Engine seals

[Genkaktos]

Im going to replace all seals in the engine due to an oil leak, just wondering if theres anything more that I should do when pulling it apart. Chech the carburators? Or anything, any ideas are welcome, im not that good of a mechanic but Im willing to learn! So give me all the feedback and input you can. The bike ofc a gs850g 1981.

[Nessism]

How does the bike run now? If it runs well and doesn't burn any oil I'd perform a compression check, making sure the engine was good and hot and you hold the throttle wide open during the test. Adjusting the valves first is always advised too. If the compression is good, you can leave the rings alone and just go after the gaskets/seals to fix up your engine. If the compression is below say 125 psi, I'd replace the rings and bottle brush hone the cylinder while the engine is apart. Also, regardless of compression, I suggest you replace the valve seals and check the head and cylinder for flatness - get them cut as necessary. Lastly, OE gaskets are the best, but the most expensive. Some of the cheaper gasket sets might be okay but I strongly suggest strategic replacement of some of the more critical seals with OE.

Good luck.

[mike_of_bbg]

Can you identify where the leak is coming from? There are only so many seals and most don't require the entire engine to be overhauled.

You didn't offer much info about the bike history or current running condition. If you're going to remove the carbs and aren't sure when they were last rebuilt, going through the entire GSR carb rebuild process for them and replacing all the O-rings and pilot jet seals is not a bad idea.

[Genkaktos]

Bare in mind that im not english so just ask if you dont understand what I type.

The bikes been running about 90 000km so far. The only thing that has been overhauled/replaced the last 3 years according to the previous owner; Brakes been refurbished, generator replaced and battery, forks been serviced.

The oil seems to be coming from both the top and bottom of the cylinder. Bought a gasket set for the entire engine so I got every gasket that fits in the engine.

In idle before it ´gets warm its crap, cant idle so have to rev the engine for 1-2 min before it atleast holds around 2-300 rpm, when its been driven and is scalding hot it holds steady around 1000rpm.

Is there anyone of you that got a bit more experience in mechanics then me and could be so kind to structure a nifty little list of what to check before tearing it down. I assume im performing the compression check before i start tearing it down?

[mike_of_bbg]

Yes, the compression test is done while the engine is still running. Like Nessism said, you need to get the engine hot to get a good reading. The base and cylinder head gaskets can be replaced with the bottom end still in the frame. 125+ PSI (~860 kPa) is ideal, with little (< 10 PSI or 70 kPa) variance between cylinders. Suzuki says 100PSI (690 kPa) is the service limit IIRC. The valves wear tight and, if they have not been adjusted in a while, may actually hang open a bit and cause leaks - which will drop your compression. So it's really best to do a valve adjustment first, then do the compression test - particularly if a valve adjustment has not been done in 3 years. If you lightly grease the valve cover gasket you can probably re-use it after only short service for the compression test.

Are you using the choke (AKA fuel enrichment circuit) when the engine is cold? It's probably due for a carb cleaning (http://www.thegsresources.com/gs_carbrebuild.htm), with new O-rings and intake tube o-rings as well. Check the condition of the intake boots, particularly on the head side. Replace any that show cracking or rubber separating from metal (give the rubber a tug).

In which country are you located?

[Genkaktos]

Thanks for your input mike, it will help alot. Im located in the capitol of sweden, Stockholm