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1993 DR 350 spark problem

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Is somebody had ever heard about a defective ignition coil on thoses bike ?? I have rebuild the engine on the bike with new piston / ring and the piston is a wiseco with a domed top for adding a little bit of compression. the bike refuse to start, i have alot of compression and even if i shoot starting fluid inside the carb, nothing happen. theres a good bleu/yellow spark when i test the spark plug outside the engine, but i think when the plug is in the cylinder, there is no spark anymore. the spark plug is new. Ihave to tell that the bike have no more light, speed indicator, battery ect... everthing was removed for make the bike a full dirt bike. At this point, my biggest problem is the fact that i bought the bike and it was not running, the compression was very bad, the carb was all dirty ect... So i dont know if my problem was there before i did the rebuild or if there a new problem ??? Any idea to fix that ??

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You sure it's a spark problem and not a valve clearance issue?

This bikes need good valve clearance or they will not run, a lot of so called carb issues turn out to be too tight of clearance on the inlet valves .

Rule of thumb , if you can't hear them , the valves are too tight.

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thanks for helping me !! Even if the valve was set too tight or too loose (not by far), with starting fluid shoot directly in the intake hole and a good and a strong spark from the spark plug,the engine should even try to start ??

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i'm tired to mess around with that bike. no one seem to know what wrong with this bike and why the engine dont start. i tought by asking question on a big web site like thumper talk i should find someone who know the DR but, i was wrong. after a fews weeks of research its enough. i will sell it for parts. how much can i get for a extra clean 1993 DR 350 ???

it got:

new piston and ring (wiseco), new clutch, new, intake and exhaust rocker, new gasket all around, fork oil and seal are new and oil the rear shock too, new front tire, 2 rear tires (1 new, not shown in the picture), new brake front and rear, new handle bar, new handle, new seat cover, new paint and decals on the tank and plastic fering. every part (cable, lever, caliper et... have been removed and clean). you can almost put this bike in a show room. But the engine dont start. Why, i dont know ?? It have compression, gas, a good spark (at least out of the cylinder) and air.

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Edited by bentech
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Don't despair just yet Mate , please give the valve adjustment a go .

3 Days ago my Son's dr350 wouldn't start , I mean not a murmur from it and it has always been a great starter .

We checked spark ,gas , fuel tank , fuel lines etc etc , no joy . Luke ran down to the auto shop and got some starter fluid , nothing nadda zip , not even the hint of a fire !

We had a big ride the next day so we had to get the bugger going , I thought the next thing was to check the valve clearance and whatta yer know the inlets were tight , adjusted them and it started instantly and has been running perfectly since .

I'm not saying I'm sure this is your problem but it is worth a shot before parting it don't yer think?

BTW Very nice Bike .

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In reading your first post again I have to ask are you absolutely sure you have the timing right with the cam chain ?

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like i said in the previous post, the timming chain is stretch a little bit, so the timing is off by a half theet. and the exhaust lobe are just a little bit under the minimum service limit. But many peoples that had the same problem said that the bike will start without problem. the bike will lose a little bit of power at high RPM. But the timing can't be that wrong because i still have compression.

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i dont know. I have the compression tester with many adaptors and no one fit the DR spark plug hole. So when i say it have compression its because it hard to crank the engine with the kickstart i it become much more easier with the decompression lever on.

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theres a good bleu/yellow spark when i test the spark plug outside the engine, but i think when the plug is in the cylinder, there is no spark anymore.

Here's a quick check for the spark strength:

Unscrew the spark plug cap from the plug wire. Jam a short wire or paperclip into the wire and hold it close to the cylinder head. If you can see a 1 cm spark, then your ignition coil/CDI/stator is not the problem. I think the manual says 9mm, but if it's in the ballpark, you should be OK. You might check the spark plug boot and wire/boot connection also.

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thank you everybody !! finally, the problem is not the fire. there's air who's coming out from the carb when the piston goes up in the compression stroke. that's mean that the one or both of the intake valves are not seated properly. i rechecked the valve adjustement and they are in the specs (0.004 in).

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