Won't start - doug_523i
Help, I put my bike away wet at Xmas, no option with our weather, and I've been trying to get it going again for the last 2 weeks. I've stripped all the switches and connectors and used wd40, replaced the plugs, there is fuel from the pump, all four carbs are wet with petrol, there is a spark at all four plugs, although it doesn't strike me as an impressive spark. I've turned the motor over with the plugs out and earthed in case they flooded. I blowlamped the plugs before putting them back in, all fuses operate, all lights and horn operate, but the thing won't start. I just flatten the battery churning the starter motor, and the best I get is the occassional half -hearted backfire, more of a splutter. I'm at a loss as to how I could ride 50 miles, park it up and then be unable to start it again. Any ideas? I'm so involved with the thing I'm probably missing something obvious.
Won't start - bazza
Air intake/filters ok? Plenty of fresh petrol in tank? Try charging battery up overnight, heating plugs in oven or blowlamp until really hot, put them in while still hot and turn over with only a little choke (if applicable). I am guessing but possibly battery is a bit down, spark is weak and you're flooding it. Others on here know much more than me though!
Best of luck,
Baz
Won't start - Shigg
I found that my bike doesn't like to be laid up, when you come to start it it's almost like it's punishing you for your absence. Loads of possible problems, I'd try along the lines of, draining tank, refill tank with 'new' fuel, take out plugs and check VERY carefully for any signs of the insulator breaking down - did on mine, check all the HT side for signs of tracking and/or faults in insulation, drain carbs of old fuel and then try again. To some extent the only way you can be sure you're getting fuel in is if the plugs are wet and the exhaust stinks. If this is the case then you're looking at the ignition circuit. Does the bike have an immobiliser - I'm not sure as to whether this would stop a spark at the plug, I guess that would depend on the type fitted, also sometimes the side stand switch fails which could cause problems - but again I would only expect this to give problems if the bike was in gear, which it wouldn't be for starting. Don't some bikes have switches on the clutch lever - again I'm not sure but I seem to think that my Rebel does. A circuit diagram would really help. Be careful heating up your plugs, it could weaken or crack the insulator. I had loads of trouble with my Rebel after laying it up for a couple months, I ended up stripping and rebuilding the carb, resealing ALL the induction system, cleaning up all the HT system and fitting new plugs. Also stripped stop tap on tank and cleaned. Filled with 'new' petrol and now it runs like a charm. Sorry if I've patronised you, didn't mean to but initially I lost sight of the obvious with my bike.

Good luck. Let us know how you get on.

Steve.
Won't start - wemyss
Steve, Dead right about motor bikes. I posted on this site a couple of months ago about my son in laws Ducatti bike which he couldn't start and had been laid up for little while.
I went and tried everything, good spark and petrol etc.
After nearly a day we down the motor bike shop and asked there.
It's nearly always the petrol he said. Our mechanics have the same problem with most bikes which haven't started for a while.
Empty the tank, fresh petrol and it will start.
Slightly disbelieving went back and did same.
It started up right away.....
Won't start - doug_523i
Thanks for the reply. The air filter is a new K&N, and I've run the petrol feed into a container to check the flow, which seems fine. It's always been a pig to start, if you don't catch it on the first turn, but there is little sign of life now. I'm wondering if it's going to be a cdi unit or the coils perhaps. I've charged the battery back to full, which made no difference.
Won't start - Dynamic Dave
Have you tried bump starting it? I have to do this with mine after its been stood for a while as the starter motor takes all the energy out of the battery and leaves very little in reserve for the ignition system.
Won't start - pmh
I know nothing about bikes...

The purists hate the stuff but I have found in reluctant ic engines 'Instant Start' or similar highly volatile aerosol sprayed in the inlet will just about start anything.

If it uses 12v electrics have you tried jumps tarting from a car battery? or using a separate battery for the ignition feed?

If it will start a ropey old BS mower after 6 months non use with old petrol, you must be in with a chance.



pmh (was peter)
Won't start - 547HEW
Hi Doug,

I used to have exactly this problem with my 84 Kawa GPz550.

The solution is to drain the stale petrol from the carburettor float bowls. Just the two outboard cylinders treated thus will get it going. The petrol in the tank is better protected from going stale, so need not be drained. On my machine this is easy to do as all four drain screws are accessible witha long thin flat blade screwdriver. On the R1, (if this is what we are considering) I am not certain how practical this method would be.

Judging from my experience, pump petrol seemed to lose its preservative qualities about 6 years ago. Even branded leaded petrol suffered this.

If the float bowls are not accessible, I would try the (Bradex?) Easy start (Ether spray) into the airfilter housing. But beware if doing this regularly that any wetting of the air filter element will allow dust to stick to it, and shorten air filter life.
Won't start - doug_523i
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.
Won't start - Dynamic Dave
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.
Won't start - Nick C
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
Won't start - doug_523i
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.
Won't start - doug_523i
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.
Won't start - bazza
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
Won't start - BrianW
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)
Won't start - guzzler
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...
Won't start - BrianW
"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)
Won't start - doug_523i
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.
Won't start - Toad, of Toad Hall.
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.
Won't start - doug_523i
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.
Won't start - Toad, of Toad Hall.
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?


--
These are my own opinions, and not necessarily those of all Toads.
Won't start - Shigg
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.
Won't start - dieselhead
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
Won't start - doug_523i
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.
Won't start - guzzler
Well done, I wondered what had happened. Long time to be without the bike though.
Won't start - 547HEW
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
 

Value my car