misfire

[mad mitch]

Hi guys...... HELP !!!!......... 1990 kr1s. 9000 miles. Missfire and rough running 8000rpm upwards and not reving out. Changed rectifier, coil and leads, plugs, made good all earths, stripped and cleaned carbs. Changed cracked valve block rubbers / mountings. Compressions good. Crank seals appear good as blocking air box etc makes no difference when altering mixture. Checked trigger on fly wheel which appears undamaged and air gaps to plates ok. Only strange thing is that the plates are marked as if the trigger has caught at some point but the trigger itself is good ?? Maybe this has been changed at some time ?? . Really starting to
Any advise ............ Had the bike 4 months and has been in the garage 3 and a half of it............ Steve ..

[Cexley]

You and I are in the same world of pain. Have exact same probs and going through the same painful forensic processes.

Look up the recent headlight post under electrical. There are several of us all wrestling with same symptoms. Rather than go over old ground, pick up the thread and with a bit of luck, between us we will figure it out.

If electrics have all checked out (as have mine) and mechanicals good (full top ened rebuild in my case + new KIPS valves, linkages seals etc) then it is looking like clogged up spannies or fuel starvation due to restricted flow from fuel tap not replenishing float bowls quick enough at higher revs. See you in the electrics section! Craig

[KwakOn]

things you have probly tried already:

powervalves - moving properly, right way round valves/links etc.
(harms the toprevs more than bottom when they
flip round/get stuck)

reed valves -

fuel pump - as mentioned fuel flow (run fuel tap on prime to bypass diaphragm)

are the carbs all standard main jets, needles etc.