Looking for more power

jrp said:
I swapped the cams when I was adjusting valve clearances, so I had the cams out anyway. My conclusion was based on my experience riding the bike before and after.

As far as quantifying the gains, I don't have a before and after dyno, but can offer this:

-A lower lift height on an intake valve reduces the maximum amount of gas that can flow into the cylinder for a given duration.
-For a given intake lift height, more duration increases the maximum amount of gas than can flow into the cylinder.
-Valve overlap makes it possible for an intake charge to be higher than the maximum obtainable by the swept volume of the cylinder alone (which is the most you'll get on the later model year Honda cams since they don't have valve overlap).

I don't understand your comment about "custom ground cams with more lift and duration". I did install cams with more lift and duration; I just didn't have them custom ground.

Honda clearly changed their cam design to meet emissions requirements. There is no other explanation.
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I didn’t realize the cams were changed in later years. Did you notice a drop in your mileage after the swap? I knew you did a lot of electrical stuff on your ST but didn’t realize you did this mechanical work too. Well done!
 
jrp said:
I know you’re trying to be helpful, thanks. I already do all that. Honda originally designed thei engine to breath better and I just put it back that way. Makes it a little more fun to ride too!
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Do you know what years had these hotter cams. Did you perform any other complimentary mods to aid the cams, jetting, airbox filter mods, exhaust system. Did it raise the power band to pull harder between 7 and 8 thousand rpm.
 
Ok Ok if we are all so determined to make a reasonably priced "Go Fast" ST then the path is clear, Nitrous Oxide! should be a few hundred dollars for about (just guessing) a 70% power increase for a few seconds, but who wants to hold on for longer than that? :rofl1::rofl1::rofl1:
 
was there any listed difference in the hp, torque and performance ratings for the different years of ST 1100? or was the compression ratio different? I am not being critical or doubting, just curious why mother changed the cams on such a great motorcycle. {EDIT} :oops:oops my bad sorry, just looked a @jrp post # 26 emissions control it is the most logical explanation.
 
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jrp said:
From '91 - '96 the standard 49 state and Canada ST1100s had the hotter cams. None of the California bikes ever had it.
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In the Honda service manual section that specifies the cam lift it shows '91-'96 as the era of the higher lift cams, but in the valve open/close timing section it shows '91-'93 as the era with the longer duration cams.

Is one of those a typo? Or was there an era between '94-'96 where the cams had the higher lift along with the shorter duration?

the parts fiche shows only two different cam part numbers, so I suspect the '91-'93 reference is a typo and should read '91-'96.

Also, the early ABS-TCS bikes had the same cams as the California bikes.
 
Really don't know what all the fuss is about. The way I see it as long as we can still out run any stock Harley Davidson motorcycle I'm good. I rode with a bunch of em last week new ones and they were slow as hell merging into traffic I almost ran over them and get this they had at least 700 more cc's than I did:rofl1:
 
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jrp said:
I know you’re trying to be helpful, thanks. I already do all that. Honda originally designed the engine to breath better and I just put it back that way. Makes it a little more fun to ride too!
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I Know you're trying to be helpful. Thanks. I wish I had a nickel for every time I've heard someone rely on their butt-o-meter to laud the virtues of an engine mod they desperately want to validate after having spent money and time on it: I would be a rich man. I've had the benefit of being in communities where these things were tested on dynos and the dyno beats the butt pretty much every time. Longer duration and higher lift cams do indeed increase the maximum possible size charge in a chamber, but that's not the same as actually providing a maximal charge or even an improved charge. The system is more complex than that. Some actual laser temp readings and a dyno run could set you up in business selling cams. Without proof, it's just another butt-o-meter legend. Of course, as we all know, legends are at least partly based on truth.
 
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