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Hey Y'all - I wanted to start a build thread to force myself to take more "before" pictures than I currently have, and of course I'll be looking for plenty of advice along the way.
I just bought an 81 GS450L a few weeks ago that was about 1/3 of the way through a rebuilt. I chopped an 88 suzuki intruder vs750 last year, and did mainly cosmetic and minor work, and the key snapped in the ignition and the front tire went flat on my first ride after I got it running again so I decided God didn't want me riding that bike. I looked for something with easier engine access and that was chain driven because the intruder's shaft drive was way outside my mechanical ability, and the 450 jumped out at me! The PO threw in a full service manual and a new chain, which both were a godsend.
When I bought the bike, it wasn't running - no battery, and it needed a carb rebuild and cleaning. It has cheapo pod air filters, so I needed to rejet for that because I knew it would run lean. The gas tank doesn't have good mounts, but I can throw it on the frame and hook it up to make sure everything is running. The seat pan was custom fabbed, but I need to do the seat foam and upholstery, and also figure out how I am going to attach the seat. And, the chain needed installed. The headers had a cheap wrap on them covering up pleeeenty of rust.
Otherwise - electrical is all good! I bought an antigravity small case 8 cell and mounted it right under the seat, and everything worked. (No turn signals or spedo are installed though, just a tac and head/brake lights).
What have I done so far?
- Installed new spark plugs
- Pulled the carbs - rebuilt and cleaned them
- re jetted carbs with a 130 main and a 120 pilot - I haven't been able to find the needle jet, or been able to adjust the clip on that, which I think I still need to.
- started painting, to keep me busy while I waiting for parts.
- Pulled the exhaust, and took some steel wool and a stripping pad to them to get rust off, then attempted at least to get them nice and shiny again.
- Adjusted throttle cable and clutch cable.
- Installed the chain. Only after fighting with about 5 stripped screws to get the case off - I've since replaced them with hex head bolts so I can just take a wrench to them next time.
- oil change.
Even with the battery, the bike still didn't start initially, and I was beyond frustrated. The PO had done a compression test before selling it, and I knew that wasn't the issue. The battery was good, and spark plugs were new, so I wasn't thinking electrical was an issue. But, even though I'd done plenty of carb work, I knew it had to be a fuel issue.
I thought the vaccum petcock was the issue, but when I tested that, it was fine. It ended up being the simplest thing I looked right over - the fuel line! the line was too short, and was kinked above the carbs. I went and got a longer fuel line, and threw in a cheap autozone inline fuel filter and routed it to make sure fuel was getting to the carbs and the bike started up.
At first start - the RPMS at idle went from 1.7k - 2kish up to 5k without me touching the bike, so I kept having to shut it off to keep it from freaking out. White smoke was coming from the exhaust, but once the bike eventually warmed up that wasn't quite as prevalent. The pipes were smoking, because I hadn't gotten the exhaust wrap off at that point, and they were crazy hot compared to my intruder's wrapped headers. There was oil leaking somewhere from the left side of the bike, I think the crankcase? but very little. The bike was clearly overheating in a hurry.
I adjusted the idle screws and air screw, and the idle stayed consisentish until I touched the throttle. The RPMS jumped up with any throttle, and then stayed high. I took it for a ride around the block because I wanted to get on the bike just to help diagnose potential issues - I made it about 1/4 mile and the bike actually ran pretty well. But, when I slowed to a stop, the bike died, and then wouldn't start back up. I gave it about 3 minutes to cool down, and then it started but RPMS were up around 5k at idle. Once I got the bike home, I stripped it down again to sit.
Obviously it was running lean - I believe it overheated, and I may have blown a head gasket. But, I realized yesterday that the throttle cable was too tight, and that was holding the throttle open - I adjusted that and it helped quite a bit.
With the throttle cable adjusted, header wraps off, and air filters restricted a bit -
- now the bike starts, runs, but bogs down with throttle, and if I close the throttle completely, it eventually dies.
I'm currently waiting for new carb boots because I did a test with starter fluid and know I've got a vaccum leak there. Is there anywhere else I should be looking for a vaccum leak?
I've ordered a new head gasket - I think mine may be blown, but I wanted to test everything else before I do a full top end rebuild. Should I be looking at the top end now, or for anything else, based on the problems I've described? Initially I knew the bike would run lean, but now isn't bogging down a sign of running rich?
Any advice or thoughts is greatly appreciated!
the bike:
file5.jpg
I just bought an 81 GS450L a few weeks ago that was about 1/3 of the way through a rebuilt. I chopped an 88 suzuki intruder vs750 last year, and did mainly cosmetic and minor work, and the key snapped in the ignition and the front tire went flat on my first ride after I got it running again so I decided God didn't want me riding that bike. I looked for something with easier engine access and that was chain driven because the intruder's shaft drive was way outside my mechanical ability, and the 450 jumped out at me! The PO threw in a full service manual and a new chain, which both were a godsend.
When I bought the bike, it wasn't running - no battery, and it needed a carb rebuild and cleaning. It has cheapo pod air filters, so I needed to rejet for that because I knew it would run lean. The gas tank doesn't have good mounts, but I can throw it on the frame and hook it up to make sure everything is running. The seat pan was custom fabbed, but I need to do the seat foam and upholstery, and also figure out how I am going to attach the seat. And, the chain needed installed. The headers had a cheap wrap on them covering up pleeeenty of rust.
Otherwise - electrical is all good! I bought an antigravity small case 8 cell and mounted it right under the seat, and everything worked. (No turn signals or spedo are installed though, just a tac and head/brake lights).
What have I done so far?
- Installed new spark plugs
- Pulled the carbs - rebuilt and cleaned them
- re jetted carbs with a 130 main and a 120 pilot - I haven't been able to find the needle jet, or been able to adjust the clip on that, which I think I still need to.
- started painting, to keep me busy while I waiting for parts.
- Pulled the exhaust, and took some steel wool and a stripping pad to them to get rust off, then attempted at least to get them nice and shiny again.
- Adjusted throttle cable and clutch cable.
- Installed the chain. Only after fighting with about 5 stripped screws to get the case off - I've since replaced them with hex head bolts so I can just take a wrench to them next time.
- oil change.
Even with the battery, the bike still didn't start initially, and I was beyond frustrated. The PO had done a compression test before selling it, and I knew that wasn't the issue. The battery was good, and spark plugs were new, so I wasn't thinking electrical was an issue. But, even though I'd done plenty of carb work, I knew it had to be a fuel issue.
I thought the vaccum petcock was the issue, but when I tested that, it was fine. It ended up being the simplest thing I looked right over - the fuel line! the line was too short, and was kinked above the carbs. I went and got a longer fuel line, and threw in a cheap autozone inline fuel filter and routed it to make sure fuel was getting to the carbs and the bike started up.
At first start - the RPMS at idle went from 1.7k - 2kish up to 5k without me touching the bike, so I kept having to shut it off to keep it from freaking out. White smoke was coming from the exhaust, but once the bike eventually warmed up that wasn't quite as prevalent. The pipes were smoking, because I hadn't gotten the exhaust wrap off at that point, and they were crazy hot compared to my intruder's wrapped headers. There was oil leaking somewhere from the left side of the bike, I think the crankcase? but very little. The bike was clearly overheating in a hurry.
I adjusted the idle screws and air screw, and the idle stayed consisentish until I touched the throttle. The RPMS jumped up with any throttle, and then stayed high. I took it for a ride around the block because I wanted to get on the bike just to help diagnose potential issues - I made it about 1/4 mile and the bike actually ran pretty well. But, when I slowed to a stop, the bike died, and then wouldn't start back up. I gave it about 3 minutes to cool down, and then it started but RPMS were up around 5k at idle. Once I got the bike home, I stripped it down again to sit.
Obviously it was running lean - I believe it overheated, and I may have blown a head gasket. But, I realized yesterday that the throttle cable was too tight, and that was holding the throttle open - I adjusted that and it helped quite a bit.
With the throttle cable adjusted, header wraps off, and air filters restricted a bit -
- now the bike starts, runs, but bogs down with throttle, and if I close the throttle completely, it eventually dies.
I'm currently waiting for new carb boots because I did a test with starter fluid and know I've got a vaccum leak there. Is there anywhere else I should be looking for a vaccum leak?
I've ordered a new head gasket - I think mine may be blown, but I wanted to test everything else before I do a full top end rebuild. Should I be looking at the top end now, or for anything else, based on the problems I've described? Initially I knew the bike would run lean, but now isn't bogging down a sign of running rich?
Any advice or thoughts is greatly appreciated!
the bike:
file5.jpg
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