Rattlesnake

[TheNose]

I know that this topic has been covered a hundred times, but, for the "warm and fuzzy" factor, I'll bring it up again.

My bike runs like a top. But I hear a faint noise (I'm old and hard of hearing so it could be loud) that sounds like a rattlesnake. It seems to come from the front of the bike, and I'm thinking it is the valves. Is this normal? Someone said earlier "if it aint making noise, it ain't running." Does anyone else experience a noice like this? It could be the tach or spedo cable, but I haven't experimented with disconnecting them yet to see. It's frequency changes with rpms. Any ideas?

Terry

 

[earlfor]

Re: Rattlesnake

Terry

I had noticed that same thing with my 79 750 last week, so after parking it in the garage for a couple days. (couldnt get to it any sooner anyway) I also figured it was time to adjust the valves. Well, checked the valves and everything was dead on. I have a points ignition system, so next, I thought maybe the points had worn enough to change the timing significantly causing an ignition rattle. I found my timing was indeed off. Retimed it and about 3/4ths of the noise is gone.
I also noticed that when the bike is sitting on the sidestand, the oil puddles very well in the cam lobe galleys on cylinders 3 and 4, but drains almost completely away on cylinders 2 and 3. There is some increasted valve clatter noise on startup until the 2 and 3 galleys are oiled. Oddly, there is less noise if the bike is started on the centerstand or straight up and down as opposed to being started on the sidestand.
Being a loose tolerance air cooled engine, there is going to always be a considerable amount of noise in comparison to a water cooled engine. The first thing I would check would be the ignition timing. You may be surprised. Mine ran well too, even though the timing was off by a good bit.

Earl

I know that this topic has been covered a hundred times, but, for the "warm and fuzzy" factor, I'll bring it up again.

My bike runs like a top. But I hear a faint noise (I'm old and hard of hearing so it could be loud) that sounds like a rattlesnake. It seems to come from the front of the bike, and I'm thinking it is the valves. Is this normal? Someone said earlier "if it aint making noise, it ain't running." Does anyone else experience a noice like this? It could be the tach or spedo cable, but I haven't experimented with disconnecting them yet to see. It's frequency changes with rpms. Any ideas?

Terry

 

[argonsagas]

Love your tag..I am permanently immature...even Victor could not argue. :roll:

Cannot comment about the sound of rattlesnakes as I have never actually heard them live. A while ago someone wrote about the high-pitched twitter of GS "crickets". This is a very valid description of what I hear every day, especially at highway speeds, and it seems perfectly normal for my GS. Hopefully you have heard both, and you can understand my comment and differentiate, if necessary.

 

[TheNose]

I set the timing about a month ago, but I will check it again. It does sound like crickets. That's probably a more accurate description of the sound. Im curious as to what is making it.

Terry

 

[saaz]

GS motors make noise when in good condition..so perhaps no worries.

Some noise can come from exhaust gaskets, loose header pipes..worth checking. My 78 GS1000 has 145,000kms on it with high compression pistons and high lift cams, so is very mechanical....

If you stop worrying, all seems ok.......

 

[TheNose]

What?? Me worry?

I think you may have hit on the answer saaz. I have a broken bolt on one of the exhaust headers. I can't get the old bolt out to replace it. That's probably where the sound is coming from. I guess I'l just ride and enjoy - worry is just intrest paid on a debt that may never come due.

Terry

 

[saaz]

My GS was making a noise that got louder over a few thousand kays...one of my race header pipe spigots was loose, nearly falling out! Bike still went great, just a little extra character....but then I put in new gaskets, first time in 15 years!!!

 

[mcycle-nut]

I find the "mysterious" noises coming from my bike are really not coming from my bike at all. They are coming from the car beside me. 8)

 

[Anonymous]

LMAO ain`t that the truth my-cycle.......been afraid a few times something was going to blow

 

[Anonymous]

Hehe, every time I smell burning motor oil I try to reassure myself that a Dodge Caravan with a Mitsibishi engine has just passed by.

 

[Anonymous]

i had a old atk250 and that bike made like a cracking noise, the guy said it was from the cooling fins, do you have those little black squares of rubber? between the fins on your bike? i guess thats what there for?

 

[TheNose]

I was wondering what those little black squares were for. Hard to believe that the fins would make noise. Maybe the air flowing through them. I'm going to check my valve adjustments soon. Does anyone know where I can get shims for the valves?

Terry

 

[earlfor]

Hmmm, this is the 2nd time I have posted this URL in answer to the "where can I get" question. valve shims for a gs750..
http://www.newmotorcycleparts.com/interest.htm

Earl

I was wondering what those little black squares were for. Hard to believe that the fins would make noise. Maybe the air flowing through them. I'm going to check my valve adjustments soon. Does anyone know where I can get shims for the valves?

Terry

 

[saaz]

I get mine (well, not that often once they are worn in) from a local dealer. Seems the same price as that link, but then I gather you guys have varying dealers over there as to price reasonableness

 

[Anonymous]

As other Mech-Techs, I always like to know where the Rattle 'n Hums come from and then decide if I want to worry about it. So far I learned to live with four: A loose something in the lefthand exhaust, the good ole clutch rattle when the engine cold (still should look at that one tho, the rattle inside the left mirror and an occasional rattle of the chain. Last week I has a new one: a light tingling sound which reared its ugly head at 3000-5000 rpm. Standing beside the bike to locate the sound, I could not reproduce nor locate where it came from. After an hour riding, it hit me: I placed my hand on the keychain, which holds three keys and lie on the steeringbar cover, and .....the sound was gone. I now put them in a keyholder sheath which I tuck under the clutch cable. One sound down, four to go.