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Post by Crusty on Oct 18, 2011 16:09:07 GMT
Up until Sundy morning everything was fine, then....
the bike would barely reach tickover speed on startup, and thats with holding the throttle wide open. But... after about 5 minutes it suddenly bursts into life and will then run fine (and I mean just like normal, including a 170 mile journey home.)
Then this morning, it burst into life as normal, but then when I stuck it in gear it died and then went back to the 'holding it on full throttle at barely tickover' routine again.
Once again, after about 2-5 minutes it was fine again, suddenly leap into life.
Same again this evening on my way home from work.
I suspect fuel starvation caused by a dodgy pump/controller (do the carbs empty themselves out slowly over a few hours) but am open to suggestions as to what is causing this problem.
N.B.
Eventually found the problem.
The valve clearances had all closed up so that the intake valves were sticking open when the engine was cold but as the engine warmed up the head expanded more than the valves, so then the bike ran properly.
It cost me £130 to have the shims done. Posted so that if you find this thread and you have the same symptoms as described you don't have to read the whole thing to find the solution....
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Post by tomster on Oct 18, 2011 16:37:06 GMT
Could be partial fuel starvation, but I suspect a poor connection to a coil, or a short on a coil. If the coil is failing it usually does so under load, rather than when cold, but cold and damp can adversely affect the connections.
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Post by Crusty on Oct 18, 2011 16:41:40 GMT
It's been neither cold nor damp since Sunday, and it had spent the night in my father's heated garage overnight (don't ask....)
And it did 170 miles after I got the bastard started at a typical speed of 90 with the occasional blat up to 'quite illegal' so it's unlikely to be an electrical problem. I also stoped twice for a 'comfort break' (nicotine injection) and it started with no problem afterwards. Longest I stopped for was 20 minutes.
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Post by Crusty on Oct 18, 2011 17:07:10 GMT
update
Well, it's not the fuel, I just took the pipe off the fuel pump and turned the key. Fuel pumped like a pimp in a whore house.
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Post by Crusty on Oct 19, 2011 18:44:25 GMT
Right, I've given this some thought.
It's something thats affecting multiple cylinders at the same time (if it were just one cylinder it would tick over, admittedly roughly on a partial throttle, rather than requiring full throttle just to barely tick over).
As the pump is working okay this rules out almost all fueling problems, especially as it clears up with a munumim of heat in the engine.
This points to the coil as its one of the few parts that could do this. Tomster looks to be right.
2 replacements ordered for just under £60 (pattern I think) and I'll let you know how I get on.
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Post by alliekat on Oct 19, 2011 19:35:39 GMT
mine had a prob similiar a short time ago, it turned out to be a the flasher unit!!!!!! teh wires from the ignition go into it !! dont know why . it is the black box behind the nose fairing on the right hand side, a couple of the wires had corroded in the connector box. one ignition wire went in then out for no apparent reason so i bi passed it going in the box and connected straight to the out wire, weird set up but cured it, the other issue was somg granules at the bottom of the carb bowles that got sucked up occasionally when on a long run, when i left it for a while it would run really rough until given a big handful.
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Post by Crusty on Oct 19, 2011 19:42:13 GMT
I'll bear that in mind. Aside from starting the damn thing it runs fine.
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Post by fz750horse on Oct 19, 2011 21:30:19 GMT
If you have a multimeter, check the continuity of the HT leads when cold. They can contract and break when cold but then expand enough to restore conductivity as they warm up. It certainly sounds more electrical than fuel anyway. Good luck.
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Post by Crusty on Oct 22, 2011 13:50:43 GMT
So things have gone from bad to completely fucking crap.
Tried changing the coils, dead.
Put the old coils back on, still fucking dead.
Next stage is to book it in for investigation/repair at a bike shop. Unless, of course, one of you fine people fancies popping over to Bath to have a look at it.
And I don't mean so that you can point and laugh.....
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Post by fz750horse on Oct 22, 2011 17:58:20 GMT
Sorry to hear that. I'd spend a couple of days with a multimeter (about a tenner from Maplin or similar if you don't have one) and wiring diagram first. It's a pain in the arse but you will find the fault if you're methodical. I'd start looking at voltages in the kill switch circuit (includes gear neutral and sidestand switches) - one corroded connector or sick wire can disable the whole ignition circuit. Good luck.
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Post by Crusty on Oct 22, 2011 18:01:00 GMT
I have a multimeter. I also have a spare spark plug so I know I have sparks....
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Post by fz750horse on Oct 22, 2011 18:02:16 GMT
Just had another thought (two in one day ) - apologies if this is teaching you to suck eggs, but faults which suddenly occur when the weather turns cold always make me suspect the battery.
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Post by Crusty on Oct 22, 2011 19:01:18 GMT
The bike turns over. The battery is starting to go flat because of the number of tries to start it, so this could be contributing to the problem.
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wheaty
Full Member
1986 FZ (1FN model) FZR1000 engine, EXUP swingarm, Ohlins shock, Marvic Penta wheels, R1 forks.
Posts: 123
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Post by wheaty on Oct 22, 2011 20:16:54 GMT
I know that the diagnosis is starting to look electrical but going over your posts makes me wonder if you may have a similar problem to one that I had a long time ago. My FZ was running fine but would eventually die after a while and with a bit of rest would run fine again. My problem turned out to be the little gauze filter on the inside of the fuel tap on the tank that had become loose and was partially blocking the fuel tap. From the outside I had a good fuel pump, good spark etc and fuel was coming through the fuel pump, just that it wasn't running out of the tank quickly enough. It may be nothing, but worth checking that its in place and not swimming around in the bottom of your tank and periodically blocking the tap. Good luck Crusty.
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Post by Crusty on Oct 22, 2011 21:54:52 GMT
I pulled the wrong pipe off my pump, and fuel positively gushed out. Tank to pump is definately not the problem...
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