GS 650 buying, what to look for, only 2 cyclinders firing...

[byronfry]

Hey guys, Im new here. Just was out to look at a gs 650gt today and the guy and I spent awhile getting her flashed up. Its been sitting for a few years, and he had it running a little while back with and everything was fine-ish, but now we got it running and only 2 cyclinders were firing. I am figuring I can get this off him for about 500 bucks, the bike is pretty clean and nice looking, but yeah, just wondering what kinda repairs I might be getting myself into. Also when he got it, it didnt have pipes, and he put some new ones on his and then found that the carbs needed adjusting but never got around to that, so I need to get a carb adjustment and all that.
So I guess that questions would be, does anything here sound like it could be a problem and are there anythings I could check for? The bike is uninsured so I wont get to try it out or anything.

[p_s]

Here's a good list of things to go through: http://www.clarity.net/~adam/buying-bike.html
I bet you'll find a lot more problems. It's a good idea to look at a lot of bikes before buying one--the first few should be seen as a learning experience. Where do you live? It's a buyer's market in most of the country this time of year.

[TheCafeKid]

Honestly i think hes asking a lil much...even if you get him down to 500 bucks, its a bit much for a bike with multiple unknown problems, and not running. Firing on two cylinders could be a simple carb and or valve adjustment issue or it could be something way worse like burnt or bent valves, blown rings etc.

[rkubik]

oddly enough, the same thing happened to me...

when I first got my dead 650 running, it too ran on only two cylinders. After sorting out minor problems with carb vent hoses and spark plug caps, it has now hummed along on 4 for several years.

That said, it took hours and hours of checking of other things to finally find those minor problems and sort out same. But WTH it was always meant to be a project/hobby. If that's what you want, buy it and enjoy the experience. If you don't like forensic mchanics, however, don't buy it, put the money toward a better running, more expensive machine.

[p_s]

Someone more experienced than me told me that if it looks good but doesn't run, to pay no more than $500--since most of the time it is just going over the valve clearances and the carbs and the timing, but that one out of ten times it's something expensive that's gone wrong.

[mark]

But WTH it was always meant to be a project/hobby. If that's what you want, buy it and enjoy the experience. If you don't like forensic mchanics, however, don't buy it, put the money toward a better running, more expensive machine.

Absolutely. Buy only if you enjoy working on bikes.

[chef1366]

Find out which cylinders aren't firing. There are two coils and one fires 1&4 and the other 2&3.

[byronfry]

Wow! Thanks for all the help.
Cyclinders 2 and 3 are the problems.
I am slightly mechanically inclined. The bike itself seems nice, the tires are good, he has kept in clean, and in the garage, newly painted tank, all the lights work. Battery wasn't working but he has another one that works that he had sitting around that I will get with it I think.
Everything was really clean, brand new exhaust.
The mechanical stuff is a little daunting but I would love to learn on it and I have friends who can help me and he had the shop manual. I have owned nothing but old vehicles, but being only 19, I don't know a lot. My first car was a 74 vw van, and since that I have had a 1980 volvo and a 71 plymouth valiant. So I understand that there will be work involved, but that is half the adventure. He seemed to think the cyclinders not firing was because of some electronic issure because it happened to him a few years ago and he wiggled some wires and it all came back.
As well he said he wouldn't mind helping me out if issues came up, he is really into these bikes as well and is only selling it because he bought an 1100 so he could put newer running gear and a big tire on it.

As well I am in canada, so prices tend to be higher, and on vancouver island, where prices are also higher. I am lucky to find a bike for less than 1000. People here are asking 2500 for 80s something enduros, disgusting.

the bike has 56 000 km on it.

[aedi006]

One pretty easy thing to check before buying ANY used bike is the compression in the cylinders. All you need is a compression tester, I got one here in the states for only $15 from Harbor Freight. The gauge measures how much pressure the cylinders can generate. If your below specs (usually below 90-120 psi) then the fix is not trivial and probably requires an engine rebuild (bad piston rings, bent valves, etc). To check compression remove the spark plug leads on all plugs you do NOT want the motor firing for this. Remove one plug at a time and attach the compression gauge (you will have to do some asking around to find the right thread for the 650). Pull the choke all the way out, fully rotate the throttle to the stops and crank the engine with the starter button a few cycles until the compression gauge doesn't change anymore (it takes a few cycles to build up enough pressure). I would NOT buy a bike without knowing if I had to re-work the engine, the mis-firing probably is no bike issue comparatively.

[TheCafeKid]

Wow! Thanks for all the help.
Cyclinders 2 and 3 are the problems.
I am slightly mechanically inclined. The bike itself seems nice, the tires are good, he has kept in clean, and in the garage, newly painted tank, all the lights work. Battery wasn't working but he has another one that works that he had sitting around that I will get with it I think.
Everything was really clean, brand new exhaust.
The mechanical stuff is a little daunting but I would love to learn on it and I have friends who can help me and he had the shop manual. I have owned nothing but old vehicles, but being only 19, I don't know a lot. My first car was a 74 vw van, and since that I have had a 1980 volvo and a 71 plymouth valiant. So I understand that there will be work involved, but that is half the adventure. He seemed to think the cyclinders not firing was because of some electronic issure because it happened to him a few years ago and he wiggled some wires and it all came back.
As well he said he wouldn't mind helping me out if issues came up, he is really into these bikes as well and is only selling it because he bought an 1100 so he could put newer running gear and a big tire on it.

As well I am in canada, so prices tend to be higher, and on vancouver island, where prices are also higher. I am lucky to find a bike for less than 1000. People here are asking 2500 for 80s something enduros, disgusting.

the bike has 56 000 km on it.

Well at least they are paired, the two non firing cylinders...you say he said it was electrical...could be a bad coil. Thats easy enough to fix..however i would second the previous post about a compression test.

[salty_monk]

If you really want to test the coil simply swap the leads over & see if the problem switches to 1 & 4. New set of coils & leads & plugs is going to run you about $140.

If you mess with the cabs yourself, new o rings etc - $30 plus some tools (or borrow some).

Dan

[salty_monk]

Also allow about $40+ for a valve adjust (tool, gasket, three or four shims).

Dan

[byronfry]

how would I go about a compression test?

[TheCafeKid]

Read a couple posts back...its explained there..but you'll need a compression gauge...get one at Autozone or Harbor Freight for cheap..i think i paid 35 bucks for mine but there were cheaper ones.

[rkubik]

need 10mm fitting

One thing to be aware of when buying a compression tester is that for the 650, you need one with a 10mm fitting. Not all car-type sets have that - found that out with the one I bought at Princess Auto. But fear not, they have sets with the 10mm adapter at Parts Source (the Canadian Tire affiliate) or Auto Value for about $40.

PS whereabout on the Island are you located? I had no idea the north end was so empty unitl I went up to the Port Hardy ferry once!