I would like to add one other warning that may save you a roadside breakdown with a major coolant leak....
The 3-way plastic tee is held up against the frame with a metal loop strap, this keeps it from vibrating, and stops the hose from kinking at this point. Make sure you secure it back into the retainer when your finished. Also, these tee's have a nasty habit of cracking, and snapping off the tubes due to being over tightened by the worm clamps (hose clamps) Do not over tighten these clamps or you will find yourself riding along, then all of a sudden, your coolant will not be leaking out, but, pumped out of your motor before you realize it etc. This type of failure under the side panel that you won't be able to see right away (while riding) could cause you to toast your motor!
Always check this 3-way tee, and only gently snug the clamps down. Or do what I do, and purchase another spring clamp (like the one that attaches to the radiator on this line) then two smaller spring clamps from the auto parts store and be done with the hose clamp issues.
Good luck.

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Roger that. Thanks for the tips. I'll inspect those when I pull everything apart in a few days. I'm waiting for the parts currently.

Had a similar issue, pulled the injector body again, checked all the lines, blew them out, and reinstalled. This time I ran it through two or three heat cool cycles, topping off the antifreeze each time. I believe my issue was possibly related to an air lock somewhere. Still not understanding why Honda hid the radiator cap under layers of plastic. So far it's been fine. My plastic T also broke, I made one out of a couple of brake lines carefully drilled and brazed. That is holding up fine. I found a company that makes silicone hose kits for any vehicles. They don't list one for the ST, but, apparently, if you send them a set of new hoses, they will manufacture them, and the first set is free to you, then they add them to their catalog. I think a set of silicone hoses would be the bees knees... I'd include all the itty bitty ones, and explain that I would like the T hose to be a 1 piece deal, just make it a couple of inches longer at each end for fine tuning.