Coming of age? . . . bike is running more like a harley than a suzuki ????

[bval]

Thanks for keeping up on this thread, guys.

Something I need to correct from one of my previous posts, was to say after installing the K&N filter (with reducer for stock jetting) that air flow was NOT the problem. In editing before submitting I must have deleted that word accidentally.

Anyway, I managed to get out to my buddie's place last week and he took it for a ride. He really noticed it and felt that it was mechanical in nature, suggesting the drive shaft bearing. Although it feels mechanical in nature to me too, I really have a hard time thinking that drive shaft play and/or bearing failure could be the cause due to the low kilometers of the bike, my style of riding and that I've been fairly anal about chain tension. I tend toward the slacker side of the recommended adjustment range rather than the tighter end just to prevent stress on the shaft bearing. However, both buddies were then wondering about drive shaft problems. So tonight I pulled the front sprocket (again) and there is absolutely no play or roughness in the shaft. The sprocket has about 0.5mm play forward and back (rotational) on the spline and about 1.0mm play side to side on the spline. By the way, is this normal? Still, I can't see this minimal amount of play causing such an obvious shudder. However, we did tighten the chain to the tighter side of the adjustment range and that did make a noticeable difference. But I think we just reduced a variable rather than touched the real problem. As "ohgood" points out, problems easily transfer throughout the drive train, so at least we have focused the vibration more by removing any amplification caused by any chain slack.

On "ohgood's", point, I'm revving it as per normal and I typically ride between 4000 - 6000 rpm when cruising. I realize there is a little shudder that is normal below 4000rpm, but I'm feeling it all the way up the scale in varying degrees depending on the gear I'm in. I'm at around 23,000km on this bike (bought it with only 500km on it) and I didn't notice a change in the feel of the bike until after 22,000km. Although I'm new to bikes, I've driven standard tansmission vehicles most of my life and I've rebuilt a number of vehicles and engines, including the B2200 Mazda I use when I absolutely have to.  I'm just mentioning this so readers know I'm not a newbie to mechanical work, just to bikes.

So I'm at the same place where "galahs" is in my thinking now. Electrical, electonics or carb. Tomorrow I'm going to work through the bike using my multimeter and see if there is anything detectable there. Then I'll drain the carbs and check the fuel for crap, then pull the carbs to check for a plugged jet. I may rejett at that time to the K&N recommendation and remove the adapter since I'm going to be in there anyway. Failing discovering something in these checks, I'm going to need a F*#king holiday, so I'm going to Anitigua for a couple of weeks. (well, truth be told that was planned anyway) 

Interesting note on the earth connection though. I'll definitely check while I'm working on it tomorrow. Thanks everyone!

[galahs]

Good luck mate 


Has the bike been rejetted in the past? Cause running a stock jetted bike with a K&N will 90% of the time cause problems.

[Kerry]

There shouldn't be any problems with the in-airbox replacement K&N since he has also installed the restrictor ring.  I've been running my '99 that way (with stock jetting) for tens of thousands of miles ... in elevations ranging from the CA coast to  Independence Pass in CO at 12,000+ feet.

It doesn't run exactly the same over that entire range, of course ... but no complaints.

[bval]

No rejet to date and as Kerry mentioned the adapter for the stock jets is in place. This was just done a day or so ago as troubleshooting elimination, so it wouldn't have been causing the problem I've experienced for weeks. Thanks, Kerry, for letting me know how well your's has been running with this configuration.

Carb balance was also asked about a few replies back, and I didn't address that. However, it didn't seem to be the problem. When put on a 3 foot long mercury based manometer, they were off by about 1/2 an inch and both travelled synchonously up the scale when the bike was revved. The guy at the motorcycle co-op shop helping me check it said that wasn't far out enough to be a problem. Not sure why he didn't take a few minutes to match them up, but I'll have to go on his advice. I'm thinking that the scale being used was so long that a 1/2 difference is very minimal.

[galahs]

Sorry, skim read the bit where you said you had the restrictor ring in place still.

[bval]

Yeah, the thread's getting a little long, so I'd be skim reading by now too. Didn't get a chance to look a the bike today, but if I don't get it solved in the next go-round, I'll repost a summary of what I've done to date.

[ducati_nolan]

A loose baffle in the muffler could be doing this. An unevenly stretched chain could cause some shudder as well but usually it's most noticeable when at a steady speed.

If you know someone else with a GS500 you could swap exhausts and see if it makes a difference. Seems to be one of the few things not yet looked at.

[bval]

Holy S__T! This is an active site! I've only been away 3 weeks and this thread is way down 7 pages!

Hot news flash . . . Just got back from Antigua yesterday and decided to take the bike to the wand-wash place this morning to get the crud off it before working on it and when I was on my way home, I stopped at a store. When I got back on the bike and headed home, just as suddenly as it appeared the vibration seemed to disappear and the bike had more power. It was running much more like normal than it has in many weeks. The only thing that happened in between was I had to get my cargo net out from under the seat so I took the seat off and put it back on. That's all that changed. There's a bunch of electrical wires under the seat that could have been moved or something, that's all I can think of that might have had an affect.

Anyway, just to make sure I wasn't hallucinating, (no, unfortunately I wasn't smoking any ganga while in Antigua) I took the bike out again later in the afternoon and it still seemed to be running much better, but I also noticed my radar detector was malfunctioning. So now I'm thinking it is electrical and I'm working my way through that before dissecting the carbs.

The radar detector (Whistler Cruisader) has always seemed to "False Laser" easily and the manufacturer says it's due to electrical noise and claims that Suzuki's are particularly noisy. The only things I added to the detector circuit was a relay and a capacitor. Anyway, I've got to send the detector in for warranty work anyway now, so I've ripped it completely off the bike and I'm going to go over the entire ignition circuit and check components with a multimeter. I may take the ignitor in to the stealership for testing if they have the proper equipment.

I'll update again when I have more info, but at least there is light at the end of the tunnel.

Cheers

[beRto]

Could it be that the method you used to wire in the detector is messing up the other bike electricals? 

[bval]

Soulution:

The problem was likely a combination of things that needed to be dealt with soon anyway, but the primary problem was that the engine mount bolts were not torqued high enough. This was partly due to me misreading the service manual description of these bolts. I had them torqued about 25 ft-lbs too low.  They felt snug for sure, but not enough to prevent some obvious vibration and even some engine movement affecting chain tension, etc. Once I torqued them up to the correct spec, the vibration disappeared instantly, chain slack tightened back up to spec, etc. Yes, I feel foolish . . . but also glad it wasn't something more costly.

Other things were certainly adding to the mix: a frozen chain link, slightly worn front sprocket, minor front tire cupping, etc. All of those things were needing to be dealt with soon anyway, so I went ahead and replaced them. I also think some of the intermittent electrical problems were due to intermittent poor grounding, because it appears this engine is only grounded through the engine mount bolts. (I can't find a ground strap anywhere) If this is true, then the engine might have been losing it's grounding to the frame momentarily when under torque, etc. Can't be sure of this one.

As far as the exhaust sound goes, I do think this is mostly "coming of age" for the bike. The vibration did accentuate things, but there was no apparent change to the exhaust sound when the engine bolts were torqued up correctly. But without the shake to go along with the deeper throatier sound of the exhaust, it doesn't seem so obvious anymore and the bike is running really well and sounding really well (for a stock muffler)

Anyway, thanks to all who helped out with the troubleshooting. I certainly learned more about my bike during this exercise than I would have otherwise!

Next endeavours . . .

Rejet - Now that I have a K&N filter, time to rejet. Considering aftermarket exhaust, but might hold off on this as the rejet kit has ability to step up later on and the exhaust is in excellent shape. Not really interested in increasing performance at this time, but who knows.

Improve Electrical headroom - LED's have been ordered and are on their way. I'm hoping these will at least match my existing light output while dropping my wattage considerably. I'm not getting cheap ones either - total cost for replacing all filament bulbs (with exception of the headlight) $160 cdn. I'll report on this once the LED's in and I have a chance to compare. I'll start a new post on which ones I bought and how well they work. I'm sure that post will see some activity!

Cheers - Brian

[beRto]

Thanks for the follow up! Glad you got this sorted out!