Topic: First steps with newly acquired 74 cb750 and moisture in oil

[emitch]

Hello all. I have just aquired a 1974 cb750 from a neighbor who had the bike sitting in his yard. The bike is in really rough shape, and I'm kinda lost as to where to begin. Right now I'm going through the points, coils, and other electrical stuff with a multimeter.

First off, I have no idea the history of this bike, as the gauges have been removed, and the po had no idea when it last started. I can turn the engine manually via the crankshaft bolt, but the kicker is stuck. There is no gas tank. I drained the oil pan, and the oil looked milky. I suspect some moisture in the system somewhere, perhaps the trans?

What should be my first course of action here, should I hook the battery up, change the oil/filter and try and start the engine? Then do a compression test. Or should I just go ahead and pull the engine out, and start inspecting the top end?

Also, is the moisture in the oil, and the milky appearance any cause for concern? Any help would be greatly appreciated.

[pknopp]

 Old dirty oil will get a milky appearance. It's pretty common BUT I'm not about to say that it's not cause for concern. Sitting out like that it's hard to tell what all's been in it.
 
 You know though, I'm never one for doing more work than is necessary though.
 
 I'd say the odds are good that it will start if you can roll it over BUT it's unlikely until you pull the carbs and clean them. Check for dry rotted rubber parts.
 
 Once I had gone through everything and fixed what needed fix to get it started, I'd give it go before tearing it completely down.
 
 That's just me.

[BobbyR]

Before you attempt any starts, drain the oil and change the filter. Put some Oil or Marvel oil in the cylinders ASAP and let it sit while you work through the electrics. You do not want a dry start. You may get lucky and she will start, I doubt it since the carbs gunk up pretty quick, but you can get lucky.

If the motor runs, go over each system point by point and you may get a great runner out of this find.

[Stev-o]

First off, welcome.

Milky looking oil sometimes means water has been introduced to the oil. If the kickstart won't turn it over, the engine may be "stuck" (rings rusted to cylinder).
It can be unstuck, mix ATF and acetone and put in cylinder for three days. Then rock it in third gear.
Search the forum for more info.

Good luck.

[trueblue]

If I was you I would replace the oil and filter, put some fuel to it and see if it will go, I got lucky with my 650, it had been sitting for 24 years, fresh oil and some fuel put some jumper leads to it and away it went, not very well mind you but it started and ran, then once I knew it ran I started on working through and tracing the faults with it to make it run well, now 12 months, a s#!t load of cash and elbow grease later I continually get compliments about how well the old girl runs and how good it looks. Wouldn't trade it for a new bike.