NTV650 poor running - advice please :-)

A while back a I bought an old Deauville as a bit of a project and to use over winter. Well, the carbs have been cleaned, the tappets done, carbs balanced, oil and coolant renewed, fork seals replaced, brakes rebuilt etc etc.

Now I put her through the MOT yesterday and I'm pleased to say she went through with no advisories - not bad for a 96k miles machine!

HOWEVER, all is not good, as she is not running well, and I don't trust it to get me about without the need for an AA truck!

The symptoms:
1) She is pretty hard to start - not impossible, just a bit of a pig. The battery is a brand new Yasuza one with full charge. She usually fires second or third attempt, with the starter motor sounding a touch strained, but I'm used to Kawazaki sports bikes so that could just be the way they are.

2) At idle, she occasionally makes a "Phuttt" noise and appears to loose power for a stroke? She will then continue to run just as before. Other than that she sounds fine to me. Note, I don't mean a backfire, it is a quite noise, a bit like gas escaping.

3) Particularly when warm she starts to misfire under load. Pulling away from a junction for instance feels very jurky as power is lost then regained. This doesn't occur so much at higher revs.

Plugs are old, as is the air filter, but although I intend to replace these I really can't see how these alone could cause an intermittent misfire. The fuel tank is full with fresh fuel.

Any ideas as to where I should start? My initial thought was the ignition system.

Cheers Org!!
Phil

The ntv is quite sensitive to dirty setup, carbs especially. It's also very very common for the fuel pump to fail and cause what you're describing. The deauvilleuk.org forum is really good with lots of knowledge about this. Get your cap and cocoa ready though.

[Spanner Man]

Good morning.


Replace the spark plugs, as a matter of course, & check all the connections to the coils, & make sure the plug caps are securely attached to the leads.

Alternatively, it could be an air leak. So, check all the carburettor clamps, & make sure the airbox rubbers are properly connected to the carbs. These are pretty prone to distorting, & consequently they don't fit correctly.


Cheers.

Thanks for the replies chaps. Those were all the top things on my list, so reassuring to know I'm looking in the correct areas. I'm actually on the Deauvilleuk.org already and have read up on the dreaded fuel pump issue. If the above doesn't sort it I will bypass the pump with a full tank and see how things go. I'm tempted to say it isn't the pump as she ran on an almost empty tank, but it's worth a go.

Phil

[jambo]

The fuel pump's a fairly easy test, disconnect the fuel line that leads from the pump to the carbs and turn the engine over. Please don't peer into the pipe to see if you can see any fuel coming out, that would be silly...

You should get a good few inches of fuel being squirted up if the pump's doing it's job.

That said, I don't think you're symptoms sound quite like a duff fuel pump, and listening to spannerman's advice is usually an excellent place to start

Jambo

I'm not a guru or anything but I would suggest the pluga and air filter.
Does it still have old fuel in? Leaky petrol cap letting in water?

Originally Posted by vardypeeps

I'm not a guru or anything but I would suggest the pluga and air filter.
Does it still have old fuel in? Leaky petrol cap letting in water?

Plugs are on the to-do list for this evening. It has fresh fuel and I have no reason to think the fuel cap is leaky (its a Honda after all )

It has been suggested on the deauville sight that the vacuum feed from cylinder 2 can become disconnected thus letting in excess air between the carb and cylinder causing a misfire. I'm going to plug it tonight to see if it makes any difference.

Thanks again for all the suggestions folks, keep em coming

Phil

[punyXpress]

You ask for advice, so here goes:
Change the NT in your thread title with an S
Simples.

[Spanner Man]

Originally Posted by vardypeeps

I'm not a guru or anything but I would suggest the pluga and air filter.
Does it still have old fuel in? Leaky petrol cap letting in water?

Good morning all.


Good point made there! Ever since the fitment of flush fitting fuel caps became more or less standard on all models, water inside the tank has increasingly become a problem.
It would be worth draining your carbs which is pretty easy providing the drain screws aren't seized.
It also causes your tank to rust, with particles getting into the carbs etc. A quick squint into the filler cap with a torch wouldn't hurt either.


Cheers.


P.S. Thanks for the plug Jambo.

Right, bit of an update:

WRT the fuel contamination and carb issue, I've only just put it back together and filled with fresh fuel, so I can pretty much rule out water in fuel as tank / carbs etc have been cleaned. Inside of tank looks free of rust.

I rode her to work this morning and whilst there is still audiable an air leak somewhere (the "Phuttt" noise still there on tickover), I didn't get the stuttering at junctions - the difference? Well, I turned my lights off - SO, it appears that there may be more than one issue here. I am now waiting for new plugs to arrive as Halfords didn't have any in stock. I'll give the HT leads, connector blocks etc a good check over with a multimeter when I get a chance, and check the charging system again. Might run a compression test too whilst I'm there for piece of mind.