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Suddenly rough idle and a glowing cat!


Brycelyoung

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Brycelyoung

Hey folks, looking for some help. I have a '98 R1100R which just had the clutch replaced (my winter project) and everything put back together. I got a throttle body sync by a very competent technician in the area and everything was running great. I rode it around for a couple days with everything running better than it ever had since I had bought the bike. Today, on my way to work, I was about to pull out onto a major street and the bike died, like when you're learning to ride and let out the clutch too fast. Since I'd been riding my KLR for months, I figured I probably just wasn't used to the release on this bike and thought nothing of it. But when I started it back up, something was not right. It ran very rough, idling very low (probably around 7500, tops) and felt like a single cylinder. Once I got going, the throttle was very finnicky. In 1st-2nd gears, it was very (overly) responsive if I gave it even a little gas, and if I let up it would drop down immediately, resulting in a very jerking feeling. Since I was late for work, I hobbled it there and tried not to think about it.

After work, I had a hard time getting it started. Even with the choke, it would not idle high enough to remain running. Eventually, I started it and just hung on the throttle enough to keep RPMs at about 1500 and rode home, where I could examine it and fix whatever's wrong. Same riding experience as on the way to work. If I held in the clutch, RPMs would drop too low and it would die. I should mention, at about 65mph in 5th, it was running at about 4k rpms and nothing seemed terribly wrong with it. Finally got home and got off the bike to find a VERY bright red glowing catalytic converter, only on the left side where it leads to the muffler.

Anyone have any ideas what the problem could be? Thanks in advance for your help!

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You'll get a more refined answer than mine when folks wake up, but first to check is both ends of the throttle cable where they enter the throttle bodies.

Make sure the cable ends are fully seated in the throttle body linkage sleeves.

Sometimes, even opening the throttle all the way a couple times ( ENGINE OFF)

Will seat the cables.

A symptom of this is the throttle feeling funny or too easy to turn.

But look at the cable ends very carefully making sure they are exactly the same (seated in the sleeves)

In the old days, we used to use the membrane tape to secure the cables to the linkage.

It's possible the tech didn't tnsion the cable(s) correctly when he synched.

That's my suggestion.

 

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As Tri750 says, check that the throttle cables are fully seated in the ferrules at the throttle bodies. Make sure you don't have a pebble or other debris stuck at the cable and the pulley.

 

If that all seems good, get a compression test done to see if an exhaust valve got chipped. How many miles on the motor?

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Brycelyoung

Thanks for the advice Tri750. I did check to make sure the cables were seated properly when it first died. Though even then, it felt like that would be a strange problem to have mid-ride (though perhaps not impossible?). Regardless, that doesn't seem to be the problem. The part that's really got me confused is how it went from a very good, smooth, ride to choking, gasping mess in a matter of seconds. Brand new air and fuel filter. Spark plugs have probably not been changed in a while, so I'll get new ones tomorrow, but even those wouldn't seem to cause these problems this suddenly would they?

Michaelr11, I'm at 39k+ with regular maintenance.

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I'd be wondering if a fuel line blew off (or cracked) inside the tank. I'd also be a little bit worried about a burned exhaust valve, although that normally seems to happen on an acceleration.

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Glowing cat is probably caused by too much raw fuel entering it and combusting there.

 

Aside from the valve issue mentioned above, you may also try the quick test to see if both spark plugs are firing. Next check for bad or leaky injector. It could also be a bad cat.

 

Either way, this condition can burn up and clog a good cat so obviously avoid riding it anymore until fixed.

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Morning Brycelyoung

 

I would also start with a throttle cycling check. Seeing as the engine seemed to run OK for a while THEN started acting up I wouldn't suspect that a throttle cable is out of it's furrel (now).

 

But I might suspect that the R/H throttle cable WAS out of it's furrel during the initial throttle sync so the system might have been synced to a the cable out of position & just now it snapped back into place.

 

Easy enough to check (especially on the R bike)-- Just have someone slowly open the twist grip while you put one hand on each throttle body cam. The cams should start out SOLIDLY on the stop screws then BOTH SIDES should start to lift off the stop screws at EXACTLY the same time then follow through together & hit the wide open stops at the exact same time. (if they don't do the above then have the TB balance rechecked or do it yourself)

 

 

If all OK on the TB balance check then suspect a spark plug wire pulled partially out of the ign coil (up under the front of the fuel tank), of you have a fouled spark plug, (probably on the colder side, not the red hot side), or you have a compression issue on the cold side, or a valve issue on the colder side.

 

I would start with the throttle body cycling test mentioned just above, then install new spark plugs & verify that the spark plug wires are plugged into the coil, & verify that the the R/H spark plug wire isn't contacting the R/H TB cam & wearing through/shorting out.

 

Also check under the bike to make sure that the o2 sensor pig tail isn't hanging down & laying on the exhaust system.

 

Otherwise the engine sensor inputs need to be verified, compression tested, intake boots checked for cuts/cracks, etc.

 

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Joe Frickin' Friday
But I might suspect that the R/H throttle cable WAS out of it's furrel during the initial throttle sync so the system might have been synced to a the cable out of position & just now it snapped back into place.

 

That was my first thought too. The symptoms match very well with this explanation.

 

Easy enough to check (especially on the R bike)-- Just have someone slowly open the twist grip while you put one hand on each throttle body cam. The cams should start out SOLIDLY on the stop screws then BOTH SIDES should start to lift off the stop screws at EXACTLY the same time then follow through together & hit the wide open stops at the exact same time. (if they don't do the above then have the TB balance rechecked or do it yourself)

 

As bad as the OP's symptoms are, I expect one side won't hit the idle stop at all. When rolling off the grip, listen for the "click" of the throttles hitting their stops; I bet you'll hear it on one side, but not at all on the other.

 

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Brycelyoung
I might suspect that the R/H throttle cable WAS out of it's furrel during the initial throttle sync so the system might have been synced to a the cable out of position & just now it snapped back into place.

This is a good description of what the problem feels like. Unfortunately, this can't be the problem, since I made sure that they were seated properly before I went in for the synchronization, and the tech also checked that before synching (if any of you are from around the metro area in MN, it was Charlie Johnson, so that gives you an idea of the mechanic's skill). However, when he was adjusting the throttle bodies, he found that someone had wrenched on the stop screws (the ones with blue paint), so the sync was kind of a "best I can do" option (which turned out as a "fine by me" solution).

Will try new plugs today. I would be pumped to find that's all it is, but also surprised, so we'll see. Thanks all for your help! I'll let you know more when I've done some more work!

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Brycelyoung
As bad as the OP's symptoms are, I expect one side won't hit the idle stop at all. When rolling off the grip, listen for the "click" of the throttles hitting their stops; I bet you'll hear it on one side, but not at all on the other.

I might be mistaken, but wouldn't this cause one of the cylinders to run higher (because of extra air from an internal TB plate that won't close all the way)? My problem is the opposite. Fuel injection is my kryptonite, so I might not be understanding your advice! :grin:

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As bad as the OP's symptoms are, I expect one side won't hit the idle stop at all. When rolling off the grip, listen for the "click" of the throttles hitting their stops; I bet you'll hear it on one side, but not at all on the other.

I might be mistaken, but wouldn't this cause one of the cylinders to run higher (because of extra air from an internal TB plate that won't close all the way)? My problem is the opposite. Fuel injection is my kryptonite, so I might not be understanding your advice!

 

Afternoon Brycelyoung

 

Possibly-- If the L/H side is open (off idle stop screw) at curb idle then THAT side will try to run faster (higher) as that would also advance the TPS (Throttle Position Sensor) & cause the fueling computer to add more fuel.

 

On the other hand if the R/H side is open (off idle stop screw) at curb idle then THAT side will usually run weaker (or not at all) as it does get more air but there is very little fuel to go with the additional air as the TPS is on the L/H side so the fueling computer doesn't see the R/H side being more open.

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Brycelyoung

Problem solved! Since, as I mentioned previously, I am easily confused by and don't like dealing with fuel injection, etc., my relief is pushing 11 now.

In the process of removing the transmission case, etc. for the clutch replacement, my brake lines got bent out of whack. Not cracked or anything, but they definitely don't look as pretty as before. What I guess happened was that the lower line pulled out from the clamp that will hold it in line and was, indeed, preventing the R/H throttle to touch down on the screw. The camera on my 10 year old phone is a piece of shiz, but here's the best pictures I could get:

 

2lcxsu8.jpg

 

2u5z20x.jpg

 

Thank you all for your advice. I will still probably change the plugs. As long as I'm here, any advice on getting those brake lines to lie flat/where I want them? I'm worried about bending them too much and breaking them, but would also like to avoid this problem again. Thanks again folks!

 

 

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A good reminder to review what we last did when a new problem seems to come out of nowhere before embarking on a new series of tests.

 

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Ok,

To repeat, for years each bike got the throttle cables secured in place on the ferrules with a Wurth product.

Available as self fusing silicone tape.

3M makes it too.

Permatex as well.

In Aviation its red and called white stripe tape .

 

Lasts a long time, can't vouch for the "As seen on TV Rescue Tape"

 

I'm sure it's "pricey" for those that use that word to explain why they won't buy something but to prevent it happening again, pretty inexpensive fix.

 

I'm sure it's

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Ok,

To repeat, for years each bike got the throttle cables secured in place

on the ferrules with a Wurth product.

Available as self fusing silicone tape.

3M makes it too.

Permatex as well.

In Aviation its red and called white stripe tape .

 

Lasts a long time, can't vouch for the "As seen on TV Rescue Tape"

 

I'm sure it's "pricey" for those that use that word to explain why they won't buy

something but to prevent it happening again, pretty inexpensive fix.

 

 

Morning Tri750

 

I seem to be missing something here. How can that tape (or any tape) prevent a

bent brake line from holding a Throttle Body cam partially open at idle?

 

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Brycelyoung,

 

Having recently done a transmission swap I can also vouch for keeping a close eye on how things are moving as the frame is split then put back together. I had to carefully re-route my fuel lines from the pressure regulator between the brake lines as I hadn't paid attention when reinstalling the air box. I had almost everything back together by then and I was not about to remove that battery tray again! Good find though and I'm sure a lesson learned about these bikes. :grin:

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