Northwindmobile has died

[northwind]

I'm a bit out of practice at this, help me think would you?

(er, and hello org! Delurking again...)

Righto, what we've got is, starts strongly, rides for a little bit, misfires then dies. Tends to single-pot first. Feels like fuel starvation. Not water related... Both sparks seem good, changed plugs anyway (30000 miles old!), no apparent difference. Managed to get it to do it in the garage so I could take it apart "in the act". Fuel seems to be the thing... So changed fuel pump just because I had a spare. No difference. Leave bike for a while, restart, runs for a couple of weeks, dies again in the same way.

Drained fuel tank... Some sediment, nothing too nasty. Filter looks clean. Take off carbs, no fuel in back carb, a little in the front. So probably fuel supply rather than stuck floats or similiar I reckon since it seems to be affecting both? Though I could never work out how to check the floats if I'm honest, something about it confuses me for some reason, it's a blind spot.

The fuel hoses were all replaced a while back, not sure exactly when but no more than 4 years I think. They seem OK, no obvious deterioration, they don't seem to be squeezing shut or anything. Vacuum hoses I think must be good since it runs perfectly when it runs.

So... Fuel tap? Seems to be working OK when I test it but then the bike runs OK most of the time so I guess it would. Anything else to try before I boot the thing over and try and set it on fire (which will fail because of the lack of petrol)

[yorkie_chris]

nice to see you :)

try chuck fresh vacuum hoses on it, they can collapse inside when old. also maybe worth rebuilding or replacing fuel tap, intermittent sticking would cause this problem.


seems you have done all the hard work of diagnosing problem!

[DarrenSV650S]

change that title. jeeeez

[gruntygiggles]

change that title. jeeeez

Made my heart jump too at first glance.

[yorkie_chris]

How many miles is that now andy?

[-Ralph-]

change that title. jeeeez

I thought he was posting to tell us his mobile phone wasn't working, but he doesn't know how to use it anyway.

Had it said "Northwind has died", my reply would probably have been "No s**t sherlock!" ;)

But I'm actually quite pleased to see he's still alive and kicking. :D How is it going mate?

[northwind]

How many miles is that now andy?

Dunno really, what with the accurate speedo underreading the odo. Somewhere north of 50000 anyway but it doesn't do so many these days, mostly just commuting. The vacuum hoses might be the only original parts :grin:

I thought he was posting to tell us his mobile phone wasn't working, but he doesn't know how to use it anyway.


Yes I do, it's like a really bulky watch. It's got a calculator in it too and it plays music. And sometimes it makes a funny noise and says something about "text messages" whatever those are, but i ignore that obviously.

And I am doing grand thanks, nothing very exciting on but doing away.

[punyXpress]

Tank breather ?

[northwind]

I did consider that actually but no, opening the cap doesn't cause a "suck" so it's not that.

Ah, symptom I forgot- every time this has happened it's been right near the start of a ride. So, I don't want to make the symptoms fit a preferred cause obviously but I think it's possible all 3 times it's got as far as you can with no fresh fuel from the tank, just off what's in the carbs and hoses. Certainly 2 out of the 3 that could be the case, the 3rd I'm not so sure.

Does anyone know the correct spec for the vacuum hoses? And the fuel hoses while I'm at it, no good reason not to as they're a few years old now.

[yorkie_chris]

That says to me the fuel tap for sure... as it sounds like once it has opened once at the start of ride it is fine.

Fuel hose that fits over spigots works ok as vacuum hose. 6mm ID maybe but not sure.

[northwind]

Yup, fits the bill doesn't it. Though like I say maybe I'm making it fit the bill... Not sure.

Well, OK, seems to confirm what I was thinking so I'll grab a replacement tap. Actually I know I've got one somewhere that 21Quest sold me back at the dawn of time but damned if I know where it is. And I'll do the hoses on the offchance while I'm at it. And if it doesn't work I'll sue YC.

[yorkie_chris]

Yeah you can have all my assets seized. That would be 1 and a half paperclips, a button and a boiled sweet with fluff on it.

[Bibio]

just going to throw another log on the fire...

my brothers duke had the same symptoms. turned out to be worn emulsion tubes and needles.

the symptoms progressively got worse till the bitch started misfiring when you tried to start it. would eat plugs in 500 miles. sorted the tubes/needles and its was like night and day.

p.s. please choose your titles a bit better next time. i nearly had kittens.

[jambo]

And if it doesn't work I'll sue YC.

Yeah you can have all my assets seized. That would be 1 and a half paperclips, a button and a boiled sweet with fluff on it.

And a lathe... I'm pretty sure Andy would take the lathe...:grin:

Glad to hear you're well Andy, fuel c*ck (as there's no pysical tap) or vauum hose to same would be my first thoughts as already covered by you and Chris.

I had a very similar set of symptoms with the ZX6R when the fuel pump died except that, as you'd expect it started well and would die when running, especially under high load/consumption conditions. I bypassed it and the problem went away, so you could always run one pipe straight from the fuel c*ck to the carbs, with a full tank you shouldn't need it anyway. That would eliminate the pump as a factor.

Jambo

[dizzyblonde]

Andy, I can categorically say its nothing to do with anything said by others.

ITS decided to get its own back because you replaced it with a mountain bike.....ner ner will serve you right until it decides you are worthy:p

[hardhat_harry]

If you need carbs I have a set going cheap

[Stu]

Thanks for the title change must admit my heart skipped a beat.
Good luck Andy glad to see you back even if it is unfortunate circumstances. :)

[NedSVS]

Similar thing happened to me about 2 years back but it was the front carb not filling properly. Either the float needle or float had stuck and it wasn't filling as much as it should, but by time I'd removed the carbs and removed the float bowl it had freed itself. Changed the carbs for a lower milage set I had and it's been fine since. Initially I'd ruled this out because when I drained the float bowls petrol came out of both; only when I double checked did I notice more petrol when draining the rear compared to the front.

[northwind]

I had worn emulsion tubes on the last set of carbs so I'm ruling that out, made it run like crap but it did still run, plus it'd idle pretty much normally and run well at high revs, where the needles had less involvement. It was a total pain in the arris though.

NedSVS, I'm pretty sure it's affecting both carbs, I know the bike'll start haul itself along happily enough on one piston... Can't rule it out though.

Well, I think I've got a suspect and it's good to have a bit of reinforcement, like I say I'm out of practice. PS spannering on motorbikes is better than cars but still RUBBISH compared to pushbikes :rolleyes:

[northwind]

Well fingers crossed, that might have worked. Need to do a few more miles to know for sure but just swapped the tap (nothing obviously wrong with the old one though it had some manky black fluid in it) and it goes. Woo! Not changed the hoses yet just so's I've got something else to try in case it doesn't :smt002

[Bibio]

yey, sorted.

[northwind]

Well we'll see eh. I thought it was sorted when I changed the fuel pump :rolleyes: Still reserving the right to kill it with fire.