1100 running problems.

[Humbug]

Got a friend who has recently purchased a 1995 R1100RS. It starts and idles fine on choke/fast idle and he finds he needs to keep this on for approx 1/2 mile. He says he got to the motorway and the bike went fine, cruising easily at the ton. Coming off down the slip road he felt the engine misfire a couple of times and he then ran it up a dual carriageway at about 50 mph. He said it felt 'jerky' as if it was going to run out of fuel. It didn't and cleared it's head and ran fine all the way home. However, the next day it did exactly the same thing again. Runs fine at high speed but when deccelerating from a high speed run and the running at lower speeds it's not so good. It's covered 41,000 miles. It was fully serviced and the throttle bodies balanced just before he bought it.

Any suggestions to what he should be looking at?

 

[(RIP) Mark H]

Could be anything really, just serviced means nothing, I brought an R1100rt, the ink was still wet on the full service receipt costing about £350, everything done apparently, it was a real bad job, re-serviced with genuine parts rather than made in Thailand eBay specials including a new fuel filter (still dated 1999 on the old filter) ran well after.

Suspect fuel filter first

 

[littleredrooster]

You're probably already aware of this, but the choke lever has absolutely no effect on mixture, it only increases the idle speed. The problem lies elsewhere, possibly with one of the sensors - oil temp or air temp would be the first ones I looked at. After that, TPS, CO pot, fuel pressure or injectors but if it's OK when hot, this is less likely.

 

[Welshman]

Could be anything really, just serviced means nothing, I brought an R1100rt, the ink was still wet on the full service receipt costing about £350, everything done apparently, it was a real bad job, re-serviced with genuine parts rather than made in Thailand eBay specials including a new fuel filter (still dated 1999 on the old filter) ran well after.

Suspect fuel filter first

Hall Sensor, getting warm, repeatable early on

 

[Deleted account 190117001]

Got a friend who has recently purchased a 1995 R1100RS.

Coming off down the slip road he felt the engine misfire a couple of times and he then ran it up a dual carriageway at about 50 mph. He said it felt 'jerky' as if it was going to run out of fuel.

It didn't and cleared it's head and ran fine all the way home.

Any suggestions to what he should be looking at?

I had a very similar occurrence on my 1995 R1100r,
you have to remember this is an eighteen year old machine and any one of the electrical connectors could be iffy.
My problem was the connection on top of the injectors,a push on socket type.
I had the bike running on the stand and set about wiggling each connection i could get to.
Upon wiggling the injector connection (gently tugging up and down)
the right hand cylinder died.

I cleaned the connections up with a needle file,
dabbed a little Vaseline on the pins,
smeared some grease around the outer plastic to prevent water getting in for the future.
Hey ho,problem solved.