Early 70's Enduro runs, boggs down when throttle is opened...

Konoc

Member
Sep 7, 2008
6
0
Hello all, thanks in advance for any help I get. I've gotten alot of info off of these boards, though this is first time posting.

I just bought an early 70s Yamaha Enduro 250. Guy I bought it from said he had it running last year, but it's been sitting since then. I am fairly mechanically inclined, so bought it as a project.

First thing I took off the tank and got rid of all the old gas, cleaned out tank, fuel selector switch, and put back on before puttin new gas in. Changed the oil and plug, then gave her a try. She started right up! It was awesome! She bogged and choked as soon as I hit the throttle though.

Took apart the carb completely and cleaned every inch of it. Floats move freely, it wasn't in that bad of shape. I'm confident the carb is in good working order. It will now start and idle perfectly, but when you hit the throttle it drops revs and sounds lean. I could be wrong about the sound, but that's what it sounds like to me. Ideas???

Again, thx in advance for any help.

r.
 

tweek49

Member
Dec 30, 2006
64
0
This happened to my '99 RM125 a couple days ago.... First I thought it was just the plug, but nope. Then I drained all the gas, maybe there was water, no. I then cleaned the air filter, that wasn't it either. So I took the carb off, cleaned it top to bottom and fiddled with the jetting, that wasn't it either. So I thought I swalloed a reed, nope they were good. Checked all the connections and they were okay. Checked the exhaust for anything pluggin' em up, nope. Adjusted my power valves, and that didn't help. Finally I took the ignition cover off, and not cause I thought that was it (it had a little crack in it and I was gonna fix it up) turns out I completely screwed up my flywheel. I don't even know how it happened...
 

Konoc

Member
Sep 7, 2008
6
0
A buddy and I fooled with the timing, seems to be in good order. Ordered a jetting kit from a shop in town, hopin that is it. I'll let you guys know.

Thank you for the help/advice all, really appreciate it.

r.
 
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