The New And Improved Unofficial R65 Forum V2

Technical Discussion => BMW Technical Q&A, Primarily R65 => Topic started by: stubmw on December 16, 2016, 08:50:40 AM

Title: Crankshaft sprocket
Post by: stubmw on December 16, 2016, 08:50:40 AM
So the winter is here, i think I'll  tackle the timing chain job. All goes well, practice relinking the chain, got the hang of that. The new kit turns up from Motobins including crankshaft sprocket, doesn't  look significantly  different to the old one ...well i have a new one so lets change it....not happening. Heated tthe old one (snowbums advice is "briefly heat") put a lot of pressure on there and tried more heat but nothing. Thinking about leaving it and just replacing the rest. New tensioner spring is 10mm longer and the guides are
showing wear so that can be done and old bearing popped off easily. Any advice on the sprocket would be welcome, thanks guys.
Title: Re: Crankshaft sprocket
Post by: Tony Smith on December 16, 2016, 07:11:28 PM
More heat required - that sprocket is a PITA.
Title: Re: Crankshaft sprocket
Post by: mrclubike on December 16, 2016, 10:46:54 PM
2nd what Tony said
Just don't screw up the end of the crankshaft
Your puller looks good 

After you get the old sprocket off you may want to  practice trying to put it back on.
putting them on is no easy task either
You have to heat it up and if you don't get it on all the way you may have to pull it back off and start over   
Title: Re: Crankshaft sprocket
Post by: stubmw on December 17, 2016, 04:13:29 PM
Thanks Tony and Mrclubike for the info. It all just gets a bit scary thinking about messing up!!?
Title: Re: Crankshaft sprocket
Post by: mrclubike on December 17, 2016, 07:00:44 PM
You definitely want to screw a bolt into the end of the crank to push against with the puller,
I cant tell in your picture if you have done that or not 
Title: Re: Crankshaft sprocket
Post by: Tony Smith on December 17, 2016, 08:37:54 PM
If don't ruin the existing seal - you haven;t used enough heat (old jungle saying).

I have found that heating the new sprocket to a "straw" colour - just a bit short of read heat is what is required to get the little buggers back on.

Before trying to beat te new sprocket on it is worth while to use a fine stone to dress any marks, lips or ridges  on the crank caused by pulling the old sprocket off.

If i can throw in one more quick comment. If, like me, you buy your bearings from a bearing shop and not BMW or a BMW parts seller (the savings can be spectacular), order the new outrigger bearing asap. Note that it is not a "traditional" clearance bearing and in fact as befits its somewhat less than accurate means of fixing it is designed with a lot of internal clearance.

Your local bearing shop is likely to only have the "precision" version in stock - don't.


But by the same rule, no matter how good it looks and no matte how easily it came off, do not e tempted to reuse this bearing,
Title: Re: Crankshaft sprocket
Post by: stubmw on December 18, 2016, 03:27:41 AM
Ok guys thanks again.
 I'm getting the idea now......., this is one of those more demanding jobs!!

"You definitely want to screw a bolt into the end of the crank to push against with the puller,
I cant tell in your picture if you have done that or not"

Yep done that, it's an Allen bolt (thought it would give the puller a better centering) with a couple of copper washers .

And, yes Tony, interesting  information  on the bearing, the new one came from Motobins so hopefully 'tis correct.
 Stu


Title: Re: Crankshaft sprocket
Post by: georgesgiralt on December 18, 2016, 05:21:04 AM
Hello !
I've got an old wax heating device women use to wax their legs.
I discovered that put at full setting it heats the oil I put in it around 150~180°c.
I use it a lot to heat roller bearings or anything else i have to heat prior to installation.
As it is electrical, no flame (safer) and no worries as to what temperature will be attained ! Only  drawback is that I can't put an engine case in the cup ;-)
I got it for free ! So I'm happy !
Title: Re: Crankshaft sprocket
Post by: tunnelrider on April 17, 2017, 01:02:25 AM
Hi everyone, it's been a while since I've posted here, a good sign that the old girl has been running well.  In between times we have a new look forum and I hope that we hear from Monte soon.  I also hope everyone is well. 

I've restarted this post because I'm heading down the path of replacing my crankshaft sprocket after my timing chain broke with 184 500km on the clock.  So far damage appears minimal, the camshaft still turns however I'm yet to take the top end apart and inspect it.  There was little noise and/or drama upon chain breakage. The Clymer manual says to take the engine out for sprocket renewal, is this necessary?  I've searched and read other posts, incl. 'Re: Timing chain replacement-help needed' but can't find that answer.It seems that it isn't necessary.

Also I'm curious if it's the original chain that broke, it has 'Renolds 06B Synergy' imprinted on the chain, can anyone remember if that would point to an original or a replacement?

Thanks in advance for any info.
Title: Re: Crankshaft sprocket
Post by: Bob_Roller on April 18, 2017, 07:32:06 PM
I did a timing chain replacement in 1998, no identification on the chain, it was an OEM BMW chain .

This chain failed on me in April 2014, the master link failed, one of the pins failed in the groove for the side link .

The engine was at idle when it failed, I removed the heads removed the valves and found no damage
.

Three years later no issues .
Title: Re: Crankshaft sprocket
Post by: tunnelrider on April 19, 2017, 01:59:42 AM
Thanks for your info Bob, I'm hoping to find no valve damage too when I get some time to take them out!!  I was taking off from a stop light when it broke, maybe 20mph. Interesting regards your plain OEM chain, I guess mine has been replaced before.  I'm unsure what failed on my chain, I'm yet to see the master link so I'm presuming it'll be in the sump when I drop it.  The chain had a number of links broken upon removal.  Still would like someone to confirm if the crankshaft sprocket can be removed and installed with the engine still in the frame, anyone... ;)
Title: Re: Crankshaft sprocket
Post by: georgesgiralt on April 19, 2017, 02:12:46 AM
I've done two timing chain change with the engine in the frame BUT I did not change any sprocket because they were very fine.
Title: Re: Crankshaft sprocket
Post by: wilcom on April 19, 2017, 02:13:54 AM
Quote
Still would like someone to confirm if the crankshaft sprocket can be removed and installed with the engine still in the frame, anyone..

I poked around Snowbum's site and came up with a page for you. He talks about changing that sproket but does not indicate that it is a "engine out" procedure.  Check it out, some good stuff there, but a tough read for sure.
http://bmwmotorcycletech.info/timingchain.htm
Title: Re: Crankshaft sprocket
Post by: Tony Smith on April 19, 2017, 07:01:03 AM
Quote
Quote
Still would like someone to confirm if the crankshaft sprocket can be removed and installed with the engine still in the frame, anyone..




The job is done with the engine in the frame. If you have a work bench or a bike lift they do help to raise everything to a comfortable work height, but not essential.
Title: Re: Crankshaft sprocket
Post by: tunnelrider on April 20, 2017, 02:00:55 PM
Thanks for your replies guys, helps to know whether engine in/out for planning the job!  Tony I thought it must be left in by your description of a planned 4hr sprocket/cyl head swap on your wife's R65/80.  Boy you deserved a good pinot after that weekend.  And Wilcom I'll have a look at Snowbum's page, I like his stuff.  I'll inspect the heads this weekend then order parts. Cheers.
Title: Re: Crankshaft sprocket
Post by: Tony Smith on April 21, 2017, 02:32:12 AM
Quote
  Boy you deserved a good pinot after that weekend. 

Tomorrow I am planning:-

Oil and filter changes to the wife's G650GS
Set tappets and change coolant KLE500
Full service R65 - change all oils and filters and set tappets and timing.
Full service as above for R65/80

If I get time I hope to put high ratio final drive on R65 and put r65 final drive on R65/80 as its final drive is leaking and is generally cactus, needing a full rehab.
Title: Re: Crankshaft sprocket
Post by: tunnelrider on April 21, 2017, 03:24:52 PM
Quote
Tomorrow I am planning:-

Oil and filter changes to the wife's G650GS
Set tappets and change coolant KLE500
Full service R65 - change all oils and filters and set tappets and timing.
Full service as above for R65/80

That's a busy day Tony but I see a few chances in there to keep yourself hydrated and enthused!
Title: Re: Crankshaft sprocket
Post by: Tony Smith on April 21, 2017, 04:40:28 PM

Just a thought.

Borescopes are so cheap now that I'd have a look through the plug hole and if the valves/pistons had no witness marks I'd leave them alone, do the cam chain and then do compression/leak down tests and if that all looked OK, then I wouldn't pull the heads.

OTOH, if there are witness marks indicating piston/valve contact, then you get to do a full top end service with new valves.
Title: Re: Crankshaft sprocket
Post by: wilcom on April 23, 2017, 10:08:53 PM
Quote
Tomorrow I am planning:-

Oil and filter changes to the wife's G650GS
Set tappets and change coolant KLE500
Full service R65 - change all oils and filters and set tappets and timing.
Full service as above for R65/80

If I get time I hope to put high ratio final drive on R65 and put r65 final drive on R65/80 as its final drive is leaking and is generally cactus, needing a full rehab.

awaiting full report.....................
Title: Re: Crankshaft sprocket
Post by: Tony Smith on April 23, 2017, 10:31:08 PM
Got as far as the full service on the R65.

Nothing ever goes smoothly and i had to put a seal kit into the rear brake caliper on the KLE, that and the bloody thing needing 20 minutes worth if disassembly before you can pull the rocker cover.

Kawasaki hang your head in shame for the absurd idea of making it impossible to pull the rocker cover without disconnecting 2 water hoses - and hang your head even lower for the method of retention on those hoses.
Title: Re: Crankshaft sprocket
Post by: wilcom on April 24, 2017, 08:14:04 AM
Quote
Nothing ever goes smoothly
Good job Tony

Taking the cooling system apart to get the rocker box off would have been enough for me to light the BBQ
Title: Re: Crankshaft sprocket
Post by: tunnelrider on April 25, 2017, 06:02:44 AM
Quote
Nothing ever goes smoothly

He he usually doesn't here either.  Upon taking the heads off, with no evidence marks of the pistons hitting the valves upon timing chain breakage I thought I may not bother taking the valves out.  Then thought it'd be good to check anyway since they were reconditioned 8mths ago and 8000km on 'em.  Found a loose exhaust valve guide able to moved up and down by hand! Luckily guide bore still good and no lateral movement, valve and valve seat look ok.  Now off to the engine shop for a warranty fix as well!
Title: Re: Crankshaft sprocket
Post by: tunnelrider on May 07, 2017, 04:45:08 AM
OK, well... I probably should have got a new woodruff key considering the abuse (by a PO) it got on starting the old sprocket.  I filed the woodruff key, checked it was straight, crankshaft smooth, new sprocket was smooth, and considering the old sprocket came off easily, in the end I've largely drifted the new sprocket on.  How many have had the luxury of sliding the new sprocket on, on heating?  I used Snowbum's tip on heating the new sprocket in oil. Guess the surfaces have to be perfect to be able to slide on.  Pretty hard to judge down on the center stand...  But at least it's done.  Just painting the timing and starter cover, top end clean and rebuild, airbox clean and new reed valve to go...  ;)
Title: Re: Crankshaft sprocket
Post by: mrclubike on May 07, 2017, 09:11:38 AM
mine slid right on with heating
But it was hotter than it would have been from just heating in oil
Like Tony said you have to get them hot to the point they turn a slight straw color
and you cant heat it very far away from the bike or it will cool of before you get it on 
It took me 3 tries before I got it on
Title: Re: Crankshaft sprocket
Post by: georgesgiralt on May 07, 2017, 11:57:36 AM
Humm...
I would not go too much above150°C when heating. I would fear that the thermal treatment get damaged if you heat too much.
Never changed the sprockets, though even if I changed the timing chain.
Title: Re: Crankshaft sprocket
Post by: Bob_Roller on May 07, 2017, 09:20:15 PM
Heat treatment of steel is usually in the 1800 F, 980 C range .

Unless your are using an ocy atcetaline torch, I don't think you're going to interfer with heat treatment .

The oil temperature in my R65's, exceed 150 C during the summer months here .
Title: Re: Crankshaft sprocket
Post by: georgesgiralt on May 08, 2017, 02:53:29 AM
IIRC from my school boy era, 150 °C was the starting temperature for a smoothing heat treatment to reduce stress in heat treated parts.
I recall it is the temperature not to go above for ball roller bearings.
But I can be wrong and I can't find my '70 vintage school books ...  :-[
Title: Re: Crankshaft sprocket
Post by: skippyc on May 08, 2017, 06:40:59 PM
When you are going old school 750 to 800 deg c is hardening temperature which is cherry red and approx 400 deg is straw color which is spring tempering temperature.
The composition of the steel makes a big difference to how it reacts to heat and how hard it remains when it is in its normal state.
Title: Re: Crankshaft sprocket
Post by: D Mann on May 27, 2017, 06:01:53 AM
Engine in the bike, no need to remove. When you reinstall, heat the bearing and cool the shaft. With no bearing heater, I warmed mine on the grill in a pan of motor oil until the oil started to smoke. When the bearing was almost hot I cooled the shaft with a can of freon. Everything slid together with just little tap on the inner race.