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1995 R1100R runs rough


Jhay77

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Good afternoon, I recently acquired a 95 R1100R for a price I couldn't turn down. The previous owner stated that it "ran rough due to needing the throttle position sensor adjusted and the throttle bodies synchronized by someone who knew what they were doing." I'm quite mechanically inclined as a former Saab Technician so I figured I could handle just about anything that could be wrong with the bike.

 

Long story short, I'm at an impasse and could use some help. The bike runs but very poorly at idle and under throttle. It seems to be running very lean all around. It sputters and "sneezes through the airbox" and bogs when the throttle is applied. I have an infrared temperature gun and the right side exhaust temp is about 200 degrees higher than the left side (and it gets up to about 800 degrees if I try to keep it running).

 

This is what I've checked so far:

Adjusted valves on both sides (found several that were quite tight).

Adjusted throttle position sensor to spec (zero'd and adjusted left throttle stop screw to a reading of .370 volts).

Started throttle body synchronization process but I can't get the bike to stay running enough to complete it.

Air filter, fuel filter and spark plugs all look good and were recently replaced.

Fuel appears to be ok (although I suppose I should drain and refill just to be sure).

 

Does anyone have any ideas as to something else to look for? A bad/dirty throttle body or injector? Faulty O2 sensor? Motronic issue? Your help is greatly appreciated!

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Afternoon Jhay77

 

Place to probably start is to POSITIVELY verify that the throttle plates are lifting off the idle stop screws at the EXACT SAME TIME -- Then verify that the throttle cams hit the Wide Open Stops at the very same time. If they don't then adjust the cables to get them close (also verify that neither side throttle cable is sitting ON TOP of the adjustment furrel).

 

If all OK throttle cable & throttle plate wise then verify that you have fuel flowing back to tank in the fuel return hose (a split pressure hose inside the tank will lower fuel pressure enough that it won't open the pressure regulator therefore not allowing return fuel flow).

 

If all OK fuel flow wise then you will probably have to go over the engine sensors & verify operation & that they are staying within their design parameters.

 

You might also try running it with the o2 sensor disconnected & (IF) that bike has a Techlusion or fuel nanny on it then totally disconnect all connections to those as a test.

 

Also verify that the R/H spark plug wire is not cut through & contacting the R/H TB cam at idle.

 

Then follow the spark plug wires up to the ign coil & verify that they FULLY plugged into the coil.

 

Otherwise a little more testing & info from you & posted here will maybe help us help you with more precise troubleshooting info.

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G

Adjusted throttle position sensor to spec (zero'd and adjusted left throttle stop screw to a reading of .370 volts).

 

I see a significant problem right here. First, unless you know the stops have been changed you shouldn't touch them. Since you have I recommend searching for zero=zero on this board and you should find the proper procedure for setting up the throttle stop. Roger04RT did a lot of research on this and I've gone through a particular setup to get mine right and it is in that thread. Setting the voltage on the TPS by using the stop screw will have the throttle way too far open.

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I know the stops had been changed. I followed the procedure on IBMW by first zeroing the tps with the throttle stop completely backed off, then adjusted the stop to attain a reading of .370v. The next step in the procedure is to adjust the right side throttle stop (by manometer and at idle) until equal mercury is obtained....

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I know the stops had been changed. I followed the procedure on IBMW by first zeroing the tps with the throttle stop completely backed off, then adjusted the stop to attain a reading of .370v. The next step in the procedure is to adjust the right side throttle stop (by manometer and at idle) until equal mercury is obtained....

 

Hi Jhay77,

 

That procedure is incorrect. Here's a link to the thread Roger04RT started. The thread is tps alignment, Idle speed, beyond zero=zero. beyond zero=zero

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So if what I'm reading what I see correctly, then according to Roger the tps (with throttle cable slackened and stop screw backed out) should be set to .250v then adjusted with the stop to .350v?

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So if what I'm reading what I see correctly, then according to Roger the tps (with throttle cable slackened and stop screw backed out) should be set to .250v then adjusted with the stop to .350v?

 

That's correct. The butterflies are only supposed to be open slightly. Setting "0" to 10mv then adjusting the stop screw until you get to 350mv will open them quite a bit. You can get it running this way, as I did initially, but using this other method is MUCH better.

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roger 04 rt

Trobinson is right. Although z=z isn't a good procedure, if you followed it accurately your bike should run smoothly.

 

Given what you're experiencing you should work through DR's list and let us know how that goes. You could also add a compression test to the list at some point.

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Thanks, that would probably explain why the BBS's have zero to little effect on the idle right now. I'll set the tps that way and go from there. Incidentally, how does the O2 sensor plug come apart? Thanks again for your help.

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Morning Jhay77

 

The BBS adjustment should have effect no matter what TPS setting method you used. Make sure that the L/H throttle cable is not tight therefore allowing the TB cams to return (solidly) to the stop screws.

 

On that early 1100 bike you shouldn't have a Bowden box (split throttle cables) so it has a single throttle cable that runs to the L/H TB then around the cam & on to the R/H TB.

 

On the old single cable (non Bowden box) 1100's I usually back the R/H stop screw off then do the above-idle cross side balance. THEN see what the idle balance is with the R/H side using the throttle cable as the idle stop. Once all is as close as possible THEN turn the R/H idle stop screw in to JUST touch the TB cam. (those old single cable systems are almost impossible to get a perfect cross side balance at idle but maintain the above idle balance AND have BOTH side throttle cams move off the idle stop screws & hit the WOT stops at the very same time).

 

It is a compromise so get it the best (& closest) just off idle as that is where the TB balance is the most important while riding the bike. A little off on balance at curb idle is meaningless so that is where I usually make the give & take.

 

On the o2 sensor disconnect-- that large ring unscrews then the connection just pulls apart .

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Have you checked the shafts that run through the throttle body's? When these ware they have a great effect on how the bike idles and makes it impossible to sync your throttle body's. If there worn enough it will sound as if your valves are very loos. When running put your finger on the cable wheels and see if there is any slop in the shaft. If so bay a rebuild kit from Dan Cata and read his write up on how to do the rebuild. It's not a bad job.

If this is your issue, and you have to do a rebuild this should help you with your issue, To help balance the throttle body's

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How many miles on the rig and what do the plugs look like? You need to find out why one bank is so much hotter than the other.

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So, I thought I'd post an update. I re-adjusted the tps according to Roger's method and the bike runs slightly better but still not well at all. I checked the plugs,plug wires and their connections at the coil (they were fine). While the plugs were out I performed a compression test. Both cylinders have 160 psi. I tried unplugging the O2 sensor and found some dirty connections which I cleaned and hit with contact oil. Unplugging the sensor had no noticeable effect. I then checked to see if there was any fuel returning to tank via the return line and of course there wasn't! I drained the tank, removed it and the fuel pump and found some hack had replaced the longer of the 2 lines with non-submersible fuel line and it was split right down the middle. I am replacing the lines this morning and will report back upon reassembly. Thanks again for your help thus far.

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I then checked to see if there was any fuel returning to tank via the return line and of course there wasn't! I drained the tank, removed it and the fuel pump and found some hack had replaced the longer of the 2 lines with non-submersible fuel line and it was split right down the middle. I am replacing the lines this morning and will report back upon reassembly. Thanks again for your help thus far.

 

Morning Jhay77

 

That would definitely cause your rough/poor running. Yes, please keep us updated on how it turns out.

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Well, that was the ticket. It runs quite well now and should be even better when I get the throttles properly synched. Now to replace the tires! Thanks again for all the advice!

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roger 04 rt

Nice work Jhay77, it would be great to see more riders using the return fuel flow test before opening up their tanks. It takes a lot of the guesswork out.

 

If you have time, you can rerun the test and (safely) collect one minute's worth of return fuel at idle. It should be about 2 liters.

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