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ReplacedThrottle Cable-now performing poorly


ridergirl

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Help!! '99 R1100RT w/ 60M on it. Runs great. Replaced a broken throttle cable (broke on highway, had to be trailered home!!!) The new cable works fine, but now the bike is running very poorly, it is very sluggish and sputters. A discussion board member sent a PM the day after we did the replacement saying that you have to do a TB Sync once it is all back together again. What is that? Did not see that step in the Haynes service manual. Can anyone out there help me with this problem?? Thanks.

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Joe Frickin' Friday
Help!! '99 R1100RT w/ 60M on it. Runs great. Replaced a broken throttle cable (broke on highway, had to be trailered home!!!) The new cable works fine, but now the bike is running very poorly, it is very sluggish and sputters. A discussion board member sent a PM the day after we did the replacement saying that you have to do a TB Sync once it is all back together again. What is that? Did not see that step in the Haynes service manual. Can anyone out there help me with this problem?? Thanks.

 

A throttle-body synch is part of routine maintenance every 6K miles, done to make sure both throttle bodies open/close simultaneously; the Motronic makes sure both cylinders receive equal amounts of fuel, and the TB synch is done to make sure they both receive equal amounts of air as well. If you replace a cable, you can get pretty close by listening to make sure they both audibly click shut against their stops at the same time; if you want it to be perfect, you'll need some kind of differential vacuum gauge, such as a Twinmax.

 

The TB synch procedure is in the Haynes manual; check the first chapter that describes 6K-mile maintenance procedures.

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Just replaced the one upper cable - the long one that goes to the handlebars.

 

I can understand his confusion.....if only replacing the long one from the grip to the left TB, why would he have to redo the sync? Changing the crossover would be another story, am I right?

 

Could you have disturbed the locknut on the left side of the crossover cable? What else is over there? The fast-idle cable isn't likely to be the culprit.

 

Like previously stated, audibly check to ensure both TBs are "clicking" closed. Something has to be getting hung up. Is there at least a tiny bit of slack in the new throttle cable?

 

Perhaps a better description of "performing poorly" is needed.

 

What else was disturbed in the replacement? I assume the tank needs to be removed. Perhaps recheck the fuel lines for a kink, check the electrical connection on the right side.....just thinking aloud, so to speak.

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Like Mitch said, you'll need to do a TB synch. Whenever you mess with a throttle cable, or TB, you'll need to redo the synch. For that matter, a good synch does wonders every 6K. I thought that my 02 was running great, and it was, and had contemplated not doing a valve adjust/synch before going on my TN to CA trip in a few weeks. Rode it yesterday, and that pesky surge reared it's ugly head. It's not bad, but I know it there, so either tomorrow or next week when I get back from my business trip, I'll be pulling the Tupperware and doing another VERY thourough service even though I just did one 3K ago. It could be that I didn't get one of the jam nuts tight enough and one of the throttle cables could have slipped just a wee bit. Not a problem, I'll have it back to it's no surge, smooth running self in no time. Your's will too, I bet.

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I can understand his confusion.....if only replacing the long one from the grip to the left TB, why would he have to redo the sync? Changing the crossover would be another story, am I right?

 

What else was disturbed in the replacement?

I'm the person who has been coaching Kathy and Mike in PMs since he replaced the main throttle cable on her bike.

 

The '99 does not have a crossover cable, it has a Bowden cable junction box. To get it out, to get to the end of the main cable, requires disconnecting at least the left cable going to the throttle body. This disturbs the setting of the cable. Thus the bike now needs to be sync'ed.

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I can understand his confusion.....if only replacing the long one from the grip to the left TB, why would he have to redo the sync? Changing the crossover would be another story, am I right?

 

Not right.

 

Even if the bike had the original cables with a crossover (which it doesn't, wrong year) you would be wrong because the cable would be a single cable that runs from the twist grip to the left throttle body and continues on to the right throttle body. To say it another way, the crossover cable is not a seperate cable but part of the main throttle cable.

 

Stan

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.....the cable would be a single cable that runs from the twist grip to the left throttle body and continues on to the right throttle body. To say it another way, the crossover cable is not a seperate cable but part of the main throttle cable.

 

 

Aahhh, yes! I see that now. I had ordered a new cable just to have...With just a quick glance, I thought it was a long cable that ran to the left TB, and a shorter joining cable. There are two separate sleeved sections; but upon closer examination, there is indeed a continuous single cable connecting the two. Not to mention the fact that I didn't know this design was changed in later years. OK, so that's two rookie mistakes in the same post!! Sorry to clutter the thread w/so much misinformation. Still learning here... dopeslap.gif(I use that smiley a lot)

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Thanks to all who offered assistance. Since I don't have the equipment to do the TB sync I have an appointment to take the Beemer to our local BMW dealer for service to perform the sync.

Thanks again.

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Thanks to all who offered assistance. Since I don't have the equipment to do the TB sync I have an appointment to take the Beemer to our local BMW dealer for service to perform the sync.

Thanks again.

Watch them do it an earn how to do it yourself. It's easy. If you can replace a cable, you can do a throttle synch with no difficulty at all.

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