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dBDawg
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More technical questions on lifters and valves.

Is it necessary to have to two springs per valve as noted in the parts list.

If so, what is the combined spring constant and how is it divided between the two springs?

Also, is there any preload with the lifter?

Many thanks again to all that help.

Twocams
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I would say yes to both. They

I would say yes to both. They designed the engine to have 2 springs. Which manufactures have been using off and on for 100 years on internal combustion engines. usually one spring is lighter and is placed inside the other. I havent seen your engine, but if there are springs involved then there will be preload on the lifters. At some point anyway. IMHO

twocams

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dBDawg
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TwoCams, Thanks for the

TwoCams,

Thanks for the reply. My engine is more or less the same as an R12 engine except with geared timing. When I took it apart it only had a single spring per valve, and I had missed the call out in the parts book for two springs until just this past weekend. I was just wondering if anyone could explain the mechanical advantage of two springs to one and if this was an absolute must. Otherwise I thought it might be good to know what the spring constants were for possible vibration problems.

Thanks

Twocams
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I guess you could use just

I guess you could use just one spring if you had the right spring tension of 2 springs. But if you should have 2 springs and only have one. Are their calculations correct. Keeping the right spring tension on the valves is very important in their opening and closing and operation.

twocams

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speight1823
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Why 2 valve springs ?

Why two valve springs ?
Only reason I can think of is that if one spring breaks the valve will not drop into the engine and destroy it but will alert you to a problem as you should develop valve float.
Anyone think of another reason ?
I would have a problem with replacing 2 springs with one .
Bill

dBDawg
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Side valve opposed

Bill,

It's a side valve, opposed 2 cycle, so it's impossible for the valve to fall into the engine any father than the closed position. But the redundancy theory is a good one. Might make sense for that time period. Thanks for the input.

Jason

Ian R11
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I can't add anything re the

I can't add anything re the technical side to your question. If it helps to know, I've fitted available new supply twin springs sets to both R62 and R11 engines. If I remember correctly Huggett supplied the R11 ones and it works great, several other suppliers have them and not expensive.

I don't know the individual spring rates but both the new and my originals feel soft compared to other engines I've done. That said these engines don't rev very high.

caker
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My understanding of two valve

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

Diablo
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2 springs on valve

I don't know why 2 springs are used , but this is common on a lot of engines . I rebuilt my car engines , Lotus Elan , Ferrari 250 ....all have the 2 prings . Perhaps the different flexibility of the 2 springs help the function.
While we are on this subject , can anybody tell me if there are marks on the distribution for its timing ; I need to dismantle my R11 engine because of a bad noise from the crankshaft . Anybody has a factory book for this engine ? I only found the user book and the spare parts book . Thank you for helping .
JC

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Ian R11
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Not sure what your asking re

Not sure what your asking re timing. Are you wanting to know about crank timing marks or magneto timing? This would also depend on which engine you have, gear driven or chain driven cam.

I've never seen any workshop type books for these bikes, would be nice if there was.

Darryl.Richman
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Timing diagram

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.

  • r11-timing.jpg
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Diablo
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Crank timing

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

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Darryl.Richman
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These bikes have a similar

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!

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Ian R11
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Something I found helps......

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
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Assembly tips

Ian R11 wrote:

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.

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mark_weiss
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Resonance

caker wrote:

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.

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Diablo
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Help for dismantling R11 engine

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

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Ian R11
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The rear bearing housing with

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
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Rear bearing

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

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Ian R11
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I don’t know if you have a

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.

PreviewAttachmentSize
scan_1.pdf1.58 MB
  • img_0157_1.jpg
  • img_1915.jpg
Diablo
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R11 crankshaft

Ian thank you . It seems my engine is a mix o different series parts .Th engine cases are serie 2 ( as the frame ) , but it seems the crankshaft is from S4 or 5 . It really look like the photo . The rods are 208 mm long , and the breather is on the camshaft , not on the crankshaft as your 1rst photo .
Also , on the crankshaft are stamped some letters : 56.S4&5 on one side , and 365 on the other side of the central part of the crankshaft . So ????
I have download the owner manual and the parts manual , but they are of poor quality .
Cheers
Diablo

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Diablo
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R11 crankshaft

I brought my damage crankshaft to a repair shop , they did not even want to work on it , it had been so badly repaired previously , crankpin welded .... So I had no choice but to find a new one . RRC offered (LOL) me a reconditionned one , I bought it and have just received it . Expensive but seems to be a nice professionnal job . They joined a dimensions report . I ordered new pistons and shall rebore the cylinders .I can now go further on the rebuild of my engine ; when I cleaned it , there was oil mud in the crankcase !!
Concerning the valves timing , some engines need clearance 0 at the valves , others need a certain gap . For the R11 timing setting , is there any clearance to leave on the valves ?
Cheers
JC

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dBDawg
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valve clearance

Diablo wrote:

I brought my damage crankshaft to a repair shop , they did not even want to work on it , it had been so badly repaired previously , crankpin welded .... So I had no choice but to find a new one . RRC offered (LOL) me a reconditionned one , I bought it and have just received it . Expensive but seems to be a nice professionnal job . They joined a dimensions report . I ordered new pistons and shall rebore the cylinders .I can now go further on the rebuild of my engine ; when I cleaned it , there was oil mud in the crankcase !!
Concerning the valves timing , some engines need clearance 0 at the valves , others need a certain gap . For the R11 timing setting , is there any clearance to leave on the valves ?
Cheers
JC

I google translated this from the manual: anyone want to confirm?

Page 42

C) Adjustment of the valve clearance: The valve clearance between the valve stem and the tappet or pressure screw, which should be about 0.1 mm when the engine is cold, must also be adjusted from time to time. For this purpose, a narrow strip of a letter-paper sheet is best used, since this corresponds roughly to the strength.

Ian R11
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Valve clearance set cold from

Valve clearance set cold from my info is 0.05 to 0.1mm for both inlet and exhaust. I have just found some hand written technical info from the 70's my father used. I don't know if it helps with the original question in the post but it indicates valve spring lengths, outer 42mm, inner 38mm.

Diablo
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Timing mistake

Hi folks
I have finish my engine rebuilt , put it back in the frame , prime the oil circuit on a roller bench , open the fuel tap , full the carb ,kick , kick , kick and ...nothing . I thought an ignition timing problem , check it , it looks fine , Kick......no response from the engine . Recheck the ign , OK . I put the bike back on my working bench , take off the left head engage 2nd gear , turn the rear wheel and look at the valves working . I was not happy with what I saw ; the inlet valve stay open for some mm when the piston move up after DDC . The timing is wrong ! ( one tooth wrong ? ) . My question : is it possible to take off the camshaft without opening the engine ? I think I should maintain the valves open with some aluminium shims to free the valves lifters for them not to touch the cams , and extract the camshaft . Is the camshaft hold in place only by the screw on the top side of the casing ? Last question , is it possible to do it with the engine in situ ?
Thank for your answers .

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deyoung2837
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Who did you source your

Who did you source your crankshaft from?
Is RRC the same as www.rrc-tuning.de?

Thank you,

Lee

Ian R11
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I would try remove the cam

I would try remove the cam with it in the bike. Never done it but I think should be possible like you say. The bolt is the only thing holding the cam front bearing. You will need to extract the oil pump drive shaft and gear first. The difficult bit maybe engaging the cam back into the rear bearing, but it's not difficult on the bench so maybe will be easy? Again engaging the oil pump shaft may be tricky but removing the oil pump from below will sort it if necessary. I guess there could be some good use of the French language involved!

Diablo
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Timing issue

Yes , I got the crankshaft from RRC .
I have taken off the gearbox and the cylinders so I can free the valves lifters . I have unscrew all the nuts joining the two halves cases , I can now move the upper case enough to free the camshaft gear ( my timing is gear driven ) . I move the gear for one tooth and check the timing . I had marked the flywheel at TDC , 1mm and 9mm BTDC so I can control without the piston in the cylinder ( which is no more in the engine ) . Bad news , the inlet valve open before the 9mm mark ! I shall recheck with one tooth back . i am afraid my camshaft does not match with the new crankshaft i have fitted , and I have to move the gear on the camshaft ; that will not be easy because the camshaft does not want to come freely , another gremlin from the previous owner ??
Concerning the French language , do you mean the Cambronne word ( m...e ) ? Yes , great use of it .
Cheers

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Ian R11
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If you have a new crank do

If you have a new crank do you also have new timing gears on the crank, cam or idler (intermediate) gear? You seem to have difficulty with tightness of the cam and I am wondering if this is due to any new gears. I fitted new (polyamide) gears on a gear driven engine and found some machining was necessary to get it spinning freely in mesh. The new gear had too large an outer circumference.
Also the intermediate gear is mounted on a bolt that is also a small cam, various amounts of cam are available and used to get a good mesh between the gears.

Diablo
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R 11 rebuilt ebgine

Finally , I did not get the camshaft out . I checked and rechecked the valves timing ; it appears it had one teeth out of the correct timing .
I had scripted marks on the flywheel at TDC and FBTDC . I controlled again these marks were OK with the piston position in the cylinder , it was right . I reassemble the engine , put it back in the frame , with the gearbox ( but without the final drive ) and the engine started second kick . It seems to run fine , I have to test it on the move .
I also discovered that the gearbox gear which move the clutch plates did not engage on the 2 plates , which made the clutch slipping and made the kicking ineffective . I think this is due to the fact I have not the original crankshaft , nor the original flywheel . I solve the problem by lengthening the gears teethes by 8 mm ; I pressed an insert inside the original gear , machined the teethes , and TIG welded every teeth of the insert to the gear teethes . Now , it is OK .

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