Topic: Cam Chain

[thumper]

 Bear with me as a newbie to SOHC4 Where is the cam chain tensioner on a CB400/4 F2 The Haynes Manual tells you how to adjust but not location.It does refer to a 10mm screw between front eng. plates to be removed to aid adjustment with a screw driver.The one on my bike has a lock nut on it and I am wondering am I looking at the adjuster. I have just bought the Bike it is a bit noisy on start up quietens a bit as it warms up. I am going to do Valve clearances as well.Can the Cam Chain and Guides be replaced with Cyl Head removed. I also habe to clean Carbs as one is leaking with Fuel on.Any advice on this Bike appreciated.I have older Triumphs but cannot Kick start due to a bad Knee gave them to my Sons who got me the 400/4 instead I am 75yo and still love my bikes.

[switchum]

 I think that is the adjuster you are looking at. I don't own a CB400 but worked on one before.



You might have to start her up, take the bolt No. 11 out and push in with screw driver or something ( NOT too hard) to quiet her down then, tighten the No.12. I hear many of the springs for the adjuster gets weak or rusted over the years.

 You can get shop manual of CB400 here:

 http://www.honda4fun.com/man_officina/man_officina.html

 Good Luck and keep on riding.

[thumper]

 Thanks for your reply and tips I can see what you mean. I should have looked closer "Senior Moment"

[DarcyCB400F]

http://www.motorcycleproject.com/motorcycle/text/headgask.html

The link above refers to a "gentle push though a plugged hole" while adjuting the cam tensioner bolt... on the 350/400 *the last 5 lines of the article.

Does this mean that there are two "bolts" that are accessed for this process???

I know of the cam tensioner adjustment bolt with the locknut... is there another??

[Bodi]

Directly above the tensioner lock bolt is a bolt that points down into the case. This just plugs the hole that the tensioner operating rod is in, it doesn't hold anything in. If you remove this bolt you can push down on the end of the rod and "help" the spring that tensions the chain.
I have to assume these springs have not aged well. I haven't come across one that actually quiets the camchain in 20 years or so. A slight push down with a screwdriver or nail with the engine running to hear when the rattle subsides works wonders.

[DarcyCB400F]

Thanks for that Bodi!
I will update when completed!

[DarcyCB400F]

Well guys here's my update...
I removed the top bolt, removed the cam chain tensioner bolt, started the bike, gently pushed down with a allen wrench through the top bolt hole... nothing moved... nothing! I tried a gentle push through the tensioner bolt hole... again nothing moved. Gave the bottom hole a long very skinny screw driver and with the engine running, and someone pushing through the top hole, gently tapped the screw driver... still nothing.
In the end, I could not get any movement what so ever in the adjuster to quiet the chain.

Becasue the bike has been sitting and not running for 10 years, could it be that the tensioner is stuck?

What do I do now??

[switchum]

  I think it is stuck. You will need to worry; dump some lube/ penetrating oil in the top hole where No.11 bolt go and keep tapping little by little. That is what I would do. Last time I worked on those, I remember I had to push bit harder than I was told- it was not gentle. But better safe than sorry. Patience is the key.  Good luck!

[DarcyCB400F]

Thanks for the tip switchum! Am I doing harm riding it untill I get it loosened? Will riding maybe help??

[fmctm1sw]

Thanks for the tip switchum! Am I doing harm riding it untill I get it loosened? Will riding maybe help??

I have a post here somewhere of what a frozen tensioner looks like.  Yours may be stuck too.  A lot of times the chain eats into the tensioner horeshoe (#3 in the picture and actually right where the arrow is pointing).  I saved one with a rotary tool one time...