High rpms at cold start st1300 ?

roadrider

roadrider

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Aug 16, 2008
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Location
goldendale wa.
My 07 st1300 when started cold revs to over 3000 rpms this occurs at 20 degrees and sometimes at 55 degrees. Revs for about 5 minutes then slows down. I understand how the cold start system functions. How can the cold start rpms adjusted ? Ride safe
 
roadrider said:
My 07 st1300 when started cold revs to over 3000 rpms this occurs at 20 degrees and sometimes at 55 degrees. Revs for about 5 minutes then slows down. I understand how the cold start system functions. How can the cold start rpms adjusted ? Ride safe
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How many miles on your bike?
This may also be a sign that your T-stat is dying and moving too slowly.
 
'High-idle' was generally adjustable on older cars. A car's black box may need to be accessed to do that now. I don't know if it's a variable metric on the ST.
 
The cold idle speed is controlled by the wax unit which is a 100% mechanical device that is (or should be) exposed to a flow of the coolant that is circulating in the engine block. When the coolant is cold the wax unit opens the starter valves which are bypasses for air to reach the intake manifolds. The starter valves are also used to control engine hot idle (when they should be held open by the idle adjuster screw) and the vacuum balance across the four cylinders (where the adjustable starter valves are tweaked to match the vacuum coming through the fixed valve). A common issue seems to be a blockage in the small coolant hoses or the wax unit itself, which will slow or stop the flow of coolant so the wax unit cannot respond correctly to coolant temperature change.

If the idle speed is excessive when cold then too much air is entering the engine at that point; that could come from the starter valves, an intake leak (e.g. a split or loose intake boot, or a perforated vacuum hose) or even possibly an over-tight throttle cable that is holding the butterflies slightly open. If the high idle is a recent issue then I'd suggest you should do a starter valve balance first and set the hot idle speed correctly, and if that does not help, you need to look for some cause of an intake leak. Ultimately you can adjust the cold idle speed using the nut on the wax unit but that is meant to be a non-adjustable part and will probably be compensating for some other fault.
 
Mine hovers around 3k RPM on cold start for a few mins (haven't timed it).

It did this evening. Before cranking the dash temp read 8C I think. I used the time to put the rest of my gear on. When I was ready to go, so was the bike
 
My '05 idles in the 3K area when cold as well. I'll actually ride the brake in 1st gear as I head down the drive to force the revs lower as I pass the neighbor's bedroom window.

Checked both maintenance manuals and each says run the bike for at least 10 minutes to warm up sufficiently before checking/adjusting idle to "1000 ±100 rpm".

Neither mentions what cold idle speed should be nor how one would adjust.
 
My '03 ST1300 would immediately go to 1,500 ~ 1,700 RPM on a cold start, then drop to normal idle in 30 - 45 sec. My '09 ST1300 would immediately go to 3,000 cold from day 1 new, and not drop to normal for 2 - 3 minutes.

I made an adjustment that some very respected members here recommended against doing, that dropped cold idle to what I consider 'normal' 1,500 ~ 1,700, with no ill effects. It's run perfectly for 26,000 mi. since the adjustment. YMMV

If one wishes to pursue said adjustment, it's here:

Cold Starting a ST1300 | ST1300 Related

Hi It's the third day that i have my ST. It is a new machine not over a 100 miles I have a question about cold starting... Outside temperature 55F start ok , start reving more and more until it reaches 3000km for about 3 minutes until the 3 bar a fully light. Is that normal...
www.st-owners.com www.st-owners.com

Good Ridin'
slmjim
 
slmjim said:
My '03 ST1300 would immediately go to 1,500 ~ 1,700 RPM on a cold start, then drop to normal idle in 30 - 45 sec.
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I'm curious– what's the ambient temperature for that? 45s seems pretty quick especially if it was really cold outside. I've always liked to drop both the fast idle and normal idle of my cars and bikes. For my cars I've never like that from the factor they'd roll at 10mph on idle! I think I need a computer to adjust the idle on my 2002 car and CA wants cars to idle high (well higher than the 650-700rpm I prefer) to help lower emissions.

So that prompts me to wonder if Honda's recommendations not to mess with the fast idle is merely emissions related and not to prevent us from steering a course that ultimately leads us to a fiery death.

At about 45ºF my ST fast idles at about 2500rpm or so for about 2min+. I don't really pay that much attention. I start the bike put my gear on and ride off at 1br. It's only a another minute before it's 2br and not even that to get to 3br.

Here's a link to your post in which you detail what you did to lower your fast idle. FYI– the link in that post is dead.
 
ST Gui said:
that prompts me to wonder if Honda's recommendations not to mess with the fast idle is merely emissions related and not to prevent us from steering a course that ultimately leads us to a fiery death.
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FWIW, my bike high idled this morning. I set off before any bars were showing.

Firey death did not occur. :thumb:
 
ST Gui said:
I'm curious– what's the ambient temperature for that? 45s seems pretty quick especially if it was really cold outside. I've always liked to drop both the fast idle and normal idle of my cars and bikes. For my cars I've never like that from the factor they'd roll at 10mph on idle! I think I need a computer to adjust the idle on my 2002 car and CA wants cars to idle high (well higher than the 650-700rpm I prefer) to help lower emissions.

So that prompts me to wonder if Honda's recommendations not to mess with the fast idle is merely emissions related and not to prevent us from steering a course that ultimately leads us to a fiery death.

At about 45ºF my ST fast idles at about 2500rpm or so for about 2min+. I don't really pay that much attention. I start the bike put my gear on and ride off at 1br. It's only a another minute before it's 2br and not even that to get to 3br.

Here's a link to your post in which you detail what you did to lower your fast idle. FYI– the link in that post is dead.
Click to expand...

Mmmm... My post is 9 yrs. old now. That link pointed to a thread even older. Point is, that's the adjustment worked for me. YMMV

My '03 has been gone for over 10 yrs. now. Working from memory as to length of time at fast idle on the '03. The extended 3K RPM of my '09 beginning new, day 1, mile 1 stood out in marked contrast to the '03.

Good Ridin'
slmjim






 
Starter valve adjustment first, very little adjustment on wax valve. Imho
 
I checked my bike today at 18C/64F, it started at about 1800 rpm and dropped to 1000 after just over 2 minutes; at almost the same time, one bar showed up on the temp gauge. The starting rpm is unchanged when the bike is in colder weather, and I would assume the heat up time won't be very much longer as the volume of coolant to heat is pretty small even if it starts out many degrees colder (although like others that is my gear-on time so I don't pay that much attention).

I would say that there does seem to be a wide range of cold start rpm among our bikes; if all else is healthy, this suggests that the starter valves are being held further open on those bikes that rev higher, which does point to the "non-adjustable" adjustment nut...

As a side note (and a thread highjack) my bike NEVER shows more than 3 bars, even when the fan is cycling on/off in traffic, and also never shows less than 3 bars once it has warmed up. That is either incredible thermostat control or the gauge is a little dodgy...
 
TerryS said:
As a side note (and a thread highjack) my bike NEVER shows more than 3 bars, even when the fan is cycling on/off in traffic, and also never shows less than 3 bars once it has warmed up. That is either incredible thermostat control or the gauge is a little dodgy...
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That is because the temperature range covered by the third bar of the temperature gauge is very wide. It is about eighty degree F from when the third bar lights to when the fourth bar lights.
 
TerryS said:
my bike NEVER shows more than 3 bars, even when the fan is cycling on/off in traffic, and also never shows less than 3 bars once it has warmed up.
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And it won't as long as the cooling system is properly maintained.

TerryS said:
That is either incredible thermostat control...
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It is.
 
My 2003 and 2008 both exhibit the same warm up behavior: ~1700 - 1800 rpms at cold start and down to normal idle rpms within five minutes.

I've never had an issue with high idle warm up, so can't answer the ultimate question.
 
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