I just bought an 89 GS500 a couple of weeks ago, haven't really road it until this week. I replaced the Air Filter, Oil and Filter, and replaced the plugs with the NGK Iridium Plugs.

On the way home from work, the bike just started bogging and as soon as I released the throttle it died. let it set for a couple of minutes and fired it back up and was able to ride it about mile further to my house. During this mile it was still sluggish to take off but ran fine after I was rolling.

Got home and put the original plugs back in (previous owner said they were new, but I wanted to use the iridium plugs per the WIKI). I took it down the street and everything seems fine. Any suggestions for putting the iriidum plugs back in and correcting the solution?

I'll know more tomorrow on whether the old plugs actually resolved the problem as I'll try to ride to work again and I'll post tomorrow evening.

Any thoughts are appreciated. Thanks

double check the gap on the indiums, and compare to the sotckers.

Quote from: mach1 on May 05, 2008, 03:11:35 PM
double check the gap on the indiums, and compare to the sotckers.

I'm not certain (because I don't use them myself), but I think the gap on Iridium plugs are factory set and should not be altered.

It says they are gapped from factory @ .9, looks correct on the gapper.

Thanks

Quote from: rblevins on May 05, 2008, 03:38:06 PM
It says they are gapped from factory @ .9, looks correct on the gapper.

Thanks

  I think the reason you're not supposed to gap them is because the electrode is very sensitive and should not be touched.

Sounds like a classic case of a bad vacuum petcock.Tri to run it on PRIme.If it runs better try these 2 links for a solution.

http://gstwins.com/gsboard/index.php?topic=19363.0

http://gstwins.com/gsboard/index.php?topic=36958.0

Quote from: beRto on May 05, 2008, 03:26:00 PM

Quote from: mach1 on May 05, 2008, 03:11:35 PM
double check the gap on the indiums, and compare to the sotckers.

I'm not certain (because I don't use them myself), but I think the gap on Iridium plugs are factory set and should not be altered.

don't touch the gap on the iridiums!!!!!!!

specs for the gaps are between 7-8

Put it on res if it runs you just need gas. If not put it of pri. The first time I ran my bike to res I thought it had a problem. It looks like it has a lot of gas when it hits res.

Put gas in it.

I did almost exactly the same thing the first week I owned mine.  It seems to have gas, but I'll bet it's the problem.  Put a gallon or two in the tank, put the petcock on PRI and then start it up and ride it.

Thanks for the replies. The bike has a full tank of gas, so I doubt that's the issue.

I'm leaning towards the vacuum problem that was mentioned and I am planning to mess with it this weekend. I believe the petcock repair has already been done on this bike, but I'll check it out over the weekend. After I put it on the side stand, it was really sucking air @ the tank. Not sure if this is normal for this bike, but never heard any of my other bikes do this.

More to come, supposed to rain up to the weekend here, so I'll take it for a ride Friday and see what happens before messing with anything Fuel relate to see if it was the plugs.

Thanks everyone

Quote from: rblevins on May 07, 2008, 03:59:24 AM
Thanks for the replies. The bike has a full tank of gas, so I doubt that's the issue.

I'm leaning towards the vacuum problem that was mentioned and I am planning to mess with it this weekend. I believe the petcock repair has already been done on this bike, but I'll check it out over the weekend. After I put it on the side stand, it was really sucking air @ the tank. Not sure if this is normal for this bike, but never heard any of my other bikes do this.

More to come, supposed to rain up to the weekend here, so I'll take it for a ride Friday and see what happens before messing with anything Fuel relate to see if it was the plugs.

Thanks everyone

Not sure exactly what you mean, but this doesn't seem normal... keep us posted!

Quote from: rblevins on May 07, 2008, 03:59:24 AM
Thanks for the replies. The bike has a full tank of gas, so I doubt that's the issue.

I'm leaning towards the vacuum problem that was mentioned and I am planning to mess with it this weekend. I believe the petcock repair has already been done on this bike, but I'll check it out over the weekend. After I put it on the side stand, it was really sucking air @ the tank. Not sure if this is normal for this bike, but never heard any of my other bikes do this.

More to come, supposed to rain up to the weekend here, so I'll take it for a ride Friday and see what happens before messing with anything Fuel relate to see if it was the plugs.

Thanks everyone

If the tank was sucking air the tank was cold.If it was blowing air out the tank was warming up.You'll get a noise either way if there's a rapid temp change.If you need to clean it check out my write up. http://gstwins.com/gsboard/index.php?topic=41061.0

Thanks Ben, I actually found this post a couple of days ago and it is on my weekend agenda. Excellent write up.

Quote from: rblevins on May 09, 2008, 04:07:53 AM
Thanks Ben, I actually found this post a couple of days ago and it is on my weekend agenda. Excellent write up.

You're welcome.

OK, Thanks to everyone, pulled the tank off and found quite a few issues. Looks like the petcock fix had already been done on the bike, but the hoses were put back on incorrectly. Also, looked at the petcock off the tak and it was sorta not right. I straightened it out, reconnected the hoses, filled the tank and was able to go about 20 minutes without dying, hoping this was the fix, but it's raining so I can't take it for an extended ride to see if it was the fix or not.

Also, not sure, but looks lilke the bottom of the tank is pretty dirty. Checked out from the outside and it's solid (no rust), but looks gummy in the bottom inside. Any thoughts? Carbs need cleaned?

I'll update after the rain passes to let everyone know how it's running.

Again, thanks for all the information.

Ok, here's the latest...(can't remember or find if I posted the update already)

Popped the tank off and it has definitely had the Petcock mod done. Unfortunately, the Reserve and On lines were crossed from the tank petcock. Made that change.

Looked like the bottom of tank was pertty nasty (no rust, but brown gunky looking). Tried to clean it as much as possible, but still not clean looking like I'd like it. Any ideas on this?

Also, bought a new petcock (one of each) and I have the hose diagram, but I have no idea where the vacuum hose is supposed to go. I'm comfortable with everything else, but I'll need this before I can put the stock petcock on.

Appreciate any info. Thanks again to all who have helped.

Quote from: rblevins on May 22, 2008, 03:11:53 PM
... I have no idea where the vacuum hose is supposed to go. I'm comfortable with everything else, but I'll need this before I can put the stock petcock on.

Appreciate any info. Thanks again to all who have helped.

Kerry's website shows a good routing diagram:
http://www.bbburma.net/FuelHoseRouting.htm

The vacuum hose attaches to the vacuum nipple on the left carb.

Quote from: rblevins on May 22, 2008, 03:11:53 PM

Looked like the bottom of tank was pertty nasty (no rust, but brown gunky looking). Tried to clean it as much as possible, but still not clean looking like I'd like it. Any ideas on this?

since there is no inline fuel filter what ever is sitting in the bottom of the tank may eventually find its way to the carbs. one of the first things I had to do for my bike was treat the tank for rust then clean and rejet the carbs. I highly recommend Por-15 marine clean. it was a weekend project that made a huge difference. its one of those things were the longer you wait, the worse it gets....

good luck.

d

Quote from: ben2go on May 05, 2008, 04:21:12 PM
Sounds like a classic case of a bad vacuum petcock.Tri to run it on PRIme.If it runs better try these 2 links for a solution.

http://gstwins.com/gsboard/index.php?topic=19363.0

http://gstwins.com/gsboard/index.php?topic=36958.0

Ditto Dude....thought mine wasn't getting spark also.Changed to a gravity feed Honda petcock and Bingo! I had the original 94 petcock.
I also put some nidium magnets in the tank to catch all the really small crap also...get them at any hobby store,just put them in the tank near the internal filter.