Cam Sprocket Bolt Removal

[signit98]

Originally Posted by Phil Y

What do you think of heating the general area and putting an ice cube on the bolt head immediately before trying to extract it?

See if you can find liquid nitrogen somewhere... or sport icing spray... if all else fails, get a can of compressed air (the stuff they sell at staples, for computers) and hold it upside down when you spray...target the bolt head.

The bolts will scare you when they come lose... it sounds like you ripped them.

Good luck.

[Guest24]

No one has had to use heat to release the camsprocket bolt to date. Your explaination as to how the hexbolt got "goobered" up doesn't necessiarily mean you need to use heat now. If the stripped bolt external surface extractor can allow sufficient torque with a pull bar, you should make short work of the job. Don't forget to set up this project just as Lennie outline in his instructions.

[signit98]

Originally Posted by Nail24

No one has had to use heat to release the camsprocket bolt to date.

And you know that how? Do you have a registry for that?

[sgoodwin]

Phil I've used heat many times & never cooled the bolt, just keep the heat to the perimeter until hot & torque loose with your nifty new tool.

[Guest24]

Originally Posted by signit98

And you know that how? Do you have a registry for that?

It has not been reported on any of the websites, Ralf. And, I don't think Lennie would have kept this a big secret if it was an issue. His instructions include much of the learning curve that has been associated with installing the rocket sprockets. The registry is the use of thread search. As you are certainly aware, the use of cold and hot are contained in many maintenance procedures. I was not dissing your suggestion.

Glad you had a nice visit to Paonia.

P.S. Check Lennie's responses in this thread.

[kpolito99]

I really do not think it is necessary to cool the head of the bolt.

I hope someone was kidding with the LN2 comment. Liquid nitrogen is not a good idea. Not trying to be a know it all or bash anyone but cooling metal to -320F/-195C (77K for tech types) is a great way to make the situation worse. Most materials become extremely brittle and a thermal quench with LN2 may cause the head of the fastener to shear completely off the shank when loaded.

Simply heat the area surrounding the head of the fastener. The large washer will promptly conduct the heat from the cam gear into the camshaft. We are not talking a lot of heat with an acetylene torch or anything. No parts should begin to glow or get white hot.

Just a slight rise above ambient temperature should allow you to break loose the threads.

[Phil Y]

OK, has anyone tried to "pin" the flywheel to lock the engine? I fab'd a pin from this site but could not locate the hole w/the flywheel at TDC--even tried a small hex wrench just to feel for the hole. Nichts! No bad jokes, pls!!

[tjs]

If the one you made is the right dimensions it should work. Make sure the TDC mark is centered in the inspection hole. Pull the sparkplugs,put the trans in 6th gear. With the tool in place, Use the rear wheel to jog the engine back and forth ever so slightly. You will feel the tool move forward when it goes into the hole in the clutch carrier. I put a point like the factory tool has on the one I made. I know it works because I also have the factory tool shown. 2cnts from tjs

[Phil Y]

tjs, is the pin about 3/8" (little less than 1cm) in diameter?

[Guest24]

The item you are dipicting is a locating mandrel not a locking pin. BMW does make a flywheel lock; but, it is normally used after the transmission has been separated from the bike (bike splin in two).



This is the tool that locks the flywheel. You can break the camsprocket bolt and then just snug it up. then use the tool you made to determine TDC. Then proceed with the sprocket change folliowing Lennies instructions.

[tjs]

that tool was not the tool Phil was depicting. but if one were to use it ..... all you have to do is remove the starter to engage tool #11 5 640 onto the clutch carrier ring gear. tjs

[signit98]

You don't really need any special tools... I have done 5 set of sprockets now and have never needed anything but 5th gear and the brakes applied...

However, I usually try to keep the amount of work involved, to a minimum... so, if your objective is to create yourself even more work that you already have... go for it.

[signit98]

You don't really need any special tools... I have done 5 sets of sprockets now and have never needed anything but 5th gear and the brakes applied...

However, I usually try to keep the amount of work involved, to a minimum... so, if your objective is to create yourself even more work that you already have... go for it.

[tjs]

Phil.
A 3/8 drill measures .3740" The BMW tool measures .3405" where it passes through the hole in the clutch carrier. tjs

[Phil Y]

OK, thanks tjs.

@Nail: my Haynes manual has a "Haynes Hint" which indicates that the flywheel can be locked with the tool depicted in the site I posted in #87.

[wiggledbits]

My $0.02.
The bolts do break lose with a loud CRACK! They must use considerably more torque in the factory as mine had zero lock-tight.

I stood on my rear break and the motor still spun. That is how I got in trouble replacing with Lennies. Yes I had good pads, rotor and a recent flush. A stop pin is excellent insurance at this point. If I was to do it again I would use a pin.

Heating it up will help and since you're not at an optimal point right now any help to reduce the torque to get them loose is good.

Take a deep breath, you'll get the job done.

The sprockets are worth the change.

[Noblehops]

I gotta say, I've spent more time reading this thread then I think it's going to take you to undo that bolt. The suspense is killing me!

Courage man! Get in there and have at it!

:-)

N.

[Guest24]

I think I'll go out tomorrow and crack the torque on the camsprocket bolt just to record the sound.

[signit98]

Originally Posted by Nail24

I think I'll go out tomorrow and crack the torque on the camsprocket bolt just to record the sound.

You do that... and then we'll spend the rest of the year talking about how much the repair cost was...

[Phil Y]

Sorry guys, it'll have to wait for a little while longer. I get a good bite with the busted nut socket but the engine still turns in sixth, even after having bled the rear brake. My clutch must be slipping because the rear wheel does not turn. :-((

tjs, one more time, pls. Still have not been able to locate hole on flywheel. Is the proper hole close to the edge of the clutch housing near the starter or is it about 1 3/4" inwards and 2 1/2" higher from this hole, in front of the airbox? If the latter, I'll have to remove the airbox (gas tank, etc.) in order to gain access.

Been trying this one w/o success (starter solenoid is in foreground), Second hole is also visible in this pic. It looks accessbile but is not.


Sorry for the poor quality of this one of the hole in front of the airbox. For ref, the throttle body inlet is in the foreground and the airbox is on the right:


REALLY appreciate the advice and encouragement. Been ready to quit several times but thanks to this board, I'm giving it at least one more try!