cylinder too hot? help me!

  • hi!!!
    i just buyed an Ural M67-36 with sidecar of 1980 with K63T carburators.
    The tachometer (and seller) say that the bike have only 24 km... maybe it is true... some particulars could say this!
    After an entire day to recondition the electrical plant and clean carburators, filters and other... the engine starts.

    Now i can ascertain that when the right cylinder is yet cold, the left cylinder is very very hot...
    i tried to let the engine on for about 10 minutes and the right cylinder was only lukewarm and start to get warm... after i turned off the engine! i dont want to crash all!!! :P

    the valves are ok, i think... with 0,08 of tollerance...

    is it normal that a cylinder stays lukewarm and the other so hot?
    which is the abnormal cylinder? the colder or the warmer?

    thank you!

  • Hi marcut79,

    unfortunately neither the very hot nor the lukeawarm cylinder seem to be in the correct condition.
    The valve clearing is 0,10 for the inlet and 0,15 for the outlet.
    What about the carbs? Did you clean them properly? What about the petrol, does it really feed both carbs?
    What about the ignintion? Timing has to be correct.
    But to me at a first glance it seems that the ignition coil is broken, you can check this by mounting any other coil with two outlets i.e. from any elder japanese bike with contact-breaker-ignition, or for a quick test change the ignition-wire form left to right, same problem?

    Good luck

  • ok... how can i test the ignition?
    i tested it seeing when the piston is up (when the valves are closed)... in this time the pins begin to open and both cylinders are ok...
    is it right if i test them so?

    i just tryed to change the ignition-wire from left to right... nothing change!

    if you need it... i tell you that when i try to start the engine often i hear some sneezes from the cylinders... and after about 15-20 attempts the engine runs.
    when the engine runs sometimes (when i accelerate a bit) the engine sneeze and after takes RPM... electrical problems?

    i observed that when i push the key to fill the right carburator (the same of the cold cylinder), fuel comes with delay respect to the other carburator... is it normal?

  • Did you trie to swap k63's left to right? Sparks?

    Somehow it sound to me that one jugg doesn't fire.


  • Hi marcut79,

    how ever, the colder one does´nt work. The other one is getting to hot, because he have to work for two.

    Now the question is, why does´nt work the coulder one????

    Usualy it can have two reasons.
    1.) The ignition do´nt work
    2.) Someting with the petrol is not ok

    Possible problems to nr. 1.)
    1.) The spark does´nt work right
    2.) The ignition coil does´nt work right
    3.) The ignition wire is broken
    4.) The sparkplug is broken
    5.) The piston is broken or not adjustet with the right gauge
    6.) The ignition time is´nt right

    Possible problems to nr. 2.)
    1.) the petrol tube is congests
    2.) the carbureter is dirty or congests
    3.) the carbureter blast pipe is dirty
    4.) the carbureter swimmer is hanging in his highest position and is holding closed the valve
    5.) the cabureter is´nt right adjustet (in comparision with the other one)

    First of all I would try to check the ignition time, piston and the right piston messurement. Than change the spark, ignition wire, spark plug and carbureter from the left side to the right side.
    In this way you can get quickly an overview over a lot of parts and you can see if one of them is causing for you problems or not.

    By the way, have you tried to measure the compression pressure?

    Best regards

  • Well, compression pressure is 7-7,5 in both cylinder, all the electrics controlled an working, the ignition pin is at 0,5-0,6 mm and the Sparkplugs are new Champion L86C (is the correct grade?),
    Carburettors cleaned in and outside (mainjet 165, lowjet 55, air screw 1-1/2 out).
    Fueltank, Tube and cock cleaned.
    Now the cylinders works at the same temperature. A light lightblue smoke exit from exhaust system, when I accelerate the smoke remain lightblue.
    When cold the bike starts with the carburettors choke onj and few kicks on nthe kickstarter and in few minutes round well (I think).
    If I turnoff the engine, It doesn't start anymore. The sparksplug are very dirty and a lot of carbon is on the electrode. I clean them and spark well but engine doesn't start. If I let the engine becaming cold it starts again in few attempts. Why? possible problems with carburation settings?

  • Well, you've got a symmetrical engine.

    Just change parts from one side to the other and try out. If anything changes, you found the litle troublemaker. Start with the spark plugs, next carbs.

    If there is no change, it's mechanical = heads or so.

    Good luck and may the farth be with you !

  • Well, you have done a good job.

    The first step is done. Both cylinder work in the same condition.
    Your last problem is, the engine runs to fat now.

    The possible problems could be now:

    - the ignition time is to late (try it earlier)
    - the sparks are totaly wrong for your engine (to could)
    - the carbureter is maybe not right adjustet
    - the carbureter blast pips are the wrong one
    - the carburetors are totaly wrong for your engine

    With type of carbureter do you use?

    Sorry Scheppertreiber, I do´nt believ on a mechanical problem, because the compression pressure on both cylinder is nearly the same and not bad.

    Edited 2 times, last by B2Cruiser ().

  • Na B52,

    Dein Mitgefühl in Ehren, aber der Bua hat einen Schrotthaufen und kann nichts damit anfangen. Fakt. Anstelle Tipps braucht er eine Werkstatt die sich damit auskennt. So wird das nur noch schlimmer und der Rest geht auch noch zum Großen Russen.

  • Na ja Scheppertreiber,

    do kannst scho recht hoam. Auskenna duad se da Bua ned.
    Aba mia hamas zminast brobiert das ma eam heffan.... ;)

  • Hi B2,

    So carburettors are K63T adjusted with the same regulation (airscrew 1-1/2 turns, main jet 165 and slow jet 55).
    What is the correct sparkplug? (I use Champion L86C).
    How can I change the ignition time? I found the way to adjust the ignition pins distance but nothing to change the time.

  • jepp ,
    und das ist auch in Ordnung, finde ich.
    Wir sind ja alle mal bei Null angefangen =)

    Ich hab nur so meine Porbleme mit den engl Fachausdrücken ;(


  • Quote

    Original von marcut79
    Hi B2,

    So carburettors are K63T adjusted with the same regulation (airscrew 1-1/2 turns, main jet 165 and slow jet 55).
    What is the correct sparkplug? (I use Champion L86C).
    How can I change the ignition time? I found the way to adjust the ignition pins distance but nothing to change the time.

    I´m sorry marcut, I unfortunality do´nt have a M67, I have a Ural 750er. This is the reason I do´nt know your carbureter and your ignition good enough.

    Normaly you can change the ignition time in this way:
    The plate where the ignition pins are mounted on, is fixed with two screws on the engine. If you open this screws a little bit, you can spin the whole plate in clockdirection and backwards. This is the way to adjust the ingintion time.
    To find out when the right time is, you can usaly find a rubberstuff on your engine nearby the place where the gear is mounted on the engine.
    Replace this rubberstuff and you find a hole with the flywheel behind. Now you have to spin the engine verry slowly (4. gear) and the flywheel moves.
    you´ll find in the best case 2 marks on the flyweel nearby together now. The first one is the point, the ignition should work exaktly now.

    The best way is, you`ll find a book (maybe for a BMW) with a description in your language to do that. This worksteps are for the most bikes with mechanical ignition allway the same.

    I´ll try to ask the specialist for your bike in german language now, and if I get answers I´ll translate it back for you, if my english will be good enough for that.

    Frage an alle:
    - Passen die K63T-Vergaser zur M67?
    - Sind die Düsen 165/55 die richtigen für die K63T-Vergaser?
    - Sind die Luftschrauben mit 1 1/2 Umdrehungen in etwa richtig?
    - Welche Zündkerzen gehören in die M67? (er hat jetzt Champion L86C drinnen)
    - Wie wird bei der M67 die Zündung eingestellt (kann man da ganz normal die Grundplatte drehen? Hat das Teil eine Zünd-Markierung oder OT auf dem Schwungrad?)

    Edited 2 times, last by B2Cruiser ().