ProducerBill Posted October 11, 2023 Posted October 11, 2023 I am so excited! Tonight my barn find 1981 GL550L idled! However a few issues. Carb 3 and 4 leaked fuel out the air inlet. Seems the floats are not stopping the fuel... but not 100% on that so if you have other ideas why that might be happening please let me know. Also cylinder 2 is not firing. It has the holy trinity fuel, air, spark. I checked the compression and it measures in at 110 psi not to spec but it is close to the other working cylinders. I have tried spraying starter fluid into the carb. Nothing. Removed the spark plug strayed it straight into 2. Nothing. I pulled the spark plug and held it to the side of the engine and it was sparking like crazy. So I am unsure what direction to head in. If you have any suggestion please let me know. Video of it running. https://drive.google.com/file/d/1REMtxDwEXCxFBEHE5-G_jdSCKBB7Khg7/view?usp=sharing Quote
wraith Posted October 11, 2023 Posted October 11, 2023 Remove carbs and give them a good clean and check settings, if it's been stud with fuel in carbs there will be all sorts of things need doing in there. Quote
ProducerBill Posted October 11, 2023 Author Posted October 11, 2023 I just finished rebuilding the carbs. I think I might have put the float in incorrectly so it might not be shutting correctly. Also for the cylinder 2 not working a friend wondered if the valves are not working correctly... That seems like a rabbit hole to find out if that is true. If that is it what external conditions could/should I see. Like no vacuum? or magic black smoke? Any suggestions? Thanks! Quote
wraith Posted October 11, 2023 Posted October 11, 2023 What's the plugs look like after you started it up, is number 2 plug wet or dry? Quote
ProducerBill Posted October 11, 2023 Author Posted October 11, 2023 22 minutes ago, wraith said: What's the plugs look like after you started it up, is number 2 plug wet or dry? The spark plug looked black. Didn't seem wet. I pulled out the boar scope and things look ok to me. Granted I don't have a ton of experience. I have attached them below. I am thinking of hooking up the vacuum sync gauges and see if there is any vacuum reading from cylinder 2. Not sure if this will help. Any ideas? Quote
TonyGee Posted October 11, 2023 Posted October 11, 2023 black/sooty plug is a rich mixture, did you do a bench test before refitting them ? it could be a leaking float valve making the mixture over fuel. 1 Quote
ProducerBill Posted October 11, 2023 Author Posted October 11, 2023 23 minutes ago, TonyGee said: black/sooty plug is a rich mixture, did you do a bench test before refitting them ? it could be a leaking float valve making the mixture over fuel. I did check to see if they produced spark before putting it back in and it was strong. As for the carb leaking fuel I replaced the float and pin... I am thinking I might have put the float in upside down. Quote
wraith Posted October 11, 2023 Posted October 11, 2023 15 minutes ago, ProducerBill said: As for the carb leaking fuel I replaced the float and pin... I am thinking I might have put the float in upside down. If so, that's your problem Quote
Gixer1460 Posted October 12, 2023 Posted October 12, 2023 Seems to spin over waaaaay to fast to me? If the float was upside down you'd never have got the cover back on ! ! ! A leak down test would be more diagnostic to check valves and piston rings and general wear in the top end. Have the valve been gaped correctly? Is it on points? If so, are they gapped correctly? Leaking carbs is never good especially after a rebuild ! Quote
ProducerBill Posted October 13, 2023 Author Posted October 13, 2023 Carbs are fixed. Not sure exactly what fixed it, but pulled them and gave floats 3 and 4 a tweak and the carbs are no longer leaking fuel everywhere. After re loading the carbs and some starter fluid it started and ran like a real motorcycle. After adding a new throttle cable it revs,,,, kind of. There is a bit of delay... And after idling and checking things out I noticed that carb two vacuum piston was rising up when I revved it. So awesome! I think it is getting closer to real bike. However now that it is running I am seeing oil leaking from maybe the oil pressure sensor, or something near there. Oil is pooling and looks to be flooding the starter motor depression. So two steps forward, one step back. As I have also noticed the clutch is not working. Video of it running: https://drive.google.com/file/d/1hE-fsP6NfsOCwj-lc1nS7XcLKJvHv6Gc/view?usp=sharing Quote
Upshotknothole Posted October 14, 2023 Posted October 14, 2023 Sometimes the floats stick and just need to be knocked around a bit to set them. Oil leak could be something loose or something needs a new crush washer. Clutch plates are probably stuck together, especially if the bike sat for a long time. You can disassemble the clutch and see how it looks, or if you're not too worried about it, roll the bike up to a wall or something to brace the front wheel with, start it up, and dump the clutch to do a burn out and see if it breaks free. I'd be more inclined to pull the clutch apart. Quote
BigT Posted October 16, 2023 Posted October 16, 2023 Oil leak could be a number of things -oil pressure switch, cam chain tensioner, valve cover Degrease and spray with foot powder to find what's leaking. 42 year old gaskets are known to fail Quote
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