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Cam Sprocket Removal - help!

Posted: Sun Jul 13, 2008 5:40 am
by young Cruiser
Hi Guys

Is there a way to remove the cam sprocket form the engine head after the engine head has been removed?

I wanted to inspect the valve seals on my TW200 and went through the whole disassembly routine but in error I skipped the part about holding the crankshaft to loosen the cam sprocket bolt etc. I was able to slip the can chain off because it was very loose.

Now the engine head and the cam chain are off and I realise I need to change both intake & exhaust valves, tappet adjuster screws, valve retainers etc. because they are severely damaged.

Is this at all possible or do I have to put the engine head back on and the can chain as well?

Posted: Sun Jul 13, 2008 6:23 pm
by BuzZz
You need to get creative and figure a way to hold the cam sprocket from turning without wrecking anything. Are you changing the cam chain? If you are, you can use the old chain to make a chain wrench with some scrap materials if you try hard enough. You may be able to use a strap wrench around the sprocket to hold it while you back the nut off.

Truth is, it's easier for me to just grab it and do it than it is for me to imagine scenarios for you to try. I can bust my nut, but your gonna have to work out the best way to bust your own nut. :wink: :laughing:

Posted: Sun Jul 13, 2008 11:57 pm
by young Cruiser
Hi BuzZz,

Thanks, I'll try it but the nut is so darn stuck. :frusty:
Yesterday I'm sure I sprained something in my shoulder trying to get it off.

I have to order some parts so I'll have a few days to spare and tinker with it. If no other way works I'll put the head back on I guess.

I can really feel my age (35) and busting this nut isn't as easy as I thought.

Thanks again.

Posted: Mon Jul 14, 2008 4:33 pm
by BuzZz
O.K. now, I have no direct knowledge of that model bike, so make dam sure that isn't a reverse thread nut on there. Depending on the direction of rotation of the cam, it is possible they did that to prevent loosening over time, since if the nut spins counter clockwise the vibes and centrifugal forces tend to tighten the nut, rather than loosen it.

Got a service manual for that thing yet? Sounds like it from your first post. It should tell you in there if it is a reverse thread or not.

Posted: Mon Jul 14, 2008 4:49 pm
by young Cruiser
I'm Glad you mentioned that Buzzz
It crossed my mind as well so I'll definitely check the manual. I really don't want to damage anything.
Thanks

Posted: Mon Jul 14, 2008 5:13 pm
by young Cruiser
Buzzz

The shop manual is no help; it just says to tighten the bolt (Cam sprocket) while holding the crankshaft. Nothing that says tighten clockwise or anti-clockwise.

I'm bloody screwed. :frusty:

Posted: Mon Jul 14, 2008 5:50 pm
by BuzZz
If they mention nothing about it in the manual, one can only assume that it is normal rotation thread.....


.....typing that pretty much guarantee's that it is reverse thread. :wink:

.... maybe you are screwed. :laughing:

Posted: Tue Jul 15, 2008 4:37 am
by Skier
Some cams have a flat spot on them where you can put a crescent wrench over to prevent turning. Perhaps your cam(s) have such a spot.

Do you have enough room to clamp the sprocket in a vice and hit the bolts with an impact gun?

Posted: Sat Jul 19, 2008 12:21 pm
by young Cruiser
Hi Guys

Well, I took some time today and put the engine head back on as I am fully recovered from my injury. I wasn't kidding when I said I tore something in my shoulder last week!! I really did. Should have put the head back on in the first place; much easier :)

GOOD NEWS!!... I got the bolt off the cam sprocket :D

Here's a pic of the engine after I took off the head..
Image


Another photo showing the cam sprocket off.
Image

I now have to take out the rocker arm shafts (yellow arrow) but I don't have the right tool. The manual says I need a Slide Hammer Bolt & Weight. Costs $130 + :shock:
How does the slide hammer & weight work?
Is it a push & pull thing or just a pull out action?

Is there another way to get it out?
I see that there are some threads in the shaft too.

young cruiser

Posted: Sat Jul 19, 2008 4:14 pm
by mgdavis
Slide hammer and usage.

Do you have someplace you can borrow one from? A slide hammer is just about as basic as you can get, I can't imagine paying $130 for one.