Internal Engine Cleaning

[Guest]

Hi all,
I recently picked up a used replacement engine for my GS750T, which looks to be in good shape but the valve cover was off when I picked it up. So naturally sitting there for a while, the top end accumulated a bunch of grit from the air. I do plan to take the top end apart and get everything clean... But just a few quick questions:
- What kind of solvent is best for cleaning the inside of an engine? I've heard varsol is good, or diesel?
- Is it also a good idea to try and clean out the bottom end? Is it necessary to take everything out like the crank and pistons?
- Is there any method of clearing out the oil passages to the top end?

Any input would be greatly appreciated!

[Cipher]

What is giving rise to this? I have rsorted to rinsing out the top end of n engine with kerosene while the sump pan was off.
Also clened the sump pan and pup screen
No ill effects.

[nastyjones]

Varsol works great too. I've used it many times on rebuilds.

[mmattockx]

The only thing to know about varsol is that it will damage seals and o-rings. Kerosene isn't quite as effective of a solvent but it does not damage seals or o-rings if that matters to OP in this case.


Mark

[Mechanically Geeky]

Okay awesome, are there any o-rings on the bottom end I should be concerned about or are they mostly on the top end? I appreciate all the responses so far, thanks!!

[Tom R]

The shifter and output shaft come to mind...

[Brendan W]

Oil pump has some as well.

[bwringer]

There are several seals in the bottom end, plus an o-ring between the upper and lower case halves.

So yeah, you do want to use a solvent that won't dissolve seals and o-rings.

If you have the engine on a bench or whatever, I'd upend it and try to wash out as much of the garbage as I can from the top. In other words, try not to wash the crud down through the engine.


You might also look at procedures for dealing with a drowned engine. My KLR650 ended up in a much-deeper-than-expected creek once and spent a good 45 minutes completely underwater, and the engine was full of dirty creek water. I trailered it home, drained about 2.5 gallons of water and oil, then poured in some cheap Walmart oil and some Sea Foam to help emulsify the water. I ran it for a few minutes, then drained and repeated. After the second change, no more water was visible in the oil. I ended up changing the oil with cheap 10W-40 I think four or five times total. That engine has since done over 20,000 miles without the slightest problem.

In your case, I'd plan on a very brief first startup or two with cheapo oil, drain that and see what you get.

[Mechanically Geeky]

This is a lot of great information. I also like the idea of cycling cheap oil through the engine to clean it out. It's time to roll up my sleeves and tackle this turd. Thank you everyone for your input!