r1100r strange problem

[saabster]

I've got a 1996 r1100r which has everyone here baffled. When I start out in the morning it runs fine. Then I park it for 1/2 hour. When I start it up and take off it has problems getting fuel. But, only for about the first 300 yards (into third gear). The bike looses power for about 1-2 seconds at a time and then picks back up. After 300 yards the problem does not appear again even after I stop and star up again. They changed the fuel filter at the shop. The replaced some cracked hoses in the tank. The charcoal filter has been taken off ant the venting hoses re-rounted. But nothing has changed.

[philr]

Hi Saabster,

Hmm, an interesting problem (not for you I expect) but more info needed.

Different people describe the same symptoms differently so, how does "it has problems getting fuel" manifest itself exactly? Are you saying it only does it on the first hot restart of the day but not the second or third etc? If so that is weird.

Does it idle roughly for a short while on a hot restart - if it does, it could be an injector leaking down which causes rough running for a short while because that cylinder is flooded - but soon clears.

It is pretty hot in WA at the moment I expect, could you be getting a bit of vapourisation somewhere? Does it fire after a couple of turns or do you have to wind it over a bit?

[beemer-biker]

Hi Saabster,
It is pretty hot in WA at the moment I expect, could you be getting a bit of vapourisation somewhere? Does it fire after a couple of turns or do you have to wind it over a bit?

Actually, it is winter in WA now. I live in central WA, the low today was 10 deg. Faren. , tomorrows low will be around 4. Sooo, I don't think the summer vaporization problem is, well, a problem.
All this aside, I agree, maybe it is a bad injector or something along those lines, rather than the filter, etc., especially since all of that was changed recently with no improvement.

[saabster]

Well, as well documented, it is not hot in WA right now. Below zero (F) on the west side this morning. She does not idle roughly after hot start. What happens, is when I put the gas to her in first gear, I first get a little acceleration then - she looses power and stops accelarating for about 1 1/2 - 2 seconds (let's call this a "blip" which is great fun if I'm in a turn). Then she "catches" again. This happens a little in 2nd gear, but not for as long and not as easily noticed since I have some momentum built up. By the time I get to third gear the problem goes away and does not re-occur as long as I don't shut off the bike. It will re-occur on later trips during the day if I shut her down and let her sit for about 1/2 hour. They spent a lot of my money at the shop the other day trying to fix this, but really got nowhere. I should mention that I do a lot of short trips since I live 3 miles from work and a ride year around. Here that means a lot of riding in the rain.

[CycleRob]

I should mention that I do a lot of short trips since I live 3 miles from work and a ride year around. Here that means a lot of riding in the rain.

Ah yes! It's a water problem. With the age and use of the bike I'd DVM check for a flooded or worn out TPS while on the centerstand at the predicted time, instead of riding it. Next would be an airbox condensation glop getting sucked in on your hot restart. I also have serious doubts about the correctness of "the venting hoses (were) re-rounted"

There's also a good chance the battery, connection and/or alternator is causing a voltage fluctuation, since your 3 mile ride really taxes the health and lifespan of both of them.

It's one of those things.

[GeoffJ]

The next time the bike runs rough, shut it off, then remove and reinstall the fuel filler cap. If the bike runs normal, the problem is related to fuel tank venting.

[philr]

Oh that WA! Yes - vapourisation definitely not a problem.

Sorry about that, I didn't look at the flag hard enough. You know, old age and all that stuff.

If the bike had carbies it would sound like a flat spot when cold; depends whether it is an ignition type dead cut-out sensation or a gasping mixture sensation. And remember, regardless of induction type, engines still suffer the same symptoms from ignition, mixture, or compression problems. It is still an Otto-cycle engine with all the same requirements. Always start with the basics.

However, since CycleRob is convinced he has it sussed, I won't comment any further except to say I hope he is correct. I have never been as confident about anything as some people are about everything :-)