Jump to content
Sign in to follow this  

1974 XL 125 won't start. Need Help

Recommended Posts

My 1974 xl 125 wont start. could anyone give me some ideas i could try to get it started?

Anything will help. Thanks.

Share this post


Link to post
Share on other sites

Well you have not said if you have spark, so....

first, power in battery

then make sure switch works check for continuity through switch.

clean the points with a good sharp file or some course paper

with all that done, turn engine over till points are closed, turn on key and with small screwdriver, open points and look for a spark from points.

get that far and let us know what you have

Edited by thumpharder

Share this post


Link to post
Share on other sites

An engine needs three things to run, fuel, compression and ignition - lose any of the 3 or a combination there of and it won't run. That being said and not knowing your plight for certain and it being new years eve, I will give you a bone...

Is there fuel in the tank and is it getting to the carb? check this by turning on the gas and loosening the float bowl drain. Also after leg exercise gained from starting attempts, remove te spark plug if it is dry fuel is not reaching the engine from the carb, (too low of a float setting as an example) if it is wet - odds are the ignition system is at fault - it is wet because it is getting fuel.

To check for spark, remove the plug insert into the plug cap and lean it against the head, turn on the key and kick it, you should see a nice blue spark. If not, then unscrew the plug cap from the coil wire - nip a wee bit off with a pair of dykes an screw the cap back on, check again for spark, if still none the move onto the points and the wiring connections, follow to the main harness and check the black and white wire is connected securely and not corroded - adjsut the points to .012 and as mentioned early clean them and check for spark at the points. This bike does NOT need a battery to run, only for checking current flow at the points.

To adjust the points - remove .... no go get a a clymers manual.

Lastly is there resistance at the kick lever? i.e. compression? if it is very easy to turn over (by hand) with the plug installed - chances are the compression is too low to make a charge ignitable. if that is the case you could kick it for a thousand years and it will nevr start. Low compression is a sign of a worn engine, and a lack of seal in the combustion chamber by the piston rings, valves or both. The only fix then is what we call a top end job, new piston rings, valves, steam seals and gaskets. Most people replace the cam chain too while it is apart.

Share this post


Link to post
Share on other sites

I do have spark, its pretty small though. Right now i do not have a battery for the bike, I am hoping to get a new one soon. The carb is getting fuel, i know that. The spark plug i think is getting wet when i try to start it but its like oily (black and wet) is this bad? and what would cause it to get oily?

Ill go try some of the things you guys mentioned and get back to u

Thanks for the replies.

Share this post


Link to post
Share on other sites

Alright, I re-gapped the breaker points to .012. then tested the spark again, and it gets a spark big enough to ignite the mixture. I tried to start it again and the first kick it sounded like it was about to start so i kept trying but it seem to not get any better. I will test the condenser when i get a battery. Should i just get a whole new electrical system, the one on the bike is pretty old and has been taped together with electrical tape. I also think it might be the coil. could it be the coil?

Share this post


Link to post
Share on other sites

Hi Jeff13....maybe it's just getting flooded...

If your plug is wet after trying to start it's wet from too much gas in the combustion chamber. It's looks oily because there's oil in there too...Giving the bike too much throttle while trying to start is usually the cause.

Take the plug out and blow it dry...while it's out, shut the key off, shut the gas off hold the throttle full open and kick it a few times to clear the rich mixture.

Put the dry plug back in. Then, without touching the throttle, turn the gas on, turn the key on, make sure the kill button is set to run, turn the choke on and kick again. Don't give it any throttle until it runs. If everthing is okay it will start.

Sparkle

Share this post


Link to post
Share on other sites

Yes i do have fuel flow. Ill try what you said patuca when i get a chance. do you think having too much oil in the engine could cause it too flood? cause when i got the bike it had too much oil and still does.

Thanks, sorry im a noob at this stuff.

Share this post


Link to post
Share on other sites

BSPS. Black sooty plug syndrome. If wet, BSOPS. Black sooty, oily plug syndrome. Most often caused by low compression or incorrect ignition timing.

Set everything to factory specifications, check the advance as mentioned earlier.

My bet is that you top end is tired and it is simply fouling plugs.

Share this post


Link to post
Share on other sites

Jeff13 don't run your bike with too much oil. When the piston comes down on the overfilled crankcase it could blow the crankshaft seals....But it also pushes oil up the

crankcase breather and into the carb and then into the combustion chamber. This could be the oil on the plug and why the engine won't start..

Drain some out...or do an oil change.

patuca

Share this post


Link to post
Share on other sites

What happens if oil does get fuel contaminated?

Is ther a way to check compression without the special tool thing? and wat exactly is the advance thingy?

i think ill try draining a bit of oil. if i can figure out if im getting compression itll be easier cuz if i am then itll have to be the ignition system.

Thanks.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Reply with:

Sign in to follow this  

×