HELP - bike won't idle & having difficulty starting

[Gabs]

Hi guru's

Need you help sorting this problem on my bike. I'm not very good and have little experience but learn fast.

Recently bought an L model (ex track/race bike) and when cold the bike won't start without spraying quick start or carb cleaner into the front of the RAM air duct. When warm she start up okay. Once started and warmed up she refuses to idle. I'm not sure if the RAM air unit will affect this? There is no choke (due to the fitment of the RAM airbox I suspect). The choke rail is fitted to the carbs but have no cable attached? Also, the idle screw is hidden inside the RAM airbox so it's a mission to get to it.

Once warmed up and running she's happy at 10,000+ RPM and runs smooth all the way to redline. Anything below and she's spluttering a little but still pulls strong. VERY strong.

Coming to a stop I must keep the throlle 1/3 open to keep the RPM at around 4000 to keep her running.

It's not really cold outside - temp is around 10deg Celsius outside in the mornings, so not carb icing.. i think..

Reading though the post I planning on doing the following this weekend:
1. check plugs condition and replace if necessary (not yet sure which kind are used but will check the manual)
2. check for leaks on the carb rubbers using the carb cleaner spray on method.
3. check carb balancing
4. check and clean jets (not sure what jettings are used)
5. check for spark from coil leads (not sure how to do this... do you simply remove the plug, connect the coil lead, hold up in the air and press start and check for a nice spark?)
6. Battery. I have been charging the battery and it's strong for 5~6 starting attempts then needs recharging. Also after hard riding (went to a local track this weekend) the battery is dead and needs recharging (about 20 mins on rapid charge mode). I suspect there is no alternator (charging circuit in the bike as it's been an ex race bike). Can a bike run without this? The battery is then the only thing supplying power for the coils. Am I right with this assumptions?

Any other ideas you experienced guys could suggest to try while I'm at it?

Something I can't get an answer on... With the RAM air box I'm thinking the bike should idle. Is this correct? What about when it's removed and the carbs are exposed? Should I be able to get it to idle while tinkering with the lean/rich mixtures and idle screw?

Thanks for any advice. This is a GREAT forum.

Cheers
Gabs

[masterofinsanity]

Hi, firstly zxrs are notorious for needed a good charged battery to start. definitely sounds like there is no charging circuit so prepare to bump start it everywhere.Re checking for a spark, use a good working spare plug and test each HT lead in turn for a spark against the engine, don't hold it! you will get a bit of a shock.

[Davw]

Sounds like this is set up for the track however it is easy enough to fit a choke cable if the choke rail is still there and that will help the cold starting problem. Dont know what sort of ram air box you have but assuming it splits to expose the cardbs then just run the cable through the side (or even better the front of the box) and finish it in a loop so that you can pull on this while hitting the starter.

As for the idle problem - that could be mixture, air leaks, dirty plugs etc but - does it have an idle adjuster fitted and what happens if you turn this. It is possible that (like mine) the bike was set to idle quite high (3000+) as it is a track bike and low revs arent really an issue.

If bike doesnt have a genie fitted then you will need to hook up to a trickle charger. If you are planning to use for track days you may want to refit the alternator windings (assuming the loom still has the connectors and the regulator is still there - big assumptions!!)

[Gabs]

Hi, firstly zxrs are notorious for needed a good charged battery to start. definitely sounds like there is no charging circuit so prepare to bump start it everywhere.Re checking for a spark, use a good working spare plug and test each HT lead in turn for a spark against the engine, don't hold it! you will get a bit of a shock.

To double check my (lack of) understanding... checking for spark against the engine... does that mean I should try and position the plug to arc against the engine block without touching the leads? Any risk of shorting something out?

[Gabs]

Sounds like this is set up for the track however it is easy enough to fit a choke cable if the choke rail is still there and that will help the cold starting problem. Dont know what sort of ram air box you have but assuming it splits to expose the cardbs then just run the cable through the side (or even better the front of the box) and finish it in a loop so that you can pull on this while hitting the starter.

The choke rail is still on the carbs - just need to fit a choke cable. I'm planning to start taking the bike apart tonight after work and try to figure out what type of ram air box is fitted and how best to fit a cable.

As for the idle problem - that could be mixture, air leaks, dirty plugs etc but - does it have an idle adjuster fitted and what happens if you turn this. It is possible that (like mine) the bike was set to idle quite high (3000+) as it is a track bike and low revs arent really an issue.

The idle adjuster is connected but inside the ram air box which makes it a pain in the behind to adjust. Will also figure out a way to run it through the ram air box for easier adjusting and feedback on the results.

If bike doesnt have a genie fitted then you will need to hook up to a trickle charger. If you are planning to use for track days you may want to refit the alternator windings (assuming the loom still has the connectors and the regulator is still there - big assumptions!!)

Will inspect tonight/tomorrow. Thx for the feedback and help guys!