Fuelling Issue?? Idle + VTECH - A bunch of weird things

Hey that makes complete sense!!

Here is something I was thinking about also.

I had taken out the SV's for a service including the reference SV.

I screwed it in all the way (the silver nut at the end on the reference SV) and assumed it is built like that. I then eyeballed them and use a thin piece of copper wire as a reference to adjust the other SV's accordingly after assembling the linkage and wax unit.

I think the datum or the reference SV is critical; if it is not open enough with the wax unit, would it exhibit this behaviour also? Sure as it warms up it will close the SV's but the fuel being dosed would be determined by the coolant temp and the IAT sensors and lean the mixture out so the RPM's may rise?

I will take the air box off this weekend and have a look over....

How much does the wax unit pull out the SV's anyway at cold? Any idea?

 

The wax unit pull while cold will vary with the ambient temperature. When I adjusted mine a few weeks back (summer), so I waited until I got a cool rainy morning to do it, probably about 68-70F. IIRC, to get it to the 1800 rpm cold idle, the orifices were pulled somewhere around 1/3 of the way open.

As for the reference starter valve, I didn't touch it. I didn't take a pic showing it, so without opening my bike back up, I can't say how the reference valve is set up.

Just check and see that the wax unit has tension on the starter valves and is holding them partially open while it is cold. You don't even have to start it. If it is loose, you will need to adjust the wax unit. However, you need a baseline first. Sync the valves and get your hot idle dialed in. Come back on a cool morning, crank the bike and tighten the wax unit until you get the high idle you want. Once that is done, the computer and sensors should play well with the mechanical changes the wax unit makes and let it idle down as it gets warm.

 

Hey guys,

Update on this:

I synced the SV's and got them all reading the same then i adjusted the hot wax unit by 1.5 turns and it has been great. Starts off around 1900 RPM on a 8-10C day and iv kept the idle at around 1,400 - 1,500 just feels better and sounds a bit louder haha..

A new problem has now surfaced and I think i am half way at solving it....once warmed up, it seems like it hits a RPM limiter at around 10,000. You can feel it slow down the revs at 9,500 then doesnt go past 10,000 at WOT. The second you let you it will rev past 10,000 and then come down...I am confident it is a fuel starvation issue...how you ask? Well it does it both in neutral and when in gear...with the tank halfway up it revs out perfectly fine and pretty quickly too...

I suspect the main fuel line or the return line are getting compressed...a quick look and a feel around with the tank down they seem pretty loose. I will have another look tomorrow...I also disconnected the fuel over flow and breather hose and it almost started cutting out at 6,000...with the tank down...i thought maybe the fuel pump wire but that seems loose also...i moved the wires coming from under the seat area to the rear valve cover for the injectors but nothing suspicious thus far...

Any tips/advice/comments..

Will report back with updates when I have another look.

 

Great that you got the cold/hot idle sorted! If it is a fuel starvation issue, it shouldn't take too long to sort out because there's not too much to it. Make sure the hoses aren't getting crimped, make sure pump and wiring is good, make sure there is enough fuel in the tank to submerge the pump and strainer while testing with tank down, make sure the strainer isn't partially clogged.

I've not seen this happen on any of my bikes, but I've seen some rubber fuel hoses on other vehicles, mowers, etc. that started disintegrating internally while looking brand new on the outside. It could be swelled or starting to break down.

 

Hey tbzep,

appreciate your insights...

The fuel delivery hose indeed had a kink in it and looked like the internal braid has broken as it is permenantly softer and seems to be 'thinning' at the area where it bends after the crimp. I managed to press it and bring it back in shape but it is anyones guess how long it will last....time to order a new one...

I have used Yoshi parts with success I was hoping to find a hose in Australia but they seem to be hard to get down here in Oz unless someone knows a good honda stockist?

The bike running well now and red lines as it should....

 

Awesome! That will get you by until you find a replacement. Just don't let it go for too long because it has probably already started sending decayed debris downrange.

 

thanks Tbzep, you think one from a used vfr with 16,000 km is worth it? 80 Aussie dollars as opposed to 200 usd on various websites..off a 2011...

 

I don't know. Fuel will sit in the lines whether the bike is being run or not, so I would think a 16k bike's fuel hose would have similar breakdown to a 50k bike of the same age. I would try to get a new one made before spending a fortune one a used one. Here in the US a hydraulic shop that makes up new hydraulic lines for heavy equipment can also make up fuel lines with banjo fittings.