Valve shims and Gas in Oil and a few other ?s

Okay, I'll try hard not to make this a repeat of every other newbie post on here. I've spent quite a bit of time on here using the search function to look up stuff. So first, here is some background:

Purchased on Craigslist a 1980 Yamaha XJ650, 28K miles, not currently running. Previous owner (said he had been a poster on this website before, Brian in Stone Mountain GA) said bike was running last year after he did a carb rebuild, but won't fire up this year after sitting over the winter, and he no longer had time to mess with it.

Some extras it came with:

-Haynes manual
-Colortune 500 kit
-Motion Pro carb manometer set-up
-extra set of carbs - really rough looking
-2 small boxes of extra parts (nuts, bolts, etc)

Here's what I have accomplished/discovered so far:

-battery completely dry - replaced with new battery -$40
-drained oil to replace - here's where I made a major discovery. Oil was really an oil/gas mixture. Seemed to be more than 50% gas. Not good.



Okay, so here are my questions.

(1) I know the gas-oil thing could have come from a failed petcock or it was left on prime setting. I think I'm supposed to HOPE that's the problem, right?? Also have read it could be stuck carb float, or the bike has been laid down. If I didn't have a stuck carb float, would the case have filled with gas no matter what the petcock was set on?

So, to fix this I do a fresh oil change, run it for a little bit, and redo an oil change, right? This should flush out the case right? Do I need to do anything more drastic like SeaFoam?

(2) Okay so I know initiation to this club of XJ owners requires a carb teardown/clean/reassemble/sync, but before i do that I need to do the valve shims right?

So, I need to order the valve hold-down tool from Chacal, but i also need to order shims right? But how do I know what shims i need until I have the tool and do the measurements? In other words, is this a two step process requiring me to order the tool and feeler gauges, check my gaps, and then place a second order for the right shims? Is there like a starter set of shims that I should order to get it all done on the first shot?

(3) I think I also need to replace the rubber intake boots between the carbs and the head. I can see some dry-rot cracks in the rubber, and I take it that an air leak here is a really bad thing. An old Fiat mechanic I knew would put RTV silicone on his finger and rub it into cracked rubber lines, and swear it would seal any small leaks. Sound feasible?


Thanks in advance for your help, I'm sure I'll have many more questions!!!!

 

1. Not unless there is a bit of CRUD trapped under a float needle, which produces the same symptom as a "stuck" float. THERE IS another possibility: a malfunctioning petcock that doesn't actually shut off fuel flow in "ON" when the engine's off. You don't need to do anything more drastic than change the oil.
2. YES. With 28K it is entirely possible they've NEVER been touched, the bike would still run but not as well as it can. Fiddling with carbs when you have a tight valve will do no good.
There is no "starter" set because the ORIGINAL shims vary from position to position and bike to bike; you HAVE to read them to determine what to replace them with. It's simply a two-step process, and a two-ORDER process the first time.
3. ONLY if you determine that they are actually leaking. It's way too easy to BREAK OFF one of the bolts holding them. They often crack HORRIBLY but the cracks equally often don't go all the way through. I do the same, smear adhesive black RTV into the cracks. Do the unlit propane torch test on it once it's running to check for leaky boots, throttle shaft seals, etc.

 

Listen to Fitz- he's the man.
As far as the shims, being in a similar situation right now... I would suggest saving the $17 and doing the zip tie tool instead of the bucket holder. It worked flawless for me, and I even left the tie in there for over a week holding it down.
It's only going to save you money to spend on new shims (get the aftermarket ones, they are $10 cheaper!)
I am not trying to steal business from Chacal - but I really don't see a need to spend extra money on something you really don't need.
Trust me - you'll give plenty of business to chacal lol.

Am I right it guessing he needs the motor at least firing all 4 cylinders @ idle to get the propane trick to work?