1977 GS750 with 20k miles: Should I buy?

[hannibal]

Hello,
I've been browsing the forums for awhile now, but this is my first post. I've been looking for a GS for almost a year now. In my area, most of the bikes on Craigslist have been modded (chopped, bobbed, or just plain butchered). I came across a 77 GS750 that looks to be in good condition and the only mod is pod filters. However, the bike has more than 23,000 miles on it. I'd like to know your thoughts on buying a bike with this amount of mileage.

I've heard folks say they'd rather have a 40 yr old bike with more miles so you know it's been ridden and not sitting for the past 10 years. Is 20k miles too much? Would you consider a GS with so many miles?

I'm new to bikes in general and this would be my first bike. I've ridden dirt bikes when I was a kid, but have never owned or purchased a bike. I saw the write up on examining the regulator/rectifier and plan to bring my multimeter with me. Any tips on what else to look for on these bikes? I've worked on cars since I was young so I understand how an engine works and I'm comfortable getting my hands dirty. I'm not afraid to rebuild carbs or tackle regulator issues, but I'd hate to get a bike that needs major work (opening up the motor). How often do these bikes need valve adjustments?

I haven't been able to find a "buyer's guide" on this site. Any tips, advice, or links would be greatly appreciated! I hope to join your ranks soon!

[akckhim]

77 gs750 is a great bike go for it. No 20k is not to many miles

[tom203]

Make sure all exhaust pipes get hot fairly quickly when started . Make sure it shifts/finds all gears and neutral .Is it currently on road ? Where are you? Might be member nearby to offer opinion.

[tkent02]

23,000 miles is nothing. Make sure it isn't 123,000 or 223,000, but even so it's probably OK. I personally couldn't care less how many miles are showing, because it just doesn't matter and a speedometer with no miles can be bought on Ebay for a song and can be changed out in five minutes or so. Learn to figure out how well it runs, how well everything works, and how well it's been cared for. There are better ways to learn the bike's history than an odometer.

Engines are cheap, and everything on the bike is replaceable. A 1000 engine fits right in a 750 frame, is fifteen pounds lighter and physically smaller than the 750 engine. It's what Suzuki should have done in the first place.

I don't care at all how it runs, I will have to go through all of the maintenance anyway, valves, carbs, ignition, tires. All easy stuff. If it isn't charging, thats easy to fix too. It's all easy, they are very simple machines. Missing a title, there are ways around that, but it costs a little bit of time and money. Missing a key is not a problem at all. Needs the carburetors cleaned and a battery, yeah they all say that.

What I won't buy is one with rust or corrosion, a bent or cut up frame, one modified by a moron who knows not what he cuts, or one that's been left outside for years. Its just not worth the effort, even if the bike is free. Also won't buy one from an ass hole, or a liar, or a punk. Just not worth the hassle.

[Rob S.]

...Is 20k miles too much? Would you consider a GS with so many miles?

20k is not considered high mileage on these big in-line fours. I bought one almost two years ago with that many miles.

[hannibal]

Thanks for the replies. Glad to hear 20k miles is nothing to worry about. I'm on the East Coast but I'm hesitant to give out my location because I don't want anyone to snag this before I do.

The owner says the bike sat for about 2 years but currently runs well. He says he cleaned the carbs and replaced the battery. Because it has pod filters, I believe this means he must have rejetted the carbs as well (or else it would run lean?). He says it starts on a few cranks with it on choke, and you can move it to half choke within a 15 seconds, then no choke after 15 more secs, then it "will idle all day".

I'll ask him to leave the bike cold (unstarted), so I can see how it warms up. Thanks for the tip on checking each exhaust pipe. I assume this is to make sure it's firing on all 4 cylinders. I plan to ask the seller the last time the valves were adjusted when we talk tonight.

[tom203]

"I'm on the East Coast but I'm hesitant to give out my location because I don't want anyone to snag this before I do."

the suspicious type! Ok, put little faith in seller's hype. He lost interest in bike two years ago for some reason. Figure it needs maintenance and hope that it's mechanically sound.

[Rob S.]

I'll ask him to leave the bike cold (unstarted), so I can see how it warms up.

Certainly agree with you there. I insisted the engine be cold to the touch when I came to see it for the first time.

[hannibal]

Bought the bike, then discovered electrical issues. Wish I had spent another day reading this forum but I consider it a lesson learned. A thread about my electrical issues can be found here: http://www.thegsresources.com/_forum...-R-and-grounds

I was ready to scream when I discovered these problems. But with the resources here, I'm confident I can dianose and repair the bike's problems. The adventure begins!

[tkent02]

I'd rather have one with 200,000 miles than one with crappy wiring. Good luck.

[JTGS850GL]

I'd rather have one with 200,000 miles than one with crappy wiring. Good luck.

The electrical systems on these bikes are so simple that I'd rather have an electrical problem then just about anything else. The big problem with electrical issues are having an educated set of eyes present to diagnose what's going on. It can become very hard to fix electrical issues over the net when the person conveying the problem is not versed in basic electrical diagnostics.

[John Park]

The electrical systems on these bikes are so simple that I'd rather have an electrical problem then just about anything else. The big problem with electrical issues are having an educated set of eyes present to diagnose what's going on. It can become very hard to fix electrical issues over the net when the person conveying the problem is not versed in basic electrical diagnostics.

I don't enjoy fixing electrics, but it's usually pretty clean work. I'm pretty qualified electronically - radio and industrial electronics - since I was a kid, so it's hard to imagine what electronics appears like to people who don't have any background. You can't see electricity, so it's voodoo. But on a GS it's just a matter of connecting up the right components the right way with good connections.

While I'm digressing, it's good to remind people that turning over an engine with the plug wires completely disconnected is not a good practice. The spark has to have a reasonable method of escape. Just because you've pulled the plugs doesn't mean the coils stop putting out a spark, and the plug won't spark unless it's grounded. On Suzuki RMs of the '70s you could blow the ignitor box immediately that way. Even if something doesn't blow at the time, you're weakening the system for no reason. Always ground the spark plug; don't leave it dangling.

It's not just bikes. I bought a truck from a lot and had them check the compression. The yard monkey left all the plug wires dangling, and I told him that he shouldn't do that, but he got snarkey so I backed off. At the end, I bought the truck but they had to replace the coil [ it was puking oil], cap, rotor and wires to get it to run again. A few months later the ignition trigger suspiciously failed. IOW, it wrecked the whole system. It makes me wonder how many ignition boxes and coils die as the result of 'spark constipation'? The system is designed for a one mm type gap.

The same goes for running without a reasonably functional battery. The regulator needs to put the excess somewhere and if the battery can't take some, it dumps it all to ground which
isn't easy on it. Proper grounding and a capable battery [it doesn't have to be charged, but just ready to accept charge] are crucial parts of the electrical system.

[tkent02]

Electrical problems are corrosion problems, I steer clear of corrosion. You fix them.
I'd rather restore an old one with no corrosion.

[Grimly]

However, the bike has more than 23,000 miles on it. I'd like to know your thoughts on buying a bike with this amount of mileage.

Mileage? What mileage?
I'm not exaggerating when I tell you that one of mine could have travelled to the moon, and the other one would be two-thirds of the way back by now.

[hannibal]

Update:
So after I got the bike home, the positive battery cable had melted itself from both the battery and starter relay. I've been through the basics of the electrical system and redid the battery wiring and added a single point ground. Thanks to posplayr for tons of help. Haven't done the charging system tests but I got the bike started and warmed up for 5-10 mins and rode around the block. It stalled once as I was coming to a stop but no hot wires or smoke. With a near stock baseline on the electrical side and waiting to find out how the stator and R/R are performing, I started thinking about the fuel system.

I was skeptical that the carbs had been rejetted for the pod filters. Took a look at the plugs and all 4 were very black and dry fouled. It was a relief to see it was running rich, but certainly not what I expected. I decided it was time to remove the tank so I could start looking at adjusting valves and eventually the carbs. So shortly after this first idling and ride, I pulled the fuel hose at the petcock and fuel came out. Didn't want it spilling onto the warm engine so I plugged it back in. Did some more reading on the petcock and found out that it's not supposed to happen (99% sure the petcock was on On). I start thinking this was the cause of my richness. I read warnings not to run the bike before fixing the petcock and changing the oil so I left it for the day.

So today I prepare to drain the full tank. I remove the petcock fuel line at the carbs and not a drop comes out. Turning petcock to Prime causes fuel to drain as it should. My guess is the petcock got stuck open after seeing vacuum when the engine was running but worked correctly after sitting overnight. Is the diaphragm either opened or closed, or does it open more as vacuum increases? If it's the second, this could also explain the stall when coming to a stop and the super rich, fouled plugs. I didn't check after running it yesterday, but there was no fuel in the vacuum hose today.

Regardless I'm looking for a new petcock. It's a 44mm petcock and I'd like to stay vacuum controlled, so I guess OEM or GeorgeFixs.com are my options. Any advice?

Hoping to straighten out the petcock then do the charging systems tests. Then adjust valves and clean the carbs. I guess I have to finish those things before I have a good baseline to judge how the carbs and jets are working.