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Hi, I recently recieved a 1974 Yamaha DT250 enduro from a friend of mine. He said it was running when the guy gave it to him 2 years ago. I cleaned it up really good, replaced the battery, cleaned out the carb drained the gas and oil, put new oil and gas in. But I cant get it to start. When I try to start it black oil sprays out of the muffler. What do I do?!?!?
 

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Super Duper Mod Man
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Hi, I recently recieved a 1974 Yamaha DT250 enduro from a friend of mine. He said it was running when the guy gave it to him 2 years ago. I cleaned it up really good, replaced the battery, cleaned out the carb drained the gas and oil, put new oil and gas in. But I cant get it to start. When I try to start it black oil sprays out of the muffler. What do I do?!?!?
Ummmmmmmm...................Punt?
 

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Sounds like the rings might be frozen, and the oil is entering the combustion chamber. I'd pull the plugs and put in some Marvel Mystery Oil (about an ounce) and cycle the engine a few times. Let it set for a week with the Marvel in it. Then crank it over a bunch with the spark plug out. If the plug is clean, put it in and see if it'll start. You could try some starting spray too, sometimes that will get it going.

If all that fails, punt.
 

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Aging Cafe` Racer
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Did you check to see if you have spark? Lay the plug against the head and kick a few times, you should see a nice fat blue spark. Try freeing up the rings like K-K-K-Ken said...

If that fails, throw a Hail Mary..(they'll be expecting you to punt)
 

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Black oil out the back end of a two-stroke? Sounds like somebody left the fuel tap open for 2 years and pre-mix leaked down into the crankcase. The fuel portion evaporated leaving black, oily residue. You may have to remove the top end (simple on this bike) and flush it out.

You need four things to run: spark, fuel, air, and compression.

Check for spark with a fresh plug grounded against the head.
Check for compression by plugging plug hole with a finger and turning the engine over.
Check for fuel by sniffing the plug after removal.
Check air filter and entrance for debris, mouse houses, etc.

Good luck, and contact me if you need it hauled away.
 

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I should have read this first. I believe the bike in question had points. You may have to clean them, and they are behind the flywheel on the left side of the engine.

Good luck!
 

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It all depends. There is a shop in my city that specializes in stuff like this. Most larger shops won't go near it as it's too old.

Where are you located?
 

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any help on the stripped alen screw?
Go to the hardware store and get a set of spiral fluted screw extractors, also known as "Easy Outs." Drill the center of the bolt per the specification on the package. Insert the spiral fluted screw extractor with the supplied tool and remove the bolt. When the spiral fluted screw extractor breaks off in the hole, discard the motorcycle.
 

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Aging Cafe` Racer
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You need a little more help than you're gonna get on line there son....

To remove a stripped allen screw you need a correct sized drill bit and the correct sized e-z out. If you're REEEEEAL good you can use a drill bit that's allllllmost the same size as the screw, drill the center out and knock the rest out with a screw driver. I'm guessing you don't have a lot of experiance so most likely the e-z- out will be the best for you.. Lots of penetrating oil..lots of patiance..lots of luck..

I'd still go with the Hail Mary, you can see there setting up for a punt, you can go right around them....
 

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Aging Cafe` Racer
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Go to the hardware store and get a set of spiral fluted screw extractors, also known as "Easy Outs." Drill the center of the bolt per the specification on the package. Insert the spiral fluted screw extractor with the supplied tool and remove the bolt. When the spiral fluted screw extractor breaks off in the hole, discard the motorcycle.
Well ya' beat me to it that time dincha'......
 

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Go to the hardware store and get a set of spiral fluted screw extractors, also known as "Easy Outs." Drill the center of the bolt per the specification on the package. Insert the spiral fluted screw extractor with the supplied tool and remove the bolt. When the spiral fluted screw extractor breaks off in the hole, discard the motorcycle.
Easier to just drill the head off with a 1/4 inch drill bit. After the cover is off, use a vise-grips to tunr the exposed screw shank.
 

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MODERATOR X
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The 1974 DT250A

Had CDI ignition. It was the first year of the "NEW" Yamaha enduro, which incorporated the MX frame from the previous years motocross bikes, along with a through-the-frame exhaust system, lower CG, thermal flow shocks, etc.

If the bike is drooling black crud out of the exhaust flange, the lower end is full of crudded up gas/oil from sitting for a long time, Also, the crank seal on the primary drive side could be blown, and is sucking in tranny oil, causing the black goo.

And no, the headlight doesn't have to work for the bike to run. If you have "no spark" the best bet would be to buy a Clymer manual, and find a donor bike at a salvage yard, to pirate igniton parts off of. The '74 wasn't as easy to work on as the REAL Yamaha Enduro of '73 (that had a magneto/points igniton).

Contact Speed & Sport Yamaha in Bloomsberg PA for all the NOS parts you want. Tell Cindy I sent 'ya.
 
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