Picked up a new engine...

[Milk_Jesus]

Picked up an engine this weekend for $100. Seems to have good compression, but I'm trying to figure out where to start troubleshooting it to see it's status. The guy I bought it from didn't know too much because it was his recently deceased father's. He does know that it runs, but "didn't sound good". Where should I start diagnosing it? Remember, I'm a newbie.

 

[manofsteele]

What exactly is "doesn't sound good"? Could of been miss firing, which would usually be a simple fix or was it making a ticking, grinding, or knocking sound. Which what be a lot more involved.

 

[Milk_Jesus]

What exactly is "doesn't sound good"? Could of been miss firing, which would usually be a simple fix or was it making a ticking, grinding, or knocking sound. Which what be a lot more involved.

that's the problem, i don't know haha. I bought it last second and just decided to go for it and risk throwing $100 away (hopefully this turns in my favor). I am ordering an engine stand today and am also getting the keys to my new warehouse today so I am really just looking for some guidance as to where to start on the engine.

 

[retiredgentleman]

http://www.xs650.com/forum/showthread.php?t=367

The link is from our "Tech" section.

 

[member3480]

What i do with all the motors i get is put them on a stand and hot wire them and fire them up. If you got compression thats a plus but unless you are going to tear it down you will really never know what you got. 70% of the motors i get have to be rebuilt. I got lucky on a couple that only had a couple thousand miles on them and they were put away correctly but that does not happen very much most people put there bikes away in a garage or outside by just shutting it off and walking away for years. So hopefully you got a good one.

 

[littlebill31]

As RG above pointed out, check some threads and prepare it to run. Go through and check, double check that it's all there.
The only way to find out what is wrong is to, first, make sure it's complete.
Then when you know it's all together correctly get it ready to start.
Don't just rip into it willy-nilly. Check to make sure it is all adjusted correctly in the correct order, the electric is hooked up and tested, carbs are bench tested and ready, all the pieces are there, exhaust is hooked up, oil changed,ect.
Then, and only then, should you try to start it.
If it's missing parts, or some are busted, they need to be addressed.
Just 'cuz the previous owner said it ran doesn't mean shit.

 

[Milk_Jesus]

Anybody have any links of good walk-throughs on hot wiring these engines? I've never done it. Once I have all the parts I need and they've been checked, that will be my next step. thanks for baring with me!

 

[littlebill31]

Depends on your ignition type. TCI, points, Pamco.

Here's a link to find out what year it is:
http://www.650motorcycles.com/XS650yearID.html
The serial number is on the front of the engine.

Here is some wiring diagrams:
http://www.xs650.com/forum/showthread.php?t=61

Do you have a manual yet? If not, get one.

 

[Milk_Jesus]

can i even test the compression properly on a cold engine?

 

[Max Midnight]

Properly? No, it would need to be at operating temperature so that pistons and the like have expanded.
However, you could still do the check when cold to see if both cylinders give a similar reading.

With the motor up to temperature you should see a reading of between 128 - 156 PSI.