Crankshaft sprocket

[stubmw]

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.

[Tony Smith]

More heat required - that sprocket is a PITA.

[mrclubike]

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   

[stubmw]

Thanks Tony and Mrclubike for the info. It all just gets a bit scary thinking about messing up!!?

[mrclubike]

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 

[Tony Smith]

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,

[stubmw]

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

[georgesgiralt]

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 !

[tunnelrider]

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.

[Bob_Roller]

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 .

[tunnelrider]

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...

[georgesgiralt]

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.

[wilcom]

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

[Tony Smith]

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.

[tunnelrider]

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.