Help please: Bike keeps cutting out

[TurboStew]

Hi all, my name is Stewart, I am new to the forum and this is my first post so I hope its in the correct location.

I Picked up a 1985 KR 250 A model about a month ago. She is in a very bad way. Any way after lots of work on it I got it running, well sort off. Some times when it starts it runs perfect, some times it just wont stars or starts on one cylinder or backfires out the exhaust. I have noticed when it is only running on one cylinder that the tacho is not working. I spent quite a bit of time today working on it checking and cleaning connections and earth points but still the same. I got it started after my right leg had just about fallen off from kicking it to death. I reved it up and it ran perfect for about 20 seconds and then cut out as if I had turned it off. I am suspecting a faulty CDI. It is not a fuel issue causing the problem as I have cleaned the carbs and fuel system.

What do you all think is the problem

Cheers Stew.

[TurboStew]

Hello, I see a few people have read my topic but no replies as yet. Hmm
Have had the bike running perfect from time to time and will run for a long time then just cut out and then will not start with no real rime or reason. Still thinking the CDIs.

Please give me your advice on my issue.

Thanks Stewart.

[mellorp]

It does indicate fuel.

I have a dodgy vacuum tap, that would let the carbs fill but the bike would only run until the carbs were empty. Once they filled up again it ran, and so on until I sorted the tap out
I also had a float needle that would sometimes stick in the closed position. I did manage to get it moving freely but it ultimately needed replacing
Last fuel one was a bit of plastic managed to get stuck above the float needle and would spin sideways then fall flat, again stopping fuel intermittently
I had an electrical fault in that water had got into connector. The connectors corroded enough to split the plastic and the loom was earthing out again intermittently but never caused the bike to actually stop just run really badly.

I doubt it's CDI. Most electrical components are robust and if a part is prone to failure you will find many people will have posted about it

hth

[Binetta Steve]

Im sure a moretechnical person will correct me , but no signal to the tacho can this be linked to rectifier problems?

Ps welcome to the forum

Steve

[TurboStew]

Thanks smoker and Heavy smoker for your replies. Its defiantly not fuel system related.

I am convinced it’s electrical. Being my first KR250 I am learning as I go. Convinced it’s something in the ignition system causing this problem. Was thinking it may have been one of the ignition CDI modules. But don’t know how to test them.

I will be testing the pickup coils when I get a chance though and the ignition coils + wiring and connectors again.

Was still thinking the CDI as I read or determined a few weeks ago from the manual that the tacho is fed from one of the CDI unit. If I remember correctly or something like that.
Whatever the fault is, it is very intermittent and will not be that easy to pinpoint I feel.

That is why I have asked for you all to post your wealth of knowledge on this unique bikes.
Thanks again to those who have assisted.
Cheers Stewart.

[500bernie]

Hi Stewart
You will get more knowledgeable replies if you ask in the KR Chat section, these are very different to our KR1 and KR1S models.
Cheers
Bernie

[TurboStew]

Thanks Bernie, I will start a new post in the KR chat section. So If anyone reads this help topic look for the new on to give advice.
Cheers Stewart.