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GS425L Restore

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    GS425L Restore

    Hey everyone. New member and complete motorcycle noon here. In fact I don't even know how to ride a motorcycle... But as a recent unemployed grad, I really wanted a hobby. Turns out, bikes are amazing, who knew. I'm stuck right now though, and was hoping the elders might help me out.

    About the bike:
    The bike looked like it was in good condition besides some cosmetic rusting, and only had 14k miles on it. The previous owner ran a motorcycle business out of his home, and he showed me that the bike would run, but couldn't idle for very long. He thought it was a simple carb issue, and otherwise it'd be back on the road in no time. The cluster lights turn on, although he had to jump the relay solenoid to get it to start.

    After bringing her home, I pulled the carbs and did a full disassembly and cleaning using carb cleaner and a thin wire to poke out all the holes. Then squinted more carb cleaner through all the inlets to make sure everything was clear. The carbs themselves looked quite good, I just replaced the O rings and main jet as it was pitted. The airbox looked filter looked brand new, so I left that in, and I bought a new battery and plugs. I verified that the starter, plugs, and petcock worked, then put the carbs back in. The after trying to get the bike to run off both the starter and Kickstarter, the only thing I got was one pop and some white smoke out of one exhaust. I pulled the carbs again and the float bowl was full of gas, not really sure what's going on here. I checked that the slides were working correctly by blowing into passage leading to the diaphragm and got nice, smooth motion.

    So this is where I'm stuck. Maybe since I'm completely new to bikes I'm making a very simple mistake in starting it? The start button itself doesn't seem to work either. I was thinking perhaps I wasn't getting enough vacuum to squirt enough fuel into the cylinders, and my next step is to completely redo the wiring. I also noticed that the o ring on the air mixture screw was pretty tight. When I tried taking it out it slipped passed the groove and onto the threads. If anyone has any suggestions on what could be the issue, that'd be awesome and greatly appreciated.

    Thanks everyone!

    #2
    Just replied to your other thread - I'll stay in this one from now, though, on since it's in the appropriate section
    1980/1981 GS450 - GS500 Cylinder + Piston Swap - "De-L'ed", custom seat, CB350 bits, 18" rear, etc.
    1977 GS550
    1977 GS750 - Cross country trip thread

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      #3
      I did a full 24 hour dip and did check both float bowls. All lines were connected I think. As for lines, this is what I have set up:

      Fuel hose going from petcock to T connecting the carbs
      Vacuum line from petcock to nipple on side of carbs
      Vacuum line going from airbox to engine
      Vent line from bottom of airbox
      2 vent lines on bottom of bowls
      2 vents near the in middle section

      I'm not sure exactly what sound it's supposed to make when you kick it but I think there's a sound coming from near the airbox, might be a leak. Is there a good way to check for those?

      As for the startup procedure I believe I'm doing it the way you said.

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        #4
        Have you checked float heights?

        Not that this would be likely to cause the bike not to start, but have you checked your valve clearances? Tight valves can lead to difficulty starting. I have the shim tool and a variety of shims and live pretty close to you if you needed to borrow them and didn't want to wait for shipping.
        1980/1981 GS450 - GS500 Cylinder + Piston Swap - "De-L'ed", custom seat, CB350 bits, 18" rear, etc.
        1977 GS550
        1977 GS750 - Cross country trip thread

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          #5
          I did adjust the float heights to 27.6 mm. Haven't checked the engine at all. There are a lot of shim sets online ranging from over $100 to just a couple for a few dollars. Do you know which ones are necessary?

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            #6
            The ones that are necessary are the ones your bike needs. So four at most - don't bother with a kit. You need to go in and check clearances to see what you need to order. There's a shim exchange program on the GSR you search for the thread or you can buy them places like z1enterprises for around $5/ea
            1980/1981 GS450 - GS500 Cylinder + Piston Swap - "De-L'ed", custom seat, CB350 bits, 18" rear, etc.
            1977 GS550
            1977 GS750 - Cross country trip thread

            Comment


              #7
              Have you checked the points gaps?
              '82 GS450T

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                #8
                I haven't checked the point gaps, I'll do that and the clearances and see where that goes. Also managed to snap a bolt inside the engine block where the carb boot attaches, looks like I got some drilling to do too. I finally did a compression test and got 100 and 80 cold. Is this bad?

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                  #9
                  its very low compression. Did you have the throttle wide open when cranking it??
                  MY BIKES..1977 GS 750 B, 1978 GS 1000 C (X2)
                  1978 GS 1000 E, 1979 GS 1000 S, 1973 Yamaha TX 750, 1977 Kawasaki KZ 650B1, 1975 Honda GL1000 Goldwing, 1983 CB 650SC Nighthawk, 1972 Honda CB 350K4, 74 Honda CB550

                  NEVER SNEAK UP ON A SLEEPING DOG..NOT EVEN YOUR OWN.


                  I would rather trust my bike to a "QUACK" that KNOWS how to fix it rather than a book worm that THINKS HE KNOWS how to fix it.

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                    #10
                    yea the carbs were completely off

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                      #11
                      So I ended up taking the whole top end apart. Piston rings are in spec, and there are no Knicks or anything in the cylinder. I tried removing the valves, but don't have the tool. I saw online you could do it using other methods, but the springs seem extremely stiff. Is this normal? I put like half my body weight on it and it barely moved. There was also a ton of carbon build up I removed. Currently soaking it in pb blaster, but in videos the valves always appear like you don't have to push too hard?

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