NC30 Fuel Tap Vacuum Hose

[NC30Mike]

Hi all,

Due to the great weather, Friday saw my first ride of the year on my VFR400 NC30. While I would never usually consider selling it, a breakdown half way between home and work in the middle of nowhere left me seriously considering something newer/ more reliable/ more comfortable!

Luckily the root of the problem was no more than the vacuum hose of the fuel tap 'popping' off at the engine end meaning that the rubber diaphram within the tap closed under the pressure of the spring and left my engine without fuel. Upon inspection the original hose was very brittle and weather/UV worn and needed replacement.

My question is, where 'at the engine end' does the vacuum hose attach? I have seen multiple posts mentioning a brass spigot on cylinder 3? Which way does this spigot face, what fairing panels need to be removed, etc..? If anyone has pictures to show the location it would be greatly appreciated!

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Before anyone mentions it, I have considered modifying the tap so that the vacuum hose is no longer needed but for me (don't do track days) the negatives seem to outweigh the positives. Again, just my personal preference/ choice, I do not suggest that it is the right option for everyone!

Thanks!

Mike

[lutorm]

There are threaded holes on all intakes, below the rubbers connecting them to the carbs, but I think normally all except the #3 one are plugged with screws, while the #3 one has a brass fitting on it. The holes on #1 and #3 face forward into the space under the carbs. If you shine a flashlight in from the left side and look under the #3 rubber you should see it.

[NC30Mike]

lutorm,

Thanks for the response. I had the tank and fairing off last night and managed to locate the spigot and successfully tested my reassembled fuel tap with it- engine ran fine with vacuum line connected and cut out after a few minutes of running without it.

Access to the spigot is a bugger, the gaps are too small to get your hand in- some long pliers are a must if you want to avoid taking the bike apart further. I'll try and get some decent pictures tonight to help anyone else in future with the same problem.

Mike

[NC30Mike]

Hi all,

As promised, I took some photos last night showing the location of the spigot:

https://imgur.com/gallery/rg2Kn

Hope this helps somebody

Mike

[Neosophist]

Yes the vaccum port on the nc30 is a pain in the ass to get to unless you disassemble everything, and / or have the hands of a small child.

The NC24 has a seperate take-off for the fuel vaccum tap in a much easier to access (although still fiddly) location on the outerside of the left hand rear cylinder (it's against the frame).

You will most likely find that the deteriation in the vaccum hose is caused by heat and fuel / oil vapour attacking the hose over time, sunlight doesn't get much chance to attack the hose due to it's location.

Make sure the new hose is the right stuff too, silicon hoses go soft with the heat and suck themselves closed causing an intermittent issue with heat.

If you change it every 5 years you shoudl never really have a problem, i stick a label covered in seloptae on replacement hoses dating when they were installed, also one of the first things I do on any bike thats not been run / serviced in a while as it's cheap an on bikes where it's a pain to access saves ripping one down at the side of the road in the middle of nowhere (Yep been caught out by that before)

It's one of the things you have to consider when riding an old bike. unless everything is new / replaced then you are riding around a highly strungout 30 year old bike.. they are usually very reliable due to the build quality but as they age theres always a chance some bearing might go, seal might bust, weird electrical gremlin will surface due to years of corrosion on the wires etc.

Sadly since the end of the bubble period in Japan and the global downturn in the bike market there are very few equivalent bikes these days, still plenty of fun bikes but nothign that's a direct replacement.

I got rid of my 30 as I mainly do motorway journeys these days and while it was certainly possible.. a modern day litre bike has more room is lighter and cruises at 70 aroudn 2000rpm...

if i was wanting something just to wing around country lanes and use all the power then an old 400 is still a pretty good choice, providing the ever increaseing prices people want for them don't rule them out... part of the appeal back in the day was the price.