Poppin` on the over run?

[Martin.]

My 1990 R100 GS has taken to popping on the over run. I changed the holed original down pipes for a Kiehan pair and the situation improved slightly.
Bike seems to run o.k otherwise, but I know over a period I can adapt to problems until someone else has a ride and notices how bad it`s got !!!
The other thing I`ve noticed is that the left had pipe has "blued" much more then the right hand one.
Any suggestions as to my next step? Ta!

 

[GEOFFREY DEACON]

either check for a lean left cylinder,(hole in inlet pipe/carb etc)? or for a rich righthand cylinder, (carb)?

 

[Martin.]

Thanks. I`ve just had a quick look at the plugs and the right one does look a shade darker. Off to the manual !

 

[bumpmuncher]

On mine the popping on the overrun is usually caused by holes/gaps in the exhaust. If I am careful with the assembly and use exhaust repair paste (fiberous one not smooth assembly paste) I can stop it. For a few thousand miles before it rattles loose and starts popping again. Must get around to doing it again lol. Also sounds like it could do with ballancing the idle jets\ throttle cables and are the chokes relesing fully. Ofcourse someone will be allong soon to say I am talking carp and tell you what else it could be.

 

[(RIP) Proff]

On mine the popping on the overrun is usually caused by holes/gaps in the exhaust. If I am careful with the assembly and use exhaust repair paste (fiberous one not smooth assembly paste) I can stop it. For a few thousand miles before it rattles loose and starts popping again. Must get around to doing it again lol. Also sounds like it could do with ballancing the idle jets\ throttle cables and are the chokes relesing fully. Ofcourse someone will be allong soon to say I am talking carp and tell you what else it could be.

More like Roach or Chub....
Mi now take any notice

 

[bumpmuncher]

More like Roach or Chub....
Mi now take any notice

Pollarks

 

[Martin.]

Did see a (Polish) fisher man on side of cut this morning. Could have asked him I suppose. I think I will get carbs looked though. They look a bit complicated to me.....
Put the manual down and pick up me rod.

 

[GEOFFREY DEACON]

He might have caught you a descent motorpike......





If you said to him,"Poppin"?, then he would have jumped in da water

 

[r100/7]

my r100gs back fires on over run as well
as there is a gap in the silencer does it harm the bike or will it be ok to leave it?

 

[bumpmuncher]

It will explode like my collector box did















It was realy realy rusty, not beyond repair though the more it pops the more bits of rust will fall off

 

[SJRoome]

Hi

There are two different problems here. As said before your left cylinder is running leaner and therefore hotter than the other. Check the carbs are clean tuned and balanced. Look at the plugs or try a colourtune.

The popping on over-run is caused by an air leak in your exhaust. I found I had to make a pair of stainless steel "sleeves" between my keihan downpipes and the y piece to get a true airtight seal and stop popping on my R100GS.

Steve

 

[Martin.]

Thanks again! I`ve had a look around the exhaust, and can`t see any obvious leaks,but I`ll pull it apart and try with a sealant.
As for carbs, I think I`ll have to book it in somewhere. Used to have a Colourtune years ago.
Now, as a third (related?) problem, on the odd occasion that I fall off,would I be right in thinking that petrol should`nt run out of the carbs?!?

 

[(RIP) Proff]

Thanks again! I`ve had a look around the exhaust, and can`t see any obvious leaks,but I`ll pull it apart and try with a sealant.
As for carbs, I think I`ll have to book it in somewhere. Used to have a Colourtune years ago.
Now, as a third (related?) problem, on the odd occasion that I fall off,would I be right in thinking that petrol should`nt run out of the carbs?!?

NO !!!



If you look in the float bowl you will see an overflow pipe..when the bike is tired and wants a little lie down fuel pisses out of them..

If you can't right the bike in seconds, turn petrol off

 

[Martin.]

Must admit, it does always give me the motivation to get it up-right. That and the desire to escape the chuckles of passers by!!!