For general Technical and Performance Discussions
Thu Mar 05, 2009 8:41 pm
gpz600r 1985
gets fuel (pulled the plugs and they wet)
has spark (checked and has it)
turns over and does not fire.
any ideas
Thu Mar 05, 2009 9:07 pm
hows the compression?
Thu Mar 05, 2009 9:15 pm
dunno will try to check this weekend.
would there be anything else to consider?
Thu Mar 05, 2009 9:26 pm
your valve clearances are too tight. Probably the inlet valves. Poor (or non) cold starting is a classic symptom of tight (or non-existent) valve clearances......
thats the first thing to check. There are other reasons for low compression

, but lets not worry about those for the moment.....
If the valves need adjustment, I think the little geeper had screw/locknut adjustment ? Its a piece of piss to do.
Next thing to check is battery voltage while turning the engine over - you want at least 12.5v or more when cranking.
See how you go with valve clearances first.
Thu Mar 05, 2009 9:36 pm
as Gos sez
but wots with wet plugs?
either its flooding (carbs ? blocked air filter?)
or spark is weak
or valve clearances are shite (yeah Gos..screw and locknut )
wots been done recently to the bike?
Thu Mar 05, 2009 10:06 pm
new plugs
new air filter
new oil and filter
all within 1000 kays
unsure of other work as i just picked it up
was hard to start cold (battery or clearances)
Thu Mar 05, 2009 10:08 pm
unfortunatly i don,t have a manual so a little unsure on doing the clearances.
any tips?
Fri Mar 06, 2009 5:05 am
not sure exactly but 0.10mm should be somehere within spec for any bike. specs for most bikes usually sits between 0.07 & 0.17mm. if you opt for 0.10 then it may be a bit closer together for the exhaust valve than is preferable. Also a trap for new players (myself included in being caught out by this at least once) is forgetting to correctly check the clearance after the locknut was pinched tight, not a good thing to do!
Fri Mar 06, 2009 12:49 pm
is there a downloadable manual or link that anyone knows of.
Fri Mar 06, 2009 1:09 pm
http://tinyurl.com/5b3qzcI have nfi if this still works, my work internet police block the site.
Mick
Fri Mar 06, 2009 2:17 pm
awesome downloaded and gives me something to do when not drunk(maybe easier if i am)
Sat Mar 07, 2009 10:28 am
inlet valves are to tight.
how wrong can i get it and whats the worst that can happen.
will try over weekend.
thanks guys
Sat Mar 07, 2009 11:30 am
If it's too tight then theres a possibility that the valves dont close if they have zero clearance when hot. Not closing means that they can overheat due to 1) continual exposure to flames from the ignition on both sides and 2) no surface contact with the head to allow excess heat to effectively disperse. Oh and then there's the fact compression is reduced, effective airfuel load reduced and generally the whole thing being totally mechanically unsympathetic.
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