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Steps To Take BEFORE Starting A Hibernating GT750K

Posted: Wed Apr 24, 2024 10:44 am
by Brealytren
All,

As I've shared in my previous "Exhaust Quandry" post, I'm attempting to bring back to life a 1973 GT750 that appears to have been hibernating for the past 30 years. That said, I'm wondering what the group's suggestions would be to restart the bike in a way that offers the best opportunity for success. While I understand many of you would suggest I completely disassemble the engine for inspection before starting, my past practice has always been to carefully prepare such engines for restart mainly to gather more information on their health before teardown. In many cases, I've found such engines are ready to ride...yet some need surgery. However, most of these engines have been 4-stroke, while my two-stroke luck has not been so good with several requiring new crank seals, etc. Big picture...when properly prepared running in this condition hasn't resulted in additional damage, they just run poorly. That said, these are the steps I've been planning to take before restarting, but I would also appreciate your wisdom: Clean/flush the oil injection tank and replace the oil feed line (BTW - what size and type of line should I use?), disassemble the Oil pump to inspect and clean (I have a new cover gasket, but wish I could also get a new metering shaft seal. Does anyone know where to find one?), flush and clean the CCI oil lines, reassemble and prime the CCI system, drain the crankcase of any oil, clean the crank oil return check valves and replace all three lines, lube the cylinders with 2-stroke oil, and attempt the first start with premix at about 20:1. That said, I'm concerned about the crank bearings not getting enough lube as the injection system purges itself. Thoughts?
On a final note, I found the neutral indicator cover broken and the transmission dry on oil. I'm concerned the previous owner drove it this way and thereby damaged the transmission. This would explain the heavy coating of dried grease throughout the chain case area. Starting it and taking for short trip around the neighborhood would not only tell the story of the health of the engine but also that of the transmission. Fingers crossed. Thanks in advance! Chuck

Re: Steps To Take BEFORE Starting A Hibernating GT750K

Posted: Thu Apr 25, 2024 5:16 pm
by karl pa
After 30 years, I would be concerned about crank seals, but like you said it won't hurt things just run crappy.
I removed cylinders and filled crankcase with diesel and seal repair to soften seals, but that is a lot of work on a 750. It worked on several of my twins, but not much luck on my triples.
Sounds like you have a pretty good plan. With the oil pump off you can use an oil squirt can or syringe to fill oil lines and push oil into the main bearings.