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expvet

MAP or No MAP?

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I am going to do a starter valve sync soon and have read different approaches as to whether the MAP electrical connector and it's vacuum hose should be attached or disconnected. The manual shows that they both should be, but I have read on VFRD and VFR World varying opinions on as to if they should or should not be attached. Any insights?

MAP sensor.JPG

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Shameless Bump

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5th gen. Leave it connected. That's what my manual says. Disconnect that and the bike won't run right (or at all) so, yeah, there's that.

 

My advice for 6th gen, do whatever the manual says.   It's available for dl here, just follow it. It looks like you are trying to get the airbox off but still have a MAP from the image you posted, so likely you need the MAP connected. Just not attached to the airbox.

 

Good luck. I have a 5th gen, and sync with it connected made an excellent positive contribution to smoothness.

 

 

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6gen manual states to have the MAP sensor electrically connected. As the Map sensor vacuum lines from each cylinder are connected to your vacuum gauges the MAP sensor will be only sending local barometric pressure to the ECM, perhaps this is required for accurate Starter Valve Synch, only guessing. I successfully did my 6gens as per the manual with the MAP sensor electrically connected. 

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 The first time I did it about 2 years ago using my Carbtune. I referenced this well done video from a VFRD member (link below). If you pick it up at 3:20 he states why the MAP is better off being disconnected of vacuum and electrical connections. I did the sync without the connections and afterwards there was a nice improvement. This time I will do it with vacuum and electrics connected as the manual states ( Grum notice the manual says both should be connected). If anyone has any further input feel free to chime in.

Sometimes these manuals either misprint or are proven wrong by practical experiences. I did the CCT swap a while ago, the manual states for the upper CCT that removal of throttle body was necessary but here I found that with just the airbox removed and extra long needle nose pliers the upper CCT was easily replaced. I did it without any problems and saved hours of labor.

 

 

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1 hour ago, expvet said:

Grum notice the manual says both should be connected). If anyone has any further input feel free to chime in.

It's not possible to have both vacuum and electrics connected to the map sensor while synching the starter valves! This may well be a typo or translation error.

The very next line in the procedure tells you to remove the vacuum hoses from the 5 way joiner and to connect each hose to your vacuum gauges, the map sensor will then be only sensing local barometric pressure as it can't be connected to the vacuum.

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I agree. It is really only interfacing with the electrical connector. The hose will only be connected as a token piece but not affecting anything. Possibly stated for ease of reattachment or as reminder to plug back into the 5 way. But they do make typos in those manuals from time to time, so they cannot always be taken as 100% accurate

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Just do what the manual says.


Video dude's logic is flawed. The map connected electrically won't be messing with the fuel flow or idle in any way that will give you less accurate fueling. It'll go into default mode since it doesn't see any vacuum, and nothing will change (since it doesn't see any vacuum) as you adjust the valves.

 

Remember, also, starter valves are a relative thing. You just want to get them balanced. There's no need to over-complicate any of this, or confuse people with shade about manuals being wrong. Take Honda's word over random youtube dude's word. The manual is right, follow it, and you'll get good results. It's an easy task once you've done it once and get past the "oh yeah, I understand now" moment.

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