was it a duff spark plug ?

[jimborbm65]

WAS "DOCTORFRICTIONS " MISSING IGNITION ON ONE SIDE DUE TO THE SPARK PLUG ?
SEE EARLIER POST FOR HIS QUESTION . I AM HAVING SAME PROBS AT CERTAIN THROTTLE OPENINGS .
neeeeeed to know !

[Airbear]

No need to shout, Jim. We hear you. Why don't you grab a comfy chair and a nice cup of something.

Ok now, what are the symptoms on your bike, and what has happened recently?

[Deleted User 287]

I found the thread he is talking about:
http://boxerworks.com/forum/viewtopic.php?t=828


What throttle openings, specifically, Jim?

[Major Softie]

The fact that the problem is only occurring at certain throttle openings suggests it's not the plug problem, although it's not impossible.

As the others asked: please describe.

[jimborbm65]

sorry about the capitals chaps , must have been on caps lock without noticing .....dont notice much these days at 65yrs !
the bike is a 1980 r65 stock 32k miles . just done new rings , platinum sparkling plugs ,air filter,oil filter,carb hoses ,
carb floats ,carb diaphragms ,bean can points ,,,,timing spot on and strobed etc ok . Did all this cos need to put new stainless push rod tubes in due to oil leaks . Now when I ask for a quick throttle opening at say 4k revs the engine thinks about it for a brief second before it responds ,it maintains speed ok .A brief second can be important to health !
Thanks for advice Jim

[Airbear]

A brief second can be important to health !

And damned irritating, Jim - especially at that all important 4000 rpm.

My R90 had similar symptoms when the points needed filing, but your points are new. What do your sparks look like - strong and bluish or weak and yellowish? Just thinking about coils / leads / caps.

[jimborbm65]

Thanks for asking but the sparks are very healthy and there is to hesitation when blipping the throttle when not
under load on the main stand.
As you see I have been busy in a few places in this bike , new for old dont seem to work for me .....at the moment .
regards Jim

[Airbear]

Jim, it sounds like this has been bugging you for a while and you are working your way through the possibilities.
If all is good with the spark side of things, fuel supply would be the next thing to examine. I'm blundering about here, but have heard that with some bikes, fuel flow can be problematic at high speeds under load. Duane addresses this here -

http://w6rec.com/duane/bmw/petcock/index.htm

I guess you can check this by taking the bike up to the point where the condition occurs, turn off the fuel, stop by the side of the road and remove the bowls to check the levels.

[Jean]

BEFORE you did all the replacements, was the throttle response crisper?
That would be a very important piece of info. for us.
Normally, lagging throttle is due to slop in the carb cables, linkage, or woosie/torn diaphragms.
Did you replace just the diaphragms, or the whole assembly?
I'm not acquainted with the insides of the bean-can, but if it advances by swinging weights, are the weights free to move easily? I mean REALLY CLEAN!

[jimborbm65]

Thanks for all replies , guess who replaced with new floats without carefully checking the fuel height setting !
Yep it was me ,I can accelerate smoothly now .
regards to all from a happy JIM