HDI Active Exhaust
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Road Captain
Joined: May 2011
Posts: 545
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From: California
HDI Active Exhaust
Am I correct in my reading that the HDI Active Exhaust Valve is only on certain "international" versions of Harleys?
There is not one on my California, USA 2011 RKC?
There is not one on my California, USA 2011 RKC?
Extreme HDF Member
Joined: Sep 2010
Posts: 14,744
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From: Phoenix '53, '88, '09 Big Twins
HDI always means non-domestic versions, California market bikes often have their own changes such as canisters
I'd like to know if the active valve could be useful to enhance torque when closed, horsepower when open--- any Aussies, Brits or other Int'l riders have a thought on that?
Mike
I'd like to know if the active valve could be useful to enhance torque when closed, horsepower when open--- any Aussies, Brits or other Int'l riders have a thought on that?
Mike
Last edited by mkguitar; Sep 19, 2011 at 09:12 PM.
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Road Captain
Joined: May 2011
Posts: 545
Likes: 5
From: California
HDI meaning "Harley Davidson International" I am guessing.
Thanks for the feedback. I saw it mentioned in my Service Manual and did some research. Then just wanted to confirm that I was correct in my understanding.
Thanks again.
Thanks for the feedback. I saw it mentioned in my Service Manual and did some research. Then just wanted to confirm that I was correct in my understanding.
Thanks again.
Road Warrior
Joined: May 2009
Posts: 1,945
Likes: 3
From: Victoria, Australia
HDI always means non-domestic versions, California market bikes often have their own changes such as canisters
I'd like to know if the active valve could be useful to enhance torque when closed, horsepower when open--- any Aussies, Brits or other Int'l riders have a thought on that?
Mike
I'd like to know if the active valve could be useful to enhance torque when closed, horsepower when open--- any Aussies, Brits or other Int'l riders have a thought on that?
Mike
Club Member
Joined: Jun 2007
Posts: 45,429
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From: Bedford UK
I've owned Harleys since the 70s. For those of us in Europe the bikes we get, I was told back in the late 80s, are influenced by Swiss regulations, that have more severe noise limitations than in North America, so we suffer from different exhausts and other things that limit performance, to keep noise down.
I also have a recent Buell and Sportster, which are stock, but to give you an idea of what the changes are, this is how my 1990 FLHS differed from US spec. The mufflers were quieter, the airbox was quieter, there was a restricter in the inlet manifold, overall gearing was higher with a 61T rear pulley, ignition timing was retarded at low engine speeds. So for us to do a proper stage 1 required undoing all those things!
So the HDI exhaust on current bikes is not something to be lusted after! Around the World owners, like our North American brethren, look for ways to disable or replace the restrictive system! If you have a factory parts list you can see where there are HDI parts.
I also have a recent Buell and Sportster, which are stock, but to give you an idea of what the changes are, this is how my 1990 FLHS differed from US spec. The mufflers were quieter, the airbox was quieter, there was a restricter in the inlet manifold, overall gearing was higher with a 61T rear pulley, ignition timing was retarded at low engine speeds. So for us to do a proper stage 1 required undoing all those things!
So the HDI exhaust on current bikes is not something to be lusted after! Around the World owners, like our North American brethren, look for ways to disable or replace the restrictive system! If you have a factory parts list you can see where there are HDI parts.
Last edited by grbrown; Sep 20, 2011 at 01:34 AM.
Extreme HDF Member
Joined: Sep 2010
Posts: 14,744
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From: Phoenix '53, '88, '09 Big Twins
Thanks GR,
I was just wondering about that, and if there might be any advantage ( you know like the muffler cut out on early bikes)
61T--- that's what I used for the overdrive on my FXRP in 1990. With a Softail belt.
( bike has a lot of grunt so overdrive no problem)
Still running it all these years later.
Best, Mike
I was just wondering about that, and if there might be any advantage ( you know like the muffler cut out on early bikes)
61T--- that's what I used for the overdrive on my FXRP in 1990. With a Softail belt.
( bike has a lot of grunt so overdrive no problem)
Still running it all these years later.
Best, Mike
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Club Member
Joined: Jun 2007
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From: Bedford UK
Hi Mike, I now have a US spec 70T on the rear of my bike! We could have done a swap. The other man's grass is always greener.....
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