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Pair valve block off

Old 07-14-2011, 03:13 PM
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Default Pair valve block off

There were some questions about how to block of the pair valves when I was researching the subject. I figured I would take some pictures and write a small how to on the mod.

1.) Unbolt the ram air duct covers and remove them.

2.) Unbolt the two 5mm allen head bolts attaching the seat to the frame and remove it.

3.) Unbolt the two bolts holding the tank to the frame and prop it open.

4.) Unbolt the air box lid and remove it.

5.) Unbolt the velocity stacks and the bolts holding the bottom of the air box. Disconnect any vent tubes and electrical connections and remove the air box. This is a good time to remove the air flapper if you wish.

6.) At this point, you will have access to the top of the engine and should be able to see the pair valve assembly. Unfortunately I didn't think to start taking pictures or write up a how to until I already had the bike torn down. I was able however to find a picture of the top of the engine which shows the pair valve assembly still attached to the valve cover.

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The pair valves are located on top of the valve cover and are joined together by a pair of hoses. Here is a picture of the pair valve unit sitting on top of the engine just to give you a better reference.

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Here is the pair valve assembly out of the bike.

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7.) There are two bolts on each pair valve that connects the assembly to the valve cover. Unbolt them, I believe they are a 8mm or 10mm, disconnect the electrical connection, and remove the assembly. The bolts have been locked in place by a thread locker. This is what you should have at this point.

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Note: In these pics I have the spark plug boots disconnected and removed.

Here's a closer pic of the pair valve flapper unit that will remain in the valve cover.

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Originally I purchased a set of pair valve block off plates from a company off of eBay called 6 Sigma Racing. They seemed to have good reviews and appeared to be of good quality but this was not the case. I later purchased Driven block off plates which are of the greatest quality. The pair valve flapper that remains connected to the valve cover is bolted in by two small phillips head screws and almost impossible to remove while the engine is in the bike. The 6 Sigma Racing brand plates are thin cheap cut pieces of metal and have been spray painted black. The edges were sharp and the plates in general were horrible. They also did not have the small recesses on the bottom of the plate as do the Driven brand ones. This is extremely important as the 6 Sigma Racing brand plates will not sit flush once bolted on the valve cover. Here are the two plates side by side for comparison.

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The Driven brand plates come with the plates, instructions, and a rubber cover to close off the air box. The 6 Sigma Racing brand plates come with only the plates and some lock washers.

8.) Clean off the bolts you removed from the pair valve assembly and reapply some blue thread locker. Place the block off plates onto the valve cover and bolt them on.

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9.) Attach the rubber cover of the air tube vent hole on the bottom of the air box. I found using a small bit of WD40 helped a lot.

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10.) Reassembly is reverse of tear down.

Last edited by ajzcamaro; 07-15-2011 at 01:39 PM.
Old 08-12-2012, 11:16 AM
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Forgive my ignorance - why would you do this mod ? Like whats it purpose ?
Old 09-19-2012, 01:03 PM
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Originally Posted by Hideo1984 View Post
Forgive my ignorance - why would you do this mod ? Like whats it purpose ?
Sorry, I've been off the forums for a while. The main reason for the mod is so that you can correctly tune your A/F ratio. The pair valves allow extra fresh air into the mix which skews the A/F mixture. It also saves a tiny amount of weight and changing the plugs are much easier now.
Old 09-19-2012, 03:40 PM
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it gets rid of useless **** on your motorcycle. its a very good little cheap mod to do.

Last edited by gotcbr; 09-19-2012 at 03:54 PM.
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