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Left of Centre
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Did this today, for the first time ever. We're in lockdown, so couldn't go far from home, but fortunately a mechanic who works from a garage in his backyard lives not far away, and was happy to lend me some old skool sync gauges. As others have said, the process yielded a smoother idle and got rid of a bit of hesitation from a standing start, which I'm happy about. Was very surprised to find the #4 cylinder vacuum line plugged, with nothing sitting on the spigot. Don't know the implications of that valve being able to pull air in, but am happy to have the vacuum line back in the right place.
 

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919 Rider
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Cool. I did this just a couple of days ago. Same reason, lock down.
Mine were out. Once adjusted idle and take off was noticeably smoother.
Your bike, no. 4 plugged off like that. Why would someone do that? An idiot?
Implications. That cylinder at idle was getting a bit of air via its starter valve AND a little extra via that vacuum spigot.
Don't know what that means. A little leaner mix. Idle for that cylinder off.
A very small amount of unfiltered air.
Good call on doing this procedure and finding that issue.
 

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Left of Centre
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no. 4 plugged off like that. Why would someone do that? An idiot?
Yeah, dunno. The hose length was kind of only-just, so I wonder if it had had a split end at some point, and said genius decided to remove it, shorten it and plug it, rather than deal with it properly. It did ease on to the spigot, but felt a tad short.

In any event, happy to have it fixed.

Do you have a Carbtune set-up? That's what I was expecting to pick up - felt a bit odd, trudging home with the sync valves and stand - it's about 1.6m tall!

Never mind, did the trick.
 

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IF your doing this on a california bike. you will have an extra vacuum line coming off EACH THROTTLE BODY for the evap system.. personally i recommend to get rid of everything involving the evap system... its easy, just unbolt everything, and put 4 small vacuum caps on the throttle bodies.

That said, the 4 vacuum connections you need to use for the sync of the tboddies are the ones that connect together to the MAP sensor in the attached pic.
So I just did this to my 919, and I was wondering why I had extra vacuum ports that the service manual didn't mention. I have suspected that I had an ex-Cali bike that someone had deleted the emissions equipment from, this may finally confirm it.

Would the vacuum signal be the same at each of the ports on any given cylinder? Like does it matter which you connected the vacuum gauges to, or which ports the fuel pressure regulator and/or the MAP sensor are connected to?
 

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McTavish
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So I just did this to my 919, and I was wondering why I had extra vacuum ports that the service manual didn't mention. I have suspected that I had an ex-Cali bike that someone had deleted the emissions equipment from, this may finally confirm it.

Would the vacuum signal be the same at each of the ports on any given cylinder? Like does it matter which you connected the vacuum gauges to, or which ports the fuel pressure regulator and/or the MAP sensor are connected to?
Suggest you see the last post of this thread, and go from there as need be:
https://www.wristtwisters.com/forums/f322/dropbox-update-66545.html

If you are jammed up and don't have access to the Dropbox, just PM me an e mail address I can send the file info to.


There's also some relevant content in this thread, it actually being the one that triggered the above Dropbox update.
https://www.wristtwisters.com/forums/f322/919-dies-under-load-81511-2.html
 

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Thanks, that was informative. It turns out that the factory manual does mention the extra vacuum ports after all, lol. However the colour coding VASTLY improves that diagram, I think I will steal some pencil crayons from my nieces. I also think I will double check the routing of the FPR tubing! The fuel tank venting has actually already come up, I think I came to the conclusion that the venting does work properly.

It was a bit tricky for me to find the link to that Dropbox though, is it prominently featured somewhere?
 

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McTavish
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It was a bit tricky for me to find the link to that Dropbox though, is it prominently featured somewhere?
It's not "featured", so to speak.
I think it's more that those in the know have a quick link set up directly on their computer.

By the way, g00gl3it is the one and only keeper of the Dropbox gate.
One has to be granted access.
I just help maintain the box for him.
Obviously, you have access, so the above is for those that don't and are wondering.
 

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It's not "featured", so to speak.
I think it's more that those in the know have a quick link set up directly on their computer.

By the way, g00gl3it is the one and only keeper of the Dropbox gate.
One has to be granted access.
I just help maintain the box for him.
Obviously, you have access, so the above is for those that don't and are wondering.
So I think the information stored there is actually backwards - the larger vacuum ports should be for the FPR/flapper, and the smaller ports should be for the MAP. I think that because both of the ports on the outside cylinders are of the smaller type - I will take a picture to back this up.
 

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McTavish
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So I think the information stored there is actually backwards - the larger vacuum ports should be for the FPR/flapper, and the smaller ports should be for the MAP. I think that because both of the ports on the outside cylinders are of the smaller type - I will take a picture to back this up.
Please do!
I'll revisit accordingly when I get home and have everything related handy.
As an aside, Islandboy has yet to lead me astray.
 

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Okay, so here are pictures of the ports on both outside cylinders. Interesting to note that the EVAP ports are in different places, but the MAP ports are in the same position. Also that they're the same inner diameter - I guess it's so that when it purges the canister it doesn't completely throw off the MAP & FPR. I was unable to remove the hoses from the inside cylinders - they're REALLY on there and I don't want to tear them, but they were already connected in the way that I am proposing is correct.




A link to Islandboy's own picture of one of the inside cylinders showing the differently-sized ports: https://www.wristtwisters.com/forums/f2/919-revival-80743-2.html#post1366303

Side note: Good grief does the Honda manual do a bad job of explaining how the vacuum hoses are connected. It took me a while to understand how the flapper thing was supposed to work because some of it was missing, eliminated by a previous owner along with the EVAP and PAIR. There is an enraging note in the margin admonishing you to "route the vacuum hoses correctly"

Edit: Expected the forum to resize the embedded images, apologies for the hugeness
 

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McTavish
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Okay, so here are pictures of the ports on both outside cylinders. Interesting to note that the EVAP ports are in different places, but the MAP ports are in the same position. Also that they're the same inner diameter - I guess it's so that when it purges the canister it doesn't completely throw off the MAP & FPR. I was unable to remove the hoses from the inside cylinders - they're REALLY on there and I don't want to tear them, but they were already connected in the way that I am proposing is correct.




A link to Islandboy's own picture of one of the inside cylinders showing the differently-sized ports: https://www.wristtwisters.com/forums/f2/919-revival-80743-2.html#post1366303

Side note: Good grief does the Honda manual do a bad job of explaining how the vacuum hoses are connected. It took me a while to understand how the flapper thing was supposed to work because some of it was missing, eliminated by a previous owner along with the EVAP and PAIR. There is an enraging note in the margin admonishing you to "route the vacuum hoses correctly"

Edit: Expected the forum to resize the embedded images, apologies for the hugeness

Re: A link to Islandboy's own picture of one of the inside cylinders showing the differently-sized ports: https://www.wristtwisters.com/forums/f2/919-revival-80743-2.html#post1366303

Not only that, one of his is in a different location.
I am now officially mystified.
 

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919 Rider
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I have it wrong. The vacuum hoses on my bike for the two inner throttle bodies, 2 and 3, were switched about. All the MAP vacuum hoses go on the four smaller diameter ports. The two FPR vacuum hoses go on the larger diameter ports.
My bike has been like this since I brought it. In the last week I’ve switched vacuum hoses back the the correct ports. Carried out the starter valve synchronisation. All were still synchronised. And have ridden the bike several times. Bike went fine.
After carefully paying attention going back over this thread the original author in their first post gave the correct information.
“-remove the vacuum lines closest to center line of bike on 2 and 3 (the outer vacuum lines on 2 and 3 are tied to the fuel pressure regulator and should not be removed)”
My bad.
 

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McTavish
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I have it wrong. The vacuum hoses on my bike for the two inner throttle bodies, 2 and 3, were switched about. All the MAP vacuum hoses go on the four smaller diameter ports. The two FPR vacuum hoses go on the larger diameter ports.
My bike has been like this since I brought it. In the last week I’ve switched vacuum hoses back the the correct ports. Carried out the starter valve synchronisation. All were still synchronised. And have ridden the bike several times. Bike went fine.
After carefully paying attention going back over this thread the original author in their first post gave the correct information.
“-remove the vacuum lines closest to center line of bike on 2 and 3 (the outer vacuum lines on 2 and 3 are tied to the fuel pressure regulator and should not be removed)”
My bad.
I will correct the info in the Dropbox accordingly.
And it makes sense.
The smaller ports will dampen, and thus smooth, the vacuum signal to the MAP.
Thanks for the work at your end.
 

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McTavish
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I have it wrong. The vacuum hoses on my bike for the two inner throttle bodies, 2 and 3, were switched about. All the MAP vacuum hoses go on the four smaller diameter ports. The two FPR vacuum hoses go on the larger diameter ports.
My bike has been like this since I brought it. In the last week I’ve switched vacuum hoses back the the correct ports. Carried out the starter valve synchronisation. All were still synchronised. And have ridden the bike several times. Bike went fine.
After carefully paying attention going back over this thread the original author in their first post gave the correct information.
“-remove the vacuum lines closest to center line of bike on 2 and 3 (the outer vacuum lines on 2 and 3 are tied to the fuel pressure regulator and should not be removed)”
My bad.
Inboard taps on the #'s 2 & 3 TBs are for the FPR.
Outboard taps on the #'s 2 & 3 TBs are for MAP.
Don't be fooled by the MAP tap on #1, which is in the Inboard position, meaning that only #1 has its MAP tap inboard.
 

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McTavish
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Inboard taps on the #'s 2 & 3 TBs are for the FPR.
Outboard taps on the #'s 2 & 3 TBs are for MAP.
Don't be fooled by the MAP tap on #1, which is in the Inboard position, meaning that only #1 has its MAP tap inboard.
For what it's worth, I checked my 919, which is an 05 that has never had a vacuum hose touched.
At the #2 & 3 TB's, I found the FPR lines to be outboard, and the MAPs inboard.
 
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