cut out over bumps

[mcollett]

Hi all I’m new to the forum so I apologise if I have managed to put this in the wrong place.
I am also new to proper bikes. I’ve had a 50cc for two years and about a month ago I purchase a zxr 400 L2 import as my first proper bike.
After some small teething issues (running out of fuel ) all seems to be well other than a couple of small annoyances.

First: the bike seems to cut out if I go over to much of a bump... but not all the time only occasionally e.g. on the same road every day at the same speed it may or may not cut out (starting to get dangerous whilst at 70 on a motorway :smt013 ). I was thinking something to do with the side stand or side stand switch but I’m not overly sure really as I don't have a lot of knowledge on how these components operate normally. mainly thinking side stand switch because if I stop put it in neutral, put the stand down and release the clutch it may or may not cut out... dependent on its mood.

Secondly: it does not seem to idle properly, whilst cold it doesn't like to tick over at all (as expected) however once warm it might idle at 2000rpm or 1500rpm or 1250 rpm (like it's meant to) without alteration to the idle adjustment. Not sure if this could be due to the problem described above.

Thank you in advance for any help and advice given

[tgal7032]

I've had similar problems with my L2. It wouldn't idle properly, and if left to idle it would cut out where it wasn't firing on all cylinders, you could either crank if for a few minutes with it backfiring, or leave it 10 minutes and try again. When riding hard it wouldn't run on all 4 when it was hot, limping it back home was a nightmare, new coils fixed these issues, I'd check the HT leads, caps and coils in case they're being jolted as you're riding.

Mine has the same weird idling, it's set to about 1500, although sometimes it idles at 2-2.5k and may drop down again. Not sure what the issue is here, but it isn't causing me major problems.

[bendog66]

Mine has the same weird idling, it's set to about 1500, although sometimes it idles at 2-2.5k and may drop down again. Not sure what the issue is here, but it isn't causing me major problems.

New carb rubbers will sort that

[RedexRobB]

Get the side stand switch off and give it a thorough clean. It gets caked in all sorts. Give the connector block for it a clean too.

[CaNsA]

I had a similar problem a few years back.
The main electrical + wire running through the loom had corroded.

[mcollett]

Thanks for the replies, will check out the side stand switch tomorrow after work... start with the easiest parts. The bike doesn't normally back fire whilst trying to restart and sometimes i can bump it whilst still going along. Did get a lick of flames and a load pop when bump starting it at 40 mph in 2nd though... scared the willies of my misses who was following at the time . Would it be obvious if the bike was missfiring?

[mcollett]

Ok... so I’ve had the side stand switch off... was covered in s*** as expected. One of the terminals in the connector block was fairly corroded, could this cause the problem? Anyway of bypassing the switch to ensure it isn't the switch?

[mcollett]

Bit of a late update, however all fixed now turned out to be a massive amount of corrosion on the smaller plug on the fuse box giving a bad connection, cleaned off and not had another problem since.