Trouble starting...

[magicmonkey]

ok, so I got a new battery over the weekend and charged it up for 24 hours before putting it on the bike. Now it's on there and on Sunday the engine just popped into life when I pressed the starter. However, the maiden voyage got postponed because I had a horrible hangover so I went and had a couple of beers instead

so last night I went to turn the engine over and it just didn't want to pick up, turns over fine, sounds like it's about to start but doesn't actually pick up. I'm sure it would if I kept on trying for ages as that's what it would do with the old battery but I'd really like to fix the problem rather than wear out a brand new battery for no good reason. Work I've done on the engine is pretty much just on the carbs but they're all sparkly clean now and shouldn't be the problem (when I did have the bike started and warm last time it was quite happy to sit at idle and rev how it was meant to with no choke on etc.). I'm starting the bike with the petrol set to 'prime' and the choke full on with no throttle as this seems to be how it prefers to start. Anyone got any ideas of things I should look at? I'm starting to scratch me head far too much now!

[bogan]

was it running after you cleaned the carbs, or is this the first time youve tried to start it. As carbs are tempremental beasties who have to be tuned properly as well as being clean!

[magicmonkey]

Yeah, it's been ticking over quite happily since the carbs have been cleaned, it's just the starting of the engine which is causing issues at the moment

[bogan]

maybe some bad fuel at the bottom of the tank got sucked through while its been on prime, also try differnt combinations of choke and throttle when you start it.

[T.W.R]

Only use prime if it's been sitting for a while without running.......you had it running Sunday so now having used the prime position you've probably flooded it

[bogan]

Only use prime if it's been sitting for a while without running.......you had it running Sunday so now having used the prime position you've probably flooded it

good point, float valves don't generally seal properly so that probly all it is.

[magicmonkey]

sounds like a good point. I'll pull the plugs out when I get home and let the engine air out for a bit before I try and start it agin

[magicmonkey]

Actually, on thinking about it a bit more, I had this problem before I was starting with the petrol set to prime so I'm not 100% this is going to work. I'll certainly try it but any other ideas would be very welcome too!

[bogan]

dont worry bout pulling the plugs out, tis the carby that will be flooded, excess fuel in the cylinder will clear out when the engine turns over (may take a few turns though), just drain the carb, some have screws near the bottom with a hose and other just have a bolt you take out, if its the latter rags and plastic sheet 'funnel' into waste container is the way to go.

[magicmonkey]

dont worry bout pulling the plugs out, tis the carby that will be flooded, excess fuel in the cylinder will clear out when the engine turns over (may take a few turns though), just drain the carb, some have screws near the bottom with a hose and other just have a bolt you take out, if its the latter rags and plastic sheet 'funnel' into waste container is the way to go.

another good point! Would probably account for the problem as well! Shame really as this means I have to get the petrol tank and the airbox off to get at the drain screws, doh!

[bogan]

another good point! Would probably account for the problem as well! Shame really as this means I have to get the petrol tank and the airbox off to get at the drain screws, doh!

really? this on your gn or zxr?, wouldnt have though either needed the tank and airbox off to get at the drian screw

[magicmonkey]

it's on the ZXR. I could probably get to the carb screws without removing anything but they need a star drive and the only one I have that will fit is on a short and wide screwdriver so it's more about that than the design of the bike itself. I'll have a close look at it this afternoon but I'm pretty sure that's how it'll go ...

*edit*
I'm pretty good at getting these off now anyway, will only add 5 minutes to the job

[bogan]

ahhh, fair enuf, spose the zxr has quad carbs as welll, have fun with that

[magicmonkey]

ahhh, fair enuf, spose the zxr has quad carbs as welll, have fun with that

heh, fun indeed! Still, if I can work out how to get the thing to start up nicely then I'll be well chuffed as that'll be pretty much the end of the engine side of the project. After that it'll all be about cleaning and paint which is going to be pretty boring but should be rewarding once it's done

[Grasshopperus]

Hey mate, I've recently had the exact same problem with my ZXR.

First, although you've cleaned the carbs the real check is to make sure gas really is getting into the cylinders; can you smell gas after trying to start it for a while? You might need to sniff the exhaust to check that.

I took the spark plugs out one-by-one and verified they had a strong spark. In my case, 2 of the spark plugs had a barely visible spark whilst the other two had a bright, fat spark.

ZXRs have two ignition coils (ICs), each powering two sparkplugs. In my case, the two weak sparkplugs were connected to the same IC meaning it was an IC problem.

I took all the leads off both ICs, removed them and inspected. What I found was that the bad IC was heavily corroded where the sparkplug leads connect (it's just got a spike that you impale the leads onto). The leads were also corroded.

So, I cut the sparkplug leads a little shorter, sprayed heaps of CRC into the IC and cleaned it up using a needle file (a bit of stiff wire would've worked too). While I had the ICs out I jammed a multimeter onto both the primary and secondary coils and verified that the resistance was within what the factory say it should be.

Put it all back together, verified that all the sparkplugs now had a good spark. Tried to start bike and yay, it's all good now.

You owe me green bling if that's what's wrong monkeyman.