Topic: Cb400f cam chain tensioner springs.

[soonerbillz]

Can the 2 springs (parts 6,7) under the cam chain tensioner push bar cap nut/bolt fall into the engine case?
  I removed the cap (parts 11,15) and the things popped off and went flying. I found the cap and washer but can't find the springs anywhere.
 Looking at this pic I can't see how the springs could fall into the case because the push bar (part 9) would block them in the hole. To be honest after going through to bike in detail and fi di g the PO did so much crap work on the bike it wouldn't surprise me if the springs weren't even in there.

[bryanj]

1 no they cant fall in
2 i didnt think they could come out upwards, i always fitted them from inside

[soonerbillz]

1 no they cant fall in
2 i didnt think they could come out upwards, i always fitted them from inside

Thanks for the response.
 I did some more research on the system and using the following image now more fully understand the way the parts are assembled.

I think this drawing clears it up for me.
 So from this I am assuming on assembly the springs are put on the plunger then the plunger is slid up into the hole in the case from the bottom.
 Though the image doesn't show it there must be a lip in the case that the top of the springs sit against that creates the spring pressure on the plunger after the horseshoe is installed.
 Am I right?
 I thought the springs went into the hole from top side and sat against the plunger and the cap bolt when screwed into the top hole then put pressure against the springs thus the plunger.
 The first part of this comment being correct would mean the springs are still on the plunger inside the engine.
Being I can see the top of the plunger looking into the hole I can only assume the plunger and springs didn't fall into the engine.
 

[bryanj]

It confused me when you said the cap popped off, made me think somebody in the past fitted the springs wrong

[Tim2005]

Hi, no they can't fall in or spring out. Maybe someone added some extra springs under Cap 11 in a vague hope of tensioning the camchain.  Does the rest of the tensioner work ok? 

[soonerbillz]

Well I loosed the lock nut and plunger rod bolt and I heard a definite click noise. Then I tried to put a pin punch in the hole and push the plunger but it wouldn't move. I'm hoping that's because the inner springvhas pushed the plunger as far ad it can go.
 Gonna put it all back together and see what it does.

[Tim2005]

That's promising. As an extra check, you could always take off the cam cover (that doesn't take long to do) and check the camchain is actually tight now.

[Bodi]

You may be able to feel the bar pop up a bit of you turn the engine back a bit but that fights the starter motor. And never turn the engine via the advancer nut!
Yes the springs and shaft only come out with the tensioner horseshoe, with the cases split.
With bad maintenance and a very slack chain, that horseshoe can be damaged and seize up. Hearing a click is a good sign.
The springs will have lost tension over the decades and the manual's method is very unlikely to work.
I have the engine running and press down on the rod until the rattling JUST stops then clamping the rod. It's worked for me well. Too much tension will erode the slides but just quieting the rattling is what the springs would have done when new.

[jonda500]

+1 on the engine idling method! The 400-4 that I used to own had the damaged horse shoe at the hing area from running with a loose chain (the adjuster bolt was snapped off in the case & an easy out bit was snapped off in the remains of the bolt!). After taking everything apart to get the bolt disintegrated out of the case and reassembling with a new adjusting bolt and nut, I learned to get the chain super quiet by carefully pressing down on the rod with the engine idling until the noise only just quiets down WITHOUT slowing down the idle speed at all, then cinch up the bolt & nut.
Note: never run the engine above idle speed with the adjuster bolt undone!
John