Author Topic: 74 Cb350F Cam chain adjustment  (Read 656 times)

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Offline kalamari

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74 Cb350F Cam chain adjustment
« on: May 09, 2019, 05:29:41 AM »
Hello

I have a 74 CB350F with 5,100 miles on it.  I have owned it for 20 years and am the third owner.

About 5-6 years ago I went thru the cam adjustment procedure method outlined at 1200 rpm.  At the time, I really didn't feel there was a difference in the cam chain noise level but figured - job done.  Anyway, after doing a fair amount of work this season already (new shocks, carbs cleaned and bench sync, new plugs & resistor caps, flasher bulb, side cover grommets, new fuel line and overflow tubing)  I decided to  adjust the cam, valves, and timing.

This time I utilized the method in which the engine s warm but off, pull points cover and crank engine drive to 1-4T (TDC) compression stroke for #1.  I recently learned of the plug above the tension adjuster and lock nut - and that the tension rod is commonly stuck -  and its use to be able to persuade (push) the adjuster arm free.  I gave it a go last night - till 1230 in the morning.

Here is what I have found:

1.  The hole in which you thread your push rod into is rather small... I could only get a tiny allen wrench or small computer screw driver to navigate down the center.  Is that right?  I have read that this may (and surely does) require a bit of force (taps of a hammer) to free up?  What have others used as a push rod?

2.  When i put the screw driver or allen wrench thru the hole and turned the locking bolt back and forth - although I could feel the motion with the screw driver - I did not feel the the tension rod was free to move up and down.

3.  I sprayed a bit of wd 40 down there and figured I pause the project to obtain some experienced info on the matter.  I assume the tension rod is stuck and looking for next steps and suggestions for a push rod.

Thanks for your time and help

Kurt

Offline Alaxy Galaxy

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Re: 74 Cb350F Cam chain adjustment
« Reply #1 on: May 09, 2019, 06:30:54 AM »
When you're pushing through the small hole, you're only pushing on a very small rod which, in turn, pushes on the tensioner "shoe." You'd be hard pressed to actually feel a great degree of movement from here, even with a hammer as the tensioners will spring back anyway. If you really want to be certain that the tensioner is free, you can remove the rocker cover and the rear cam tensioner holder. Afterwards, it should be quite easy to move it back and forth with a screwdriver in that top hole on the front.

Honda's original theory was that slacking the adjustment bolt would let the spring take up the tension required and that tightening it back up would be just fine. 40 years later, that's not often the case.

There's a member here who manufactures a neat solution that goes through the top hole to help push it in place:

https://4into1.com/ttr400-manual-cam-chain-adjuster-bolt-honda-cb350f-cb360-cb400f/




Offline kalamari

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Re: 74 Cb350F Cam chain adjustment
« Reply #2 on: May 09, 2019, 07:13:46 AM »
OK thanks for the info.  I really do not want to take the rocker cover off to determine if the tension rod is free at this point.  I have seen other videos where it appears the rod had some spring back and forth when the locknut  is loose - mine has demonstrated no movement as presented in other videos.

I guess I am concerned in making something bad to worse if it requires the need to be addressed.  I am understanding the setup better now and have been making myself familiar with the system - I also dont want to create a problem where there is none

I may take a trip to the local hardware store to see if I can find a good push rod tool candidate

Thanks for your help

Kurt