Author Topic: vintage 2 stroke question  (Read 4313 times)

Offline yoman

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vintage 2 stroke question
« on: August 30, 2011, 06:29:29 AM »






1978 KE 125 oil injection question

I have a 1978 KE 125 project and I have a few questions about the oil injection system. Should I use it or disconnect it and run pre-mixed fuel? What is the best way to disconnect it. If I do disconnect it what fuel/oil ratio should I use?

Thanks and ride safe
 Yo
2002 Semi-naked Connie

Offline George R. Young

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Re: vintage 2 stroke question
« Reply #1 on: August 30, 2011, 07:13:19 AM »
I had 3 2-strokes, Bridgestone 350GTR, Yamaha R5 and Yamaha RD350. They all had oil injection and it always worked flawlessly.

Having said that, the ignition from that era (early '70s) was rather anemic, and a 2-stroke needs all the spark it can get. The symptom is short plug life before fouling. If your bike has points/coil ignition, you might try an automotive or some other ignition coil, with a ballast resistor to limit current thru the points - I did this on the RD350.
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Offline westkyguy

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Re: vintage 2 stroke question
« Reply #2 on: August 30, 2011, 08:10:38 AM »
 Depending on jetting we always ran 20-1 in our old Yamahas, sometiemes 16-1 on a screaming WFO flat track. If there is nothing wrong with the oil pump or cables I would leave it on, why have to mess with premix?

Offline Cholla

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Re: vintage 2 stroke question
« Reply #3 on: August 30, 2011, 10:17:35 AM »
I would rather use mixed fuel. It never gets mixed with premix.;-)
As for the ignition system there is bound to be an electronic unit still available. As for the gas/oil ratio I haven't a clue.
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Offline rcannon409

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Re: vintage 2 stroke question
« Reply #4 on: August 30, 2011, 01:19:31 PM »
I had one of those. The odometer quit working with 15,000 DIRT miles on it, and was ridden for several more years.  The only thing the bike needed was to have the points filed occasionally. Sure, new points would have been nice, but I had no flywheel puller. As George mentioned, the ignition system is pathetic, but easy to repair.

The oil injection system on that bike worked very well. I woudl not bother messing with it other than to make sure the left sidecover does not pinch the plastic oil line.


Offline Silver Connie

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Re: vintage 2 stroke question
« Reply #5 on: August 31, 2011, 09:50:18 PM »
i had a ke 100 when i was a kid, ran that thing wot most of its life. i never had any oil inj problems.  i had a 77 rd 400 and no problems with it. id leave it on. its way too convienient.

Offline mjrfd99

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Re: vintage 2 stroke question
« Reply #6 on: September 02, 2011, 07:33:32 AM »
The stock pump on mine works great. The newer synthetic 2-stroke oil makes almost no smoke and I haven' fouled a spark plug yet since using synth.  Most of my friends are not pre mixing.