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Pressure Testing Two Stroke Engines

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  • #16
    Originally posted by matt89
    Anybody got a link to where I can buy a Mikuni Pressure Test Kit. I've been looking the last 15 minutes and all I can find is the Pop-Off gauge.

    Mikuni only makes pop-off testers for carbs. What kind of pressure tester are you looking for?
    "Insanity is doing the same thing over and over again, and expecting different results"

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    Porting by Lowell Horning "2-Stroke Porting.com" http://www.2-stroke-porting.com/


    01 SUV-1.8L SHO Conversion (Alex's Ski) Build has begun http://www.greenhulk.net/showthread.php?t=172812
    01 GPR 1300 Ported BB (77.1 @7100) (Sold Cuda67)
    02 GPR 1440 Stroked and Ported by 2-Stroke-Porting.com, Factory Triple Pipe project (Under Construction)
    99 GP1200 Ported by West Coast Porting, Bored 1mm over, Secret Mods Motor Broke in, tuning in process. This thing pulls hard with a 14/20 J prop.


    • #17
      Contact Lowell, he will take care of you...

      I Wanna Go Faaaaaaaaaast!


      • #18
        Sounds like Lowell is the way to go. I will give him a call. Thanks.


        • #19
          where do you attach the hose to pump the air in? oil injection port?
          04 GP1300R - IR R&D plate, Riva grate, PPK, Solas 13/19, Free Flow, Riva stuffers, Riva Filter

          02 Chevy Silverado 2500 HD

          99 Malibu Wakesetter


          • #20
            With Lowell's kit you hook the pump up to the plate which blocks off the top of the exhaust manifold.

            You want to seal off the oil injection ports if you are going premix.
            I Wanna Go Faaaaaaaaaast!


            • #21
              can this be done with the carbs attatched? Cap ceach carb and the ex mani exit? any precautions I should take?


              • #22
                gotta take the carbs off and block them
                2001 GPR

                Build Thread


                • #23
                  Originally posted by fivespeedsteed
                  gotta take the carbs off and block them
                  Any reason why? Just asking since it seems like you would need to check for leaks and then remove the blockoff plaes for the carbs and loosen everthing back up. what if you aquire a leak when removing the plates and installing the carbs? I guess its more of a common problem getting leaks between the intake and reed plate than the carbs? just curious.


                  • #24
                    Good stuff, thanks for the info


                    • #25
                      Do you have to test each intake/cylinder individually? Or, do you just pump air into one of the intake manifolds and it goes through the whole bottom end?


                      • #26
                        Originally posted by Shogun2
                        Do you have to test each intake/cylinder individually? Or, do you just pump air into one of the intake manifolds and it goes through the whole bottom end?
                        they get tested all together.

                        2stroke-porting.com sells nice pressure test kits if you need one or msg lowell on here
                        Winners Never Quit and Quitters Never Win.


                        • #27
                          Is it possible to pump air through one of the oil ports (I've also seen them called pulse lines). There are three of them and they sit right above the intake manifold and reed assembly.


                          • #28
                            I finally got my motor put together and was running to the hardware store (Home Depot & Auto Zone - the guy at Auto Zone looked at me funny and said he had never heard of pressure testing a motor....) to get the pressure testing parts, but they did not have the pvc pipe caps. They only had 1.5" and 2". I need 1.75" to fit my GP1200. Does anyone have any other suggestions of where I can look so I can get this thing pressure tested and on the water this weekend? Now I can tell I should have spent time sourcing these parts last week, if I could have.

                            And will the 1.75" PVC Pipe Cap fit snugly enough inside the intake? I am talking about the white PVC piece in this picture here. I also cannot find the black 1.75" compression caps either.

                            Thanks all.


                            • #29
                              Nevermind. I am going to blind flange off the intake with a rubber gasket and bolt the carbs down on top of that. Then use the pulse lines to supply the air.

                              Thanks O'side for the reminder.


                              • #30
                                Originally posted by OsideBill
                                I will never build a motor again without pressure testing before use.
                                +1 pressure testing is a must!! It is especially suicidal for anyone not 100% certain with engine assembly knowledge and experience to NOT pressure test. There are people here that have built many many engines and I would bet almost all... if not all, have the tools and pressure test each one, I know I do. Don't think that because you only plan on doing a repair once you don't need to pressure test. Buy, make, or borrow the tools or you WILL get bitten. On vacation in Lake George NY last year, I had WFO mail me a used cyl and piston set due to a failure. When the dealership performed a recall on my buddies 1300, they changed the sparkplugs for whatever reason, and left them finger tight. He melted cyl 1. I performed the repair in a parking lot with my buddy and WFO's used stuff, however my pressure testing stuff was at home. After riding for 4 hours or so my buddies machine once again bogged and melted. This time cyl #3. Because we were both thrashing on this thing to get it fixed,and didn't PRESSURE TEST IT, it cost him another cyl. My buddy only finger tightened 2 of the 4 cyl#3 powervalve cover bolts because the powervalve cables needed to be hooked up. Then they were never tightened after the cables were attached eventually causing the failure. It would have been easily noticed during pressure testing. Because I was helping him, I felt responsible. The point of all this rambling is, weather its your 1st engine or your 40th, anyone can get distracted and forget something stupid. You only remain feeling stupid if you don't catch your mistake.
                                03 GP1300R aka: "Nadine"
                                06 GP1300R aka: "Sarge"
                                Special thanks to "The Heavies"...you know who you are!