GS850G T back on the roads - time for thanks the GSR community

[Guest]

After a first GS project last year, I bought a non-runner GS850G (T - 1980) last march with no known maintenance history.
The government registration report I got confirmed the mileage at 45kkm. Appart missing parts, it was most stock.

I had basic mechanic skills from working on a farm in my younger age but just to give a sense of talent: I never had changed the brakes myself on my cars.

So it was a fairly long journey from the initial bike condition:

- the remaining fuel in the carbs bowls was filthy
- the air box was empty of any air filter nor element.
- the oil pan was full of crude and rtv silicone worms.
- the crankcase was missing 16 bolts
- the headlight was from a 1983 GR650 forcing the front turn signals misaligned.
- the side stand was absent.
- the swing arm boot rubber sleeve had been cut to length, sealed with silicone and attached with a tye-rap.
- the intake manifolds were full of deposits.

At the end of July, I was able to start and run it a few hundred of feet to find other issues.
- there was a major oil leak from the front center of the base gasket.
- the petcock was not holding the fuel.
- engine oil was leaking near the filling cap
- all 4 secondary drive bolts were missing

At that point, there was no work around to a major engine overhaul.
When I removed the valve cover, I found the camshafts misaligned by a link.
When I removed the engine from the frame, I found a broken support bolt on LH center.
When I removed the cylinder block, I found the gasket broken and missing 1/4" at the front of the chain passage.

At this point, I judged there was no apparent necessity to split the bottom so I started the "rebuild" from there.
- new base gasket. Special thanks to Nessism and Grimly for useful hints.
- disassembled the head, cleaned with Simple Green, removed, cleaned and lapped all valves. Special thanks to zed1015 .
- I measured everywhere I was able to. Torqued everything to spec. Rigorously followed the Service Manual.
- I learned the hard way how easy it is to time the valve on wrong timing mark. Removed the valve cover and started again.
- Completely dissembled the carbs per Nessism procedure, dipped in Gunk Carb cleaner. Confirmed all jetting are stock. Replace all o-rings with Nessism's.
- Replaced any part with OEM whenever available.
- Changed the clutch cover gasket and found there was a hole missing for the oil passage.
- Couldn't find an OEM petcock, tried a chinese one w/o success and end up happy with a rebuild kit from K&L.
- Removed the fuel sending unit from the tank and confirmed it works.
- Replaced those dried air intake boot with Class Studios's and very happy with them.
- Repaired the broken lens of the tach with a Lexan sheet. Special thanks to Suzukian

- Yes, I cheated a bit on various point mainly from a budget perspective when the parts seemed good enough:
. I reused the head gasket
. I reused the valve stem seals
. I let the valve at 0,006 ish

I really didn't put effort nor money on appearance yet but I'm please the bike is now registered and fully conform to ride next season.

With the knowledge base of the GSR Forum and the kind advices for several members, I manage to get the bike good enough to get the government mandatory mechanical inspection and get compliant registration papers earlier this week. Thanks a lot for that.

Comments and questions welcomed.
PXL_20221118_144922674.MP by pwauthy[url=https://flic.kr/p/2o1pR7W]PXL_20221118_031810390._2_exported_1668978277840_2 by pwauthy[/URL]

 

[1978GS750E]

Let us know how reusing the head gasket works out for you.

Good looking bike!

 

[Rich82GS750TZ]

Nice work. As Ron suggested, you’ll know soon enough whether reusing the head gasket was a good idea or not.

Please clarify your valve clearance figures with a proper decimal and a unit of measure -inches or mm. This is an area where a little looser than spec is OK. Tighter is not.

 

[Grimly]

If those are the original brake lines, they needed to be replaced thirty years ago.

 

[rphillips]

Very nice job, congrats... Black was an OEM color for that bike, I think there are repro. stripe kits available if interested.

 

[Suzukian]

I was working as a sales person at a Suzuki dealership at the time this year 850 was sold. What an excellent machine. It's low end, to mid range torque was astounding. You could reach 100 mph so fast on that bike. I always thought it would strong enough and durable enough for a sidecar. I ran a hack for almost 6 years. I machined special brackets, 5 minutes to take it off, 15 minutes to put it back on. It was a Velorex sidecar. You have a great bike there, and it's a looker too. Best of luck, that bike will be around for many years because you rescued it.