NTV650 poor running - advice please :-)

Sorry for raising the old thread but I have precisely symptom 3 on my Deauville and I'm at my wit's end. Misfire when pulling away, at almost exactly 2500 rpm, especially when warm, only when the lights are on, rides fine with the lights off.

I would be eternally grateful to know if Philbut ever got that issue sorted and what it was!

The old beast died a long time back, but I found a set of Irridium plugs sorted the starting and the hesitation under load. I think at high mileage the coils were maybe on their way out and a weak spark under load was the result hence the splutter. Irridium plugs did the job.As a side note, the engine also had low compression, so may be worth checking yours, as this will also show up with poor starting and misfire under load - but the fact you get a misfire when the lights are drawing power is either a sign of weak ignition OR you need to check the output from your genny and / or reg rec.

Phil

I am eternally grateful!

[embee]

For my sins I have a Deau. Well, actually I get quite defensive of the old girl, she does exactly what it says on the tin and does it well.

Check out the owners' forum if you haven't already
http://www.deauvilleuk.org/forum/index.php

They are generally very reliable, just a few quite well known issues, mainly easily sorted.
Fuel pump points often cause issues, you can get Wemoto replacement points for around £20, and there's a mod to fit a diode which cures the points burning issue, excellent article here . Alternatively you can fit a Facet pump for around £35 with the various fittings.

PAIR valve faults can sometimes cause backfires, simply disable it.

The reg-rec is nowhere near as prone to problems as on the SV650, but it isn't unheard of.

Very rarely the carb diaphragms can fail, but pretty uncommon. Similarly coils are fairly bombproof, can't recall hearing of one failing but it must happen. The 700 version had some faulty plug caps, but those on the 650 seem to go on for ever.

Your issues sound rather like it could be switchgear, again not common but I can remember a few cases. Take apart and thoroughly clean/lube usually sorts it. The main 30A fuse in the starter relay can get corroded, it's behind the right side black panel below the seat, and clean/check all other fuses while about it.

I'd also recommend Iridium plugs, just remember there are 4 of them!

Go to the forum if you're not already on it.

I love my Deauville! I'm finding the misfire very frustrating, and I've had professionals look at it a few times now but they always claim it doesn't happen for them

I have cleaned the points on the fuel pump and I can hear it ticking nicely.

What's the PAIR valve? Is that the secondary air cleaning system thingy?

The reg/rec gets very hot and I am indeed suspicous about it. However the voltage over the battery doesn't drop below 14V when the engine's running, even when the problem is happening. I'm too much of a newb to understand where to poke my multimeter next. Nothing seems to look the same as the photos in my Hayne's manual, as I assume they are of the NTV Revere etc.

The Hayne's manual doesn't list a nominal impedance for NT650V coils, and says to do a peak voltage test. That's far too scary for me.

I've polished the contacts on all the fuses. I've checked the main ground connection on the engine block and the ground connection on the reg/rec, and they are both clean and shiny.

By 'switchgear' I suppose that would mean the handlebar controls on both sides, plus the sidestand switch? Good idea.

Ordering 4 iridium plugs now!

[embee]

One other easy thing to try (=free!).

They can be very sensitive to the carb breather pipe positioning. It's one of the 3 (?) that come down just in front of the rear wheel. I can't remember which one it is, you really need to lift the fuel tank and trace it. It's a small diameter black hose coming from the carbs under the rear of the airbox, running down across the rear cyl head near the plug lead. Trace it and, as a trial, lift it out and fix the end somewhere near the fuel pump for example, cable ties or similar as a temporary measure.

If this sorts it then you have a couple of options. Either try to find somewhere for it to go which provides a downward run from the carb but ends up somewhere in "quiet" air (remember it's intended as a drain if the carbs flood), or as I did, put a T-piece in it just behind the airbox with another short piece of hose looped up and over and cable tied to the back of the airbox. This gives the carb breathers a less turbulent pressure.

Do you have the foot deflectors fitted? These are known to upset the pressure at the carb breather and cause hiccups especially after overrun.

The carbs do run pretty lean generally and it doesn't take much to upset them. You can always try richening the idle mixture say 1/4 turn. Note the 2 carb mixture screws are physically different so look like one is further out than the other.

Oooh I've not heard that tip before, thanks. If I remember correctly all of the breather pipes are incredibly mucky, maybe I should try cleaning them all and making sure they're not squished or anything.

I don't think it can be to do with turbulence though, as I can sometimes get the problem to happen with the bike stationary when the engine is warm and the headlight on. I can hold the throttle in position so the engine is at 2500rpm and watch the engine speed indicator make a sudden downward tick every few seconds.

I've just had the carbs stripped, cleaned and rebalanced and everything seems good now! Much more like the bike I remember it being back when I got it in 2000. I've no idea why the problem was happening more with the light on.

(edit)... or maybe not. Hiccupped twice on the way in to work today. Back to going over the electrical connections.

Turns out the problem has been with the fuel pump all along. It failed to start at all over the weekend and I bypassed the fuel pump. Bike now runs fine and the intermittent hiccup has gone away. So fuel pump problems can result in intermittent problems, even if the pump appears to be operational. I'm going to try replacing the points on the pump first as that is the cheapest option.

Edit: Points didn't fix it. Gonna try replacing the pump relay (found one for cheap off a broken bike).

[embee]

2 things worth noting when replacing the points.

Some people have not engaged the slot in the pump shaft properly so the pump doesn't work afterwards, check carefully, it's pretty obvious.

Second, take the time to fit a diode across the points, a very good detailed article here http://hankeln.net/freizeit/nt650v5/...-diode_en.html
It prevents the burning and the points then last almost indefinitely. Get the diode the right way round! The spec of the diode isn't important, almost anything will do, they are pennies.