Fuel and front brake failure??? 1995 R1100GS

[MinnesotaRik]

Twice on my 2600 mile round-trip to Colorado I noticed that after a fuel up the engine would sputter as if there were no fuel getting to the heads. I increase the throttle until it cleared. The front handbrake would always fail at the same time. The lever would go right to the handgrip. Rear brake continue to work As soon as the engine started to run smoothly, the front brake would start working again.
This sounds like an electronic problem. Anybody have any experience with this and is it something that needs repairing?
Rik
In MN

 

[gsaddict]

Chances are you still have the black rubber original brake lines. They will either balloon and result in a loss of brakes or they will fall apart inside and clog the calipers and ABS module.
I have replace many sets of these lines - it is a very serious safety issue.
Replace all of them with SS teflon lines
https://spieglerusa.com/brakes/brak...w-r-1100-gs-front-rear-brake-line-kit-144.htm

As far as the sputtering goes after fillup - chances are your charcoal canister is still there and getting clogged.
Most people remove them - google "Canisterectomy"

 

[MinnesotaRik]

Simultaneous

The lost front brake and the sputtering only happen at the same time as if there is something they have in common...

That said- yes: replacing the 21 yr old brake lines sounds pretty obvious now- and will look for the canister..

Rik
In MN

 

[gsaddict]

The lost front brake and the sputtering only happen at the same time as if there is something they have in common...

That said- yes: replacing the 21 yr old brake lines sounds pretty obvious now- and will look for the canister..

Rik
In MN

There really is no link between the 2 systems

While installing new lines, you may want inspect your front master cylinder for corrosion in the bore. Earlier models did not have an anodized bore.
It may need to be honed and a rebuild kit installed.

 

[pauls1150]

The only thing in common is the computer ... perhaps a corroded pin or two where the harness plugs in to it? Take off the big plug (carefully) and inspect it, maybe spritz some contact cleaner in there before reassembling.
Rik, does your clock or Rider Information Display (gas bars) ever blank out or reset? That would indicate a loose connection either at the battery, a main plug in the harness, or even inside the ignition switch.

 

[gsaddict]

The only thing in common is the computer ... perhaps a corroded pin or two where the harness plugs in to it? Take off the big plug (carefully) and inspect it, maybe spritz some contact cleaner in there before reassembling.
Rik, does your clock or Rider Information Display (gas bars) ever blank out or reset? That would indicate a loose connection either at the battery, a main plug in the harness, or even inside the ignition switch.

No link with the hydraulics on that generation, unless the ABS is activated.
The OP said the lever went to the handgrip - that is NOT good - strictly hydraulics and the rubber lines are most likely to blame.

 

[pauls1150]

Absolutely the brake lines must be updated, and the master cylinder thoroughly checked, no disagreement there;
but I have to wonder if his "right to the handgrip" is actually the "Residual" non-braking that happens when the ABS fails (for any reason)...? That it seems to be restored is a clue, thus my specific question re the RID.

 

[MinnesotaRik]

big plug

[I]The only thing in common is the computer ... perhaps a corroded pin or two where the harness plugs in to it? Take off the big plug (carefully) and inspect it, maybe spritz some contact cleaner in there before reassembling.
Rik, does your clock or Rider Information Display (gas bars) ever blank out or reset? That would indicate a loose connection either at the battery, a main plug in the harness, or even inside the ignition switch.[/I]


I would like to check this=--- the big plug-- is that under the gas tank with the electrickery?

I don't have a clock or display -- 1995 -- just the low fuel light, abs light, Neutral and direction signals.

interesting idea that all the trouble that the simultaneous problems is from the right hand grip... throttle and brake...

I had thought about the ABS failing but it seems to only fail at the front while the back is still operating fine. Still, it sounds electric with a sudden on and off effect.



Rik
in Minnesota

Yes, Uff Da does happen!

 

[pauls1150]

Yes, under the tank, left side.

As it happens, try to watch for anything else electronical mis-behaving - headlight, tach, anything else visible while riding. Also LISTEN - if it's the ABS itself, there may be a soft "clunk" if a bad servo (pump motor) is trying to engage; very difficult to hear with the engine running plus wind noise.

ADDENDUM - Perhaps a piece of degraded hose lining is inside the ABS unit...?

 

[MinnesotaRik]

Update!

Super busy just finished the SS brake line swap.
I have been riding with the new lines for about 3 weeks expecting that my problem was solved: then it happened again today.
I realized that the engine part of the problem was just the motor lugging because the brake turned on without me! Engine fighting brake slows and lugs- pull in clutch and engine is fine- but the bike comes to a gentle stop as if braking normally but there is no firmness to the handbrake. The rear seems fine. Then, if I switch off the key and the turn it back on, the brake un-sticks and everything is fine... until the next time!

Since this is acting like electric triggering of the brakes, that is probably the ABS somehow. I tried riding with the ABS turned off, but I don’t know if the switch worked. The solid lower ABS light was on for about a minute. Then, they were both out.

BTW- I was panicking about failing to bleed the rear until I found out about the under tank ABS bleeder! I plan to re-bleed the rear and the front including this time ABS bleed for the front. Maybe there is some cloud of rubber floating in there!

I have to get her all set for the Des Moines Rally! I even got a speaking slot on Saturday!


Dr Rik
In MN