VFR owners' thread, for VFRPS members and prospective members

**monchopper** · 15th January 2015, 20:07

Originally Posted by Icemaestro

maybe slightly on the high side? 4999? you have done a lot of work but unfortunately that doesn't always go to a direct increase in price :-). also few scrapes that would put people off. Low KMs though :-)

Cheers for the feedback,
Unfortunately a car backed into the bike in a car park and knocked it over, the crash bungs did take most of the impact, it was totally mint before that. Then the b@stard drove off.

**sil3nt** · 17th January 2015, 16:32

Spent Friday at Taupo for an open pitlane test day.

Bike was quite saggy at the rear so wound in a heap of preload and dropped 3 seconds from my lap time straight away.

Got a chance to ride an Aprilia RS250 as well. I have always wanted a 2 stroke so was very excited by this opportunity and the bike did not disappoint! Very sharp handling and amazingly powerful brakes. Lacked a bit of power up top as my bike was able catch it down the back straight but otherwise was impressed. The kid that normally rides the Aprilia had a go on mine and didn't want to get off. He loved the NC30...first time he has ridden a big four stroke.

Also got a chance to ride an R6. This was like the RS250 on steroids. Razor sharp handling, a lot of power and the loudest motorcycle I have ever heard.

So an r6 and a 250 two stroke on the shopping list!

**Vinz0r** · 17th January 2015, 19:07

I think my fuel tap diaphragm is buggered.

I've been noticing that after extended higher rpm operation, my bike will sometimes stall when returning to idle. It idles fine otherwise, and will happily idle when hot (90 degrees+) so it's not too rich. Float heights are good, A/F screws are good, all jets and passages are clean as a whistle, and carbs have been recently balanced.

I am thinking it is a fueling issue, where the carbs are emptying too much after higher RPM riding. So when I come to a halt the level in the carb bowl is too low, which causes the stall.

When I balanced the carbs recently, I tested the fuel tap to make sure it was flowing when vacuum was applied. It did, but it wouldn't hold the tap open. Sucking on the pipe and then sealing it resulted in a spurt of fuel, rather than constant flow. Even sucking on it and blocking it with my tongue right away only resulted in a single spurt of fuel.

Correct me if I am wrong, but I am under the impression that the diaphragm should stay open when vacuum is applied and the pipe is sealed.
Can someone please confirm that there should be a constant flow of fuel when vacuum is applied and hose is sealed?

It seems that there is a vacuum leak on the fuel tap end. I checked the vacuum line and there were no splits or holes in it, so I assume this means I have a faulty fuel tap diaphragm.

Are there any clever ways to fix this? Or am I going to need to buy a rebuild kit.
Any other thoughts or advice on this, please feel free to chime in.

Or if anyone has a good NC30 fuel tap they'd like to sell..

**Icemaestro** · 17th January 2015, 20:09

It sounds all right? You say ful flows when you suck on the vacuum tube , and then stops when you stop sucking...that is normal?? A failure in the fuel tap diaphragm usually results in the tap leaking when no vacuum is applied

Sent from my iPhone using Tapatalk

**Vinz0r** · 17th January 2015, 21:24

Originally Posted by Icemaestro

It sounds all right? You say ful flows when you suck on the vacuum tube , and then stops when you stop sucking...that is normal?? A failure in the fuel tap diaphragm usually results in the tap leaking when no vacuum is applied

Sent from my iPhone using Tapatalk

Yeah but when you apply vacuum to the fuel tap you should be able to seal it and the fuel will keep flowing. When I seal it the fuel stops flowing, which is why I think there's probably a vacuum leak in the diaphragm.

How I see it is:

When engine is running there is a vacuum on the fuel line which opens the fuel tap. The fuel tap will be open 100% because there will be always be a vacuum applied to it due to the diaphragm being sealed.

If my fuel tap is faulty, the diaphragm will not be completely open all the time, it will constantly be trying to close and the pulsing vacuum coming from the cylinder will keep pulling it back open (the vacuum won't be constant because of the leak in the diaphragm). This will restrict the amount of fuel allowed to flow through the carb which leads to low fuel in the float bowls after I've been using more fuel than usual (lots of high RPM).

**HenryDorsetCase** · 17th January 2015, 21:26

Do the HRC fuel tap mod ~ google. Make sure you block the carb body screw properly

**HenryDorsetCase** · 17th January 2015, 21:28

David Silver has spares too

**Icemaestro** · 17th January 2015, 21:32

I would politely disagree with the mod...I seem to be able to run the bike at 9k +rpm for 15-20mon without any issues? The prob with doing the hrc mod is that you have to remember to turn it off every time, and if one of your floats sticks, cylinder gets filled! My last bike I had to keep tools with me until I got a repair kit, as cylinder kept hydro locking

Sent from my iPhone using Tapatalk

**Vinz0r** · 17th January 2015, 21:33

Originally Posted by HenryDorsetCase

Do the HRC fuel tap mod ~ google. Make sure you block the carb body screw properly

This is probably the best way to go for determining whether the fuel tap is the problem, and I have considered doing it.
I just know that I won't remember to switch the tap to 'Off' after every ride. I dread the thought of filling the cylinders with fuel because of a fickle float valve.

In fact I think I remember Icemaestro reported doing that a hundred or so pages back when his float valve got stuck :P

**Vinz0r** · 17th January 2015, 21:49

Originally Posted by Icemaestro

I would politely disagree with the mod...I seem to be able to run the bike at 9k +rpm for 15-20mon without any issues? The prob with doing the hrc mod is that you have to remember to turn it off every time, and if one of your floats sticks, cylinder gets filled! My last bike I had to keep tools with me until I got a repair kit, as cylinder kept hydro locking

Sent from my iPhone using Tapatalk

Hah, yeah that's what I am worried about happening. Don't want to bend a valve by cranking over a hydrolocked engine. If my fuel tap was functioning I wouldn't do the mod, but it would probably fix my issue as it would stop the diaphragm from restricting fuel flow. This would also be a good way to diagnose the issue before spending money on a fuel tap rebuild kit.

Can't do it right now, just filled her up with gas yesterday

**Icemaestro** · 17th January 2015, 22:00

I think I got my last one from another uk company, was cheapest...
Usually with a split diaphragm the pressure of the fuel combined with sucking from the engine causes fuel to be pulled into the ?3rd cylinder, making it run crappy....

Sent from my iPhone using Tapatalk

**HenryDorsetCase** · 18th January 2015, 13:15

Originally Posted by Icemaestro

I would politely disagree with the mod...I seem to be able to run the bike at 9k +rpm for 15-20mon without any issues? The prob with doing the hrc mod is that you have to remember to turn it off every time, and if one of your floats sticks, cylinder gets filled! My last bike I had to keep tools with me until I got a repair kit, as cylinder kept hydro locking

Sent from my iPhone using Tapatalk

fair enough. Mines a track only thing so it never sits with fuel in it really.

**williamshatnerspants** · 21st January 2015, 07:33

Hi Guys,

I messaged Robert at Carbon Garage who have the 2 RC30s and RC45 for sale. He is keen to get a group of V4s together for a ride. I have suggested he brings all 3 to Hampton Downs, if not for the track day, then just for fun.

If you want to join us for this or another ride please go to Carbon Garage's facebook page. You can find the thread with the photo of the 2 RC30's outside the shop. I'm Matt Hancock BTW.

FYI on groups for the track day. I've been in both novice and medium groups on the NC30. If its your first time on the track going in 'novice' is obvious, but if you have some experience then I would suggest medium. Jonathon and I did low 1:30 times which is within the recommended times for the medium group. Yes you will get passed by the straight line heros but I find it better than watching out for noobs ;o)

Either way, hope to see you all there.