The New And Improved Unofficial R65 Forum V2

Technical Discussion => BMW Technical Q&A, Primarily R65 => Topic started by: kenbev on March 09, 2013, 11:08:58 PM

Title: Weak engine cylinder.
Post by: kenbev on March 09, 2013, 11:08:58 PM
Right hand cylinder very strong, left weak as as water. Compression both the same and carbies rebuilt. timing etc all spot on. any idea's most welcome. ken. ::)
Title: Re: Weak engine cylinder.
Post by: Barry on March 10, 2013, 04:52:26 AM
Just to rule out the ignition coil, lead and plug on the left cylinder do you get the same symptoms if the spark plugs and leads are swapped over.

If there is no change then it has to be mixture.
Title: Re: Weak engine cylinder.
Post by: montmil on March 10, 2013, 08:45:58 AM
Ken, Is this an idle issue or  noticeable during road operations? Did you remove the Bings or manually open the butterfly and lift the carb slides during the compression test? Check float bowls for water, confirm float level correct, both needles extend same distance out bottom of slide, no air leaks at connector hose to head... Something simple that needs attention.

Might you describe your concerns and the bike's in a bit more detail? Perhaps aid all of us in our on-line diagnosis. [smiley=thumbup.gif]
Title: Re: Weak engine cylinder.
Post by: Bob_Roller on March 10, 2013, 10:06:54 AM
Did you have this problem before the carbs were refurbished ?

Did you perform a carb synchronization afterwards ?

If you did, were the valve clearances checked/adjusted before the synch ?

What year bike do you have ?

Title: Re: Weak engine cylinder.
Post by: montmil on March 10, 2013, 10:41:35 AM
Couple older posts by Ken indicate it is a 1986 model R65.

Want more and better responses to questions? A good way is to always state model and year in your posts and/or add the bike to a sig line or avatar... please. ::)
Title: Re: Weak engine cylinder.
Post by: kenbev on March 10, 2013, 09:13:59 PM
Sorry folks should of mentioned that the problem is with my R1000.( R65 purrs like a kitten) 8-). Will try all your suggestions and see how we go. Problem was there before carbie rebuild hence the rebuild. I lean towards electric problem. Will let you know how it turns out. Thanks all. Ken.
Title: Re: Weak engine cylinder.
Post by: Bob_Roller on March 10, 2013, 09:16:25 PM
What year R100 ??
Title: Re: Weak engine cylinder.
Post by: kenbev on March 11, 2013, 03:30:24 AM
1990 R80 with cylinder and piston upgrade to 1000cc :-[
Title: Re: Weak engine cylinder.
Post by: montmil on March 11, 2013, 09:49:08 AM
Quote
What year R100 ??

:D Where's me cricket bat?

Title: Re: Weak engine cylinder.
Post by: Bob_Roller on March 11, 2013, 11:57:27 AM
If swapping the ignition leads and plugs doesn't cure the problem,  would go back to the carbs .

I had an exasperating time getting my '81 R65 to run, the left cylinder wouldn't run no matter what I did .

I finally found the problem after spending way too much time troubleshooting the problem .

The idle jet was clogged, what I didn't realize, when I was cleaning the carb parts, is the idle jet has two holes drill in it, when I sprayed carb cleaner in it, the cleaner came out the holes in the sides of the jet body, not out the hole at the end , that meters the fuel .

Hope it's a quick fix for you !!!!!
Title: Re: Weak engine cylinder.
Post by: kenbev on March 11, 2013, 08:56:25 PM
G'Day again, Tried swapping plug leads. No difference. Spark same at both plugs and compression same both pots. Will pull carbie to bits again and see how that goes. Thanks every one for your input and will let you know out come. regards Ken. :D :D
Title: Re: Weak engine cylinder.
Post by: georgesgiralt on March 12, 2013, 04:57:24 AM
Hello !
There is a breathing hole on the side of the carbs (near the BING badge) which is often clogged by dirt. This is used to keep the bowl at atmospheric pressure. Check if it is not clogged. That could explain some miss functioning...
Title: Re: Weak engine cylinder.
Post by: Luca on March 12, 2013, 07:55:32 AM
When I can't get an engine to run right I always read the plugs.  It won't fix the problem, but might give you an indication as to where to go... and it only takes a minute.

Also a couple little oopsie-daisies that have coaxed some unsavory words out of my mouth are:

1) Not unscrewing the pilot screw after putting a carb back together

2) Not capping or losing the cap for the vacuum port on the carburetor.  I have removed the emission system and put the little BMW screws in the vacuum ports.  I used to use just the rubber caps, but they fall apart and if you have an intake side backfire they will go flying.
Title: Re: Weak engine cylinder.
Post by: kenbev on March 12, 2013, 10:16:56 PM
Well folks all fixed. Now when I tell you what the problem was please do not laugh just  take pity on a poor old 72 year old as I should have picked it up right away. I now have the cleanest left carbie in Australia. I know you are now dying to know what it was, so here goes. My bike 1990 model has the original mufflers still fitted and the baffle in the left pipe had rusted out and blocked about 80% of the pipe. There for most of the pressure was coming out of the right pipe which of course sounded much louder and stronger than the left. To  all, have laugh if you want to but thanks for your advise ' Never to old to learn. Regards Ken. ;D ;D ;D
Title: Re: Weak engine cylinder.
Post by: steve hawkins on March 13, 2013, 08:40:08 AM
Glad you found it.

Nobody is laughing too loud (not that you can hear : ) as we have all been there at some point.

Rev. Light
Title: Re: Weak engine cylinder.
Post by: georgesgiralt on March 13, 2013, 09:12:49 AM
Well, Ken, I would not had though of this. So, I, for one am not laughing at all.