First off, hello, long-time reader (lurker) first time poster. There are a few questions towards the end of this long post, but I'll also introduce myself and the history of the bike in question.
Thanks to everyone for this great forum! With the information here, and related sites, lots of time, stubbornness and brute-force & ignorance, was able to get my '90 GS500 up and running. The bike had a hard life long before I ever saw it. Someone (or multiple someones) had raced it and my buddy had bought it a few years ago as his race bike, then had a kid, got a shiny newish SV 1000 for commuting . . . and rolled the GS under his porch. We pulled it out 2 years later, and his wife, from up on the porch, said "I didn't know you still had that bike."
If I'd known how much work it was going to be . . . well, it's probably for the best I didn't. The local shop basically refused to work on it when I got to the point of wanting to pay someone to sort-out the carbs. That just doubled my resolve to get the thing running, right. (Once I figured-out it had Dynojet needles and a tiny pinhole in a diaphragm, and I replaced both, things went much smoother.)
Anyhow, it's been my learning bike for wrenching and riding. After getting it running well, took it out on a track day (http://www.2-fast.org/images/PR-2002-Aerial.jpg) (last one of the season over here), which was a blast in a personally challenging way. Here is the one picture the track photographer got of me:
(http://img513.imageshack.us/img513/1666/5835616a8c5371cl1.th.jpg) (http://img513.imageshack.us/my.php?image=5835616a8c5371cl1.jpg)
That was before I laid the bike down, twice. On the same $%# corner (downhill into a hairpin followed by another hairpin, had me totally spooked). Went wide and into the shoulder once, bent the bars, broke a brake lever and added some scrapes, etc. Ran to the 'local' bike shop (Bent Bike in Auburn) and picked-up new bars and lever. Was back out on the track without missing much--they'd had it shut-down for most of that time because of two different ambulance trip-worthy crashes. Ouch.
Anyone, second to last run of the day, I laid it down on the inside of the curve (overcompensated). This time the bike fared a bit worse--in addition to bending the bars, breaking the brake lever and scraping it up a bit, I tore off the signal generator cover. (This was not the first time that cover had seen asphalt. Someone had ground it down pretty well at least once in the past.)
(http://img413.imageshack.us/img413/5606/signalgenbl2.th.jpg) (http://img413.imageshack.us/my.php?image=signalgenbl2.jpg)
The two rear bolts were sheared-off in the case, the front one broke the casing. I got it home and thought I got it all back together enough to ride, got about 1/2 mile (downhill) from my house on it, and it started to run really poorly. Finally to the point of unrideable. Got it home and figured-out that the rotor in the signal generator was damaged. It was striking one of the two pickups (right term?). Both the rotor and one of the pickups has some wear/damage from that interference. The pin aligns the rotor with the crankshaft was broken (and/or now gone, didn't realize it existed till after I lost it) and the bolt was so badly stripped it was completely threadless at the last 1/2 cm. At this point the rotor was completely uncoupled from the crankshaft. The engine was making some really awful sounds at the end there.
Questions:
1. Until I get the replacement pin (97cent part that will take a week to get here) I can't really tell if it will all go back together correctly. It appears as if the rotor rotates with a wobble now--what are the chances I could have bent the crankshaft? It seems unlikely. I'm guessing/hoping that's just because the rotor is not properly bolted down and aligned with a pin.
2. Is it possible my rotor and generator assembly (plate with pickups) is salvageable even if a bit banged-up (they are pricey)?
3. And the real question: what's the damage I may have done to the engine running it as the signal generator failed? Will completely mistimed spark firings destroy valves and such?
:dunno_white:
The bike is pretty ratty, and isn't worth dumping a lot of money into (don't ask me to explain the time), but, I'm fond of it and am hoping to get a lot more riding, and track days next season, out of it.
Thanks,
Barnaby
fix the problem and then get some case guards.....i know duh....
replace the bolt that holds the rotor in.
the pin also ..... could use a screw with the head cut off in a pinch
spin it over and see if the rotor is bent ...replace if needed
replace the cover with one for a GS 400/425/450 a little bit thicker but it will rub on the rotor bolt....have to relieve it in the center
if the pickups are a little chewed up..... wrap 2-4 loops of safety wire on them to get the gap to the rotor a little bit closer
I did same crash at RRR and wondered why bike had a high speed stumble....about a year later....the bolt holding the rotor on snapped the head off...easy fix once i figured it out :cookoo:
Quote from: BumbleBee on November 01, 2007, 11:38:16 PM1. Until I get the replacement pin (97cent part that will take a week to get here) I can't really tell if it will all go back together correctly. It appears as if the rotor rotates with a wobble now--what are the chances I could have bent the crankshaft? It seems unlikely. I'm guessing/hoping that's just because the rotor is not properly bolted down and aligned with a pin.
Hmmm ... hard to say on that one. I guess you'll just have to see after you get things back together.
Quote from: BumbleBee on November 01, 2007, 11:38:16 PM2. Is it possible my rotor and generator assembly (plate with pickups) is salvageable even if a bit banged-up (they are pricey)?
If they're NOT salvageable, I might have a source for both the plate and the pickups. I have a seized '96 engine in my possession, but I can't remember the arrangement I made with the previous owner. He paid for a replacement engine, and I didn't pay him
anything for this one, so I'm not sure if he would like to recoup some of his costs, or what. He's been semi-
incommunicado in Russia for the past two years, but he'll be coming home in the next week or two, so I can ask him. Ditto on the (black) side cover, by the way....
Quote from: BumbleBee on November 01, 2007, 11:38:16 PM3. And the real question: what's the damage I may have done to the engine running it as the signal generator failed? Will completely mistimed spark firings destroy valves and such?
I wouldn't worry about it until you have evidence. Mistimed sparks can cause backfires, but they won't make valves hit each other or anything like that.
I"ve got a side cover, and multiple parts you may need, unfortunately I dont have the ignition stuff, but I've got a motor with the internals if you need em. just gimme a holler and I'll pull what you need.
Well, finally got the pin in at the dealership. Then I promptly lost it it while putting things together. Fortunately, I'd measured it first, and found a hardware store that carries metric dowel pins. The one supplied by the dealership was a 3mm (dia) x 8mm (approx length) pin. The pin seemed too long though. Anyhow, I ended-up cutting down a pin from the hardware store to be about 5 mm long (and then rediscovered the OEM one where it'd rolled to--I need to redo my garage and driveway concrete slabs, and epoxy paint them, they are all cracked and weedy, which makes it way too easy to lose bits).
The signal generator rotor still "wobbled" on the crankshaft, and would not set/seat properly. Trimming down the pin helped a bit, but didn't fix it all. Then I noticed that the inside mating surface of the rotor, where it sits against the generator shaft end, was a bit banged-up--the pin had bent a small lip up at the edge of the slot it slides into. I filed/dremeled down that ridge so the rotor could again sit tight against the crankshaft. New pin, new (longer) bolt (who knows whether the previous was stock or not, but it took a longer one so I used it, so as to get into more threads down the crankshaft).
All that seemed to help, but with it all bolted back together, it still had some eccentricity to its rotation. Figure that rotor is just mangled-up enough not to be perfectly square/straight anymore. The bike started and idled just fine though. Didn't get it out on the road yet. I'll see how it holds up.
Thanks for all the suggestions and offer of parts/help. Will update as I get a chance to get it out and road tested.
FYI, I think the signal generator cover is one off a GS400/425/450 as it is very thick and has the inside center ground-out a bit. I probaby should get some engine guards, previously I'd not been worried as the bike was already a good bit battered. I saw some threads here about fabricating guards. Are they not available retail anymore?
-B.