popping on deceleration

[doconabike]

Hi all,

A little background - picked up my 82 gs650g pretty cheap, low miles (66xx). Was rear ended literally my second or third time riding it, but with the help of a gs'er (pegs) and some ebay parts got the bike running and looking great.

In terms of maintenance since I bought it, I'll be honest I haven't done much. I've checked the oil level is fine but oil change/new oil filter is high priority. Bleeding the brakes/changing brake hose/and if I feel like I can do it valve adjustements are on my to-do list.

But ok, to the point. I've noticed that the bike is having a few issues in day to day running. The main thing would be that their is a fairly loud popping that happens when decelerating. If I'm accelerating/maintaining speed the bike runs beautifully, as soon as I ease off the throttle (especially in 1st and 2nd gear) their is a popping noise as it slows down. I think this may be related to the air filter, the one I have right now is seems like its in decent shape but for the life of me I can't get it to stay on the air filter inlet hole. Its kind of just floating around in the box. Is their some kind of trick to get it to seal onto that oval shaped hole in the airbox and then close the lid? And could this be the reason for the popping?

I have some other issues that I really want to resolve that - as time permits - I'll definitely ask for help. I really appreciate all the help on this forum!

[Zimquidl]

Check to see if your exhaust needs tightening at the engine.

[Octain]

Check to see if your exhaust needs tightening at the engine.

Just dont try to tighten it too much.

There are several things that can cause this. Exhaust to head seal(gasket) is just one. Assuming from the description the bike is most likely original with the factory exhaust. Lots of places for those old pipes to leak.

[chuck hahn]

Deacon.. glad the pegs worked for you.. I still got that set of clocks if ya want them from the 81 650 G.. also check all the clamps for tightness and look to see if theres any pinhole rusted through thatb you hadnt seen coming on.. The poppping from these situation happens when the cold air is sucked into the super heated exhaust gasses. The cool oxygen fresh air provides the oygen for little mini explosions inside the pipes.

[Zimquidl]

Just dont try to tighten it too much.

O...k...
I'm sure doconabike could figure out what I was saying.

How about this: Check for a loose exhaust at the engine. If it's loose, apply pressure with the appropriate tool in a clockwise direction until the looseness is no longer there.

Do not use a cheater bar to tighten it to the point of breakage. Also, do not check the level of gas in your tank with a match. Probably shouldn't roll the bike off of a cliff either. Whatever you do, DO NOT try to ride an inverted bike. Also, keep screwdrivers out of our eyes. Pressing your face up against a hot exhaust is a no-no. Don't check for electrical output with your tongue. Face forward when riding. Put gas in the tank, oil in the engine, not the other way around. Use the brakes to stop the bike, not your feet. Speaking of feet, put them down on the ground when you do come to a stop. The engine has to be running in order for it to make vroom vroom noises. It helps move the bike forward also, unless you're going downhill on a big mountain, and then we're back to not rolling the bike off of a cliff.

[atb1998]

It is running lean due to the problems your having with the airfilter not staying on. with the filter slipping loose your air flow is too lean, kinda like running pods on stock bike, fix that problem first. If still persists, check your exhaust.

[Octain]

O...k...
I'm sure doconabike could figure out what I was saying.

Never assume anything..

[chuck hahn]

and all that coming from a ZIMQUIDL What the hell is a ZIMQUIDL?? I think my DR vacinated me against that as a child!!!!!! LMAO.... Welcome brother.. your day to be F&**&^ed with...LOL

[TheCafeKid]

O...k...
I'm sure doconabike could figure out what I was saying.

How about this: Check for a loose exhaust at the engine. If it's loose, apply pressure with the appropriate tool in a clockwise direction until the looseness is no longer there.

Do not use a cheater bar to tighten it to the point of breakage. Also, do not check the level of gas in your tank with a match. Probably shouldn't roll the bike off of a cliff either. Whatever you do, DO NOT try to ride an inverted bike. Also, keep screwdrivers out of our eyes. Pressing your face up against a hot exhaust is a no-no. Don't check for electrical output with your tongue. Face forward when riding. Put gas in the tank, oil in the engine, not the other way around. Use the brakes to stop the bike, not your feet. Speaking of feet, put them down on the ground when you do come to a stop. The engine has to be running in order for it to make vroom vroom noises. It helps move the bike forward also, unless you're going downhill on a big mountain, and then we're back to not rolling the bike off of a cliff.

Actually, Octain (for once) had a very valid point. No need to get all testy about it. Often, depending on the studs/bolts, and exhaust systems, the bolt will continue to tighten and never bottom out, and then, suddenly, *snap* it breaks... My kid brother did this to my 1000G, "It never felt like it was getting tight" he cried as I retarded my anger to avoid beating him senseless... Its pretty easy to over-tighten an exhaust bolt and then find the other side of it sitting in your socket.. So, in that respect, he was simply warning against it. It's ok there Zi...whatever the heck that is... No one is trying to make you look like a dumbass...

[Zimquidl]

Apparently humor doesn't translate well over the internet.

Or some people don't have a sense of it.

[cyclefvr2]

check the timing chain re set the tension, it might be getting to the limits

[chuck hahn]

ZIM...The humor translated very clearly. Thats why me and the KID were joking back.. All in goood humor ..We all take our turn getting razzed. At least I have more than once.

[tfb]

Popping in the zorst usually happens for two reasons:
1. A super-free breathing exhaust, eg. straight-through pipes, or a 'megaphone' muffler, or some other custom loud sparingly-muffled setup.
2. Lean mixture, which is what happens when the throttle is shut, esp. at higher engine revs. Lean unburnt mixture gets drawn into the exhaust system, where it ignites and 'pops'.

If #2, a number of reasons:
1. Your ill-fitting air filter won't be helping. If in a stock airbox, it won't be staying put because the spring retainer is missing or mishapen.
2. Pilot mixture too lean.
3. Dirty carbs with dirty jets. Dismantle and clean. See the excellent articles elsewhere on this site for help with this.
4. Leaking exhaust flange gaskets. If this is a prob., you will usually hear the 'clicking' sound of the exhaust gases at idle, esp. before the engine has warmed up properly.
5. Leaking inlet manifolds. Usually the rubber manifolds, or the O-rings that help the manifolds seal on the head, are hard & perished and leaking air.

There, all that should give you something to go on with.

[doconabike]

Popping in the zorst usually happens for two reasons:
1. A super-free breathing exhaust, eg. straight-through pipes, or a 'megaphone' muffler, or some other custom loud sparingly-muffled setup.
2. Lean mixture, which is what happens when the throttle is shut, esp. at higher engine revs. Lean unburnt mixture gets drawn into the exhaust system, where it ignites and 'pops'.

If #2, a number of reasons:
1. Your ill-fitting air filter won't be helping. If in a stock airbox, it won't be staying put because the spring retainer is missing or mishapen.
2. Pilot mixture too lean.
3. Dirty carbs with dirty jets. Dismantle and clean. See the excellent articles elsewhere on this site for help with this.
4. Leaking exhaust flange gaskets. If this is a prob., you will usually hear the 'clicking' sound of the exhaust gases at idle, esp. before the engine has warmed up properly.
5. Leaking inlet manifolds. Usually the rubber manifolds, or the O-rings that help the manifolds seal on the head, are hard & perished and leaking air.

There, all that should give you something to go on with.

Perfect, between what Chuck said about leaks, tightening the exhaust, and your laundry list hopefully I can narrow this down! I was looking at the manual for my gs650 that was on bikecliff's website, I don't have the spring retainer at all which would explain why I've been unable to get the filter to stay. Before I open anything up I'm going to try to get this on as it seems like the simplest and most obvious solution.

Oh also, regarding number 1. The previous owners sawed off the ends of both exhausts....its beyond me why they did it.

Thanks everyone for their help (and sorry zimquidl for setting you up )

[waterman]

I am not sure there is a spring retainer used with the 650g intake. Both of mine use a cone shape foam style air filter that fits onto a plastic "cage". This filter, cage then presses into the D shaped opening and is held in place by the outer airbox cover. This cover is attached to the inner half by two sliding fasteners, which are a royal PITA to get back in position without dropping several times.

Supposedly, the cage comes with the factory air filter if you are missing one. One of my bikes was running without the cage with the filter just stuffed in and it ran fine. I really don't think the 650 were plagued with the lean-ness as other bikes. The 850 and 1000's seem to suffer more if their airboxes weren't sealed well.