1100 Flat spot / Backfire

[Raven]

Hello.
ref 1996 1100 GS
I need a bit of help. I have started to get a flat spot on the bike while accelerating hard. If cuts out for just a second then picks up again and runs fine during higher revs. If I then slow down using the engine braking, I can get a backfire.
I dont get any problems if I accelerate slowly and evenly, but any change in rate brings on the problem.
Seemed to start in the wet weather, but now still not ok in the dry.
Does anyone have experience of this. I'm bothered as I am due away on a Stelvio run in the next 2 weeks!!!

 

[DrFarkoff]

You sure it's a misfire ??

Read this http://www.largiader.com/tech/oiltrans/

 

[jamesv]

Coilstick?

Sounds like a coilstick breaking down to me, had it on my 1150 when I first got it, a new one sorted it.

HTH,

James

 

[DrFarkoff]

Jamesy 96 R1100 didn't have coilsticks

only december 2002 onwards R1150 version had

Sounds like a coilstick breaking down to me, had it on my 1150 when I first got it, a new one sorted it.

HTH,

James

 

[jamesv]

Ahh I see, they do say that we learn something everyday!!

 

[Vern]

Mine does that every once in a while and it does feel like it's just missing a spark for a split second. I thought it might have been a gear turning on a shaft for a second,then warming up and stopping slipping.I've just got a new/second hand gearbox to go in, in the next week or so when I do the clutch.

I'll report back, unless I get fed up and do something else instead

 

[THE PICT]

Have a look at the ht leads

 

[Vern]

Have a look at the ht leads

How do they get in the gearbox then

 

[Ugly Cow]

Hello.
ref 1996 1100 GS
I need a bit of help. I have started to get a flat spot on the bike while accelerating hard. If cuts out for just a second then picks up again and runs fine during higher revs. If I then slow down using the engine braking, I can get a backfire.
I dont get any problems if I accelerate slowly and evenly, but any change in rate brings on the problem.
Seemed to start in the wet weather, but now still not ok in the dry.
Does anyone have experience of this. I'm bothered as I am due away on a Stelvio run in the next 2 weeks!!!

IF you get this problem under no load.ie just reving hard in neutral then I would remove all rubber covers from coils and spark plugs and when its dark rev hard and if there is any visible spark thats your problem. That said I don't have an 1100, IF this has a single coil and you cannot see any arcing in the dark (under no load) I would go for the coil breaking down under load.

Hope you can follow and its of some help

 

[DrFarkoff]

Its an early 1100 It's a well known problem with them

"My bike 'skips' in second or third gear...

...almost like the ignition cuts out momentarily, or some gear is skipping a tooth." You need transmission work. This can happen to any gear, but usually second or third suffers first.

From Mr "Anton Largaider"

 

[Vern]

Its an early 1100 It's a well known problem with them



From Mr "Anton Largaider"

It's no use, they're off on an ignition fault search

Mine was done once under warranty about 15 years ago because it jumped out of 3rd gear.

 

[Ugly Cow]

It's no use, they're off on an ignition fault search

Mine was done once under warranty about 15 years ago because it jumped out of 3rd gear.

The OP states it backfires on overrun, started when raining, now when dry, gearbox jumping out of gear does not give these symptoms.

 

[DrFarkoff]

Perhaps he has two issues?

The accelerating hard and "Skip" is a known gearbox problem

The backfire sounds like there is air getting into the induction system somewhere

 

[Ugly Cow]

Perhaps he has two issues?

The accelerating hard and "Skip" is a known gearbox problem

The backfire sounds like there is air getting into the induction system somewhere

He could have two issues, but I think air should be in the induction system, just not drawing air into the exhaust.

 

[Vern]

Hole in the exhaust somewhere I'd guess

 

[davegs]

Hole in the exhaust somewhere I'd guess

I know, I know,..... the one in the end!!!!. YES!"!!!

(I do hate clever bastards!)

 

[Raven]

Thanks

Thanks for all the suggestions. As it turned out, the problem got better after me playing with the Ht leads. I am guessing the insulation has broken down. New set on order.