I have a 76 KD 175 that rips through first and second gear no problem, but as soon as i hit third and hammer the throttle it bogs down and dies if i dont let off.....I have had the carb off and cleaned didnt do a carb kit on it though. Changed the fuel line from the origional clear hose that was pretty much solid brittle plastic after all those years, the line i replaced it with is slightly larger in diameter from what i can see, that didnt change anything so i thought i would check the "pep-****" (if that's what its called still lol) cause i was told there might be a filter in there. Sure enough there was a screen there but one of the previous owners decided to take a 3"x3" piece of gauze and fold it up to fit in there and jammed it on top of the exsisting screen. So i got rid of that cleaned the screen put the tank back on and went for a boot, It ran alot better but still the same prob.....I have spoken to countless people about it and no one can figure it out.....So if anyone has any ideas about this pls let me know

Thanx a crap ton!!

 

One thing i forgot to add dont know if it means anything but.....When it did run good before this problem the choke had to be on. Still to this day to idle or anything even after its warm the choke has to be on. Not on full but on. i took the cover off to expose the carb and it spits fuel out of a hole on the front of the carb when the choke is on. Im no mechanic but i know cars enough to fix my own, when it comes to small engines especially 2 strokes im clueless.

 

Sounds like the carb needs to be cleaned. There are a lot of little passages. Youtube has lots of videos. I found diagrams on the Ninja 250 site that were pretty good, though for a diaphragm carb. Gives you an idea how to make sure all the little passages are clear.


Cleaning the carbs 2 - Ninja250Wiki

My dad has a 1973 F7 175 and I cleaned the carb up a few years ago but it fogs a lot of oil till 3rd gear then runs like a raped ape. I'm suspecting an internal seal might be leaking oil into the piston area and I'm not motivated to tear into that.