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#4745474 - 05/02/18 12:08 PM 1974 Yamaha dt250 Enduro
Richwood Offline

Registered: 04/30/18
Posts: 1
Loc: MI
I was gifted this bike in original state but has not been played since '86 and ORV since '88. Kick start still moves and there's surprisingly no leaks of fluids anywhere. My question is, what oils do I need to start getting it ready to be fired up again?!

#4745484 - 05/02/18 12:19 PM Re: 1974 Yamaha dt250 Enduro [Re: Richwood]
Dyusik Offline

Registered: 09/26/14
Posts: 2072
Loc: US-WA
I'd throw some kind of lube in the spark plug holes before anything. Drain everything, fill fresh, check the wires for oxide, clean the carb out, and try to start it. If it worked when parked, really these are the only things that will prevent it from starting and running just like it did the day you parked it.
95 Cherokee 190K DELO 10W30,XG8
07 IS250 98K Napa 10w30,FULL
04 YZF-R1 19K DELO 15w40,XG7317
99 HD XL1200S 18K VR1 20w50,1515
14 RX450h 32k PP MIX,NAPAG

#4745504 - 05/02/18 12:36 PM Re: 1974 Yamaha dt250 Enduro [Re: Richwood]
KMJ1992 Offline

Registered: 01/01/18
Posts: 100
Loc: Iowa, United States
Check the specs for oil, as old as it is it probably calls for 30w. I helped a friend fix one of those once, but a 350 i think. It was 2cyl and syncing the carbs was a biznatch. I use Valvoline 10w30 4 stroke oil in all my small engines. Does its job and i get it cheap at the local farm and home store. Its good for wet clutches if that has one. We didnt have to rip the motor apart on the 350, just fix the carbs, hoses, and wires.

#4745538 - 05/02/18 01:31 PM Re: 1974 Yamaha dt250 Enduro [Re: Richwood]
Reddy45 Offline

Registered: 08/15/08
Posts: 3070
Loc: USA
The OP's bike is a 2 stroke engine so a 4T oil wouldn't be the right suggestion.


#4745561 - 05/02/18 01:55 PM Re: 1974 Yamaha dt250 Enduro [Re: Richwood]
dinkydau Offline

Registered: 03/12/12
Posts: 96
Loc: RDM Oregon
It is a two stroke so make sure the injector tank is full of two stroke oil. Access under seat.Gear box/clutch should take 30wt. oil. Haven't seen a set of thermal flow shocks in ages!
Enjoy the your new ride.

#4745566 - 05/02/18 02:00 PM Re: 1974 Yamaha dt250 Enduro [Re: Richwood]
maverickfhs Offline

Registered: 12/28/16
Posts: 2113
Loc: VA
I LIKE these bikes, 2T is a bonus wink
2006 Civic EX 202K/AT
2006 Acura TSX 180K/AT

#4745592 - 05/02/18 02:21 PM Re: 1974 Yamaha dt250 Enduro [Re: Richwood]
Panzerman Offline

Registered: 12/16/06
Posts: 4217
Loc: Port Orange, Florida
I love these bikes. I have two. These are the true apocalypse motorcycles. 10w30 in the crankcase. Any oil will work. Doesn't matter if it's wet clutch compatible. The wet part is what's important not the oil. I put 10w30 conventional in mine. I would premix the gas but wouldn't worry about anything in the spark plugs hole. They have oil injection but it was a ancient design and not a really good one due to it's hooked to the throttle. Alot if these siezed because if your flying down the highway let off the gas no more oil to a high revving engine.
I unhooked the oil injection blocked off the oil feed into the crankcase and mix the oil 32:1 using a semi synthetic two stroke TC rated oil. I very had my little Yammies for over 5 years and they are a barrel of fun because they so little and wicked.
Lots of fun. I get more comments on my Yanaha DT at bike week then $20,000 Harley's. I love it.

2006 Dodge Ram 2500 Hemi 4x4
2016 Dodge Challenger Scat Pack

#4745596 - 05/02/18 02:24 PM Re: 1974 Yamaha dt250 Enduro [Re: Richwood]
Panzerman Offline

Registered: 12/16/06
Posts: 4217
Loc: Port Orange, Florida
Another thing I can let mine sit for 6 moths to a year and it usually starts by second kick.
Super simple, reliable design. You can take the battery out and still runs. I leave my battery in so the power has a place to go but truly a apocalyptic motorcycle that will run on anything.

2006 Dodge Ram 2500 Hemi 4x4
2016 Dodge Challenger Scat Pack

#4745602 - 05/02/18 02:28 PM Re: 1974 Yamaha dt250 Enduro [Re: Richwood]
CT8 Offline

Registered: 10/09/14
Posts: 11480
Loc: Idaho
2 stroke injector oil in that tank on the side below the seat, ATF or a 30 wt HDEO or a MC 4 stroke oil oil in the transmission. The DTs are beautiful.
"Don't let your preconceived notions get in the way of facts."
Geoff Metcalf

#4745722 - 05/02/18 04:33 PM Re: 1974 Yamaha dt250 Enduro [Re: Richwood]
gman2304 Offline

Registered: 08/11/11
Posts: 3115
Loc: n.c.
I had a DT250 back in the day. Even the same color! I would take the oil tank off and clean it, and possibly the gas tank and carb as well.

#4745727 - 05/02/18 04:40 PM Re: 1974 Yamaha dt250 Enduro [Re: Richwood]
Blkstanger Offline

Registered: 08/13/11
Posts: 1992
Loc: Lakeside, CA
Love the old DTs. I had a 74 DT 360 in High School. At the time the local PD had officers riding the same bike. It was strange seeing them around town on bikes just like mine.

Edited by Blkstanger (05/02/18 04:40 PM)
99 Jeep WJ 4.7 186,000 Maxlife 10w30, Fram Ultra.

#4745788 - 05/02/18 05:50 PM Re: 1974 Yamaha dt250 Enduro [Re: Richwood]
JimPghPA Offline

Registered: 08/22/09
Posts: 3875
Loc: Pittsburgh,PA U.S.A.
Put new tires on it. Tires that old are blowouts waiting to happen and a blowout at speed is something you do not want to experience on a motorcycle.

Back in 1973 I bought a 1964 Yamaha 175 2 stroke. I did not trust the 2 cycle oil injector so I pulled it off and ran pre-mixed gas.
Boy will I be happy when ALL vehicles on public roads are autonomous.


#4745819 - 05/02/18 06:12 PM Re: 1974 Yamaha dt250 Enduro [Re: Richwood]
Linctex Offline

Registered: 12/31/16
Posts: 6189
Loc: Waco, TX
Clean the mice out of the airbox.

I always left the oil injection pump in place and the oil tank filled, mine never quit - but I always added a tablespoon of STP to the gas, just in case!
"The evidence demands a verdict".
(Re:VOA)"it's nearly impossible to actually know the particular additives that are in there at what concentrations."

#4745826 - 05/02/18 06:15 PM Re: 1974 Yamaha dt250 Enduro [Re: Richwood]
AZjeff Offline

Registered: 01/14/11
Posts: 2839
Loc: PV Az
Blast from the past. I didn't have one but riding buddies had them from 125 to 360 and beat them mercilessly. True jack of all trades ride. The only thing that seemed to kill them was letting the 2 stroke oil tank run dry. Looks real stock except for the rear shock upgrade.
86 Samurai 1.3 leftovers
14 RAV4 2.5 5W-20 PP
16 Silverado 1500 4.3, DI, AFM 5W-30 PP

The most important thing to do in your life is to not interfere with someone else's life. - Frank Zappa

#4745904 - 05/02/18 07:19 PM Re: 1974 Yamaha dt250 Enduro [Re: Richwood]
Cujet Offline

Registered: 02/15/03
Posts: 7300
Loc: Jupiter, Florida
Those bikes had oil injection. Due to it's age, and unknown condition, I suggest pre-mixing the gas and oil at 40 to 1. The oil injection pump is very likely to NOT function (at least initially) due to congealed oil, air or a clog.

Use any quality two stroke oil designed for air cooled engines.

Also, many of those bikes had a unique electric start feature. They energized the engine's generator with battery power to directly turn the crankshaft over. There was no starter motor.

I can't recall if that particular year had that feature, but I think so.

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