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Thanks for the input, the bike was only off the road from Dec 24th to 2nd Jan, I'd have thought the petrol wouldn't have gone off in this short time, but maybe... The bike is a ten year old YZF750R, standard pipe, but is fitted with a Datatool alarm/immobiliser, but there is a spark at all four plugs when I turn it over. When the filter housing is taken off all four carb slides are wet with petrol, so it's getting that far. As far as bump starting is concerned, my R1 is a doddle, but the 750 just locks the back wheel.
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As far as bump starting is concerned, my R1 is a doddle, but the 750 just locks the back wheel.
Have you tried a higher gear - say second or third? Also with some weight on the seat. Get a mate to push you while you're sat on it - or use a hill.
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Hi all,
Not sure if this will help, but might as well recount it.
I had a problem with a Ford Capri that I parked and when I tried to start it a day later it wouldn't. Checked the usual, plugs, spark, fuel. Two days later the garage advised me that I needed a new engine. Not convinced I took it to a guy who builds capris for racing. 5 minutes later.... Started!!!!
Turned out that although there was a spark it wasn't strong enough to start the car, diagnosis, faulty condenser on the distributor. New condenser and the car ran perfectly until I sold it.
Hope this helps.
Nick
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I'm sure the spark isn't as strong as it might be, but it's cdi and doesn't have condensors. As for bumping, I already use 2nd gear and I weigh 14 stone, so a hill seems the next best bet. I'm just worried about getting to the bottom of the hill and it still not running, and having to push it home :-) With four carbs, twin coils, etc I can't see why I'm not getting any sign of life, the problem must be a single point of failure, dirty petrol or weak spark, so I'll try the petrol before exploring the cdi black box.
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We had an RAC engineer at work today, and he reckons the splutter as you turn the starter off points to the CDI being faulty.
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Hi Doug
Many years of bitter (and costly!) experience lead me to advise you to try the simple approach first. I am sure that the advice in these posts concerning FRESH fuel, charged battery, Ether start etc is all you need to get it going.
Baz
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Hi
Bikes do not like standing (experience).
The techies have suggested most avenues to explore, and this is not your answer because you say you have a spark, but may help others, I've been caught out by the emergency cutout switch being knocked to the "off" position.
Brian
Still learning (I hope)
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Have you checked your leads? Try turning it over when it's dark and see if there is any arcing, that can lead (no pun intended) to a poor spark.
And on a different note, I could not get my old R45 to start one rainy morning, no life whatsoever so I stripped the switchgear, charged the battery, nothing, 3 days later I was at work thinking about it when a picture came into my head, no neutral indicator! Got home, moved the gear lever a fraction of an inch and lo and behold, light. It started straight away, Doh...
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"Got home, moved the gear lever a fraction of an inch and lo and behold, light. It started straight away, Doh... "
Yep, got caught on that one too ! ! !
Brian
Still learning (I hope)
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I've just read Andrew's request, so here's an update. The bike is still dead. I've found a slow burn fuse alongside the relays, it's an Aussie import and these fuses seem popular over there. The terminals are brass and they had disolved into a green powder, now I've remade the connection, 30amp, I'm getting a couple more backfires, and the occassional sign it would like to catch. I've put fresh petrol in, but this weekend I'll strip the carbs to see if they have water in them, or if the choke plungers are faulty. I suspect it's a couple or more little problems that are causing this.
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The YZF750, like most bikes is famous for not starting after a lay up. (1 week seems extreme though)
It can take me an eternity to get my Divvy going after a month or so.
If you've got fuel and a spark a prolonged attempt (with jump leads) with/without choke throttle wide open (to clear flooding) and closed might just do the job.
Problem here is you seem as technically able as anyone else here so I imagine you will have checked the obvious things.
Jump starting on a hil in top gear should be ok as long as you don't mind the push back if it fails!
Might I suggest uk.rec.motorcycles and rec.motorcycles and rec.motorcycles.tech news groups. The first in paticular will gaurentee some responses.
--
These are my own opinions, and not necessarily those of all Toads.
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Thanks Toad, I'll try them. The funny thing is my R1 sits in the shed waiting for sun and doesn't get used for weeks on end and starts first time, whereas the 750 has done 22,000 miles in 18 months, 100 miles a day commute, and won't start after a week. I'd have sold it as a non-runner last Sunday, but I've got my gander up now, so I'm going to get it running, perhaps.
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Thanks Toad, I'll try them. The funny thing is my R1 sits in the shed waiting for sun and doesn't get used for weeks on end and starts first time, whereas the 750 has done 22,000 miles in 18 months, 100 miles a day commute, and won't start after a week
Carbs verses injection?
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These are my own opinions, and not necessarily those of all Toads.
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The try it in the dark tip (!) is a great suggestion. My brother came across this one (!!) on a Nissan Micra that had deleveloped a strange misfire. In the dark the dizzy cap lit up like a plasma ball - his words not mine. I would be suspicious of the plugs if you've been baking them.
Steve.
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I dont know if your bike (or any bikes) has a ballast resistor on the coil..i think ballast resistor coils are designed to operate on 8v (on cars anyway) so that their is plenty of energy to make the sparks when the starter motor drops the voltage or something like that ..if the resistor isn't being short circuited when the starters going their wont be enough voltage at the coil giving a weak spark...might be worth investigating
the bike should push start ok if this is the cause
hope this helps
steve
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I finally got it going today. I found a dodgy cutout switch on the clutch lever, it stops you using the starter motor if the bike is in gear, which I've removed. Also, the ignition pickup coil was open circuit, so I've replaced that, and it still wouldn't start. Three lads pushing the bike with me on it trying to bump start and still no joy. So my brother in law ran a rope from the tow bar of his Vauxhall Astra and towed me at approx 15mph, it took a quarter of a mile to catch, it backfired like a shotgun a couple of times and then started. I took it home, switched off, let it cool, switched it on, and bingo, it fired with the first press of the button, wierd.
Most of your suggestions were correct, I just didn't expect all of them to affect the bike at one time, so thanks for the input.
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Well done, I wondered what had happened. Long time to be without the bike though.
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Hi Doug,
Well done, and thanks for keeping us informed.
Your mention of the clutch switch reminded me that I had exactly the same fault (and symptoms) om my GPz 550. Didn't get it straight away - went to trouble of replacing corroded coil connectors first.
Happy motorcycling
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