To Desmog or Not to Desmog.... That is the question!

[michaelyoung254]

Pulling my fat girl down for some major maintenance and also some improvements, and I'm wondering while I have the carbs out if I should desmog while I'm at it. I'll at least replace all of the vacuum lines and so forth, but not too sure on desmogging. I'm 2/3 deaf, so the clicking of the pair valve obviously doesn't bother me, so back to the question...... What are the pros and con's of desmogging. I tend to one of those who feel like it was put there for a purpose, and if it ain't broke, don't fix it, but if doing so will make a noticeable difference in performance or mpg (or both) it may well be worth it.

[Ricky-D]

It won't.......

Leave it alone and maintain it.

You'll be Ok.

***

[Chiefy]

This is one of those topics that could be debated forever.

My bike was 12 years old when I got it, and the vac lines looked original, dried out and cracking.  I heard heard a lot of stories about leaks on the Valk, and how hard it can be to trace them out.  Plus a friend of mine was always trying to talk me into desmogging.  So I Desmogged, I used the "shiny" kit that Red Eye sells.  I also changed the air filter and checked the carb mix while I was doing it.  When it was done, it ran ever so slightly better.  But that could have been the air filter for all I know.

Bottom line.  I'm not sorry I did it.  But unless you already have a leak somewhere, it won't make your bike run any differently.  OTOH, there is a lot less stuff to cause vacuum leaks now, plus it's easier to work in the under the tank area now.

[Patrick]

As long as you replace the lines and caps with good quality 'stuff' every few years you'll be fine.. The only thing a desmog does is help eliminate vacuum leaks and cleans up the valley.. Does the Valk really have a valley?? Humm, maybe its a plateau..

[JC]

The only regret I had was not doing a complete desmog the first time. I used caps that were not up to the heat and got brittle quickly (not Redeye's), resulting in noises I'd never heard form the girl before.
Pulled everything off and made cover plates for the case openings, never a problem since. I recommend doing it while you have the carb bank out so you don't have to deal with it later, but that is just my opinion. Left plenty of room for a new set of horns.

P.S Hope the windshield works well.

[Patrick]

Yep, I don't know anyone who has been happy doing a 'quicky' desmog.. Eventually it'll jump up and bite ya..  It pays to do it right the first time..

[Maddog vrcc#508]

I bought a 97 from a guy in Calif. that had been desmoged.  i rode it for a year and could not tell the difference. The only real difference was it was bloody loud.

[Farther]

.. The only thing a desmog does is help eliminate vacuum leaks and cleans up the valley.. Does the Valk really have a valley?? Humm, maybe its a plateau..

I think the proper word is cleavage!

[Bigwolf]

Desmoging will not improve MPG or performance.  It will eliminate several things that can cause problems though and that may be worthy of consideration.  Things that can go wrong in the PAIR system are cracked vacuum lines, leaking PAIR control valve, and broken reed valves (there are 6 of these).  My 98 standard has 25k on it and the PAIR control valve is leaking vacuum badly.  A new control valve is over $100.

I will try to maintain my smog system as long as I can but sometimes I am just crazy that way.  I'm not suggesting one way over the other.  Just stating the facts.  It's your bike.  Do what is right for you.

[Mr Steve]

I was a desmog holdout for a while.  After years of chasing leaks in maintenance of that system, I finally just bit the bullet and desmogged when one of the reed valves broke.  I don't regret it.  I will say for a while I was extremely tempted with the partial kits, but after reading so many reports here I did it the full  with the kit from F6 (it was not that difficult).  As the other posts said, no change in performance, but it's quieter and it's one less maintenance item to have to keep chasing.

[texaninsouthfl]

I have a 97 Standard with 19,000 miles on the clock when I purchased her last fall... very little popping when I first brought her home... 5000 miles later... mild popping that turned into full blown backfiring at all speeds... sounded like a mini-gun coming off the freeway. It was annoying as hell but I have to admit it was sort of fun scaring the bejeebers out of cage drivers with their windows rolled down.

Anyway, I had enough of it and bought the shiny de-smog kit from Redeye. Four or five hours later... a pile of tubes and crap and no more popping. I changed out the o-rings while we were at it as I'd read that those can go bad too.

I'm pretty deficient when it comes to wrenching and motor knowledge and agree that performing a de-smog on a bike with no vacuum leaks won't see any performance improvement, but it seems that getting rid of the leaks (both center carb hoses had big cracks) did seem to make my bike run, and sound better. Getting rid of all that crap that can cause it seems like a good investment of time to me.

By the way, I bought Redeye's pilot screw tool and it worked great... the PO had apparently set the pilots out 2 and THREE quarter turns so we set em back to 2 and ONE quarter.

I don't know if all that has anything to do with it, but on the ride today I got 33mpg... usually I get 28-30 at best.

[john]

pull the trigger .....
life is good ......

[michaelyoung254]

Thanks to all for the input. I think that I may look into scoring one of the kits from Redeye. JC, I appreciate the windshield, and can't wait to get it put on, and I like the way you used the extra space that you cleaned up from your desmog. I'm installing the cruise control kit from Audiovox, and maybe I can use the space for a homemade vacuum canister. Hey texasinsouthfl, I only get about 28 to 30 mpg too, but I'm always riding two up with my better half on the back.

[YoungPUP]

Desmog's the way to go, just make sure you buy Quality vacuum caps, not the cheapies from the local big box auto store.  Won't make that mistake again...

[Patrick]

The best desmog article is written by our very own Normand [Quexpress]..

[texaninsouthfl]

This is the lovely result of desmogification surgery on The Beast:

[texaninsouthfl]

If you hunt and fish like I do, you're probably are concerned about the quality of our air and water.  Has anyone determined if the "desmog" modifications turn a Valkyrie into a big pollution generator?  Autos are often measured this way, but motorcycles not so much.

I noticed you're from Apopka... I was up that way not long ago for a Patriot Guard Mission.

Anyway, it seems to me that all the smog plumbing on the Valkyrie basically is for the purpose of injecting air into the exhaust side of the combustion cycle ... sort of like diluting the exhaust with air so it is seemingly cleaner for tailpipe emissions testing. If that's the case, it wouldn't actually reduce the hydrocarbons (or whatever it is that people are always bleating about) that the bike produces.

Whether any of that is correct or not... I can't say that I've ever spent as much as a nano-second worrying about whether my Dragon has bad breath. 

[Patrick]

Yep, what he said..
The solution to pollution is dilution.. Early auto emission systems were the stupidest things I think I've ever seen.. Well, maybe not the stupidest things I've seen,but, certainly the dumbest things that could have ever been put on an automobile.. Take an engine that gets 20mpg and has decent CO/HC readings, reduce compression, stupefy the valve and ignition  timing, pump outside air into the exhaust and end up getting 12 mpg.. For the heck of it, stop the air injection and the CO/HC go thru the roof.. So, the end result was an engine that really polluted more..
All that said, the Valk isn't much better.. Emissions do rise on decel, so Honda decided to inject some air into the exhaust on decel.. Does this help with pollution? Yep, but who would ever notice?
Newer engine designs along with some of computer controls do help with keeping the exhaust a bit cleaner,but, there is a point of no returns..
I could go on and on,but, I'll get off the soap-box now..

[Ricky-D]

There are some who after doing a de-smog, still had no trouble passing inspection station testers in their state.

A Valkyrie in good tune has no problem with emissions even after a de-smog.

That statement has to be couched in cautious terms when the 35 jets are replaced with 38's.

***

[Bigwolf]

I keep seeing posts of people thinking the PAIR ( or smog or exhaust air system if you prefer) work ony on decel.   ???  The Honda manual on page 5-25 clearly shows and states that the PAIR system works all of the time except for decel.  The PAIR system shuts off when the vacuum goes over 15.7 inches of mercury if the control valve is working properly.

If I am reading my manual wrong, please correct me, but I do not think so.  I have read and reread this several times recently because my control valve was not working and I was checking the whole system and trying to figure out why I was hearing one thing on these boards but was not seeing nor reading the same thing.

Wolf

[pBrain]

It won't.......

Leave it alone and maintain it.

You'll be Ok.

***

I'm no expert, but I agree.... It was put there for a reason.

[BF]

The best desmog article is written by our very own Normand [Quexpress]..

Got a link?

[Chattanooga Mark]

My Interstate is a 1999 model so all those vac lines, connections, plastic T's and such are now over 13 years old. I just bought the Red Eye shiny de-smog kit that I'll install this month. I see no reason to wait for the vac lines etc. to start cracking so IMHO, it's simly preventative maintenance. Plus I like the looks of the engine after being cleaned up a bit of all those hoses, connections and assorted parts. Each item, hose and connection is just a potential leak anyway. No downside to removing the stuff and plenty of reasons to relocate them to a box on shelf in the garage.

If I end up in an place that requires a 13+ year old motorcycle to pass a smog test, I can always re-install it if need be. But as others have said, it should pass the sniff test with or without those parts. IMHO, it only makes sense to remove the stuff if you don't mind removing the tank and airbox anyway. The de-smog instructions are excellent in the Tech Section by the way.

All the best,

Mark

[Patrick]

'Got a link ?'.. Its in shoptalk..http://www.valkyrieriders.com/shoptalk/desmog.htm

[dubsider]

'01 Standard purchased last March with 30K on her. We did a de-smog shortly after, along with a I/S ICM and carb springs and a 4* trigger wheel.   We did the no return method with caps, plugs and JB Weld.   

[john]

" It was put there for a reason "   
yeah ..... 90 bucks an hour shop time           

[Chattanooga Mark]

Doesn't mean the reason or the execution was sound.

Just Sayin',

Mark

[texaninsouthfl]

Doesn't mean the reason or the execution was sound.

Just Sayin',

Mark

Indeed... I had my mechanic buddy help me with the desmogification and he was just shaking his head and saying, "this is just a stupid design" ... of course in part he was referring to the design of the air box and all the fun it is getting it back in and the rubber doohickeys re-attached. It actually wasn't too bad with two pairs of hands... just hooking one of them back up to #2 carb gave us a bit of trouble.

[Mr Steve]

I don't get the concept of dilution being a solution.  If I put a drop of oil in my swimming pool, there may be a high concentration of oil in that drop, but the end result is a drop of oil in my swimming pool.  Now, if I fill a glass with water from the pool, add a drop of oil to it, there may be a lesser concentration of oil in that glass, but when I pour that glass back into the pool the end result is still a drop of oil in my swimming pool.  So in other words, what is the difference if the dilution happens before it leaves the exhaust or after?  The same amount is still going out.

[texaninsouthfl]

I don't get the concept of dilution being a solution.  If I put a drop of oil in my swimming pool, there may be a high concentration of oil in that drop, but the end result is a drop of oil in my swimming pool.  Now, if I fill a glass with water from the pool, add a drop of oil to it, there may be a lesser concentration of oil in that glass, but when I pour that glass back into the pool the end result is still a drop of oil in my swimming pool.  So in other words, what is the difference if the dilution happens before it leaves the exhaust or after?  The same amount is still going out.

Exactly.. and that's why it was a stupid way to do it. The only result is that the exhaust SEEMS cleaner for the tailpipe testing that is done in some states but the same net amount of pollution is being produced. Older cars used to have these "smog pumps" for the same reason but with the increasing use of fuel injection, better catalysts and electronic engine management, the smog pumps went away... or at least that's my understanding.

[Patrick]

Back in those 'good ole days' I was an auto repair instructor and was very familiar with emission systems, factory reps and engineers.. I have a BS in auto engineering myself and have been in and around the business before I learned to walk.. Early emission systems were a joke.. The old myths are still around..  As I said before, the solution to pollution is dilution.. And its still as true today as then..

[Patrick]

I guess I can't tell you why your old 307 didn't run well.. Are you saying it ran OK before you removed the pump?? There could be a lot of reasons it didn't run right, from a simple vacuum leak[line or valve] to a bad camshaft[ I used to replace 2 a day on SBCs back then] or anything in between.. But there were a lot of those GMs with the AIR system with a missing pump that ran OK..
That old Ford in my avatar is a mid-year 1931 that I've had since 1976..
So, you have a ' T ' ?? I wish I knew more about Ts than I do, I've not been around many of them.. They are interesting to drive though..