Valve Spring Constants R11

[Darryl.Richman]

The owners manual has this timing diagram in it. If you study it hard enough, you'll be able to find clues to all the timing settings.

[Diablo]

I have not yet open the engine , only heads and cyliders are off . I did not want to go further before getting some infos about this important point that is the crank timing . I am more familiar with the BMW /2 series , I own a R 69S .
I think my engine has a gear driven distribution because the magneto is gear driven .Now , I can progress with the dismantling of the engine .I bought this very beautifull bike from a seller shop in Beigium ; the bike was supposed to be fully restaured . But , from what I can see inside the open engine ( it is old burned oil black ) , they have forgotten the mechanic side of the full restauration ! As we say in France , I have been f...k !
Thank you for your replies .
JCL

[Darryl.Richman]

These bikes have a similar oiling system to the /2s, but no sheet metal "slinger" to capture dirt and wear particles. This means that you can't judge how full of dirt the hollow crank pins are. If the crank is in good condition and doesn't need to come apart, I would use a strong solvent (carb cleaner or MEK here in the US), fill up each pin and let it soak for a long time, then try to spray it out into the connecting rod bearing area with compressed air from the web side of the pin. Eye protection is very important!

[Ian R11]

Something I found helps...... having a mark on the flywheel visible in the bottom of the two “windows” on the right side of the engine. Set this mark with the piston at 12mm before top dead center and a corresponding mark on the case. It will be visible and helps with ignition timing when the engine is fitted back. With another mark on the case you can set TDC in the top window. My late model series 5 has two small drillings at 180 degrees to each other on the flywheel. When it shows in the bottom window it is 12mm BTDC and when it shows in the top window its at TDC, don’t know if this is original or been done as an after thought, either way that could be considered too.

[Darryl.Richman]

Something I found helps...... having a mark on the flywheel visible in the bottom of the two “windows” on the right side of the engine. Set this mark with the piston at 12mm before top dead center and a corresponding mark on the case. It will be visible and helps with ignition timing when the engine is fitted back. With another mark on the case you can set TDC in the top window. My late model series 5 has two small drillings at 180 degrees to each other on the flywheel. When it shows in the bottom window it is 12mm BTDC and when it shows in the top window its at TDC, don’t know if this is original or been done as an after thought, either way that could be considered too.

I have done a very similar thing on my R52. It is extremely helpful for setting the valves and verifying the ignition timing. In my case, while the motor was apart on my bench, I used a flat bladed screwdriver to put a mark on the edge of the lower window, then positioned the crank at OT and VZ (full advance) and made a corresponding mark on the front of the flywheel to match the case mark, and stamped them as OT and VZ. Then I dabbed a bit of white paint into the marks and stamps to make it easier to read.

I would do this again with any split case motor. It helps so much in verifying your assembly and installation of the magneto and setting the valve timing.

While we're talking about assembling these motors, one thing I do after bolting together the two halves is add oil to the sump and, using the conrods, spin the crank (clockwise looking from the front of the motor). After a few dozen rotations, I want to see oil leaking from the conrod big ends. This verifies that the oil passages are clear and the oil pump is working.

[mark_weiss]

My understanding of two valve springs has to do with spring rates. Having two different springs with different spring rate properties means a reduced chance of valve float through the RPM range.

-Chris

Essentially, this is the answer. Not so much different spring rates as different resonances. Dual (and even triple) springs are not uncommon in high performance applications. Each spring has a different wire diameter and different number of coils. This helps to damp resonant vibration, thereby reducing the likelihood of spring breakage.

[Diablo]

I am progressing on the engine disassembly and I need some information ; I have no workshop manual so I have to face some problems .
I have difficulties to extract the bearings from their housings , and also to take the timing gear from the crankshaft . I have heated these parts but none want to get out . There is perhaps a special mounting point I ignore .
Thanks
JC

[Ian R11]

The rear bearing housing with bearing should come off the crank with some heat and a little help from a puller. There is nothing else holding it on both early and later engines.

The brass housings are close to the crank and I used a couple of wedges to start them off until I can get the puller legs under the edges.

Not sure which engine you have.... If you have the gear driven cam engine it has a pin holding the gear through the crank. I think it is tapered, it is a few years since doing this and my memory isn’t what it was! I had to take my early type crank to the crank rebuild guy to remove the gear. Mine was very tight and wouldn’t pull off with the puller I had, so I’m not too helpful with that. The gear also has a key internally so will not twist off with the pin removed. The bearing and housing should remove the same way as the rear.

If you have the chain driven cam engine the timing gears are on a key and should come off with a puller after removing the nut. The front bearing housing should remove with some heat and puller. Nothing fixes the bearings into their housings, they should remove with some heat and pressing out.

[Diablo]

Ian , thank you for answering . My engine is gear drivencam , think it is a S2 ( Nber 66558 ) . The gear has a key , I can see it , and it is hold on the crankshaft with a nut .I shall look if I see trace of a pin holding ; I don't see why ther should be one plus the nut . Problem is the front bearing cannot be extracted before I pulled of the gear .
Regards
JC

[Ian R11]

I don’t know if you have a parts book so attached the relevant pages, it shows the variations of crank and parts used on the R11, maybe this will help. If yours has a nut holding the gear in place it is different to the ones I have experience with. The second crank down, (an R16) does have a gear held by nut but also a hole for the pin. The pin appears to be listed for all series.

The pin on the early version is clear in the photo. The second crank is a series 5 version. If you need the part listing pages to go with the image let me know.