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dt125lc (mk3) ignition problems


NEwin
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hey,

I left the bike outside over winter (covered as much as possible, but i don't have any inside storage space).

When I tried starting it up again a few weeks back, the engine wouldn't start. I don't really know too much about the mechanical side of things, and I figured this would be a good excuse to start.

Any ideas?

I thought I'd start by changing the spark plug - i've no real reason for thinking this will solve the problem, but again, it seems like a relatively basic task that I should probably learn, even if it doesn't solve my immediate problem.

cheers!

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so i suppose a good start would be to ask, what sort of things should i be looking for, in order to help me diagnose the problems.

cheeers.

The newer DT's differ from the older bikes in that the battery has to be charged for them to start, the clean plug will help. Other than that it should go.

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If it's been left over the whole winter with fuel in the carb, you'll almost certainly have a blocked starter jet preventing the choke from working and possibly likewise for the pilot jet.

You will need to drain the carb and flush it through with clean fuel at least. If you are very lucky that might be enough to do it.

Won't be a battery issue as MkIII models use AC flywheel CDI system.

Cheers.

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Turn the petrol off, kick the bike a good few times to clear it out incase you've flooded it.

Take the spark plug out.

Put the lpug into the ingition cap, you may need someone else to kick the bike whilst you watch the plug to see if its sparking. If it is, make sure the sparks are continuous. If it doesnt spark or its sparking randomly, get a new spark plug.

If its fine.

Check that there are no bits of dirt or anything in the gap. If there are, clean them out or get a new plug.

If that dont work try...

Holding the business end over your gas burner in the kitchen (whilst its lit usually helps :P) to warm it up. You need to burn all the petrol out of the gap and area that goes inside, if that makes sense?

It will get hot so have some gloves on or somthing to protect your hands.

Put it back in the bike.

Put the petrol onto reserve, incase its low on fuel.

Put the choke on, and kick it a few times. If nothing happens after a few times.

Petrol off, kick it a bit to clear the engine, and try again.

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hey guys - cheers for the advice - very useful!

I'll try all this over the weekend, and see how it goes.

cheers!

When you check for spark, put plug into cap but remember to rest it on cylinder head, to earth the threads or hexagonal part of plug! Do not hold it! This should then show if sparking or not.

The most likely cause of this problem is that the carb jets will be blocked due to non use during winter and therefore the carb will have to be dismantled and cleaned carefully.

Do this by removing float bowl to get access the brass or nylon jets. Remove and clean them out with suitable cleaner or try blowing them but best not to use wire etc. on soft brass jets as this may damage them.

Make sure fresh petrol is used as it goes 'off' after a while, or so I'm told.

Good Luck!

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so tried the spark plug, and didn't see a spark whilst kick-'starting'. Replaced the plug and still didn't see a spark. I'm assuming that you don't have to worry about the gap size for a new plug? (I don't have anything that's capable of measuring a small gap accurately anyway :) )

it is possible/likely that the ignition coil is damaged?

also, ran the carb through with petrol and that didn't fix anything so maybe i need to play around with the jets.

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