Forums 🚥 PIT STOP 🔧 Hyosung Technical Help Finding the right needle & seat float valve for GT25R

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    • #5227
      Robert Wilde
      Member
      • Topics: 3
      • Replies: 5
      Joined:
      Apr 6, 2019
      @mrwilde
      Australia
      GT250R

      Hi and Hello, how are you doin?

      Here is my story… I got all the good bits from the shop recently, some main jets of the correct size (for some reason I had 95 front and 100 rear jets), mixture screws etc but I totally forget to get the full rebuild kit witch has the Float Needle Assembly.  I need that pretty badly it seems.

      The old ones were very embedded and had been mangled somewhat by previous attempt to remove them. I managed to get replacement o-rings on there and new needles (they also may be a problem). Bike started well and ran much better than before until I left it after the ride. I returned to find fuel leaking out of the front carb at a large rate, as well as the front cylinder intake full of fuel.  Not happy Jan! I should have expected that with the condition of the seat I put in there.

      So anyone way, I plan on ordering the Carb Rebuild kit but it won’t get here (Australia) until after NYE. I have found a local Mikuni Distributor that has a large number or parts but I am not 100% certain what Mikuni is in the GT250R 2006. I found I another forum that said it is the Mikuni BDS26 Double but not able to confirm.

      What I am hoping to find is the dimensions of the seat in the above kit and it matches the specs of this N133.200 Mikuni I can get locally. I want to double check the ones in the bike are the correct ones as well which is why I don’t just take those measurements and I have not dissembled it yet.

      It looks the same but I know, when it comes to carbs and most engine parts, 1 millimetre can make a difference.

      If anyone happens to know where I can find confirmation on the Mikuni in my bike, the seat dimensions or perhaps has one they can measure will be greatly appreciated. I also need to know the Feed hole size

    • #5232
      ♠️ MARCEL
      Administrator
      • Topics: 38
      • Replies: 511
      Joined:
      Apr 6, 2019
      @mf448kxn6
      North UK
      GTR

      I forgot the exact dimensions but you are right to say even a few mm off make a difference.  I know that the Hyosung Carb is based off BDS26 BUT… it doesnt use mikuni part numbers ,  notice on your own parts list.  The numbers are OEM based.  So Mikuni makes certain parts spec’d to Hyosung  while the empty skeleton body BDS26 is generic and used. Such as idle cables , metal hinges/guides, float bowls and that.

       

      It looks like you are totally rebuilding the carb at this rate!

      I do have loads of used parts for the carb in my trays taken off the hyosungs themselves.

      // Meditation doesn't mean you have to sit still....

    • #5238
      Robert Wilde
      Member
      • Topics: 3
      • Replies: 5
      Joined:
      Apr 6, 2019
      @mrwilde
      Australia
      GT250R

      Yes pretty much. I was lucky with the diaphragms still looking pretty good, everything on the vacuum side seems OK.

      I just found a guy today selling the vacuum pump and a carb of my exact model bike and he is shipping both those and some other bits for $100 AUD tomorrow. Hopeful that will get me all the other bits I need, mainly that t shaped overflow tube that sites in between the carbs.

      Appreciate all your help Marcel. Will be some more purchases next year to make sure everything is sorted on the bike. Being I bought it for $450 AUD I am doing OK so far.

       

    • #5243
      Robert Wilde
      Member
      • Topics: 3
      • Replies: 5
      Joined:
      Apr 6, 2019
      @mrwilde
      Australia
      GT250R

      I wanted to post update to my progress on rebuilding my carburettor for my 2006 GT250R.

      I have ordered rebuild kit from the shop, thanks Marcel, but due to current global issues (talking about you Rona) the shipping will be delayed. Due to my pending move, see above, I need to get the bike running now.

      The second hand carb I scored for $100 AUD arrived it was in very good condition pulled from the exact model I have. A great win for me, YAY. I also received the float needle and seat I ordered from Mikunioz. I outlined it above but you can find it here  N133.200 Mikuni . I purchased some digital vernier calipers, measuring down to 100th millimetre. The are identical, as far as the measurements go, also measuring the needle sizes as well. I found the spec for the Hyosung feed hole to be 1.2 mm (can’t recall where but that’s what I got)

      I took a photo and the N133.200 is the top one and the bottom one is pulled from the 2006 GT250R carb I bought second hand. Yes it was damaged pulling it as it was very hard remove. The original seats in my bike where way worse and were destroyed removing them. The o-ring was like hard plastic.

      I also connected a tube to the fuel intake and tested the needles are not leaking, by blowing into the tube (something I saw online for testing). Only thing I need to do now is get a new fuel filter as I put the last one in backwards 🙁

      Hope this info helps someone in a pinch, I am awaiting the arrival of the rebuild kit from the shop but will test this one until then, for science! (and I have no choice at this point)

      needle-and-seat-

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