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Block off plates

snarf

snarf

Member
Member
Tired of the top of your valve cover looking like a junk yard of spare parts?  I can help.  I have been making some block-off plates that takes the place of the exhaust emissions (reed valves) that sit on top of the valve cover.
They are are $20  for a set (plus screws) or $25 for a plug and play kit.  The kit includes 4 SS button head screws, a brass splice for the vacuum line, and a plug for the air-box.
You can get in touch with me at lilliefabrication at gmail dot com, or leave me a message here.


IMGP5286-1.jpg

 
Wanted to add that I tried a set of block off plates from ebay and they fit like crap. They were generic ones that claimed to fit a Concours. But in reality made from some other mold, and fit like crap.

These are the ones to get. Designed for the C10 Concours and fit is perfect. Black to match the valve cover and comes with hardware too.
 
Slybones said:
Wanted to add that I tried a set of block off plates from ebay and they fit like crap. They were generic ones that claimed to fit a Concours. But in reality made from some other mold, and fit like crap.

These are the ones to get. Designed for the C10 Concours and fit is perfect. Black to match the valve cover and comes with hardware too.
Click to expand...
Thanks for the kind words Sly. 
 
Is it a street-legal modification to install the block-off plates?
I have a 1987 connie so I guess it's 24 years old now, 75K on the dashboard but I don't know if it's ever been rebuilt or replaced.  I'm also ignorant about the emissions rules, when I learned them the older models hadn't had any emissions rules.
I'd like to renew the PCV parts so it's perfect, but if there's a lot of blow-by I don't think it will work right in the stock configuration.
 
Legal? Well that is a good question.

However this is not a PCV system. The Connie has one of those and its under the airbox down in the transmission area, and vents into the airbox from underneath.

The way I understand it is, this was call the clean air system, or something like that. During deceleration when the carbs create some amount of vacuum ( as small as it is ) it opens the valve at the top of the reed block assemblies. This in turn allows fresh air into the exhaust ports to help burn any unburnt hydrocarbons. During acceleration or when there is no vacuum the valve closes and no air flows into the exhaust ports. The reed valves insure air flows in one direction and you don't have hot exhaust gases flowing up into the airbox.

This system is only on the US models. The rest the world, called the GTR1000 did not have this at all. There was no reed block assy in the valve cover, etc.

Note they key here is to get these to block off and seal well. If you have a leak of some kind then it has not accomplished anything, if not worse. Now instead of only flowing fresh air during deceleration, you are flowing fresh air all the time, as now there is no vacuum controlled switch and fresh air is allowed through the air leak.

With the block off plates installed and sealed properly, and a plug in the airbox where the hole now is, the Connie now operates the same as acceleration mode, no vacuum mode, only all the time. Which is the way it works in the rest of the world.
 
I think I have all the symptoms of an air leak.  Using the choke/enricher there's kind of a rough-harley idle to 15 or 18 hundred, then it hits a certain point and leaps to 2500-3000 or more.  When warmed up fully, no choke and decelerating, the rpms tend to stay up after the throttle is closed so slowing down is delayed.  And there's not always power at idle, sometimes when the throttle opens it gags (so I tend to wind it up at the trafffic lights & stop signs, probably looks like I think I'm hot stuff).
I really thought (assumed) the thing on the valve cover was a fancy PCV valve.  It's the only thing I havren't checked because it's the least accessible.  I'm going to have to hit the books a little.
 
It sounds to me like you may have some carb issues.  Perhaps a sticking slide or two that is messing with ya in conjunction with some plugged idle passages.  Check for any vacuum leaks first.  I do not think this problem is at all related to this thread, the block-off plates, or the air injection system unless it is the line going to the diaphragm.
 
Easy way to check for an air leak is to spray some WD40 or similar around the carb boots while the bike is idling.  If the idol speeds up you have a leak.
 
I think I have 4 vacuum ports in the front of the carbs, if I remember right, 1 is blocked, 1 goes to the fuel prime/run/reserve petcock, and 2 are T-connected to the thing on top of the engine that would be eliminated by the block-off plates (I think).
Or maybe it's 2 to the fuel valve, 1 to the top, I'm sorry, my bike & manuals aren't here right now.  I hope I'll see them again wednesday or thursday.
 
I checked my bike and it has all the gadjets (but it's hard to see up there without pulling the fuel tank).
It has vacuum from carbs 1 & 4 tee'd together to activate the valve/switch between the reed plates and the air box.
The OEM manual describes it as 'US model and Swiss model' but Bike Bandit has the 'Valve, Air Switch' listed as a California part (in the Air Cleaner thumbnail and it's $109.32 for that valve alone).  BB also has the reed valve parts as CA,US (under engine in the Cylinder Head thumbnail).  The best illustration seems to be in the supplements section of the OEM manual's 1994-1999 Engine Top End ZG1000-A12 (Germany).  It shows all the parts there, valve cover, clean air system, and air box.

My OEM manual is brand-new so it has all the C10 models in it and it might be different from the 1987 issue in some ways, I'm not sure whether 'US' models had all these parts then.  Anyway I'll post in the C10 tech section if I have any more questions.
 
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