Frustrated and considering selling GS650G - kinda long

[Guest]

Hey All,

Bought my 81' GS650G not too long ago with the idea of buying a running older bike, and doing all the baseline maintenance items myself. This is my first bike and I am handy in the garage, and wanting to learn more.

The bike ran great when I bought it, I was showed a cold start and everything, and the bike ran very well, since I got it home I have not been able to start it at all. Since this is my first bike, I'm just excited to get out riding, but after weeks of dedicating full days to this bike, I cant get it to run for the life of me, so I'm considering selling it. The previous owner did the starter solenoid and ignition.

Here is all I did on it:
New Brake lines
Rebuild rear caliper/cylinder
New petcock/fuel line/inline fuel filter
rebuild front calipers
Cleaned the carbs
Coil relay Mod w/ inline fuse
valve clearance adjustment
change motor oil
change gear oil (shaftie)

The master cylinder had the piston stuck in it and after rebuild, fluid was going everywhere, so looks like the housing is bad now...was working when removed from bike

From my reading the hard start could have been a combo of weak spark, tight valve clearances, dirty carbs. So I did all that work hoping and praying that would help it start.

This morning I hook it up and crank crank crank crank with nothing firing. The spark is blue, there is gas, the battery is being jumped by my car battery (out of car & not running of course).

At this point riding season is here and I have a non running bike with no front brakes and I still need to replace the tires, I purposefully didn't buy a "project bike" but now the bike has turned into a project bike. I also was hoping to take a road trip on it this summer, which it obviously need to be running and have front brakes for, not to mention all the other things. I bought it for $1,000, have put about $450 into it, not counting the labor. When I can buy a very well maintained GS off here for around $2,000, scrapping this and buying another sounds appealing.

I'd like to hear what you would do in my situation.
Should I turn this thing over to a pro for diagnosis ($$$)? Should I sell this thing and start over? should I keep, but another newer running bike and work on this one on the side?

Watch this be some super small thing that wont make it run...Yes there is gas getting to the carbs.

Thanks for reading the rant and giving opinion.

Justin
IMG_7013.jpg

[Burque73]

I've thought the worst and realized I hit the kill switch. Feeling like a real doof, flipped it to run and life was good.

Is that you're issue, the kill switch?

Edit, you mentioned spark so not the kill switch. Best of luck to ya.

[Gorminrider]

I have a 650.They are a little lean on startup at least mine is....ideas in order:
Turn gas tap to PRIME....wait. It takes awhile to top those 4 carbs up. The fuel tap's vacuumsettings-Run and RES -aren't going to flow well until the bike is running.
double check the "choke" is actually lifting the enrichers on the carb ...No go? squirt a little gas into the plug holes...no action?

UNDO coil relay mod.still no action? Undo headlamp. I'm glad you're using a car battery but the headlight undone will still help given the wiring system is prone to voltage drop anyways...
Finally, yes,
probably an idea to to take the bike to someone for an hour's labour to see what's wrong. Hopefully you spot a decent mechanic. Old bikes in the shop is one clue.... It's likely easy to find the problem if the bike was running well before and is often the area of the last "thing-you-did " that has a problem

Added later: almost always, a little bit of gas down the plugs will make something happen for a little while if the ignition and timing and valves are ok. Compression(valves) can generally be crossed off the list by putting your thumb over the plug hole and rotating engine with the starter motor.
need mention that It's remotely possible that your cam chain has jumped setting everything a little wrong at sometime in your go-over of the bike...doesn't happen easily but with all the posts on cam chain tensioners here- well....have a close look where other things fail to indicate the issue.

oh, and the advance weights to check too..that they are moveable-not jammed-they don't come up as an issue ever for me , but it's a simple thing that could stop a bike starting

[Steve]

All good points so far, but I will add one more:

Make sure you are using the "choke" properly.

To use the "choke" (notice the quote marks?), start by making sure there is gas in the float bowls. Turn the petcock lever so it is pointing to the back (the large part is the pointer) for about a minute or so. Move it back to the bottom (the RUN position). Pull the "choke" knob out all the way. Squeeze the clutch lever (unless you have bypassed the "safety" switch). Make sure the kill switch is in the RUN position. Turn the ignition key ON. Push the START button. KEEP YOUR HAND OFF THE THROTTLE. If the engine starts, and races to more than 3000 RPM, move the "choke" knob in a bit until engine speed is between 2000 and 2500. Still, KEEP YOUR HAND OFF THE THROTTLE. The enrichener circuit needs the high vacuum of a CLOSED throttle to work. Opening the throttle AT ALL will destroy that vacuum and it will try to start on the 'normal' jetting, which is nearly impossible.

.

[Gorminrider]

^^

KEEP YOUR HAND OFF THE THROTTLE

indeed, it could be that simple.

[jswhite]

All good points so far, but I will add one more:

Make sure you are using the "choke" properly.

To use the "choke" (notice the quote marks?), start by making sure there is gas in the float bowls. Turn the petcock lever so it is pointing to the back (the large part is the pointer) for about a minute or so. Move it back to the bottom (the RUN position). Pull the "choke" knob out all the way. Squeeze the clutch lever (unless you have bypassed the "safety" switch). Make sure the kill switch is in the RUN position. Turn the ignition key ON. Push the START button. KEEP YOUR HAND OFF THE THROTTLE. If the engine starts, and races to more than 3000 RPM, move the "choke" knob in a bit until engine speed is between 2000 and 2500. Still, KEEP YOUR HAND OFF THE THROTTLE. The enrichener circuit needs the high vacuum of a CLOSED throttle to work. Opening the throttle AT ALL will destroy that vacuum and it will try to start on the 'normal' jetting, which is nearly impossible.

.

I have read this elsewhere so haven't been using the throttle and choke, only choke. As for the prime setting, i have only had it on prime for less than 20 seconds prior to trying to start so maybe the bowls just arent filled up all the way before putting onto run.

[jswhite]

I have a 650.They are a little lean on startup at least mine is....ideas in order:
Turn gas tap to PRIME....wait. It takes awhile to top those 4 carbs up. The fuel tap's vacuumsettings-Run and RES -aren't going to flow well until the bike is running.
double check the "choke" is actually lifting the enrichers on the carb ...No go? squirt a little gas into the plug holes...no action?

UNDO coil relay mod.still no action? Undo headlamp. I'm glad you're using a car battery but the headlight undone will still help given the wiring system is prone to voltage drop anyways...
Finally, yes,
probably an idea to to take the bike to someone for an hour's labour to see what's wrong. Hopefully you spot a decent mechanic. Old bikes in the shop is one clue.... It's likely easy to find the problem if the bike was running well before and is often the area of the last "thing-you-did " that has a problem

Added later: almost always, a little bit of gas down the plugs will make something happen for a little while if the ignition and timing and valves are ok. Compression(valves) can generally be crossed off the list by putting your thumb over the plug hole and rotating engine with the starter motor.
need mention that It's remotely possible that your cam chain has jumped setting everything a little wrong at sometime in your go-over of the bike...doesn't happen easily but with all the posts on cam chain tensioners here- well....have a close look where other things fail to indicate the issue.

oh, and the advance weights to check too..that they are moveable-not jammed-they don't come up as an issue ever for me , but it's a simple thing that could stop a bike starting

Thank you for the suggestions. Ive been using prime, but for only 15 seconds or so, looks like I need to try for longer.

When I took the carb apart I made sure the choke parts were all moving, so that should be good to go. The enrichers are nothing more than the rail and pin that moves in/out of carb when choke is pulled right?

I'll have to try some gas in the plug holes too, havent done that.
I do have a shop here in town which I can bring it too, maybe an hour or so after trying these things would be a good idea.

Please excuse the ignorance, but what are the advance weights?

[BigD_83]

I won't top up the technical knowledge here, but I would encourage you to keep going. With the work done and money spent, you are closer than you think to having it running. Selling it would have to be at a relatively huge loss considering you'd have to declare it as non-running.

I love my 650G. I had loads of issues getting it going when it was gifted to me, but it is now a very reliable ride that requires little extraordinary maintenance. Most of the non-starting problems came down to:

1) poor/loose wiring connections and grounds,

2) dirty and/or poorly adjusted carbs and

3) weak spark (fixed by upgrading the wiring)

[Steve]

Please excuse the ignorance, but what are the advance weights?

No problem with ignorance, especially if it's accompanied by a quest for knowledge.

The advance weights are on the right end of the crank. As the crank spins faster, they are spun outward agains spring pressure, moving the ignition trigger assembly slightly to advance the ignition timing for high-speed running.

They need to be free to move, so clean and/or lubricate them if necessary.

.

[Admiral Beez]

If it was me, I’d cut bait now and take it to a mechanic knowledgeable on this old bikes. That will give you a bike that’s now running, that you can now fiddle and work on from the new baseline. I rode a 1960s Triumph for over a decade and after all those years of wrenching and trying to figure out what I don’t know, I decided that the next bike will be going to the mechanic for anything beyond oil changes, cleaning wire connectors, changing brakes and cables, and valve clearance checks. Money’s for spending, IMO.

[Redman]

................... Ive been using prime, but for only 15 seconds or so, looks like I need to try for longer. .............

Yes, a minute or two. But do not leave it there and walk away.
Sounds stupid, but I put to PRIme and dont take my fingers off it, standing there and holding it for a minute or so, the back to ON.

After your coil relay mod: you have a good 12v at the coils?

After you cleaned the carbs: you verify that the "choke" lever is actually operating the "choke" mechanism on the carbs?

Of all the work you say you did, the carb clean and the coil relay mod are the only ones that seem like could have effected it running.
Was it after one of those that it quit....?

Seems like the valve clearance chack/adjust would not make it worse so would not run.
(You did just check cleaance, maybe swap some shime by depressing the bucket, right? Did not take out cams or anything.)

.

[chuck hahn]

Got to be a member close that can run over and help you.... just ask and maybe someone will offer assistance before your blood pressure goes whacko.

[Redman]

....
Is that you're issue, the kill switch?.....

On GS the kill switch interrupts the starter button/solenoid also (unlike most other brands) so will not crank.

.

[jswhite]

Thank you for the input everyone.
I took the advice of gas directly into cylinder from plug holes and I got it running! Warmed up, adjusted the idle turned it off. Turned back on again easily. I took out the plugs (which are new) to see if any clues are there and plug 1 is extremely sooty, 2 & 4 are perfect, and 3 is a little sooty. Here is the pic of #1 plug.IMG_7143.jpg

@Redman: I did not check the voltage after the coil mod...probably should do this. I just test the positive & negative leads going to the coils for 12V right? Of course battery hooked up and kill switch turned to run.

@Redman: I can see the choke mechanism working from the outside, moving the bar for all 4 carbs. This is what you are referring to? The valve clearances I found were very tight and out of tolerance. I changed the shims in all 8 valves to open them up in spec, presumed this would help it run better.

Book says carbon fouled means, rich mixture or weak ignition system. I'm sure there is a thread on adjusting individual cylinder mixture right? I mean it is 2 out of 4 cylinders which are black (one much more than the other) but most likely means mixture? Or does the fact that the two cylinders which I put gas directly into the cylinders have dirty plugs mean that the gas I put in there made the plugs dirty? I'm sure the mixture was crazy rich when I put gas in to try and start. If so, should I just clean with carb cleaner and put back in, start (W/O) gas dumped in and see if they get dirty again?

@Steve thanks for the explanation of the advance weights, and that valve spreadsheet. The Excel doc helped me get back where it should be.

Thanks again everyone!

[chuck hahn]

At the top of the carbs section is a STICKY concerning CV carb tuning procedures..you may wish to check that out also.