[Ren]

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Hi all,

First time on this very useful site and hoping somebody has had the same problem and fixed it.

Just bought '81 Interstate with 76K miles that has a horrible clatter that sounds like a primary chain problem when pulling away from stop. Once moving all is well and quiet all gears except for an occasional cough from what feels like one cylinder. I was thinking the problem may be due to a missfire at low RPM but the jerking noise is so bad I can't tell if it's due to the missfire.

The missfire is also there when idling. Tried pulling plug leads one by one but it then runs so rough it's difficult to tell what's going on.

I've dumped a 3rd of can of Seafoam into intake manifold and changed the plugs. The rest of the can went in the crankcase in case there was a stickly valve causing the missfire.

The bike has only done 2K the last 4 years so I suppose it's possible something is sticking in the carbs. Don't think it's a sync problem because it idles well except for the cough once every 4 to 5 seconds.

Thanks in advance.

 

[hossners]

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From one Portland newbie to another -

I also have just aquired a '81 Interstate, 94k miles, with the same noise pulling away from the curb. It happens only when the engine lugs at low RPM for me, so I just have been slipping the clutch a bit more til I get it figured out. Was told by a gear-head it may be a bad idler on the timing belts. I'll be interested as well to hear what the more informed here in the forum have to say... (I'll bet they know the answer, too!)

hossners

 

[englishted]

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The big Hyvochain can make a noise on the 1100s. It's more likely to do so when the carbs are out of synch or the 4 cylinders are't all pulling together for other reasons. Balance the carbs first snd see if that fixes the problem.

 

[twisty]

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Ren wrote:

Hi all,

First time on this very useful site and hoping somebody has had the same problem and fixed it.

Just bought '81 Interstate with 76K miles that has a horrible clatter that sounds like a primary chain problem when pulling away from stop. Once moving all is well and quiet all gears except for an occasional cough from what feels like one cylinder. I was thinking the problem may be due to a missfire at low RPM but the jerking noise is so bad I can't tell if it's due to the missfire.

The missfire is also there when idling. Tried pulling plug leads one by one but it then runs so rough it's difficult to tell what's going on.

I've dumped a 3rd of can of Seafoam into intake manifold and changed the plugs. The rest of the can went in the crankcase in case there was a stickly valve causing the missfire.


The bike has only done 2K the last 4 years so I suppose it's possible something is sticking in the carbs. Don't think it's a sync problem because it idles well except for the cough once every 4 to 5 seconds.

The missfire is also there when idling. Tried pulling plug leads one by one but it then runs so rough it's difficult to tell what's going on.

Ren, you can't do that on a Wing as it kills two cylinders. To test each cylinder you must short the plug wire to ground. Pulling it off removes the ground path for the other plug on that coil.

The bike has only done 2K the last 4 years so I suppose it's possible something is sticking in the carbs. Don't think it's a sync problem because it idles well except for the cough once every 4 to 5 seconds.

That cough means you have a misfiring cylinder, that alone could cause your noise & chain clatter. See if you can find the poor performing cylinder (maybe even do a compression test).

Start by installing new spark plugs & if still a problem verify the plug wires are in good shape & fastened correctly on BOTH ends.

If your ignition system is in good shape & your compression is good then you probably have a failed pilot jet air control in a carb or dirt in the idle system on one of the carbs. You will need a service manual to go through & test those carbs.

Twisty

 

[exavid]

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Englishted and Twisty are telling you right, the primary chain can make a bit of noise if things aren't running right. Anything that increases the torsional pulse of the engine, unbalanced carbs, ignition problems, etc. can do it. Especially when clutching in on a start up when the engine is just coming under load. It will do it on idle if the engine is rough enough. Torsional vibrations cause all sorts of problems with engines, the more cylinders the less problem. That's one reason the 1500 is quieter, more cylinders more bangs per revolution, less accelleration/decellerationin the crank. That's why V twins shake, uneven firing order and fewer bangs per rev. A sixteen cylinder bike would really be smooooth!

 

[FitzAl]

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My GL1100 does this as well at times, when it does I regard it as a sign of a tune-up time. I usually balance the carbs and change the plugs at that point and the rattle goes away.

 

[Ren]

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Thanks all for the advice guys. It does sound like a carb or ignition problem then. Thank goodness it's not a serious mechanical defect. I'd like to sort it though because slipping the clutch is not good. Good call on pulling the plug caps - I looked at the schematic and see that the plugs are paired. Blocked pilot jet sounds very plausible. I'll take a look and get the misfire repaired before doing the carb sync.

Any idea what a dealer would charge for a carb sync or would it be cost effective toinvest ina 4 guage set up?

Ps. Good to new see another Portland Newbie. We probably looked at the same bike for sale!

 

[axelwik]

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Ren wrote:

Thanks all for the advice guys. It does sound like a carb or ignition problem then. Thank goodness it's not a serious mechanical defect. I'd like to sort it though because slipping the clutch is not good. Good call on pulling the plug caps - I looked at the schematic and see that the plugs are paired. Blocked pilot jet sounds very plausible. I'll take a look and get the misfire repaired before doing the carb sync.

Any idea what a dealer would charge for a carb sync or would it be cost effective toinvest ina 4 guage set up?

Ps. Good to new see another Portland Newbie. We probably looked at the same bike for sale!

You could probably save some money by buying gauges and doing it yourself. Go to ebay and put this numberinto the search engine 4547428517

I think JC Whitney sells the same thing as well as others.

If you still get the clanking after a tuneup and carb balance, tryto advancethe timing a bit.

 

[Ren]

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Thanks Marco. Looks like one tuneup and you've saved the cost plus a set of gauges to boot. Never can have too many tools.

Thanks again to everyone else. Let you know what fixes it.

 

[Jerryk]

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I have the same problem on both my 83's. My mechanic just did work on my Aspencade and said that the problem has to do with the clutch basket or he may be referring to the clutch housing. He said in order to fix it the engine needs to come out. This is confirmed by the Clymer manual. However he says it's very livable as long as you slip the clutch just a tiny bit on take off. I've gotten to the point that I don't even hear it anymore.

Jerry

 

[Ren]

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Jerry,

I hope that's not my problem although if I slip the clutch enough I'll be looking at the clutch basket pretty soon anyway!

Ren

 

[Jerryk]

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We are not talking about slipping the clutch a great deal, just a little on take off. It's mainly having to give the bird a little extra gas on takeoff. Your not go to burn the clutch. Try it a few times and see if it helps. You'll get the feel for it. I guess what happens is the clutch housing gets some wear and the clutches chatter in it.

Jerry

 

[Hobie1]

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When I first bought my '83 last year, I tried to ease away from the stop. Clatter Clatter. Now I just rev up a little bit and slip the clutch a bit and no more noise.

Hobie

 

[KIDATHEART]

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I havehad my 1100 for about 15 years or so and the chain has always made a racket at idle and it chatters when pulling away from a stop.I was told about 14 years ago that syncing the carbs would fix both problems.

Not liking to rush into things i still havent synced the carbs. There that should bring me to the point here. Im to cheap to buy a set of gages so i plan to make my own up. Today i made a list of stuff to get to do so.I pulled the screw out of the vaccum port in the intake manifold and it looks like its a 10-32 screw cause it also holds on a chrome cover.

Cant find a barrbed fitting for a vac hose to plug onto that size,they are all pipe thread. Any ideas besides spending money on a set of adapters?

thanks kidatheart

 

[PatinIdaho]

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LOL KIDATHEART your my kinda guy:cheeky1:

I'm thinking of making my own set also. Shoot i have almost everything i need sept theclear tubes and they arestill at the hardware store waiting for me. As for the adaptors i plan on getting some screws from work putting in adrill press so the hole is through the center and cut the heads off them.

 

[Gearhead76]

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My 77 gl1000 made the same noise, I wasn't getting spark all the time on the 3&4 coil, It was a bad coil, Took care of my problem,

but now my floats are sticking, So the carbs got to come off anyway, The joy of old bikes.:gunhead:

A easy way to check spark is to hook up a timing light, And wach for it to light up on each cylinder

 

[KIDATHEART]

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Thats correct Mr.Patinidaho us cheapos have to stick together.

I thought about drilling out a screw but i dont have a drill press.Kinda a tuff task with a Black and Decker and a vise. I will think of sumthin even if its 2 feet of adapters

 

[twisty]

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KIDATHEART wrote:

I havehad my 1100 for about 15 years or so and the chain has always made a racket at idle and it chatters when pulling away from a stop.I was told about 14 years ago that syncing the carbs would fix both problems.

Not liking to rush into things i still havent synced the carbs. There that should bring me to the point here. Im to cheap to buy a set of gages so i plan to make my own up. Today i made a list of stuff to get to do so.I pulled the screw out of the vaccum port in the intake manifold and it looks like its a 10-32 screw cause it also holds on a chrome cover.

Cant find a barrbed fitting for a vac hose to plug onto that size,they are all pipe thread. Any ideas besides spending money on a set of adapters?

Kidatheart, those vacuum port screws are metric (mm) not 10/32". I made my own from small plastic hose connector barbed fittings. I just ran a 5x.8 metric die over one end of the barbed fitting & that made the proper threads to fit the manifold vacuum ports. I also just use a single (high quality) gauge with a series of 4 valves. That allows an exact sync to the control carb, it takes a little valve flipping to get a perfect balance but is very accurate as using only one gauge leaves no chance of error between milti gauges.

Twisty

 

[KIDATHEART]

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Thanks twisty.Yes i just figured out they are 5mm,didnt know the thread pitch though so thanks for that.I didnt see any small barbed fittings at the hardware store though they all looked like 1/8 pipe or sumthin,guess ill have to take a better look when i go metric tap and dieshoppin. I was goin to make an oil manometer but your way may take less time to fabricate.The problem somtimes here in florida is finding what you need at a reasonible price(squeeeeeeeek!)or finding what you need at all.

Maybe once i balance the carbs ill be able to hear the radio when im sittin at a red lite.

KIDATHEART

 

[Gearhead76]

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Try an auto parts place for the plastic barbed fitting, I know they have them in Y's and straights, And they're pretty cheap