Yesterday, my GS500F overheated while stuck in traffic on the hot NYC roads. White smoke started coming out of the exhaust but it was a while before I got somewhere safe to pull over. Almost immediately after I pulled off the highway, my engine made a pop noise and started sputtering... I fear the worst. I rode it somewhere safe to park nearby and left it for a few hours.

As of last night the bike still runs. There is a slight rattling noise coming from the engine that seems to match with the revs. There is a lack of throttle response whenever I start moving from a stand still. Even if I give the throttle a good twist, it would not so anything for a split second and then shoot up to 5k pretty quickly. There is a lack of power and acceleration at higher speeds but I'm too afraid to ride it anymore to test it. Idle is pretty low around 1000-1200 and still sputters occasionally. Oil level is good.

What kind of damage do you guys think I'm looking at? And how much do you think it'd cost to repair...  Any suggestions you guys have will be greatly appreciated as well. I'm probably going to bring it to the shop soon so I will update with details as I learn more.

A healthy engine should not have overheated due to traffic.  I'm guessing your exhaust valves were running tight and you burnt a valve.  All bets are off on what else could be damaged.   Worst case scenario is $500 for a new used engine on eBay.

How many miles are on your bike?

There are roughly 12,xxx miles on the bike right now, a little on the high side I think.

I thought one reason my engine was running so badly is because one of the cylinders is malfunctioning. I took a look at the spark plugs; they were dirty but there was still a spark. Unfortunately, I don't know much about how to diagnose and fix bikes so that was the most I could do. What are some symptoms of exhaust valves running tight? Are there any checks that I can do, short of pulling the engine?

I'm remaining hopeful because my engine can still run so I am hoping to avoid the hassle of finding an engine and replacing it. Unless whatever I broke is more expensive to fix than just buying a new engine..

Bro, mine has 80 000k's plus on it and still pulling like an ox ('99 gs500e). 12000 miles isn't that much for these engines. Properly looked after, they seem to live for ever.

My bike jus did the same thing and my engine is totally garbage once you overheat a Gs ND it starts making tht rattling noise mine as well start looking for another engine

Good to know that my engine is still a baby. Now if only I could nurse it back to health...

Florida, did you get your bike looked over yet? If so, what was the diagnosis?

Check oil.  Bet it's related to that in some regard.

Never-mind...Just read the oil part.

I think you have an intake manifold leak or an exhaust leak.
Your symptoms all match, spray wd 40 in the inatke area ... if revs go up that = intake leak.
Cool.
Buddha.

My quick googling seems to confirm your suspicions, Buddha, thanks. I'll test it on Wednesday and report back. Although it doesn't deal with the rattling sound? (Unless that is caused by the burnt exhaust valve that bombsquad mentioned)

No dice, Buddha... I sprayed some WD40 on whatever parts of the intake manifold I could reach but there was no increase in revs.

A couple things I noticed though, in order for the bike to even start and idle, I need to have the choke fully open. Even with it fully open, my idle hovers around 1000. Also, the air coming out from the exhaust is pretty forceful, much more so than before. I can now very clearly feel each puff of air coming out.

I'm quite lost... I'm taking it to get looked at on Sunday but I would still like to find out more in the meantime. Any more suggestions on things to check?

Here's something that might help. I took a video as I was spraying around the manifold and you can hear what's wrong. Exhaust valve?

I cant look @ video clips @ work, but rattling with either intake or exhaust is common ... air's getting in or out through a non air passage ... so does sound. Exhaust leaks can be rather loud ...
Cool.
Buddha.

So the verdict is in... Bombsquad called it right from the beginning: the mechanic says its a bent/burnt/broken exhaust valve. His quote to rebuild the engine was expensive, a quick estimate was $900. Even to replace the engine with a new one would be just as expensive.

Here's my question now, it seems that the quote for $900 mainly consists of labor and not parts. How hard would it be if I were to attempt to replace the valve on my own? I have never taken an engine apart before. Would I be in over my head? Any special procedures that I wouldn't be able to do on my own?

My other options would be to source a new engine cheaply and try to replace it on my own or just cut my losses, sell the bike for whatever I can, and buy another.

Oooo bud...having never cracked a block, I don't know if i'd recommend it. Valves need specialised tools: valve compressors just for a start. Not only that, but it's getting cams re-aligned, timing back in, re-seating if the head is slightly damaged from the valve...to use a south africanism it is a kak load of work.

No better way to LEARN about an engine, but don't expect it to be a two-hour job. So, if you're keen for the challenge..go for it. Sure there will be plenty of guys on the forum willing to lend a hand along the way as well.

Personally, i'd try find a back-yarder friend with all the right tools already and offer him a good bottle of whiskey or such like for his advice, tools and hands (being a first-timer). It's not a 'change a sprocket' or an oil-change sort of a job, so some knowledge and experience would help you a lot.

Good luck, man...keep us all posted.

Broke valve ... motor is a paperweight. It will have beat the hell out of the lower end.
I'd prolly look for a motor ... or in fact see if a dr650 motor will fit.
Cool.
Srinath.

Look around for GSJack's post about replacing a broken valve. Then put several miles on the undamaged bottom end.

Thanks for the replies guys.

Nutmunk, that's exactly what I needed to know. I do have a friend who knows about engines, although he works on cars. However, I figure the functional aspects between a car and a motorcycle engine must be pretty similar. In any case, it won't hurt to ask and see what he says.

I'll also check and see if I can pick up any motors (as Buddha suggested) for cheap although I'm not sure if I want to be on ebay and craigslist for a long time waiting on a good deal.

I'm most likely leaning towards selling the bike and see if anyone will want to pick it up. Maybe even scrapping it or parting it out? It is heart wrenching to do so but financially, it makes the most sense. I'll do more research on my three options though (rebuild the engine, swap the engine, sell the bike) and update everyone as I move along.

Here's another thought I just had: Can I just search for a new top end of the engine and swap out the whole thing on my own? That seems to be easier and bypass a lot of the things that Nutmunk mentioned (don't need a valve compressor, don't need to re-align cams, timing back in, reseating head if damaged). I reason that would be a fair bit easier than dismantling the head and replacing just the valve on my own? I came across something that said that if you want to replace the exhaust valve, you need to send the head to a machine shop. Is that true?

On the other hand, as Buddha said, the lower end could be beat up and I wouldn't have much of an idea of what's going on down there till unless I open it up. Do you guys think just replacing the head is a viable option?

EDIT: I lied. Reinstalling a new head would mean taking off the camshafts to sneak under the timing chain so I'd still need to worry about the timing.

If a valve, then a replacement top end from any year GS500 would fit. Not hard to replace a top end. Just be careful you separate the head from the jugs so you don't pull the jugs up and off of the pistons (pain to get the pistons back in).

A replacement top can be $100-$200. An hour or three to put it on. You do not have to remove the engine to do it.

No harm in removing the head to check it out. I'd do that before paying someone more than the cost of a replacement engine to repair it.

Quote from: adidasguy on July 02, 2013, 12:17:08 AM
If a valve, then a replacement top end from any year GS500 would fit. Not hard to replace a top end. Just be careful you separate the head from the jugs so you don't pull the jugs up and off of the pistons (pain to get the pistons back in).

A replacement top can be $100-$200. An hour or three to put it on. You do not have to remove the engine to do it.

No harm in removing the head to check it out. I'd do that before paying someone more than the cost of a replacement engine to repair it.

Adidasguy for the win....didn't even think about a head swap. That'll work perfectly.