NTV troubles - new plugs, oil, fuel filter & coolant = f

[ttr]

Hi there

Recently decided to give the NTV a bit of attention, changed the oil & filter, fresh coolant, new plugs and chucked a new fuel filter on there (the old one looked a bit skanky).

Tried firing it up afterwards, ran fine for a few seconds, then cut out (presumably when the carb drained).

After that wouldn't start for shit, so, assuming it was that fuel wasn't getting to the carb, I swapped the filter back to the old one to check if that was the problem.

It then started, but would only just about idle, given any revs it would sputter and die.

I still think this must be fuelling, but I'm really not sure where to look next. The only other thing I changed that might affect it (that I can see anyway) is the plugs, but they're brand new and it was running (reasonably) well before on aged horrible ones.

Any thoughts? I'm stumped!

Cheers in advance!
____________________
GS125-> NT400->VFR400->CRM250->Z750 + GS125->NTV650 rat + VMX1200->GSF600 + GPz550

[stinkwheel]

Did you turn the fuel tap back on when you put the tank back on?

If it's anything like my VFR tank, there is a fuel shut-off tap up under the tank that lets you remove the tank without draining it.

I recently had my tank off to change the shock. Bike was doing exactly what you just described. Then I realised the tap wasn't flicked on properly but it took me a bit of head scratching.

Certainly sounds like fuel starvation anyway. Check the usual trapped fuel line, blocked breather, disconnected vacuum hose (no petrol in the tank? ).

Got the filter in the right way round?
____________________
“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[ttr]

Hi there

Filter's the right way round, and I've tried the tank on res & on positions just in case (it is quite full also).

I don't belive I have trapped any lines as I haven't disturbed any barring the ones between the tank, filter and pump. I checked these repeatedly when it started being difficult!

Cheers again!
____________________
GS125-> NT400->VFR400->CRM250->Z750 + GS125->NTV650 rat + VMX1200->GSF600 + GPz550

[stinkwheel]

I wonder if it's possible for a fuel pump to get airlocked? Or an airlock further up the line.

Not sure how you'd check.

It would be nice if there was some way of checking that fuel is actually flowing to the carbs so you can rule that in or out. I presume detaching the fuel line at the carb end, putting the end in a jam jar and cranking the engine over would give you some idea about the fuel flow or lack thereof. Never tried this though so if it catches fire, don't blame me.

Are both pots firing. Both exhausts headers getting hot? Stick a drop of oil on each and watch for it burning off.
____________________
“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[c_dug]

When we took the_godfathers tank off of his Thundercat we had issues getting the fuel to flow past the pump again, I think we fed some directly into the carbs first to make sure that was the issue.

Really unhelpful but I can't remember how we sorted it in the end

Will get him to take a look at this and see if he remembers.

Still you can check if it is a problem with an air lock in the pump by bypassing it completely and see if it starts like that, you may need to hold the tank up a bit for it to work, guessing the pump is there because the tap is below the level of the carbs or something hence having to raise the tank a bit.
____________________
I am a bellend, I am a man of constant sorrow, I am a gummy bear, I am a rock.

[Odie]

If you have changed all 4 plugs check to make sure you have not pulled the wires that feed the front coil.
____________________
You are so ugly when you were born the doctor said "I?m gonna drop it, if it falls is a rat, if it flies is a bat."

[el_oso]

check that you haven't been a dipstick (like i was) and crushed the fuel line under your fuel tank.
you can make an external fuel tank out of a bottle of water and a length of hose to check
keep the hose in the fuel and above the pump. the hose needs to be filled with petrol as well. gravity will feed fuel through the line when you crank the engine over
____________________
Duke 390
Previous: '05 XR125L | '96 XJ600S Diversion |'05 Suzuki GSXR1000 | '05 Honda CBR125-R | '97 YZF 600R Thundercat | '11 Honda CBR250
Car: Jeep Wrangler 4.0L

[map]

[stinkwheel]

I'd go with the "Odie got confused when stinkwheel was going on about his VFR having a similar fault." option.

Odie rides a Bros with an africa twin engine which is pretty much the same as an NTV engine, give or take a shaft drive. (Assuming it's the same Odie I've met before).
____________________
“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[Kickstart]

[ttr]

confirmed: NTV & Bros engines both have 4 plugs.

I'm away from my bike at the moment so can't check the stuff suggested but will report back ASAP. Pretty sure I've not fouled any lines though - as said, only disturbed two and I'm certain I haven't trapped them.
____________________
GS125-> NT400->VFR400->CRM250->Z750 + GS125->NTV650 rat + VMX1200->GSF600 + GPz550

[c_dug]

Also, my NTV has had the fuel pump bypassed and runs fine.
____________________
I am a bellend, I am a man of constant sorrow, I am a gummy bear, I am a rock.

[ttr]

[Odie]

[c_dug]

Pulled all right to over 100mph, seemed fine to me
____________________
I am a bellend, I am a man of constant sorrow, I am a gummy bear, I am a rock.

[Odie]

[map]

[Vincent]

[Odie]

[Kickstart]

[Vincent]

[Vincent]

On the subject of two plugs per cylinder, some 70s Japanese trial bikes had two plugs, but only one had a plug cap! The idea being that as soon as one packed up, (quite common then), you just swapped over the lead. I don't think it worked very well as the "spare" one was probably knackered by he time you came to use it like the first one. Although I don't suppose he electrode would wear as quick.

[yen_powell]

On my Africa Twin you can bypass the pump at the side of the road with just fingers. Whilst it's fine with a fullish tank up to about 50mph, attempting to overtake at 70/80 on a motorway results in the engine cutting out, the bike rolling to a stop on the hard shoulder, a 10 second wait whilst the float bowl fills up again.

Facet contactless pump is a more reliable, much cheaper alternative to the Honda/Mistubishi original. My Facet fuel pump has done nearly 50,000 miles with no problems.
____________________
Blackmail is a nasty word........but not as nasty as phlegm!
XT1200Z and a DR350 in bits

[Vincent]

Hmmm, interesting. I wonder if Honda use smaller float bowls with pump fed bikes I guess there's 375cc per cylinder too so bigger "gulps" of fuel than my 400-4.

[ttr]

managed to make it home this evening so will be taking a look to see if I can get her running.

If it seems to be a pump issue - are they at all user serviceable or is it new pump job?

Also if I bypass it, anyone know how many miles I can expect to get from a tank (given I wont have reserve if levels are the issue!!)
____________________
GS125-> NT400->VFR400->CRM250->Z750 + GS125->NTV650 rat + VMX1200->GSF600 + GPz550