New Owner - troubleshooting '82 GS650 that won't start

[Guest]

Hey Everybody - thanks in advance for any advice and help. I'm completely new to bikes and engines in general, so I'm learning as I go.

I bought my bike a few months ago, it started right up and I rode it for a few days immediately after purchasing it. Unfortunately I laid it down within those first first days, but with minimal damage. During my rides, I stopped at the store and when I came back out it wouldn't start. I was able to push start it and rode home, but when I tried to start it again a few days later, I got nothing, even after trying to push start again.

I checked the old lead-acid battery and it was totally dead, so I replaced it with a new one which is still putting out about 12.1 volts. The bike cranks with the new battery, but it won't start. I took apart the carbs and to my untrained eye, they didn't seem too gunked up and the jets seemed alright. I checked the spark plugs and they had a solid spark. I'm looking for some direction now as to how I should move forward troubleshooting this issue. What I'm thinking is this, please tell me if there is more to consider and how to check it:

1) Since I get good spark, that means that the signal generator, coils, spark wires, and plugs are good.
2) The carbs didn't seem gunked up, if anything I was surprised by how clean they were so it doesn't seem like they are the issue
3) The filter in the air box definitely isn't the one for this bike, as it doesn't fit in the box very well when I take the cover off. Could this cause an issue?
4) I bought a timing light to see if the spark is firing at the right time.

I'm sure that I'm missing something to troubleshoot. What else can I do?

[Steve]

First of all, welcome to the nuthouse.

Let's address your questions (assumptions) first.
1. That is a good start for spark, but just seeing a spark is not enough. It is possible that it will spark in open air, but not when the air is compressed inside the cylinder.
2. You might be surprised by how clean they look, but they <could> be totally clogged in the IMPORTANT areas that you CAN'T see. Since the history of the bike is unknown to you, it's best to assume that NONE of the required maintenance has been done, and do it yourself.
3. The only 650 I have worked on did not have a stock filter, so I don't know how it's supposed to look. It would also be nice if you could tell us which model 650 you have, as there were the E, G and GL.
4. Not a wasted purchase, but generally, they do not change timing. That is one of the advantages of electronic ignition. In your case, since you don't know the history, it is good to verify that the timing is good, then put the light away and don't worry about it.


Now, on to other things that should be checked:
1. Valve clearance. Since the bike did start (at least a few times), you might not have damage, but many "previous owners" neglect checking and adjusting clearance. It is not just important, it's CRITICAL to have them set properly.
2. Electrical connections. You need to make sure they are CLEAN. Take each and every connector apart (ONE at a time), clean the brass terminals, apply some dielectric grease, put the connector back together. Start at one end of the bike, continue to the other, doing EVERY connector.
3. Charging system. You say you have a new battery and mentioned a voltage. I would presume that you therefore have a voltmeter? Check the battery voltage before turning the bike on, before starting it, while pushing the starter button, and at idle and at 5000 RPM. Report those numbers, we can see how well it's charging. A low battery will obviously not start the bike, and a poor charging system will not charge the battery.

.

[Rich82GS750TZ]

Welcome.

Best place to start is the Top 10 Newbie Mistakes thread linked in my signature. Written by and added to by people who know these bikes inside and out. Many of your questions will be answered there, at least as far as your ideas about wether what you’ve done so far is sufficient. Then use the sites search function to find specific answers. They’re all here. Best tip on using search: enter your keyword(s), and search Titles only. It’s the only way to get worthwhile results.

Another great resource is BikeCliffs Website- also linked in my signature. There you’ll find owners manuals, factory service manuals, stand-alone wiring diagrams, many how-to’s, including how to really clean those carbs.

And we like pictures. We need to know if you if you have the black one or the red one. Tips on using Imgur for pic hosting linked in my signature.

Oh, and create a signature with your bike info in it. It will be much appreciated. It’s under settings near the top right of This or any page on the forum.

And I see you’ve already met Steve. Pay attention to that guy. He’ll get you going for sure.

[_chaboi]

Hey Rich! Appreciate the info and basics on how to navigate the site. I believe I created my signature and added a picture properly. I'll see when this message posts.

[Rich82GS750TZ]

Great. Signature is there. no pic. If you're trying to add an avatar, like the pic next to my username, it's in settings too. It's been a while since I set it up so don't remember exactly how It's done. There are, unfortunately, some things about this site, like using pictures, that aren't very intuitive. If you fumble around with it enough, you'll get it. That's why I wrote the specific instructions for using Imgur you host pics you want to post in the forum.

[_chaboi]

Steve,

I really appreciate the thorough response. I bought a carb rebuild kit from Z1 Enterprises, but I just read in the "Top 10 Newbie Mistakes" post that many carb rebuild kits are a waste. Should I return this and just replace the O-rings like mentioned in that thread?

[Rich82GS750TZ]

sorry, yes your avatar is there. Well done.

[_chaboi]

Rich - I saw in your Newbie Mistakes thread that buying a carb rebuild kit is a classic mistake, which I've already made lol. Would you recommend returning this kit: https://www.z1enterprises.com/carbur...0-1981-83.html and just ordering the O-ring kit?

[Rich82GS750TZ]

Having never rebuilt carbs, myself, I will defer to Steve or others. But the consensus among those that know better, seems to be that carb "kits" are of varying quality and may contains more or different parts than you may need. And I didn't write the newbie mistakes thread. I just find it important enough to have placed the link in my signature, so that I and others can easily find it.

[Steve]

Carb kits are generally not a good idea. Yeah, they replace the jets, but the quality of the new jets is sometimes rather "questionable", to put it nicely. And, ... replacing the jets does absolutely nothing to clean the passages inside the carb body in between the jets. To do the job properly, you need to strip the carbs down to virtually nothing, soak them in carb cleaner dip overnight, then re-assemble them with an o-ring kit from cycleorings. Since the carbs end up in about 250 pieces, it can be an intimidating task. If you don't feel comfortable doing the task yourself, there are a few of us that will be happy to rebuild them for you, for a modest fee, of course.

.

[cowboyup3371]

Returning them is up to you but you will find they won’t have all the orings you need. At least get the full set from cycleorings and if you do return them at least you’ll come out money ahead

[_chaboi]

So here's the thing: I completely disassembled the carbs following an incredible step-by-step guide. They're current totally taken apart, but in the process I stripped the heads of a couple of the jets because they were REALLY stuck in there. I ended up having to use an extractor kit to get them out, because even after soaking in penetrating oil for an hour, they still wouldn't budge. Unfortunately I guess that means I'll be replacing them with the questionable quality jets in this kit :/

I'm also going to purchase the o-ring kit because several of the o rings crumbled into nothing during the teardown. I'm waiting on some tools to test the valves like you said. Once that's done I'll post some updates with a (hopefully) running bike

[_chaboi]

I just ordered the o ring set, I'll have to hang on to the rebuild kit because I stripped some of the jets when removing them!

[rphillips]

Bike running fine, turned it over, now it needs the carbs cleaned or rebuilt???. Possible but don't seem likely. Hope this does fix the problem for you. Just to ask, did you try starting & running on Pri. after it turned over?

[_chaboi]

This is something I planned on doing anyway as the bike is older and I'm unsure of the carb maintenance. Plus I figured the experience would be a good one for me. As of now, the bike cranks but will not start, also the petcock is extremely difficult to adjust - I had to use a pair of kleins to get a strong enough grip to adjust it. I ordered a new one and will be installing shortly. Any opinions on what else I should be looking at?