Trouble starting...

[magicmonkey]

Hmm, nothing seems obviously wrong to me there (I'm a noob mechanic though).

Do change the oil and though, doesn't have to be the best oil, just get some new stuff in it. You may find that the current oil is so gunged up that it's actually providing too much resistance to start the engine (just guessing, I'm not sure if old oil can have that effect or not)

generic 20w-40 car oil and a "HiFlo" HF-303 oil filter is what I'm using on my zxr at the mo.

I'm not so sure that an oil change would fix a starting problem, I'd assume that if it was that gunked up it wouldn't just dribble out the drain but I could well be wrong, I'm also a complete noob mechanic (in-case you hadn't noticed!)

I find that as my bike is catching I have to lightly play with the throttle a bit to make it fire into life. However, that's only required for the first start of the morning when it's cold. After that it starts fine in about 1 second.

yeah, mine seems to like the tiniest amount of play at the closed end of the throttle and then a small rev as it's catching

I think your problem must be electrical;

you're obviously getting gas (it idles and revs up no probs)
you've got compression (revving up)

I think I've got an electrics problem for sure, what I'm really worried about is the problems I'll find when I've fixed that!

Do you have a multimeter? It may be a bad battery. Test the batteries resting voltage with bike off, and then with ignition on, and then after starting it too (verify charging system is working)

Yup, the battery which came with the bike was on it's last legs so there's a new one in there at the moment, it's fully charged and the charging system is definitely working (I love multimeters, got to be one of the most useful tools ever made!)

Also, the next time you take your carbs apart make sure that the main jets are the correct factory size, #122 for cylinders 1 and 4, #125 for cylinders 2 and 3. Getting the sizes right is what fixed all my engine rev-up hesitation problems.

well, that's going on the to do list

Someone has obviously tried to do some mods or something to your bike (like the spark plug leads) so you probably don't know what else they've tried to do.

yeah, I get the impression they knew fuck all about bikes and had an over inflated sense of their own mad mechanic skillz! The wrong kind of leads is just a complete idiot mistake and shows that whoever it was didn't bother talking to anyone who knew what they were doing or read a manual, makes me worried :S

Lastly with the choke, I guess you've tried varying the position of the lever, full choke floods mine so I play somewhere between 50-80% choke just 'searching' for the right setting.

good point, I am starting with 100% choke at the moment, I'll bring that down some and see how that goes...

[T.W.R]

What's the air gap between the pulser coil & the timing rotor like???

[magicmonkey]

What's the air gap between the pulser coil & the timing rotor like???

the what between the what and the what?????

I'll have a peek at the manual in a bit!

[MSTRS:Me]

generic 20w-40 car oil and a "HiFlo" HF-303 oil filter is what I'm using on my zxr at the mo.

Bad boy. Get bike-specific oil in there. Mineral or semi-synthetic...4T for sportsbikes is the one you want.

[T.W.R]

the what between the what and the what?????

I'll have a peek at the manual in a bit!

exciter coil & timing rotor (under the cover righthand side of the engine) it's the magic wee article that sends the important pulses to the coils.
the air gap is clearance between the coil and the timing rotor........don't bother trying to measure it with a feeler gauge as it's a curved surface (if you do you'll get a incorrect measurement) best is a piece of paper folded in two (it only needs a small gap...not touching nor a large gap)

[magicmonkey]

exciter coil & timing rotor (under the cover righthand side of the engine) it's the magic wee article that sends the important pulses to the coils.
the air gap is clearance between the coil and the timing rotor........don't bother trying to measure it with a feeler gauge as it's a curved surface (if you do you'll get a incorrect measurement) best is a piece of paper folded in two (it only needs a small gap...not touching nor a large gap)

ok, I get you now, I've always called the pulser the 'pickup', hence the confusion. I think I'm going to hold off on that though as itwas working before and now it's not, the problem seems to lie with something I've actually done rather than something else at the moment.

It seems that the engine now wants to backfire and not catch immediately after I've sorted out the spark plug leads. Considering that the spark was really weak but still fired up I'm beginning to wonder if the air/fuel ratio was adjusted for the weak spark and the decent spark is having trouble igniting it. I can't quite work out how that would be the problem (too lean, too rich etc) or even how the air/fuel ratio would allow it to ignite with a weak spark but not a strong one. I'm thinking that some playing with the pilot screws might be in order but if anyone has a better suggestion I''d be very happy to try it out!

I might also get the engine cover off and just line up the timing markings to make sure that it hasn't been advanced by the previous guy (apparently that's a common mod on these to get more out of the mid-range) ...

[T.W.R]

pulser/exciter/pick-up all the same just depends on where you've worked & who you've worked with...just slang terms for the same thing.

Just odd that you've had it running prior to all this diddling around and now it's playing up ???
2000rpm idle you mentioned in a previous post doesn't sound right though even if these wee sewing machine engines rev like buggery...1500rpm I'd consider a high idle.

Pilot air screws hardly get fiddled with but if you do adjust them remember the setting is taken from a soft bed not firmly wound in.....they have a small rubber O-ring that does harden quite significantly and can alter the prescribed setting a lot.

[magicmonkey]

pulser/exciter/pick-up all the same just depends on where you've worked & who you've worked with...just slang terms for the same thing.

Just odd that you've had it running prior to all this diddling around and now it's playing up ???

yeah i know, it seems that something I've done has cocked it up and I'm completely in the dark about what that is. It worked fine after I did the carbs and I only improved the spark so I can't see where one of those things has screwed it up. Still, these are the joys of a beginner mechanic with a broken toy I suppose

2000rpm idle you mentioned in a previous post doesn't sound right though even if these wee sewing machine engines rev like buggery...1500rpm I'd consider a high idle.

well, it seems other zxr owners think that about 1500 is normal and I probably could have dropped the idle speed to around there but I was worried about stalling when it was so bloody hard to get started again, hence all of this messing around! I'll probably revise the 2000rpm figure once I've got the starting issue sorted ...

Pilot air screws hardly get fiddled with but if you do adjust them remember the setting is taken from a soft bed not firmly wound in.....they have a small rubber O-ring that does harden quite significantly and can alter the prescribed setting a lot.

I'm beginning to think that playing with the pilot screws is probably a bad idea, I just can't see how they'd fix the problem I'm having considering that I haven't touched them so far and the problem didn't exist a couple of days ago.

I've decided to have a day away from the bike today as it's just pissing me off at the moment and I'm bound to do something silly if I'm wound up with it. I've decided that beer and sun can come before the bike just for one day tomorrow night I'll go back over everything I've done and check it against the manual, hopefully I'll find something really stupid that I've done!

[magicmonkey]

ok, now I'm completely stumped!! I've checked spark to each cylinder and that's fine, I've triple checked the wiring and they're all firing in the right order, I've had the carbs off again and put them back together with the manual and checked everything there. So there's spark to each cylinder, there's fuel getting in there (I can smell it from the exhaust) but it just refuses to kick into life, not even the slightest hint of one cylinder firing. I'm sure it's something to do with the work I've done, which is all spark and carbs, but I've checked them over thoroughly and I still can't get life out of the damned thing! Any ideas are gratefully received at this point!

[CookMySock]

Halve the spark plug gap - that'll make it not quite so sensitive. Trailer it up the top of a really big hill, stick it third gear and ride it all the way down.. fiddle with choke and throttle. You should be able to get at least one backfire outa it.

Steve

[magicmonkey]

Halve the spark plug gap - that'll make it not quite so sensitive. Trailer it up the top of a really big hill, stick it third gear and ride it all the way down.. fiddle with choke and throttle. You should be able to get at least one backfire outa it.

Steve

lol, I thought the mechanicas forum wasn't for messing around in

[MSTRS:Me]

You haven't done something silly like flicked off the killswitch?
It happens - DAMHIK

[magicmonkey]

nah, the kill switch is off, the engine does get turned over by the starter, just doesn't actually sping into life

[CookMySock]

lol, I thought the mechanicas forum wasn't for messing around in

LOL you think I am joking.

Steve

[MSTRS:Me]

nah, the kill switch is off, the engine does get turned over by the starter, just doesn't actually sping into life

OK.
We all know an engine needs 3 things to go...but each must be present in the right quantities/time etc. The higher performance an engine is, the more critical those factors.You prolly need an 'expert' there with the bike. And maybe, some starting rollers like a few of the racers use...