Topic: cb350f/cb400 cam tensioner question

[Dos]

Hey all,

I have a continual cam chain rattle in my bike.

I have attempted to tension it however anyone with this bike knows how bad the auto tensioner is.
according to the  diagram to "manually" tension you unscrew (11) loosen (17) and (12) and apply pressure on the rod (9) while the bike is on idling at 1200rpm. You apply slight pressure until the rattle quiets and then you tighten (17) and (12) and screw (11) back on top and done.  Correct?

I thought I successfully did this. When I was done I turned the bike off, let it cool off, started it back up and heard nothing at 1200! I rode around and everything sounded cool however there was this whining noise that started. I thought I tensioned too much and the whining was coming from the chain rubbing on the guide ( 8 ) I loosened the tensioner system  and I believe it went away however the raddle came back.

Recently i changed my oil and I found two little plastic flakes. Sort of like if you took an apple peeler and stripped it off of the tensioner. SO I assume I tensioned it too much and the chain rubbed it off and that  was where the whining sound was coming from. I made a post about this before..

Today I retensioned and i have no cam slap at 1200 however i still hear it when i rev or im just driving and my whine is back.

What's going on? what the heck do I do. Am i tensioning wrong?

Is 17 just a locking mechanism and is 12 just a safety nut or are you only supposed to screw 17 in a certain amount?

Like can I set the tension correctly without 12 and just 17?

I usually apply pressure to the rod uptop and screw 17 in untill it gets tight and then turn 12 until its tight.

is 17 supposed to screw in a specific length or no?

Thank you

[flybox1]

Is 17 just a locking mechanism and is 12 just a safety nut or are you only supposed to screw 17 in a certain amount?

Like can I set the tension correctly without 12 and just 17?

I usually apply pressure to the rod uptop and screw 17 in untill it gets tight and then turn 12 until its tight.

is 17 supposed to screw in a specific length or no?

Thank you

Apply pressure to the rod top, screw in 12 too hold the rod (9) in place, and then secure 17 in place to lock 12 from spinning out.
Its likely that the PO overtighened 12, which created a divot in 9.  The tip of 12 will continue to find this same divot during normal operation/use.
8 & 10 may be over-worn, and need replacement.

[Dos]

Ug.
If I continue to let it rattle and the chain eventually snaps how bad does my motor get screwed? Just need to replace the chain the whole tensioner system and possible a cog?

[Flyin900]

4 into 1 has a replacement bolt / lock nut system that pushes down from the top of the assembly and removes the lower lock piece you are having trouble adjusting.

I have one and yet to try it until I get the 400 running. I didn't like the self adjusting set up Honda uses in the Factory Manual on the CB 350 I did last year. I found trying to get the cam chain tensioned with the motor running made it noisier, so I did the pressure on the top rod as suggested and turned the motor over by hand. There was one point where the rod moved slightly lower and I tightened the lower lock bolt set up to lock the assembly. It was quieter yet probably not as quiet as it was in 1973 new.
This was very hard to do with the motor in the frame, so this year I bought the 4 into 1 adjuster bolt. It is suggested that you carefully adjust this set up as it is applying pressure directly to the rod and ultimately the cam chain adjuster face on the guide.
Usually the whining on the motor can be a sign of too much tension on the guide face.
It is a little bit of trial and error and realizing if the motor has done 15-20K miles then there is likely wear that will never be factory quiet totally with the used parts and 40 years of aging.

[Dos]

4 into 1 has a replacement bolt / lock nut system that pushes down from the top of the assembly and removes the lower lock piece you are having trouble adjusting.

I have one and yet to try it until I get the 400 running. I didn't like the self adjusting set up Honda uses in the Factory Manual on the CB 350 I did last year. I found trying to get the cam chain tensioned with the motor running made it noisier, so I did the pressure on the top rod as suggested and turned the motor over by hand. There was one point where the rod moved slightly lower and I tightened the lower lock bolt set up to lock the assembly. It was quieter yet probably not as quiet as it was in 1973 new.
This was very hard to do with the motor in the frame, so this year I bought the 4 into 1 adjuster bolt. It is suggested that you carefully adjust this set up as it is applying pressure directly to the rod and ultimately the cam chain adjuster face on the guide.
Usually the whining on the motor can be a sign of too much tension on the guide face.
It is a little bit of trial and error and realizing if the motor has done 15-20K miles then there is likely wear that will never be factory quiet totally with the used parts and 40 years of aging.

I tried to search for this piece you are talking about on 4 into 1, can you  link me here?

[Flyin900]

Under the CB 400F just plug in "cam chain adjuster" in the search box and it comes up. It is OS presently and is a TTR400 manufacturer part number 400-007. TTR manufacturers a number of aftermarket parts for these bikes.

[strynboen]

its easyer to remove the front engine Mount..to do the adjusting..just unscrev 3 schrevs..it gives some more Space..but still the hot exhosts is in the vay..
i have made this adjuster bolt..and some more advansed ones..but this basis do vork

[Dos]

How bad is it to just let the chain snap?

Will it fly me off the bike?

[flybox1]

How bad is it to just let the chain snap?

Will it fly me off the bike?

probably not, but it could result in total engine failure.
a chain put under load(accelerating) and then slacked(quickly off throttle) can cause mucho damage to the valve train and chain tunnel.

[strynboen]

a Loose thain do harm..any minut you drive.

.the thain eats the engine block..and take a bite of the horseshue tension part.
..i have mine open and inspekt..and faund a lot of metal..and some eaten material in the block.
..so a broken thain..is not the vorst senario...its metal in the oil..and holes in vital parts..vho vill brake Down at somemore  time..running...mine thain vas looking fine..and vas abel to be adjusted to be hardly no slock..
but the other thain(bottom thain) can also make rattel and clonking..do a good syncro..and hope it can take most rattel..i can not adjust all rattel aut of the engine....so think i bay new thains. just for safty.and Mount them NeXT vinter

[Dos]

If anyone wants to stop by and check it out with me is greatly appreciate it.