Vitpilen 401, Engine Control Lamp and neutral flashing, bike twitching

vitp401

new rider
Joined
Jun 6, 2021
Messages
3
Location
Germany
Hello,

first of all some general information about my bike.
I got it about two years ago, did the 1000km (600miles) check a year ago and currently it has run about 3000km (~2000miles).

On Friday I was riding on the highway and at about 120km/h (~75mph) I took a bump in the road. The bike choked a bit and I knew something strange had happened.

On the further ride now very often, but in irregular intervals, the engine control light and in parallel the "neutral" indicator lit up. When this happened, the bike twitched strangely(like it would jump), as if I pulled the clutch and immediately let it come back, while accelerating.
However, I either just held the throttle or accelerated without shifting much.
This condition only lasted for a few seconds at most before everything seemed normal again.

Sometimes I could then drive for 1 minute without problems and sometimes these problems were there again every 3 seconds.
Thankfully I didn't have far to go and made it home in one piece.

Now when I start my bike and move off in first gear, everything is normal until I let the clutch out completely. But when the clutch has come, the bike has these weird twitches and the two lights flash on.
The problem always occurs (it is also over after a few seconds, but occurs very often) and not like on the highway only sometimes.

I have already tried to find out what it is, but could not see anything unusual.

Does anyone know what to do before I have to take the bike to the workshop?

Thanks for the help!

P.S.: I'm not a native speaker, if you have any questions, feel free to comment.
 
I'd suggest checking for loose electrical connections in all the areas you can reach since you said it occurred right after you went over a bump at high speeds. Start with the battery and go from there...
 
+1 for checking the connector plugs. It sounds like something has come adrift somewhere and is intermittently making/breaking connection.

From what you describe my first guess would be the quick shifter but I don't know if a two year old 401 has one. The QS cuts the fueling for an instant and that is what it sounds like is happening.

Second guess concerns what you say about letting the clutch out fully and the problem happens. Associated with this is that the neutral light comes on as well as the general fault light. Check the operation of the clutch switch. The switch lets the bike start in gear when you pull the clutch. If something has happened to the switch or a connection along the wire somewhere perhaps it's causing a problem with the computer. If it only happens when the clutch is fully released then it's a strong indicator of that circuit being the problem.

If it was my bike I'd also remove the switch temporarily from the lever and set it open or closed as if I've pulled the clutch in. Then take the bike for a test ride to see if it stopped the problem. Then set the switch up the other way and test again.

I don't know where the neutral light switch is, sometimes they are inside and not accessible, but that is another thing to check. There must be a connector plug somewhere.

Next thing sounds a bit weird, but pull out all the fuses and make sure they are seated properly. Sometimes a bad fuse can cause strange results to appear elsewhere on the bike.
 
First of all thanks for your help guys! I'll try at the end of the week whether I get it working again with your tips.
I'll keep you guys posted.
 
+1 for checking the connector plugs. It sounds like something has come adrift somewhere and is intermittently making/breaking connection.

From what you describe my first guess would be the quick shifter but I don't know if a two year old 401 has one. The QS cuts the fueling for an instant and that is what it sounds like is happening.

Second guess concerns what you say about letting the clutch out fully and the problem happens. Associated with this is that the neutral light comes on as well as the general fault light. Check the operation of the clutch switch. The switch lets the bike start in gear when you pull the clutch. If something has happened to the switch or a connection along the wire somewhere perhaps it's causing a problem with the computer. If it only happens when the clutch is fully released then it's a strong indicator of that circuit being the problem.

If it was my bike I'd also remove the switch temporarily from the lever and set it open or closed as if I've pulled the clutch in. Then take the bike for a test ride to see if it stopped the problem. Then set the switch up the other way and test again.

I don't know where the neutral light switch is, sometimes they are inside and not accessible, but that is another thing to check. There must be a connector plug somewhere.

Next thing sounds a bit weird, but pull out all the fuses and make sure they are seated properly. Sometimes a bad fuse can cause strange results to appear elsewhere on the bike.
No, there is no quick shifter with my bike.

The clutch was also my first thought, I'll take a closer look.
I'll check the fuses, too.
Thanks for your detailed reply!
 
As mentioned above, can check connectors for battery, sidestand switch, clutch sensor, gear position sensor, and pretty much every accessible connection point.

When mine was new it had some strange electrical quirks which were improved by cleaning and reconnecting the battery, and then solved finally by change to Better Battery.
 
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