Having an extra duct tube, I'm wondering if there is any benefit to adding a second one to the right side of the 99, the way the early ones had them on both sides. The mounting points are there, just not used on that side.
Fresh air intake duct tube (x2?)
- Thread starter DeanR
- Start date
- Joined
- Feb 5, 2005
- Messages
- 8,538
- Age
- 77
- Location
- Kingman, Arizona
- Bike
- 2000 ST1100 ABS TCS
- STOC #
- 004
Word from year's ago: Honda removed the second tube because of carb icing in the right conditions; just too much fresh air at high humidity and low temps causes trouble. Neither my 91 Silver (Feb 90 build date) nor my 91 black had the second one so have to assume they dropped it pretty early in the production run. I have a spare but have never bothered to install it for my own test. Only reason I can think of would be a small chance of increased gas mileage in our hot desert.
John OoSTerhuis
Life Is Good!
What George said. I did order the second tube parts and installed them on my 1991 Silver (Oct 90) a very long time ago. JuST because I could. I've never experienced carb icing on the ST.
John
via iPhone 6
John
via iPhone 6
OP
OP
Speaking of that tube guys, I can't fit my fairing pocket in. Air duct tube is in the way and I can't figure out how to position it so the fairing pocket can clear it. This has not been a problem previously. Got a description or picture of where to position the duct?
ST1100Y
Site Supporter
I got the 2nd intake duct on all ST's I've owned/own... and they did cure the vapour-lock issue I sometimes had on hot summer days after idling at a red light... never had any carb icing either, and I rode in some pretty odd, winter conditions...
No photo of the exact location/lay-out, its a tight fit, might need to squeeze the one air-hose a bit oval on one spot to fit that infill/pocket, but it works fine.
IMO Dean, wouldn't worry too much about it. They weren't even on my bike when I got it 10+ yrs. ago. Has never been an issue, and I've ridden in some pretty hot(insert Caly) stop and go traffic. With LD 'slab' mileages being in the low 50's@80+mph, not having the cooler outside air obviously doesn't affect it either as I would have normally suspected. Your choice of course
.
CYYJ
Michael
I installed a 2nd duct tube on my 2001 ST 1100, primarily to move more cool air under the false tank area for the purpose of keeping the false tank cover from getting too warm. I've since put 160,000 km on the bike and never had any experience with carb icing.
Be aware that carb icing most commonly occurs when the engine is rolled back to idle or very low power settings for prolonged periods of time (e.g. during prolonged descent in normally aspirated piston aircraft engines). It is quite uncommon for us to operate our motorcycle engines for prolonged periods of time at idle power or at very low power settings. I think this is why none of us has ever reported encountering carb icing on the ST 1100.
Michael
Be aware that carb icing most commonly occurs when the engine is rolled back to idle or very low power settings for prolonged periods of time (e.g. during prolonged descent in normally aspirated piston aircraft engines). It is quite uncommon for us to operate our motorcycle engines for prolonged periods of time at idle power or at very low power settings. I think this is why none of us has ever reported encountering carb icing on the ST 1100.
Michael
docw1
Bill Rankin
I experienced carb icing once, on my '95, with one air tube. Riding hard following a rain storm at higher elevations in coolor weather, out in the middle of nowhere NM. Got a little worried as there was nothing around for miles and miles. Fortunately, it started right up after letting it sit and let the engine heat melt any ice.
OP
OP
I put the fairing pocket in fine without the left hose, but would prefer it to be there. With the fairing pocket in place I can't visualize where the thing would go and in my old age I have no recollection of its position. Like I said, it always fit however.
I need a clue. Please?
Figure it's gotta go between the pocket and the air cleaner, but I sure don't see how.
I need a clue. Please?
Figure it's gotta go between the pocket and the air cleaner, but I sure don't see how.
OP
OP
Got it in, more or less. Tight.
wjbertrand
Ventura Highway
Actually the right side one should already be in there, it was the left side Honda later deleted. I added the left side one to my ST1100, the biggest benefit was the cooling effect on the left side of the top shelter and left side cover. Never had any icing issues at all.
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OP
OP
Partzilla fiche looks like it's on the left side OEM, if I'm seeing it correctly.
I can do either, both, or none.
http://www.partzilla.com/parts/search/Honda/Motorcycle/1999/ST1100+A/COWL/parts.html
I can do either, both, or none.
http://www.partzilla.com/parts/search/Honda/Motorcycle/1999/ST1100+A/COWL/parts.html
John OoSTerhuis
Life Is Good!
There's a wire bail/half-loop on the left side of my '91 that routes the OEM original hose it came with. I added the second hose to the right side.
ST1100Y
Site Supporter
By the orientation of the fixing bolt in your fiche its the right side that had been continued (same by my memory ;-) )
Compare it with the fiche of a '90 model:
http://www.bike-parts-honda.com/pieces-honda-detail-3803-13MT3L41-ST1100L-1990-F__3800-PAN+EUROPEAN+ST+1100.html
I personally somehow don't buy the story about the carb icing...
I think its a way simpler reason: space issues during installation/assembly costs...
Cause as also Dean found out is it a tight fit due to the mains wiring harness running along the left frame-backbone.
Also I had (and have) to push the wiring aside and squeeze the air-duct a bit to get the grey infill/pocket into place... don't get it right and face issues fitting the false tank...
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wjbertrand
Ventura Highway
Maybe they did it differently for different model years, but my '93 had only the right side hose. At any rate, both sides are the same P/N.
-Jeff
-Jeff
OP
OP
Yep, in comparing those fiches (I didn't zoom in enough), it does look like the right side was the single one (after struggling with the darn left one). Looks like I'll do both for now.
ST1100Y
Site Supporter
So did my '92, I had to "upgrade" it by buying the parts (intake, duct and the two bolts)...
In any way: cooler air gives better volumetric efficiency ;-)
In summertime in Texas I could probably use two hoses to help cool the shelter, but only have one on my '99.
In the winter I plug the one with a black rag to help warm the shelter.
In the winter I plug the one with a black rag to help warm the shelter.
OP
OP
I bet it's the right side one!
DaveWooster
'95 ST1100ALS and '98 Standard ST1100W
Has anyone else mentioned the purpose of the first air tube?
(I think ST1100Y answered that question: It is to keep that petrol/fuel valve device from overheating, right?)