Trail 50 factory air filter makes motor bog down

Discussion in 'Tech Area' started by Clayton, Nov 10, 2019.

  1. Clayton

    Clayton Member

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    Hello every one first time poster here, I recently restored a 74 mini trail 50 (frame off) and found when I put the air box and filter on the motor bogs down when you go above 1/4 throttle. If I remove the filter the motor accelerates just fine. This is the factory air box and filter. The filter had a lot of oil on it when I opened it so in my trouble shooting I removed all the oil from the foam filter and it still bogs down. I am using a aftermarket carb that I bought from CHP motorsports, other than that every thing is factory. Any and all help would be greatly appreciated!!! Also I would like to thank everyone here for the great info iv got over the past year reading this forum.
     
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  3. Anthony Campano

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    Hi wondering what carb you purchased from chip. Was it the Chinese version. I like the cheaper version it runs great .
     
  4. Clayton

    Clayton Member

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    It was the cheaper one not the Honda brand one. It seems to work great with an aftermarket “sock filter” but with the factory air box and filter it bogs down. I still haven’t found a resolution, iv been using the “sock filter”.
     
  5. Anthony Campano

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    Hi you know you can purchase a correct Honda filter for your air box. I did just the opposite I took the stock air box off and replaced it with junk thinking it would run better I’m going back to stock this spring. I also learned so much from this forum hope all works out for you.
     
  6. racerx

    racerx Administrator
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    Obviously, the air filter assemblies are affecting the air:fuel ratio. You need to figure out if the assembly you want to use is a flow restriction...or less of of a restriction than your aftermarket replacement. As long as there's not more restriction than stock (in tip-top condition) then you should be able to adjust the carb to get the right A:F ratio (mixture). OTOH, if there is a significant amount of restriction, I'd want to figure out how to correct the problem...that little 49cc motor doesn't make a ton of horsepower, certainly nowhere near enough to sacrifice in the name of convenience. There is a reliable metric...top speed. MPH equals horsepower. Get the engine making full power with each setup, then compare top speed; if there's more than 1-2mph difference, there's one helluva restriction.
     
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