KH125 wont run

[graeme]

I bought a kh125 for my wife, non runner.

When i got it the guy said the exciter coil was damaged, it had some superficial damage.
Bike had no spark.

I unwound a very short bit of wire from the exciter coil to get past the damage, re-soldered everything and now it has good spark.

Battery is flat though.

Ive stripped and cleaned the carb and fuel is getting through but it wont start. Will it not start with a flat battery? I figured it should as it has spark.

Any ideas?

Damm things 6v so cant even put my good 12v battery on it (i assume), got no charger either.

Cant even get a manual for it!

Wiring is a little chopped about but i downloaded a wiring diagram and went over it and it all seems to be correct.

Bit lost now as to why it wont run, not even bump starting on a decent hill would do it.

[dungbug]

Does it have compression? Might be an idea to get another battery for it, I'm sure Terra will be able to put up some more pointers.

[twoblackcats]

Points or condenser may be worth a shot if it has spark fuel and compression.

NB; Many a bike with low comp has been started by dropping a little 2 stroke down the plug hole to do a temp job of what the rings should be doing. Often this allows start up and the bike will then run, not really a long term fix mind!

[graeme]

I think it may be more serious. Doesnt draw through teh carb very much and seems to blow back as much as it draws.

I think its either a rotary valve problem or crank seals.

Ill pull the motor and take it apart, quicker than all teh guess work.

[TerraRoot]

Is the plug wet with fuel? best way to check if the fuel is actually going in.
Some body could have done a bodge tuning job in the past and chopped up the rotary disc for more inlet duration, not good.

[graeme]

Its wet, and smells of fuel so i figures some is getting through.

I was shown a link to a thread of a guy with the same problem, turns out it was the previous owner of my bike.

He got it running, then took some bits off again.

He was unsure about teh valve and which way round its fitted, apparantly it can go 2 ways and each way varies valve timing.

I think it still didnt run great though.

Its had a rebore and piston apparantly, i thought these weren't lined? Its not got a new barrel so its either been expensively re-bored and re-plated, im wrong about no liners, or its not true.

I dont think ive much choice, i need to take it apart to be sure of whats going on.

[TerraRoot]

show us the previous owner thread, might spot something.
with all that work, something has bound to have gone wrong, piston fitted backwards?

[graeme]

its here

kawasakiownersclub.com/topic/7195313/1/

[TerraRoot]

nothing of use there im afraid, try easy start to rule out stale petrol?

[graeme]

Its had loads. I even put petrol and ether down the bore and still no joy.

Im ignoring it while i re-plum the kitchen and put the gsxr together. Maybe that'l teach it and it will run out of shame.

Left it in the rain as punishment.

[TerraRoot]

well with petrol and spark it should run, unless you have no air (disc timing very wrong) or it's sparking at the wrong time or a weak spark. borrow a spare coil and wack it on?
what does a kh125 have? points? cdi?

[graeme]

points, no advance mech that i can tell either.

[jonw]

Sounds like either a weak battery of bad connection. 6V is a bugger as loosing a volt is one 6th of your potential gone. (or about 5000V at ignition!!!!!)

I have this with the cub. The battery has to be tip top for good running.

[argentum40]

might sound like a daft thing to say but have you tried another plug?... reason i say this is my RXS which is also 6v by the way had a spark when the plug was out and resting on the engine but wouldnt fire.... i replaced the plug and she has been as sweet as a nut ever since..

also if the battery is totally flat it will really struggle to start... my old rS125 wouldnt start with a knackered battery