I have a yoshi full exhaust and the carbs were never rejetted. I picked up my bike today and it sounds like its running on one cylinder. It didn't sound like that when I brought it in, but I blame the plug wire boot. My bike has been running lean since I bought it.

I am going to replace the plug boot, rejet the carbs (and get a new air filter, too) and go from there.

If the new plug wire solves 90% of the problem, I think that adjusting the pilot screws is a good next step.  The GS comes stock in Canada and other lands with larger pilots, but you can effectively increase the flow through the pilots with just their adjustment screws.  If you try to adjust and run out of travel, then you'll know that you need to change at-least the pilots.

The "full" GS-rejet also involves shimming the needle, which supposedly improves performance of roll-on from a stop; and increasing the main jet, which should enrichen at wide-open-throttle.  
But changing pilots will change everything from start & idle up to WOT, so I'd get  that right first.

Hmm, I replaced the spark plug boot and ran the engine for a while tonight. Yeah, carbs my ass. I think I might rejet anyways becuase I already ordered the parts, but I'll bet $50 that what I'm feeling isn't carb related. It is running lean, but its been running lean since I bought it in april.

I don't think that it was ever an ignition problem. It runs the same no matter which plug wire i removed, and for the most part the engine runs fine. I just notice the noise and the vibration. My dad was outside when I was listening to it, and he says that he can't hear what I am talking about. I assume that he (and he does admit this) doesn't know much about engines and never really heard it before this all started. I don't think I am making stuff up, but I suppose it might be possible.

So I'm pretty much back to square one. I took a movie of my engine running tonight. My sound card isn't working, so I don't know how well the sound was recorded but here it is.(sorry, large file)

I am feeling a lot of vibration above 5k. I don't feel it in the handlebars, mostly in the seat behind the gas tank. I am also hearing a loud noise that seems to be coming (well, it seems loudest anyhow) from the lower right front (on the right side toward the front tire)) It sounds kinda like something is vibrating really fast or something might be grinding (engine does have oil) I thought it might be the chin ferring (one of the mounting screws broke off) so I removed the whole ferring. no dice. The noise is still there.

I think I'm going to start by retorquing bolts and adjusting the pilot screws this weekend. Specifically the engine mount bolts and the bolts on the exhaust. Any other thoughts or suggestions would be greatly appreciated. I don't want to take this engine apart or replace it, but I get the feeling that I'm headed in that direction.

OK maybe the synch screw or spring or somethign has fallen off leaving the 2 carbs wildly out of synch...
Cool.
Srinath.

Quote from: goatI'm going to start by retorquing bolts and adjusting the pilot screws this weekend. Specifically the engine mount bolts and the bolts on the exhaust.

That's a good idea.  The sound in that clip was a little too "saturated" (or something) to give a clear idea of the problem, but it does show that the engine runs well.

My first thought - back when you started the thread - was loose exhaust header bolts.  But I'm starting to think that you might have a broken engine mounting bolt.

I sure hope it's nothing internal....  

Well, I think I found out what was making that noise. Look at what I found in the engine   :



Now I need to figure out what I'm going to tell its owner!

It's friday. I figured that people could use a good laugh. :lol:  :lol:

EDIT: I guess people can't see the pic, so I'll have to put it on my normal page once I get home. Oh well, it will still be funny then

I can't see your last pic...?

Ok, now that its hosted properly let's try this again:

I think I have figured out what has been making the noise on my bike:

Take a look at what I found in the engine!


Now I just have to figure out what to tell my neighbor about his missing....

Better late than never, right? I figure its good for a laugh

Yep... Gremlins.... stratching and shaking trying to get out...
Cool.
Srinath.

well, I spent the day trying to fix my bike. It is running again, but the vibration and noise is still there.

I dissasembled, cleaned, reassembled and adjusted the carburators. I haven't replaced the jets yet, but the engine is running better. The throttle cable is too tight, but that is easily fixed.

I also checked every bolt I could find. Engine bolts, exhaust header bolts, valve cover bolts, cylinder head nuts...

I checked my valve clearance, too. Unfortunately I have the same issue with only having a .038 feeler gauge and it was bigger than any of the gaps. I noticed a decent amount of oil had collected in front of the left side front valve. I chalk it up to just leaning that way. The gasket is still leaking, but that will have to wait for another day.

I took out my plugs when I checked the valve clearance, and I learned something. Use the wire type spark plug gap tool. When I replaced my plugs, I had used a disk type tool and the gaps were pretty far off. I recently got a wire type tool so I fixed the gaps.

I also drained my oil and checked the filter. There were no noticeable metal shavings in the oil. There were some metal shavings in the filter, but not many. If something exploded, it isnt obvious.

The vibrations are still there, and the noise is too. The noise seems to be getting louder. Its almost as loud as the exhaust is, now.

My dad still thinks that I am crazy and nothing is wrong with my bike. The tech at the dealer thought so, too. Maybe I am  :dunno: . I think that a friend is going to stop by tomorrow to put in his two cents, but if anyone here wants to stop by, listen to what I am talking about and either give suggestions (or join the crowd that thinks I am crazy ) it would be appreciated.

I think I am going to rejet when my parts come in the mail and I'll see if that does anything. Other than that, I'm out of ideas besides a rebuild/replace and I really would rather not do either of those.

Quoteplease help me, I have have been off my bike for FAR TOO LONG, I am a SICK MAN and WILL push the nearest squid off his ride soon just to get my fix.

Hope you all had a good saturday! Ride extra for me since my bike is still not well    

OK carb synch ... did the screws or springs fall off, did you check.
Cool.
Srinath.

after looking at this post I think I am going to check the cam chain, too. Should have checked while I had the valve cover off earlier today. Oh well, gives me something else to check.

As far as I know nothing went wrong with the carbs. I stripped the hell out of one of the float bowl screws (even with the impact driver. damn that thing was in there good!). The mix is still off but thats becuase I stopped trying to get it perfect since I am going to be rejetting soon.

I checked the cam tensioner, and the camchain and everything seems to be fine. The 21 pin length is less than maximum, and as far as I can tell, the tensioner is working like it should.

I think I'm done for the weekend. I need to replace the cam tensioner gasket before I run it again, and I might tear the engine apart next weekend.

Thanks again for the suggestions. You can be sure that I will be posting if I figure anything out.

Well, I think I am going to be tearing apart my engine this weekend. I am pretty nervous about doing something this major on my own, and I have a few questions about what to replace (other than what might be broken)
93 gs500e with 6600 miles

Is it worth the money to replace the bearings (crank and counterbalancer)  even if there is nothing wrong with them at this mileage?

What else should I replace/do? I looked at this post and at the moment, I am planning on replacing lots of gaskets (kit from partsnmore) but I'm not sure about replacing piston rings, reseating the valves or rehoning the cylinders.

out of curiosity, if I wanted to have the cylinders bored while I have the engine apart does anyone have an idea what the cost would be? Is it worth the $?

My haynes manual mentions the possibility of inspecting the main bearings without dissasembling the top of the engine. Has anyone ever done this before, and if so is there a place I can find instructions?

Last question: is it a bad idea to rejet my carbs while they are out of the bike? Should I wait to rejet until after I have the noise/vibration thing fixed?

Thanks

I haven't "been there" or "done that" yet, so I'll defer to the pros.

I just wanted to make sure you knew about the GS500 engine gasket set on [THIS PAGE].  I don't know if it's the best price, but it's the only link I've got.  (And the shipping is free!   )

I have not had the thrill of rebuilding a bottom end yet, so I guess I cannot help either.  Reading and following the manuals have been the way I have learned.

For cylinder honing, I have seen different prices depending on the area. $10-30 is a common range. Better that the $65/hole I paid for my 79mm, He had a lot more material to remove, 5mm. the honing will help with compression and oil consumption, but you will need to replace the rings to utilize this completely.

As for the gasket sets Kerry linked to, these are the same ones I buy. Great guy to deal with and he ships them quickly. That is the best deal I have found yet. He sells them on ebay for a little less but adds shipping, which ends up costing a few dollars more.

Quote from: goatWell, I think I am going to be tearing apart my engine this weekend. I am pretty nervous about doing something this major on my own, and I have a few questions about what to replace (other than what might be broken)
93 gs500e with 6600 miles

Is it worth the money to replace the bearings (crank and counterbalancer)  even if there is nothing wrong with them at this mileage?

What else should I replace/do? I looked at this post and at the moment, I am planning on replacing lots of gaskets (kit from partsnmore) but I'm not sure about replacing piston rings, reseating the valves or rehoning the cylinders.

out of curiosity, if I wanted to have the cylinders bored while I have the engine apart does anyone have an idea what the cost would be? Is it worth the $?

My haynes manual mentions the possibility of inspecting the main bearings without dissasembling the top of the engine. Has anyone ever done this before, and if so is there a place I can find instructions?

Last question: is it a bad idea to rejet my carbs while they are out of the bike? Should I wait to rejet until after I have the noise/vibration thing fixed?

Thanks

Rejetting with carbs off is fine... but how ever do you conclude the motor needs rebuilding.
Vibrations... OK but is one cyl lower significanly in compression than the other, also maybe one spark is bad, It does spark when you test it in the open, but its a little off... you cant see it... but its just enough to not light up the mix completely. Also make sure the carbs are equally synched... did you check that, and in all other terms they are equal. Diaphragms should slide up  and down easy and have no rips. Choke sticking in 1 carb also might make it act weird. Hell actually send me your carbs... I'll make sure they are equal in all aspects. Might save you a rebuild. 6600 miles is nothing. 66,000 miles is still OK for this motor.
Cool.
Srinath.

I just can't imagine how this could be carb problems. It's not that the symptoms aren't the same; but this happened so suddenly. My bike was running fine earlier that day, and then all of a sudden I heard a sound like something broke off inside the engine and was bouncing around for a while (left side, I think but I haven't been able to reproduce it) and now there is a bad vibration and an ungodly noise coming from somewhere (not completely sure if its the top or the lower end but i think its the front of the top end)

If you ignore the vibration and the extra noise, the engine is running pretty well. There has been a little bit of a power loss, but not much. If it had started gradually; I would be spending more time on the carbs but they were clean and aside from the fact that the float valves are starting to look a little worn (and will be replaced when i rejet)  nothing was out of the ordinary.

The only other things that I can think of that would start up suddenly require engine disassembly to inspect (main bearings, counterbalancer bearings, camchain guide).

I just read my last post, and I sound a little like I'm a hard a$$ who is dead set on rebuilding his engine. :guns:  :x   :guns:  :x   :guns:  :x   :guns:

Let me assure you all, this is not the case. I would be so incredibly happy if I am wrong      . I would rather not tear my engine apart if I don't have to, I just can't come up with another explination :dunno:

It was my understanding that carb problems don't usually happen suddenly with the exception of physical damage (something breaks off etc.) to the carbs. Do I have that wrong?

OK I read all your posts on this topic... 1 question.... did you check for a intake manifold vacuum leak. Mine also blew suddenly at 16K miles, and it was loud and rattly and sorta like a chainsaw on concrete noise. I luckily was by cycle gear in Hayward... and they tested it and sprayed wd40 and said manifold leak. I ordered the parts at the dealer and got home on it with the choke. Then fixed it and its not happened since. Poor spark also will make it vibrate more, but the loss of power will be huge.
Cool.
Srinath.