Poor running R69S

[Dominic]

Kurt,I meant that the floats were upside down not slides ....sorry about that,.....no wonder it seemed impossible, as it would be.

I will recheck the timing myself (It is an S that should be in the window) & recheck carb synching, the advance unit seemed to working & returning OK.

Thanks

[Discogodfather]

I would check your valve clearances. If the rockers are too loose you would be experiencing tons of noise, if they are too tight it might not be noisy but there would be a lack of power. Lots of problems diagnosed with carbs are really just extremely out of spec valve issues.

Also check your rocker up/down clearance. Sometimes the valve clearance is in spec but the rockers are floating up and down and not allowing the valve clearance to be in spec while running, especially at high rpm's. Grab the rocker and see if it moves up and down. Little to no movement is good, ticking noises or grossly sloppy movement is bad.

Someone earlier described removing spark plugs from a hot engine?? This is a huge no-no on /2 bmw's. Read Duane's website on this issue- the spark plugs holes are dainty at best and removing plugs from a hot engine is the worst abuse possible. If you fall into the 62-68 pre LK heads (butterheads) you can literally pull out the entire spark plug threads with the plug and have a nice smooth bore hole left. I can understand this is a valid way of checking for fuel in the cylinder but it's just not possible on a bmw engine of this vintage.

[schrader7032]

RE: up and down movement of rocker arms.

On the /2s, there's very little adjustment capability for these bikes if that's what you're suggesting, certainly not like the /5-on bikes. The rocker arms are indexed to the posts. If they do move a lot, then you have a whole bigger issue to deal with.

[Dominic]

On the weekend I am going to go through valve clearance & timing again, thanks guys.

As for carb floats they should be installed wire side up flat side down? Im not convinced this mechanic I took it too has got it right telling me they are installed upside down.......

[schrader7032]

IIRC, there's a thin metal shoulder that extends out past the circumference of the float. That should be on the bottom. It helps keep the float centered in the bore of the float bowl. You can sort of see that here, but you can also see the rounded top of the carb.

http://www.bingcarburetor.com/pdf/2x2.pdf

[Dominic]

Got the bike sorted out with the help of a guy who has alot of /2 experance & showed me alot of little things I had not quite right, the combination of all a liitle out combined to make it hard to start & run & very tempremental.
We replaced coil, new plug caps, Points & condenser, set timing advance by points backing plate method ( I had advanced timing by Clymer manual method & was not getting enough advance), tweaked carbs.


Running well know & took it on a classic run on Sunday which went well. Thanks all for your advice, I have learned a hell of alot over the past couple of months.

(There was NO WAY I had put the carby floats in upside down........ lesson learned on that one, professional advice is not always right.......)