Mechanic says its time to let go of '81 GS750EX

[hillsy]

Fixing the root cause is easy, just replace the petcock and change the oil. However, I can tell you exactly why the mechanic wanted no part of this.

If the bike was running on thinned-out oil for a long time, there's no telling what damage was done to the engine internally. In the best case, no serious damage was done and you'll just have to rebuild the engine at 90,000 miles instead of 100,000 miles (to pull figures out of thin air). In the worst case, your pistons and cylinders are shot, crankshaft bearings have spun, and the camshaft lobes are scored. Your engine is probably somewhere in the middle but you won't know where without a complete tear-down and inspection of the engine.

The other thing about working on old bikes is that you dont know what else is going to break when you remove parts to get to the initial problem you want to fix. It can sometimes be a massive rabbit hole - especially when replacement parts are NLA or difficult to find.

I was lucky in that the shop I worked in was also a wrecker (boneyard, breakers, whatever) so we had access to a stockpile of parts bikes to obtain parts from. Even then, when you charge for labour at reasonable rates and parts at below cost people were still thinking they were getting ripped off.

 

[posplayr]

The other thing about working on old bikes is that you dont know what else is going to break when you remove parts to get to the initial problem you want to fix. It can sometimes be a massive rabbit hole - especially when replacement parts are NLA or difficult to find.

I was lucky in that the shop I worked in was also a wrecker (boneyard, breakers, whatever) so we had access to a stockpile of parts bikes to obtain parts from. Even then, when you charge for labour at reasonable rates and parts at below cost people were still
thinking they were getting ripped off.

When I bought my GS750EX, I quickly realized the same when my starter clutch started to go out. I drove 2 1/2 hours to pick up a $250 basket case GS750EX as a parts bike. It was low mileage and had great sets of spare on it that paid for itself several times over (starting with the starter clutch assembly).

 

[GSXR7ED]

Parts Bike is where it's at!

Buy an identical bike like I did. Spare parts!!!

Like was said, other than major surgery, do the work yourself (if you can). Otherwise, set aside a bike fund and find a great bike shop like I did.


Ed

 

[hillsy]

When I bought my GS750EX, I quickly realized the same when my starter clutch started to go out. I drove 2 1/2 hours to pick up a $250 basket case GS750EX as a parts bike. It was low mileage and had great sets of spare on it that paid for itself several times over (starting with the starter clutch assembly).

I did the same thing when I bought one of my XJ900's - the guy I bought it from had a 2nd bike which I picked up in the deal.

Funny thing was I never needed any spares for the XJ - it never missed a beat

 

[SamSeattle]

Brake fluid change out last spring with new hoses installed; air filter cleaned last spring; pulled and replaced plugs last spring; tires replaced in 2012; chain and sprocket in good condition.

As for the steering head and swingarm bearings, I haven't checked them. Haven't gone through the charging system and aside from periodically replacing the battery haven't gone into anything in the electrical system.

 

[SamSeattle]

Perhaps the OP should ask if there are other GSR members living in his area, so that a knowledgeable member can take a look at his bike to determine what is wrong, and then guide him through the maintenance tasks, allowing him to learn.

I'd love that. I've got space to work, and some time but nothing by way of experience.

 

[cowboyup3371]

You may want to replace those tires again depending on what the date code is and what shape they are in

 

[hillsy]

Brake fluid change out last spring with new hoses installed; air filter cleaned last spring; pulled and replaced plugs last spring; tires replaced in 2012; chain and sprocket in good condition.

As for the steering head and swingarm bearings, I haven't checked them. Haven't gone through the charging system and aside from periodically replacing the battery haven't gone into anything in the electrical system.

Did you do this work on the bike? If so, changing the fuel tap and cleaning the carbs is within your skill set.

 

[GS1150Pilot]

And check the valve adjustment, for the love of cod.

With parts like this just waiting around, you can keep this bike going:
http://www.ebay.com/itm/SUZUKI-GS75...ENG-GS750-750E-GS-750-E-1981-jh-/311626760601

 

[JJ]

Brake fluid change out last spring with new hoses installed; air filter cleaned last spring; pulled and replaced plugs last spring; tires replaced in 2012; chain and sprocket in good condition.

As for the steering head and swingarm bearings, I haven't checked them. Haven't gone through the charging system and aside from periodically replacing the battery haven't gone into anything in the electrical system.

You don't ride much, do you? The tires are probably older than 2012. Check the date codes. You may need to replace them.

 

[Nessism]

Unless the tires are all cracked out (or worn out) I wouldn't replace tires made in 2012.

 

[JJ]

Unless the tires are all cracked out (or worn out) I wouldn't replace tires made in 2012.

Neither would I, Ed. But....

He didn't say they were MADE in 2012. He said they were REPLACED in 2012.

That's why I suggested checking the date codes, to see when they were actually made.

 

[SamSeattle]

Update: oil changed - very full, smelled strongly of gas.

Waiting for new petcock delivery (44300-45471, plus the gaskets). Aside from some built up deposits, the old petcock appeared fine from what I could tell. Is there something I should be looking for? The gasket was intact, and the spring still had some spring to it. I had to apply more force than I expected to separate the assembly, and the interior appeared clean and functioning.

When the new one arrives I'll let you all know what happens. I appreciate all the sage advice. I've got a mechanic lined up for a valve adjustment who said he would be fine with me looking over his shoulder.

 

[chuck hahn]

Its the oring on the shut off plunger that dries up and shrink..thus it leaks. Sometimes its a combination of shrinkage and some corrosion buildup also. Rebuild kits that i have tried have all failed. The orings in them dont fit into the hole and they are a useless waste of money.