R65 Resurrection

[TomHoldom]

pretty sure its wrong - trouble is I can't get the glass separated from the the reflector now......probably makes I good seal....
I think I'll have to cut off the protruding part as I can't fit the rim over it....

[TomHoldom]

Has anyone got any advice on fitting my new hydraulic pressure activated front brake switch.

Presumably if I leave the master cylinder cap on only a limited amount of fluid will come out when I unscrew the old switch.
(I'll be sure to bleed the system after installation)

[TomHoldom]

OK here's a summary of my outstanding right cylinder issue

on start up it tends to run mainly(?) on left cylinder
With the right spark out, the engine will run on just the left cylinder - this is not the case on the other side

The right cylinder mixture screw doesn’t effect idle speed - it idles even turned fully in.
Whilst riding it appears to run well on both cylinders especially when accelerating, though cruising it tends to become a lumpy (both at 30 and 60 MPH (and inbetween)) which I assume is my right cylinder not firing all the time?

This is what I have done so far:
- O rings, gaskets and diaphragms changed on carbs (all all cleaned out-jets all clear)
- I have the choke apart - could see nothing wrong, but replace o ring and gasket
- checked for air leaks - could see no problem
- float level - ok at 23mm
- needles are both 3 clicks in
- New spark plug leads
- swapped leads so coils are swapped -  problem stayed on right
- swapped spark plugs themselves - problem stayed on the right.
- checked valve clearances

So things left to check:
pressure test and timing - I don’t how to do this, so may need to take to a garage

I also want to re-torque the right (problematic) cylinder head as there is oil seeping at the engine body - see photos
first photo show a small pool on the top of the cylinder where is meets the body, and the second a drip on a sump bolt which I’m pretty sure has run down from above.

Can inadequately torqued cylinder heads result in loss of pressure and this side mis firing?

The heads were removed at the beginning of this project as a friend helped me release a seized piston (the seizing happened at some point over the 12 years the bike was unused in my shed) and put back without a torque wrench.

As I type this I’m wondering whether the seizing has left this side with some resistance between piston and cylinder - the cylinder was very lightly sanded to remove the slight marking from the seizing……I don't recall which side was seized, but there's a 50% chance its my problem right side......

whats my next move - re-torque of that cylinder, then reset valve clearances?

[Bob_Roller]

Your right cylinder is not running at idle, but when you advance the throttle it starts firing  .
Your idle circuit is not providing fuel .
I mentioned something about this earlier, I would swap the idle/pilot jet between carbs and see if the problem follows the jet that was in the right carb .
While you have the idle /pilot jet removed from the right carb, I would remove the idle mixture needle, and place a finger over the hole where the idle/pilot jet goes take can of carb cleaner with the extender tube installed and spray it where the needle goes and see if the cleaner comes out in the carb throat . 

[wilcom]

spray it where the needle goes and see if the cleaner comes out in the carb throat . 

Make sure it is coming out the air orifice on the outside of the carb, no air in there will be no fuel out. Bob Roller put me wise to this one a while back when I had one carb that quite idling nicely

[mrclubike]

STOP !!!!
Don't do anything else until   you  do a Compression check  on both cylinders
And tell us what you find

[TomHoldom]

ok I'll get going with a compression test.

would this be the correct procedure?
- engine hot
- spark plugs out (and grounded?)
- throttle fully open and hold the slide up while cranking, or just remove the carburetor altogether.
- turn over (5-6 times) to obtain reading

couple of questions - do both spark plugs need to come out at once, or can I do one at a time? I assume they need to both come out as otherwise the engine may run on one cylinder?
If this is case do I need to rig up some earth connector for each plug, or can I simply disconnect the positive leads to the coils?


I'll report back once I've got a gauge.

In the meantime.......

FLUID ON FRONT FORKS
I've noticed some oil has appeared on my right side fork shock absorber after a bumby ride on a country lane - is this question of tightening something, or replacing a seal....?
see photo

INSTALLING FRONT BRAKE PRESSURE SWITCH
Also still got to do this job - do I need to drain master cylinder before starting this?

[Bob_Roller]

Fork seal will require replacement .
The pressure switch is below the master cylinder, depending on how fast you can remove and replace the switch, all of the fluid from the switch and the reservoir on the master cyclinder will drain out .
You could drain the entire front brake system, put a hose on each of the bleeder screws on the calipers, open the bleeders and let the fluid drain into a container .

[georgesgiralt]

Hello Tom,
If you remove the positive wire to the coils, no need to ground the plugs.
IMHO, it is better to disconnect the carbs during the compression test.g
As per the forks, if you change the seals, a complete dismantling, cleaning and reassembling may be useful ;-)
Have you got the BMW paper for the registration ?

[Sejati]

For compression test, you can pull out both spark plugs, and grounded it on engine fins, with lead attached still.

With open throttle, start cranking couple of times until peak steady reading.

If you have less pressure, you may try to pour in a tea spoon engine oil in to the cylinder via spark plug hole. And retest with cranking to see if the pressure will eventually increased.
If it is increase than you may have piston ring failure. If still low, than other problem is suspected.

Suppose the normal would be around 9 Barg. While 8 Barg is still acceptable.

[TomHoldom]

Thanks again for everyone's input

While you have the idle /pilot jet removed from the right carb, I would remove the idle mixture needle, and place a finger over the hole where the idle/pilot jet goes take can of carb cleaner with the extender tube installed and spray it where the needle goes and see if the cleaner comes out in the carb throat .

Whilst waiting for my compression test I cleaned the idle circuits as suggested which did seem to improve idling on that side, but has introduced a new problem.....

Now when idling (but also at higher revs), the engine suddenly drops to nothing - I've never seen anything like this behavior before, its feels quite different - maybe electrical? - both sides suddenly drop to nothing. Sometimes if revs are high enough it cut back in again, sometimes it'll stall - Not really sure where to start with this one - as always any ideas appreciated.

Have you got the BMW paper for the registration ?

Hi Georges, not quite; I'm waiting until these last few tweaks have been made to increase my chances of making it all the way to the garage and back (to get my attestation stating speedo and light have been changed). but I've got both front and back brakes operating the light now, and my headlight seal seemed to go alright in the end

[georgesgiralt]

Tom, when you suspect it is carburetor, in fact it is the ignition and when you suspect it is the ignition, in fact it s the carburetor...

[TomHoldom]

My previous post's electrical problem is resolved - There was a loose connection in the bean can (first time in there so that was quite exciting....)

Today's issue is my left hand throttle cable has an issue.
I noticed that the revs seemed a little slower in releasing, so was looking around the cables, and noticed that the inner grey sheath of the left side throttle cable has slipped through at the connection to the carb - see photo.
Is this something I may be able to fix, or is a cable replacement the only option?

[Bob_Roller]

I don't think there is much you can do with that cable to repair it .

[TomHoldom]

Hi all
heres an update of the bikes situation.

generally running pretty well
My friend arrives this weekend and brings with him his compression testing kit, so hopefully some interesting news to follow shortly on that front.....

In the meantime, I still have an issue on the right side with that spark plug sooting up more than it should and also the idle adjustment screw not cutting out that side when turned all the way in, but instead  running faster when turned all the way in....?

Any pointers on what to look at regarding that carb?
pretty sure all the passages are clear.

Could this behavior be related to a possible loss of pressure on this side?
Thanks as always