1980 GS850GLT Road-worthiness Project

[eil]

Welp, I took it out for a second spin around the neighborhood today...

I got the tach drive gear in yesterday and very nearly scrapped the bike. I had the valve cover off to remove part of my tach drive plug and dropped one of those teeny-tiny nuts down into the cam chain tunnel. After much wailing and gnashing of teeth, I got up the courage to find my mirror to have a peek down. By the Powers, it hadn't fallen all the way down. I counted myself VERY lucky since this is now the second time such a thing has happened. It took some doing to figure out how to snatch it out of there but I eventually settled on a neodynium magnet attached to a thick feeler gauge. Three extremely careful tries and it was out.

I will never NOT stuff a rag down into the cam chain tunnel, even if the cover is off for only five minutes, pinky swear. Not onto the rest...

On the previous run, I had the idle set way too high. I didn't realize how high because I didn't have a working tach. So today before I took it out, I dialed it way back and added some slack to the throttle cable. It still idles a little under 2k and hangs around 2.5k while out riding so I think I'm lean. But then again, it starts real easy with not much choke, and I can push the choke all the way in after 15-20 seconds of running, so maybe it's rich? I'll have to do some troubleshooting in this area; right now my suspicion is on the carb's mixture screws. After I got back to the garage and shut the engine off, I pointed my nifty new infrared thermometer at area where the pipes join the head. Around 300 degrees (Fahrenheit here) on number 1 and 2 and around 400 degrees on 3 and 4. Not sure what it means yet, but I would think a 100 degree difference is worth noting.

Oh yeah, and the speedometer broke. I noticed it start to whine while I was riding around and made a mental note to take it off and lubricate it. A few minutes later, the needle was gone. So it seems as though I am destined to have either a working speedo or tach but not both.

As for my riding skills... I need much practice. Getting moving from a stop, especially when turning at the same time, is definitely my weak area. Haven't stalled it yet, but I attribute that to this bike's extremely smooth clutch with it's enormous friction zone. I am starting to have more confidence in these new tires, however.

And finally, I did forget to take an "after" picture of the bike yet again. Next time, I promise!

[pureinstinct]

Eil did you remove your carbs butterflies when cleaning your carbs?
Im dipping my carbs in barryman dip, an im not sure if that would harm the butterflies.

[eil]

I did not remove the butterfly valves when cleaning my carbs, but word on the street is that they'll be fine. Only dip the carbs for as long as it takes to get them clean and you should be alright.

[eil]

Had a little treat last weekend...

The fam and I went up north to my wife's place for her parents' 50th wedding anniversary. I got put on grilling duty (as always) when a good friend of the family, Bob, sidles up and asks me how my rebuild is going. He says he's thinking of buying a road bike sometime soon. Then proceeds to tell me about one of his friends who restores old bikes.

Oh reeeealy?

Bob offers to take me up to his friend's place and I'm like, is right now too soon? After the shindig he gets a hold of his friend and we drive across town. He introduced me to Chris. This is some of Chris's current stable:



He says he'll rebuild just about anything that looks cool but he seems to have a weakness for 60's Hondas and Super Hawks in particular. His work is meticulous. Here's his current masterpiece:



This thing is flawless and just looks totally badass. Even if it wasn't all shiny, it looks like a handcrafted piece of art compared to the Honda CBs of just a few years later. I don't think I've seen a finer gas tank in all my life.



Apparently Chris only started doing motorcycle restorations five or so years ago. While trying to find parts, he evidently ran into some wealthy old collector who has literally hundreds of old Hondas in various states of quality and has recently worked out a deal with him: The guy sends Chris two bikes to work on at a time. Chris restores them both to identical showroom-quality condition. When they're done, Chris sends one bike back to the Honda gentleman along with the parts bill and gets to keep the other bike as payment for the job!

I asked him if he ever enters his bikes in shows and he said not really. It's not that he doesn't want to, he just doesn't have the time. Like most of us, I imagine the balance between work, life, and motorcycles doesn't leave a lot of time for much else. He didn't mention where he sells the completed projects, but he did say that he's never in a rush to sell and is fine with admiring the bike and waiting patiently for the right buyer to come along.

Here's his current project:



He says he's going to turn it into a red, white, and blue cafe race of some sort. The frame has a silver ceramic coating. Almost looks like chrome from a distance. I forgot to ask what model this was, but I noticed it had new aftermarket Mikuni carbs.

It wasn't until after we were on our way back to the in-laws' house that I remembered all the good questions that I should have asked him. (Unfortunately for me, I'm very shy when meeting someone for the first time.) If only Chris didn't live almost three hours away from me, I'd beg to apprentice for him! Oh well, hopefully I'll run into him again.

[eil]

What I did to my speedo on test ride #2:



I'm in talks with a member to buy another one. Hopefully he'll be able to ship it soon. I'll definitely have to lube that one before install to spare it from the same fate.

And then on Sunday, I went for test ride #3. Here are the "after" photos I've been promising for weeks:





Doesn't look half-bad from about 10 feet away... with your glasses off... in the shade. Except for the disaster that is that seat. Still debating over whether to try and tackle it myself with vinyl pleather from the hobby store or drop the coin on a new cover. I'm not sure about a cover because I sorta think that the foam might have been modified to make it a wider seat. Where does one buy new seat foam anyway?

I'm also doing some tweaking of the carbs to get the mixture right across all four cylinders. Details on that are in another thread. One of the mixture screws is giving me grief, so I'll have to replace it. And I may have to remove the carbs again in order to double-check the float heights.

Insurance and registration are in the works.

And finally, the front suspension is pretty bouncy. I'll order and install new progressive springs at some point when the budget allows. Anybody have a favorite vendor for those?

After these are addressed, the bike will pretty much be where I want it. This isn't my dream bike by any means, so I probably won't hold onto it for too long. This season, maybe next. But it is my first and taught me a lot so far. And it still has more to teach me before the summer is through!

[eil]

After spending 9/10th of the weekend laboring for the wife in the back yard (new flower beds and whatnot), I managed to squeeze in another ride at the end of the day.

I still haven't gotten around to fine-tuning the carbs and checking for air leaks. But at least it's properly insured and licensed now, giving me the courage to leave the neighborhood and get the bike up to speed at little bit.

Revs climb pretty steadily until around 4.5k RPM and then it's like flipping a switch. A big fat red one with a label on it that says, "hey you, get the lead out". And it does.

I'll get used to running it up, I'm sure. But the biggest thing that had me concerned was the wind. The current handlebars are from a G model so they have quite a bit of vertical rise. I'm 5' 10" or so and they have me sitting almost completely upright. At 50mph (guestimated, my speedo is still broke) or so, the force of the wind pretty much had me hanging on for dear life. My fingers still ache a bit from that. Leaning forward helped a little, but that crunched up my arms and made it impossible to steer.

I have some daytona bars (at least that's what I think they are) that I'll probably try out to see what difference they make. The main thing I didn't like about those was that they appeared to be narrower (hand grips closer together) and I'm not sure if that's what I want.

[Dogma]

Daytona bars is what I have on mine, I think. I'd prefer euro or GP touring bars on it though. They're a little straighter too, so you don't grip the throttle diagonally so much.

[eil]

My new speedo came in. Major thanks to new_guy... I asked to buy the speedometer, he sent me a whole dash cluster! Which came in very handy as I needed a few extra parts off it.



I was originally a little discouraged that I'd have to calculate the bike's new mileage in my head, but when I took apart the old speedo (to see if it could be fixed), I saw that someone had cut a hole for the reed switch that goes the self-cancelling turn signal unit. Meaning the broken speedo already came off some other model! No clue on the actual mileage of this baby now! But at least I have a trip meter reset knob.

I took apart the old one to see what was inside and if I could fix it. Found out that the hole for the reed switch is pretty much all the access you need to lube the gears inside. But otherwise, the internals of the old one are toast. Bearings on the input shaft are worn or rusted (or both) which caused the squealing and allowed the magnet wheel to hit the speed cup, which is how the needle broke. Plus the gears leading to the odometer were pretty worn down.

The new speedo seems to work great. Squirted some lithium grease in through the reed relay switch hole for good measure.

I also tilted the handlebars forward a little, to see if that helps with countering the wind. It made a big difference. I'm reasonably comfortable at 60mph, but now my arms get tired from being held up so high. :P I'll still swap on the daytonas at some point.

I noticed amongst some other tinkering that my choke knob cable had no slack, leaving the choke partially engaged with the knob pushed all the way in. I was hopeful that maybe this would solve my low-end idling and power issues. It helped, but not much. There's still something else going on.

So anyway, my current biggest issue now is this. The bike starts, idles, and runs just fine to begin with. Responsive throttle, gobs of power. It needs a small amount of choke to start, but I'd say after about 30 seconds it idles fine with close to none. However, after about 20-30 minutes of riding, I have a loss of power on the low end (under about 4k) and a high idle. This makes starting from a stop sign or intersection very difficult because I either stall it or rev it up so high that I feel a little out of control until I get up to speed. Especially problematic when turning. Is this indicative of a lean condition? (If so, probably means I have an air leak somewhere.... yay.)

Last night I rode around the neighborhood for about an hour and used something like 1/3 a tank of gas. Went 28 miles in total, although much of it was acceleration and deceleration. I guess it's probably normal to burn through a ton of gas under those circumstances. Except for the low power issues when hot, I'm starting to have much more confidence in the bike.

[Good Times]

Sounds like a lean condition caused by worn out o-rings and or hard intake boots. The high idle is a typical symptom. Replace the intake boots if they are not pliable and replace the intake boot o-rings as well.

When the bike heats up it is causing the boots or o-rings to leak.

[eil]

Sounds like a lean condition caused by worn out o-rings and or hard intake boots. The high idle is a typical symptom. Replace the intake boots if they are not pliable and replace the intake boot o-rings as well.

When the bike heats up it is causing the boots or o-rings to leak.

Yeah, I kinda suspected it might be the intake boots. I didn't replace them when I pulled the carbs because they seemed to be okay at the time. (And more importantly, run about $100+ for the set.) I did put new o-rings under them, though.

[eil]

Well, I worked on the motorcycle all weekend long but in the end, didn't really make any forward progress.

I ordered new intake boots (at great monetary expense) and compared them to the old ones. Honestly, the new ones are not leaps and bounds better at first blush. They both have about the same amount of squishiness, the only real differences is that the old ones lack the rubber coating on the metal flange. Which I guess could contribute to them leaking when hot, if that's what was causing the lean condition. I put the new ones on anyway but it remains to be seen if they'll help at all.

Since it appears that I may have a charging problem, I spent the majority of Saturday cleaning electrical connections and grounds. Used De-ox-it and Q-tips, mainly. Found a couple of nice PO surprises and fixed those. My R/R appears to be original, so I'm certain it's shot. I plan a thorough test of the charging system in the near term, but not immediately. Until I'm sure I have the engine running right, I can muddle through with relatively short rides and keeping the battery topped up with a charger.

Wrapped up the day by installing the new choke cable and putting the carbs and airbox back on. Now, I know a lot of people say that installing the carbs and airbox on the 850 is waaaaay simpler than almost any other bike out there, but I still dread it every time. Mostly, it's because getting the boots and clamps exactly where they need to be is a real pain. (And yes, all boots are brand-new.) Every time I tried to tighten the airbox clamps, the bottom end of the clamp (and boot) would slide off the carb. I ended up jamming two pieces of wood in behind the airbox to push it forward as much as possible and that got everything lined up mostly right. I still feel like those airbox boots are going to just slip off the carbs one day while going down the road.

On Sunday, I tell myself I'm going to go for a test ride. Put on my boots, get the mesh jacket out. I start up the bike. As usual, it starts right up, no questions asked. But seems to be running just a little rough. Is it? I think it's always sounded like this. Anyway, I let it idle for a minute and then shut it off to check the oil. Oil looks good. On a whim, I whip out my IR themometer and check the head temperature in front of the exhausts. 100(F) degrees on #1, 200+ on the others. The #1 header is only slightly above ambient temp, I can touch it no problem. The others are way too hot to touch.

So cylinder #1 is not firing. And it's probably not been firing since I got the thing running again, because I never thought to test for a non-firing cylinder before. And because I don't know exactly what a properly-running GS850 sounds like. Guess I'm not going for a test ride. I started it up again and pulled the #1 spark plug boot. No change in engine speed or sound, so I guess that confirms it. Spent the remainder of Sunday trying to figure out which of these things is failing me: compression, spark, or fuel.

Compression: Surprisingly good. About 130-135psi across the board.

Spark: I looked up the wiring diagram for the ignition system and I see that the secondary winding of the coils runs through each spark plug and through the engine to complete the circuit. So if I have no spark on #1, #4 would not be firing either. Yet I know for sure that it is because its cylinder is getting hot and pulling the plug boot from #4 consistently stalls the engine. My only concern here is that... because the plugs #1 and #4 are in series, wouldn't pulling the boot from #1 also kill the spark for #4? Because this doesn't appear to be what's actually happening...

I unscrewed the innards of the spark plug boots and noticed the resistors were visibly toast. The metal terminals on each side were severely worn down by arcing or missing altogether. The one for #1 had a carbon trail along it, showing that current was now preferring to go around the resistor rather than through it. I replaced the resistors with equal-length pieces of metal (cut-off machine screws) and put the plugs back together. Cylinder 1 is still not firing.

Turned my attention toward the plugs themselves. Verified gaps, although I had already done this before. I noticed for the first time that these are not B8ES, they are BR8ES. Meaning they have resistors in-line as well. Thanks, PO. Verified with a multimeter that the spark plugs have 10k of resistance exactly. I feel that with the 5k resistors removed from the spark plug boots that this is not a big enough difference to cause a problem, so I will continue to run them for the time being.

Fired up the engine again, same results. Tried swapping the plug boots, same results: cylinder #1 doesn't fire, engine stalls with #4 removed. Measured the cap-to-cap resistance on the second coil (going to #2 and #3) and it was within acceptable Service Manual limits. But I could not get any kind of reading between boots #1 and #4. So, open circuit. Infinite resistance. But apparently not so infinite that a few thousand volts can't get through to fire the #4 cylinder.

So I know one coil is not good, but since the #4 cylinder is still firing, for the moment I'm going to consider it marginal. I will probably take the coil off the bike in order to give it a better visual inspection. I may also try swapping the coils to see if the problem stays. (Although at this point, I'm sure it will.) I am not looking forward to replacing these coils if OEM ones aren't available because all of the aftermarket ones I've seen are freaking expensive.

Fuel: Since swapping around the plug wires still revealed #1 cylinder failing to fire, I'm falling back to carburetor issues as the most likely culprit. The #1 carb was the only one of the three that looked gunked up in the beginning. I suppose I might not have cleaned it well enough? Float height is correct because I just set that. I know it's getting gas because a bunch of gas poured out when I removed the drain screw. I removed the carbs from the bike again, unganged the #1 carb, and started disassembling it. Removed all the bits and pieces. Could not see any plugged up jets, but I haven't dipped the carb body yet. I'll try to get that done this week.

So that is where she sits. I don't mind actually working on this bike, but I am starting to get very tired of constantly having to throw money at it. At this point, I really just want to ride it.

[eil]

Old boots on top, new boots on bottom:



I didn't want to be back to this stage again so soon:



Spark plug resistors. Wonder where I can buy new?

[eil]

I spent a bit more time out in the garage tonight.

Finished up cleaning carb #1 again. Couldn't find any blockage or issues, but at least I'm sure it's clean and that nothing got in there since the last time I cleaned it. Everything seems to function normally. Carb cleaner squirts through various passages like it should. Float level is correct. Everything looks as perfect as I know how to get it.

I also did a static check of the fuel level on all four carbs. Amazingly, they were all spot-on at 5.0mm if I measured from the bottom lip of the carb body to the bottom of the fluid "bubble". So unless I was measuring wrong, I know the floats are correct.

Since there were no issues with the carbs, I turned back toward to the ignition. Now that the carbs are off, I can check for spark a bit easier and not worry about the engine starting up. I'm not an expert at this, but I've read here that I'm supposed to look for a fat blue spark. I saw no fat, and only somewhat blue. Spark was thin and seemed to alternate between blue and orange. That's not good, eh?

Possible weak spark, check. I checked the voltage going to the coils. Voltage at battery was 12.71 volts. (Freshly charged.) Voltage at both coils, however, was 10.48 volts! Smoking gun? Man, I hope so. But I'm keeping my fingers crossed. I'm also going to pick up some proper B8ES plugs from the parts store after work tomorrow, see if taking the extra resistance out of the loop makes any difference. Although... hmm. I removed the resistors from the caps. Those must have been 10k ohms, because the plugs are 5k ohms. So we're actually 10k less than factory specs.

I'll do the coil relay mod (or at least a temporary bypass until I have time to get a relay and some wires) and see if that helps, but I still have a hard time believing that it will cure my #1 cylinder not firing issue. Maybe I'll pose the question in the Electrical forum since I don't think anyone reads this thread anymore. :P

[GateKeeper]

A 2 volt drop is enough to cause you some major issues.....do the coil relay mod and get that voltage up as much as it can get....

[tkent02]

Or at least hot wire it to test if that is the problem.
The 1980 and later are more susceptible to ignition problems from low voltage than the older models with points ignitions, I believe 10.something Volts is about where the problems start to show up.

Have you swapped the spark plug wire from #1 to #4 to see if the cold cylinder moves with the wire? Leave everything else alone, just swap the wire. (it will reach) This will tell you for sure if it is an ignition problem or not.

The low voltage does sound like a likely culprit.