r1100rs - possible fuel starvation

[blake]

i might end up with a buddy's r11rs in my garage (1994, about 90k miles).

the only issue it has is what seems like a fuel starvation issue. i have been told that if you "get on it" a bit that it will kinds stumble a bit, then pick up. happens the same whether hot or cold.

it has the external fuel filter mod. the filter has been changed, still persists. i'm thinking that the hose used might not be FI rated and is perhaps collapsing.

does this sound plausible?? what are some other things i can check out?

also, the bike isn't in front of me. i'm going to pick it up soon and will be riding it home (only about 200 miles).

 

[mtboulder]

The problem could be one of many things. I doubt it is the type of fuel lines used. You can check the fuel pressure to be sure. Hook a fuel pressuer gage with a 'T' fitting on the hose that fits into the bottom black plastic fuel line. When you turn on the ignition the fuel pump will come on for about 2 seconds. The pressure should build to around 3.5 bars. Then start the bike, the pressure should maintain a steady 3 bars. You can even tape the gage somewhere on your bike and observe it while the problem is occurring to see if the pressure is dropping at that point. If it is dropping, then it could be a fuel delivery problem (pump, filter, or some other blockage).

Try running a half bottle of Tectron injector cleaner through the gas tank. Your problem could be the injectors are plugged. You can also pull the injectors from their housing and point them into a glass jar. Turn on the ignition and see if you have a fine even mist/spray vs liquid gas coming out of them in a stream. You want the former.

Other things to check:

-Look for any air leaks around the Throttle body intake manifolds (black rubber tube the TB's are attached to.) With the bike running at idle, spray carb cleaner (or use an unlight propane torch) around each TB. If the RPMs pick up, you have an air leak that needs to be fixed.

-Replace air filter if dirty

-Replace spark plugs

-Could be a bad coil or spark plug wire.

-Synch TB's.

Start with the simple stuff first. Good luck and keep us posted.

 

[blake]

thanks for the tips. i'll add those to the list of things to check out. some of them i'll do before i ride home and some i'll have to do after unless more time magically appears in my schedule.

The problem could be one of many things. I doubt it is the type of fuel lines used. You can check the fuel pressure to be sure. Hook a fuel pressuer gage with a 'T' fitting on the hose that fits into the bottom black plastic fuel line. When you turn on the ignition the fuel pump will come on for about 2 seconds. The pressure should build to around 3.5 bars. Then start the bike, the pressure should maintain a steady 3 bars. You can even tape the gage somewhere on your bike and observe it while the problem is occurring to see if the pressure is dropping at that point. If it is dropping, then it could be a fuel delivery problem (pump, filter, or some other blockage).

Try running a half bottle of Tectron injector cleaner through the gas tank. Your problem could be the injectors are plugged. You can also pull the injectors from their housing and point them into a glass jar. Turn on the ignition and see if you have a fine even mist/spray vs liquid gas coming out of them in a stream. You want the former.

Other things to check:

-Look for any air leaks around the Throttle body intake manifolds (black rubber tube the TB's are attached to.) With the bike running at idle, spray carb cleaner (or use an unlight propane torch) around each TB. If the RPMs pick up, you have an air leak that needs to be fixed.

-Replace air filter if dirty

-Replace spark plugs

-Could be a bad coil or spark plug wire.

-Synch TB's.

Start with the simple stuff first. Good luck and keep us posted.

 

[pglaves]

i might end up with a buddy's r11rs in my garage (1994, about 90k miles).

the only issue it has is what seems like a fuel starvation issue. i have been told that if you "get on it" a bit that it will kinds stumble a bit, then pick up. happens the same whether hot or cold.

it has the external fuel filter mod. the filter has been changed, still persists. i'm thinking that the hose used might not be FI rated and is perhaps collapsing.

does this sound plausible?? what are some other things i can check out?

also, the bike isn't in front of me. i'm going to pick it up soon and will be riding it home (only about 200 miles).

I would make sure that the filter being used is a big one and not a little one. And check the adjustment of the TPS.

 

[blake]

thanks paul. how can i determine "big" or "small" on the filter?

it may be an obvious answer, but i'm totally new on the oilhead front. as i said, the bike isn't in front of me, so much of this is happening on the phone.

i was thinking from the pics on the ibmwr site (one of lentini's articles) that it was similar in size to the filter on my old k75.

I would make sure that the filter being used is a big one and not a little one. And check the adjustment of the TPS.