Pair Value

[godfire]

This is a tech board question, but I thought I would start here.

I recently had the tank off and found that the vacuum line to the pair value was not connected.
I hooked it up, checked everything else put it back together and now when I let off of the gas the bike pop and crackles like mad.
I have after market pipe and I have basic knowledge of what the pair value does, so now I'm thinking about removing the pair value assembly......any opinions?

http://www.valkyrieriders.com/shoptalk/desmog.htm

[Houdini]

I have been thinking about desmogging my scoot to avoid any of the vacuum issues I keep reading about and to 'purdy up' the engine area.  If you want to make a day of it we can do both bikes.  I have all of tools we could possibly need and I printed the desmog article off of the national board.

Chuck

[Doc809]

You guys let me know when you do this, cause my two wheeler has some serious popping when letting off the throttle.  Larry

[godfire]

Sounds good Chuck.
I'm busy for the next couple of weekends, but we need to make a plan.

[Houdini]

I have weekends off Jim so let the Doc and I know when you are free and we will git-r-done.

Chuck

[SideCar]

I was an early desmogger.  Unless you have a bad pair valve, there is no benefit to desmogging except not to have to do occasional hose maintenance.  Even with the timing you described, the popping you mention is not likely the valve itself, but a vacuum leak showing up from somewhere else.  A bad pair valve doesn't normally show up acting as a vacuum leak (but it can).  Suggest you check all hoses and exhaust and intake fasteners.  The desmog isn't difficult, but comes with it's own set of issues. 

[Flyboy]

I have done about 8-10 de-smogs. If you need any help just let me know. We might even be able to do it here at the shop.

[Wanderer]

Must not have anything better to do than pick on your Valk? I am not surprised to once again agree w/ Mr. SideCar, but I would take it even further. There is probably a total of about 3.5 feet of vacuum hoses to be replaced every six or seven years to keep your bike GREEN.

Your bike will run better with a small vac leak or two than with a stopper plug installed as part of this mod blowing out on the road. This has happened more times than reported. I might have heard of one bad p.valve. Right up there with the one bad coil I heard of years ago.

Love the sinner, hate the sin - against your perfectly good, well engineered Honda product. ~Jeff

[Houdini]

Ok; I have an open mind.  What set of issues comes from a desmog?  I searched the national board and couldn't find anyone complaining about their bike running poorer after a desmog.  I found lots of people talking about their scoot running better and a reduction in maintenace.

Chuck

[SideCar]

If it's done right, it won't run better or worse.  It just makes no difference in performance at all.  A little less green seems accurate.  I'm not against it if someone wants to do it, but having done mine and a number of others, and understanding how it's plumbed, my question for folks is why do it.  If someone is installing cruise and wants the extra room under there, I understand.  If there is a bad pair valve, desmog is cheaper than a new valve. 

The issues with desmog:  Depends on what method you choose.  It is a pain to get the lower tubes off completely, which is why many cut, clamp and seal them.  Top tubes are relatively easy as you can use freeze plugs, but they aren't pretty and can collect water since they are cupped up. Some say the freeze plugs allow more noise to come through, but I'm not convinced. Caps for vacuum nipples need to be high heat resistant as standard vacuum plugs will rot, often in less than a year and you'll be doing maintenance when they blow off the nipple out on the road and you hear the tell tale ticking and it runs a little (not much) rougher because of the vacuum leak. 

I don't have an ax to grind one way or the other.  Unfortunately, some people have posted about some extra smoothness or performance solely as a result of desmog.  It isn't going to happen.  If you have a vacuum leak (which usually is what leads folks to desmog), of course it runs a little better when it is fixed in the process of the desmog.  Just don't want folks to run out and desmog because they think that there has been some rash of catastrophic pair valve failures or that you get better mileage from desmog.  Neither is true.