Skip to content
  • Recent
  • Tags
  • Popular
  • Users
  • Groups
Skins
  • Light
  • Cerulean
  • Cosmo
  • Flatly
  • Journal
  • Litera
  • Lumen
  • Lux
  • Materia
  • Minty
  • Morph
  • Pulse
  • Sandstone
  • Simplex
  • Sketchy
  • Spacelab
  • United
  • Yeti
  • Zephyr
  • Dark
  • Cyborg
  • Darkly
  • Quartz
  • Slate
  • Solar
  • Superhero
  • Vapor

  • Default (Slate)
  • No Skin
Collapse
Brand Logo

DT125R FORUM

  1. Home
  2. Technical Zone
  3. Brakes
  4. difference between 3BN and 3MB head

difference between 3BN and 3MB head

Scheduled Pinned Locked Moved Brakes
19 Posts 5 Posters 7.9k Views
  • Oldest to Newest
  • Newest to Oldest
  • Most Votes
Reply
  • Reply as topic
Log in to reply
This topic has been deleted. Only users with topic management privileges can see it.
  • britshgigoloB Offline
    britshgigoloB Offline
    britshgigolo
    wrote on last edited by
    #5

    0_1483566895065_DT125RHeads diffrences.jpg

    1 Reply Last reply
    0
    • D Offline
      D Offline
      dtr mkd
      wrote on last edited by
      #6

      thanks for the photo. i just need to grind off the ring. what compresion should i get then. the bike has new top end
      thanks

      CalumC 1 Reply Last reply
      0
      • D dtr mkd

        thanks for the photo. i just need to grind off the ring. what compresion should i get then. the bike has new top end
        thanks

        CalumC Offline
        CalumC Offline
        Calum
        wrote on last edited by
        #7

        @dtr-mkd No, simply just no.

        Did you not read my response bud. The Squishband is critical in getting performance out of a two stroke. A high percentage of power can be made or loss at the head.

        Seriously bud, if you don't know what you are doing then get a specialist to do it.

        Always Originate, Never Pirate!

        D 1 Reply Last reply
        1
        • britshgigoloB Offline
          britshgigoloB Offline
          britshgigolo
          wrote on last edited by
          #8

          just spoke with Mick Abbey and he charges £35 to do a 3bn head money well spent

          1 Reply Last reply
          1
          • CalumC Calum

            @dtr-mkd No, simply just no.

            Did you not read my response bud. The Squishband is critical in getting performance out of a two stroke. A high percentage of power can be made or loss at the head.

            Seriously bud, if you don't know what you are doing then get a specialist to do it.

            D Offline
            D Offline
            dtr mkd
            wrote on last edited by
            #9

            @Calum thanks calum but as i said i am not from uk and not specialist near me at all so i will have to figure it out by myself. now i have to learn about Squishband. are there any measurements about that. thanks anyway and i forgot: happy new year 🙂

            CalumC 1 Reply Last reply
            0
            • D dtr mkd

              @Calum thanks calum but as i said i am not from uk and not specialist near me at all so i will have to figure it out by myself. now i have to learn about Squishband. are there any measurements about that. thanks anyway and i forgot: happy new year 🙂

              CalumC Offline
              CalumC Offline
              Calum
              wrote on last edited by
              #10

              @dtr-mkd I'd suggest buying Graham Bell's Two Stroke Performance Tuning. That book would contain everything you would possibly need to know about building a two stroke motor, including modifications to the head.

              Always Originate, Never Pirate!

              1 Reply Last reply
              0
              • J Offline
                J Offline
                Jens Eskildsen
                wrote on last edited by
                #11

                I wouldnt bother, the performance between the 2 alone should be hardly noticable... You still wont win any dragraces... 🙂

                CalumC 1 Reply Last reply
                0
                • J Jens Eskildsen

                  I wouldnt bother, the performance between the 2 alone should be hardly noticable... You still wont win any dragraces... 🙂

                  CalumC Offline
                  CalumC Offline
                  Calum
                  wrote on last edited by
                  #12

                  @Jens-Eskildsen I beg to differ. As said, most of the power of a two stroke can be found in the cylinder head. It's well worth investing money into the head.

                  As said, don't take my word for it, read that book.

                  The head alone won't win races, but it's a really good place to start, other mods like exhaust, jetting and intake will see noticeable gains.

                  Although the single one thing I'd recommend over anything else is a custom ignition.

                  Always Originate, Never Pirate!

                  1 Reply Last reply
                  0
                  • J Offline
                    J Offline
                    Jens Eskildsen
                    wrote on last edited by
                    #13

                    @Calum said in difference between 3BN and 3MB head:

                    @Jens-Eskildsen I beg to differ. As said, most of the power of a two stroke can be found in the cylinder head. It's well worth investing money into the head.

                    As a genral rule yes, but this was specific between the 2 heads listed by the PO.
                    Heck, some people even tried and had a hard time noticing any difference.

                    So I still stand by my comment, I dont think its worth the cost for us foreigners who cant just get a head fixed for 35 quid. Most shops here charge you about 35 quid for just walking in to the shop. I think a normal skimjob is more than 35 here in Denmark. Let alone any custom work.

                    1 Reply Last reply
                    0
                    • britshgigoloB Offline
                      britshgigoloB Offline
                      britshgigolo
                      wrote on last edited by britshgigolo
                      #14

                      my reprofiled 3BN head by mick abbey tuning is done and looks great just need to get it back and fitted now 0_1484252329973_3bn head reprofiled.jpg

                      CalumC 1 Reply Last reply
                      2
                      • britshgigoloB britshgigolo

                        my reprofiled 3BN head by mick abbey tuning is done and looks great just need to get it back and fitted now 0_1484252329973_3bn head reprofiled.jpg

                        CalumC Offline
                        CalumC Offline
                        Calum
                        wrote on last edited by
                        #15

                        @britshgigolo Nice one mate that looks a million.times better

                        Always Originate, Never Pirate!

                        1 Reply Last reply
                        0
                        • britshgigoloB Offline
                          britshgigoloB Offline
                          britshgigolo
                          wrote on last edited by
                          #16

                          cant wait to get it to try it out as got new cylinder waiting to go on as well

                          1 Reply Last reply
                          1
                          • CalumC Calum

                            The 3BN head has a combustion ring around the combustion chamber. Disrupting the combustion flow.

                            The 3MB head does not have this ring.

                            Grind out the ring, correct the squish band and have the compression corrected and it'll be just as good, if not better, than a 3mb. Mick Abbey ported my 3MB head for £30. So I'd imagine he'd be able to derestrict a 3BN for around the same price.

                            S Offline
                            S Offline
                            scotty
                            wrote on last edited by
                            #17

                            Grind out the ring, correct the squish band and have the compression corrected and it'll be just as good, if not better,

                            What do you mean by ''correct the sqish band''..what a sqish band ?
                            And how do you correct the compression bud ?

                            CalumC 1 Reply Last reply
                            0
                            • S scotty

                              Grind out the ring, correct the squish band and have the compression corrected and it'll be just as good, if not better,

                              What do you mean by ''correct the sqish band''..what a sqish band ?
                              And how do you correct the compression bud ?

                              CalumC Offline
                              CalumC Offline
                              Calum
                              wrote on last edited by
                              #18

                              @scotty Correct the compression is simply getting the compression ratio back to how Yamaha specify it.

                              The Squishband determines how the combustible mix is compressed.

                              I suggest if you really want to know more that you perhaps read a book on the subject. I would be lying if I said I know what to do, it's a tuners job. I would suggest Graham Bell's Two Stroke Performance Tuning as a good book.

                              Always Originate, Never Pirate!

                              S 1 Reply Last reply
                              0
                              • CalumC Calum

                                @scotty Correct the compression is simply getting the compression ratio back to how Yamaha specify it.

                                The Squishband determines how the combustible mix is compressed.

                                I suggest if you really want to know more that you perhaps read a book on the subject. I would be lying if I said I know what to do, it's a tuners job. I would suggest Graham Bell's Two Stroke Performance Tuning as a good book.

                                S Offline
                                S Offline
                                scotty
                                wrote on last edited by
                                #19

                                @Calum cheers mate,I'll look out for that book

                                1 Reply Last reply
                                0
                                Reply
                                • Reply as topic
                                Log in to reply
                                • Oldest to Newest
                                • Newest to Oldest
                                • Most Votes


                                • Login

                                • Don't have an account? Register

                                • Login or register to search.
                                • First post
                                  Last post
                                0
                                • Recent
                                • Tags
                                • Popular
                                • Users
                                • Groups