Brainstorm my breakdown

[Owenski]

The main thing I've learnt in biking is that it's not who you know it's how many you know. If I know enough people who ride I'm bound to know someone who has had the same reasons for breaking down as me. So please if you've had a similar problem then let me know as it may give me the brain wave I need to explain mine.

After the fueling issues I've had previously I seemed to resolve these by just taking it all apart and putting it back together. However this morning I rode 60miles as opposed to my normal 16mile commute. After a 20min stop the bike wouldn't start, starter screwing and engine blurp'in I left it another 20min and tried again... Started first time.
Rode another 10and needed fuel so pulled in, filled up and tried to depart only it wouldn't start again. So I text you this stood in a petrol station forecourt looking at the Humber bridge fully expecting it to start if I give it another 20min but what I wanna know is why the fuxk am I not getting it to start right away.
FYI when I've ridden my normal 16mile commute and called for petrol in that last mile it starts first time without fail so I'm doubting it's directly related to running heat.

[Owenski]

Had to wait a further 20min or so (had a nice chat with a lorry driver in that time) then it rode perfectly for 40miles until I hit Leeds where it died at the first opportunity to get low revs.

I'm still none the wiser as to why this fate has befallen my bike but it adds to my list of "to-do's" before I can be happy the bike is sound.

[Bibio]

hhmmm hard one to diagnose over the net but i'll have a bash.

does it foul plugs?

how does it start when its cold?

how does it tick over cold/hot?

[Owenski]

Starts fine cold, needs choke in a morning but only so much as that it turns the motor, ones it's popping you can knok choke straight off. Idles fine.

Normal riding involves varied speed for 16miles and since taking the carb off 2 weeks bak everything seemed perfect all the way start middle and end of ride. Idle and restart were instant and as per expected.

Today's the exception and the only thing changed were the miles and type of riding, IE I did 60+ miles and 50 of those were at constant speed and throttle. It's worth noting that when I came off the motorway(then A63) in Hull I had to travel through town in stop start traffic i knew reserve tank would be need switching on shortly and in traffic thats a ball ache so switched to it at this point. the bike didn't miss a beat for any part of this journey. I parked up and turned the key off as normal. Only when I returned to the bike after 20min on site did the fun begin.

Wouldn't catch, just churned the starter, added throttle and the rev counter read more pulses at the coil but still i had no combustion. I Left it for 10min and spoke to YC to see if I may be over looking the obvious and waited to try again.
Looked around my location on my phone and saw a garage 150m away, pushed it to there and explained i hoped it may run if I left it long enough but should I have any issue could I borrow some of their tools. Guy seemed happy enough so I hung about for 15min and tried again at this point it started first time. Idled fine then too!

Got on and set off, rode 10miles into a petrol station to fill up. Did this, got on and it fired once I thought I'd be ok but touched the throttle and it died. Then wouldn't restart, or a brew pushed it out into the rain in a hope that may cool any heat issues sooner. Drank my brew and tried again, no joy exact same result as in Hull. So went and got a choc bar, and had a chat with a biking lorry driver. Spoke for a good 20min before he had to head off and I gave it another go, coughed a bit and did a nice pop but started and idled once again idled fine. So now I thought "as long as I don't turn it off I'll be fine"

How wrong I was, pulled off the slip road some 45miles later and it died at the top. Figured I had a long wait ahead of me so started playing phone games and texting. About 5min after stopping I Decided to do one for good luck and it fired, awesome, got my gear back on and rode it to work. Sat outside work and it happily idled (WTF!!! )

Left work to come home, started First time. Did exactly the same as above though, approached a junction and lost all power I then failed to bump start it but oddly it started then off the button (again WTF!? ) anyway I got it home and I'm now none the wiser.

[Specialone]

Coil and or lead is my guess but...

Is it trying to fire or just turning over?

Is it turning over strong?

Is fuel getting through?

[Icanopit]

Contamination in fuel tank, obstructing outlet only allowing "drip feed", is the outlet in an indentation where flakey type debris can gather but is too large to pass through the tank outlet and show up in the filtration system??? common known problem on some earlier Ducatis.

[Owenski]

Coil and or lead is my guess but...

Is it trying to fire or just turning over?

Is it turning over strong?

Is fuel getting through?

Direct responses to each one squire:

Coil is the cap on coil kit it 'could' fail but it's stupidly more reliable than a HT kit, hence it's creation.

Trying to fire, reason I phoned YC Was it sounded flooded but I couldn't understand how it would be.

Yup starter was turning as per normal it's only 2 weeks since I'd fully charged it during my last little saga.

Yeah fuel is good, ie after cranking it for a while there is a distinct smell of it.

[Owenski]

Contamination in fuel tank, obstructing outlet only allowing "drip feed", is the outlet in an indentation where flakey type debris can gather but is too large to pass through the tank outlet and show up in the filtration system??? common known problem on some earlier Ducatis.

tank outlet isn't at the lowest point but during riding all fuel moves anyway so it's all fresh and in daily use so fuel in there today wasn't even a week old. Actually filled on way to work on Wednesday thinking about it!
Flow rate out of the tap is good, it's only 5/6mm dia outlet and if you pop the hose off it's a steady stream of similar bore.

[Bibio]

as said coil breaking down or water in fuel.

other than that then worn emulsion tube and needle or float/valve sticking shut when hot. worn emulsion tubes are quite hard to see as its slight but tell tale sign is sometimes a ring on needle, the needle rattles in the tube causing the tube to elongate which results in running rich.

float valve if there is any contaminates on the tip of the valve or orifice then this can cause the valve to become sticky or clogged so it can stick open or closed, open is an easy one to spot as the float bowl usually overflows closed is more difficult and usually results in loss of fuel delivery to combustion. you could also have a bent valve pin which is moving about and only causing the problems occasionally. next time it happens tap the float bowl with a screwdriver handle wait a minuet then see what happens. if the bike fires up then bingo.

worn emulsion tube/needle will eventually result in fouled spark plug.

coil breakdown will eventually get worse.

only other suggestion is the engine breather being clogged which will result in to much pressure which if left will eventually dissipate letting bike start again.

it's a long time since i messed with carbs so brain not completely firing like your bike :-)

[flymo]

when the problem occurs, try it with about a quarter throttle and hit the starter.

[Owenski]

when the problem occurs, try it with about a quarter throttle and hit the starter.

What would this identify?

Lance, I tried the carb tap (read clout) and it had no effect, I'm gonna leave everything exactly as it is tonight (although I've charged the battery as its taken some hammer today) see if the problem persists after its had a day to cure. If I get a good commute home and back then I can relax for a few weeks and just abstain from long journeys. In the mean time I should have sorted a new carb and a new engine so may be able to rule out a few options there!

If I get to work and can't restart it then I'm going to check and change everything (again) tomorrow night that includes putting in entirely new fuel and breather hosing.

[flymo]

What would this identify?



Can indicate a dirty or poorly jetted pilot circuit in the carb, especially when hot.

One other thing I could think off, although far less likely, is a fuel flow problem caused by partially blocked fuel filter. Dont forget that there is often a secondary filter/s built into the carb assembly itself.

[millemille]

Blocked/obstructed tank breather.

When it fails to start next time, open the filler cap and try again.

[Owenski]

Can indicate a dirty or poorly jetted pilot circuit in the carb, especially when hot.

One other thing I could think off, although far less likely, is a fuel flow problem caused by partially blocked fuel filter. Dont forget that there is often a secondary filter/s built into the carb assembly itself.

Ok cool I'll give that a go. I do think my jetting is out, I'm waiting on a some new 135PAJ which are recommended for my set up.

Yeah I did the carb service not too long ago and ultrasonic cleaned then rinsed (and dried with compressed air) the carb so its a clean as it'll ever be I'm confident of that.

Blocked/obstructed tank breather.

When it fails to start next time, open the filler cap and try again.
Nice one thats just annoying enough to be possible lol.



*UPDATE:
Rode to work this morning, almost completely without incident. There were some definite pops/misfires only trouble is they were so inconsistent I couldn't tell you if they were excess fuel pops or actual misfires. I'm going to change the plug and await the correct carb jet sizes.
Also when I arrived at work the bike idled without issue, better still when I shut the ignition off, I popped it back on and it started again first push.
Im starting to think its a combination of everything in its own minor way coming together to make one huge headache.

[Owenski]

Ride home was a little more eventful, had opportunity to test both Flymo and Ians ideas. Ian's yours just made me look like id run out of fuel to passing motorists. I know this because some helpful **** on a scooter shouted "they work better with petrol in" I'd have been annoyed had he not impressed me with his wit.
Anyway that didn't work so I played with a quarter throttle and got some off firing, this moved me onto the choke and having a fettle down there, and it started. I couldn't be entirely sure why it suddenly started but it did.

Rode a bit and it died again, but fired first time... Then a couple hundred yards further died again and pretty much rode like poo once I got it going again.

So I would now assume that what ever problems I'm trying to diagnose are now been hampered by what sounds like a fecked plug BUT is the plug a symptom or a cause??? That's the big question.

[Bibio]

well if it started with 'having a fettle down there' then your in the right ballpark so you just need to be a bit more precise in your fettling.

the symptoms your explaining sound exactly like the ducati when the emulsion tubes were worn. it would run fine for a wee while with new plugs but soon ate them causing the bike to start but die or start and run for a while eventually the bike would just sit and back fire when trying to start. new emulsion tubes and needles later and the bike ran sweet as a nut. have a look at the plug to see what condition it's in, if it's black and sooty then it could well be your problem.

i'm not saying that's what's wrong with yours as it could just be a loose connector/plug cap etc.etc.

[flymo]

yep, sounds very similar to symptoms I've seen on older engines or worn/dirty carbs.

The 20 minutes wait allowing things to start properly is just about enough time to let excess fuel evaporate. I would start with a good carb service, check/reset the float levels, check the choke plungers are working/closing properly etc.

[andrewsmith]

Sounds like the carb. Now do you know someone with a healthy set of carbs?

The spluttering is a sign and firing on a twisted throttle is similar to the issue I had with a fouled set of floats. It'll be running lean if there is a problem so it'll make it worse