Cam sprocket onto cam shaft. [Archive]

Magua

19th February 2009, 18:37

Trying to reassemble my bike, but it's being stubborn.

Cylinder's back on, so's the tensioner, tensioner blade, head etc. Trying now to get the bloody cam shaft sprocket on now.

I can get the chain onto the cam sprocket, but it will not go onto the cam shaft shoulder. Just refuses to, like the chain's too small or something.

Suggestions?

1980 Honda, cb400n.

Magua

19th February 2009, 18:38

Btw, my head and base gasket cement is rapidly drying, so any quick suggestions would be greatly appreciated before they're ruined.

EDIT: Maybe if I add the rocker assemblies and then add the engine bolts (they pass through them), torque them up. Might push the head and cylinder down, giving me more room to work with the chain?

Double Edit: Wont work, can't add one of the rocker assemblies because the fucking sprocket's in the way.

Shaun P

19th February 2009, 18:53

Usually you would do the tensioner last?

Magua

19th February 2009, 19:04

No. You need to remove the camshaft to get to the tensioner.

The Pastor

19th February 2009, 19:10

Tbh i saw this coming aye.

No idea how your going to do it.

Magua

19th February 2009, 19:14

Maybe my tensioner's fucked?

The Pastor

19th February 2009, 19:30

Are u sposed to rivet it last?

Magua

19th February 2009, 19:34

Rivet what last? If you're talking about the cam chain, no. It comes off the sprocket as a whole, it should go on the sprocket as a whole.

Bonez

19th February 2009, 19:40

What bike?

Magua

19th February 2009, 19:41

1980 Honda Cb400n. Should have specified in the first post. :P

Squiggles

19th February 2009, 19:47

Tensioner is taking up the slack in the chain?

Ixion

19th February 2009, 19:49

You usually have to manually retract the tensioner tensioning spring. Often by something like an allen key in the adjuster. What does the manual say ?

Magua

19th February 2009, 19:57

It says to put the chain onto the sprocket and then to lift the sprocket onto the shoulder. :P Ill consult the Haynes.

Bonez

19th February 2009, 20:01

Try loosening off the tensioner lock nut, then with a tyre lever or large screw driver push the tensioner blade back a bit then nip up the nut to hold it back. Be careful not to gouge the tensioner blade.

Ixion

19th February 2009, 20:03

Yes. The nice new chain is tight, so you have to force the tensioner back to allow it some free play. How you do that on a Honda I do not know. On a Yamaha you put an allen key into the chain adjuster shaft and turn it anticlockwise and lock the tensioner at full retract.

Bonez

19th February 2009, 20:09

Sometimes you need to hold your tounge just so, say a chant and the sprocket magically mounts in position. Generally happens after a good night sleep after wasting a whole day on the problem.

Magua

19th February 2009, 20:12

The Haynes manual says that when you're putting the tensioner in you pull it up and lock it into place to remove tension. I removed the head and the tensioner can be pushed up and down by hand with the nut in place. Something's not right. I'll take a closer look tomorrow.

Bonez

19th February 2009, 20:33

Was the upper bolt and o'ring fitted?

Magua

19th February 2009, 22:38

It was indeed.

Magua

20th February 2009, 11:13

Idea. Feeding rope beneath the tensioner and pulling up on it to reduce its effect upon the chain. We'll see how it works.

The Pastor

20th February 2009, 11:55

Hey that was my idea you idea thief!

Magua

20th February 2009, 11:58

I don't know what you're talking about. :D

The Pastor

20th February 2009, 16:51

I don't know what you're talking about. :D
update ?

roadracingoldfart

20th February 2009, 21:22

If the tensioner has both a 10 mm head bolt (that comes out) and a 14 mm locknut then the secret is a 3 mm screw threaded into the inner part and then you can pull on it to allow a small amount of tension relief.
Then when all is in place let the tension off and tighten the back nut according to the torque spec.
PS , you may have to tap the 3 mm screw a few times to free the inner rod if it is semi siezed and a bit of CRC wont hurt.

:niceone:

Ixion

20th February 2009, 21:26

Have you tried the BLOODY BIG CROWBAR ?

roadracingoldfart

20th February 2009, 21:31

Have you tried the BLOODY BIG CROWBAR ?

You bloody rough bastard . use a bloody shovel and do it once ..... properly

xwhatsit

20th February 2009, 21:43

I went over today (not just because I'm an exceptionally nice guy, but also to use a chain splitter that's there) and we scratched our heads and puzzled about it and managed to get it on.

Even with the tensioner fully backed off, it's still not going to go on with hands alone. So I got frustrated and rotated the engine 90 degrees around -- that way it was possible to get one bolt-hole lined up, but not the whole sprocket up onto the shoulder. G-clamp to hold one side on the shoulder, then crank the engine back over to TDC and it pulled itself on there.

I think Mr Magua is putting the whole lot back together as we speak.

roadracingoldfart

20th February 2009, 22:03

The Pastor

20th February 2009, 22:08

sweeeet! get my car bacK!

xwhatsit

20th February 2009, 22:09

:shit::shit::shit::shit::shit::shit::shit::shit:
What? What's wrong with that lol? Nothing was resting on any bearing surfaces or under any undue tension. The only thing that was being leaned on was the camchain itself, which needs to back off that far to run the engine anyway.

xwhatsit

20th February 2009, 22:10

sweeeet! get my car bacK!
Dude -- I have to say -- that is an exceptionally sweet ride.

Duncan was overwhelmed with the power when it spun up in the wet.

The Pastor

20th February 2009, 23:09

Dude -- I have to say -- that is an exceptionally sweet ride.

Duncan was overwhelmed with the power when it spun up in the wet.
it has the more horsepower.

FROSTY

21st February 2009, 03:01

dude are you sure its the rtensioner you are playing with --is it front or back of the motor??

emory says theres a cam chain guide at the front and the tensioners at the back

xwhatsit

21st February 2009, 10:04

dude are you sure its the rtensioner you are playing with --is it front or back of the motor??

emory says theres a cam chain guide at the front and the tensioners at the back
Yes it's the tensioner. It is at the back. It's spring-loaded and you can hold it in position with a bolt.

The Pastor

21st February 2009, 20:41

well if captain snap bolt didnt strike again i'd be a rich man.

xwhatsit

21st February 2009, 21:27

well if captain snap bolt didnt strike again i'd be a rich man.
It's funny, his upper body doesn't look that strong, but you can't argue with the results, can you.

The Pastor

21st February 2009, 22:27

you hear he snapped the exhaust bolt now?

Magua

21st February 2009, 23:01

He knows, he didn't know that I snapped the camshaft bolts though lol. Wrong setting on the torque wrench.

So far I've (we've) replaced the rings, cam chain, base gasket, head gasket, lapped the valves and their stem seals have been replaced. Not looking forward to a 500 mile run in period at no more than 1/3 throttle. No full throttle until 1,000 miles and then only sparingly until 1,500 miles.