Topic: 1973 CB350F "Freakshow Build" completed! Stay tuned for updates...

[Spikeybike]

Is the engine going to go "kerplunk" and fall down onto the frame rails after all the bolts are out?

yes it will

i wouldn't worry about damage too much, a jack or some sort something to hold it up would be fine.           

[Tim in Ohio]

   Engine out:

[Tim in Ohio]

Time for exploratory surgery, eh guys?   Anybody care to layout a general gameplan?

Reminder:  Wanting to renew/refresh this engine so that it can:
A) Get well past its current max of 60% of rated top speed
B)  Help it achieve its spec fuel economy
C) Try to solve the oil hemorraging problem that has the jugs all grimed up.

So I assume we will take the valve cover off next.  What will we look for, measure, adjust, correct...

After that... remove heads and ________________  (please help me fill in the blank)

Thanks for all of your input Team.  You already have me farther than I would have ever had the guts to go on my own. 

[Spikeybike]

take the breather off first (very top case)  then remove all the tappet covers and back out the tappets , might be a good idea to remove the tappets completely (make sure to mark witch one goes where) then take the head off, make sure to use a cross pattern loosening the bolts, you what to relieve the stress on the cam evenly

[scunny]

hi Tim, I only said to check the valve clearance as to see if that may have been the problem. then proceed as spikeybike said, checking for signs of wear or damage as you go.

[martino1972]

hi Tim, I only said to check the valve clearance as to see if that may have been the problem. then proceed as spikeybike said, checking for signs of wear or damage as you go.

+1 on that......when you got the camshaft exposed,look for signs of wear on the cam lobes and rocker arms(where they meet)cam journals etc...

[Tim in Ohio]

Cam Cover off.  Things noticed on initial inspection:
First, when removing the cover bolts one came out with some material that looked like a spring:

Could this be from the use of helicoil in this hole previously?  I took note of the specific hole... special treatment required upon re-installation?


I noticed that the right oil manifold has less left to right play than the left one:


The left oil manifold has more play and will actually move far enough to touch the camshaft.  Note the section that has been worn flat on the camshaft.  I always noticed more of a "clanking" noise on the left side of the motor.  Could it be due to this?

[scunny]

sorry, can't help you on the 350 but wouldn't think it should touch.
that does look like a helicoil

[Spikeybike]

i too am at a loss , PM mattcb350 he would know

[hoodellyhoo]

When I took my valve cover off I remember those having some freeplay, but not enough to touch the camshaft.

[MCRider]

The area you have identified as "worn flat" is more likely a factory machining mark from when they balanced the cam?

[Artfrombama]

If you send the head out to have the valves ground/lapped tell them to replace the heli-coil.
Easy operation.

[kghost]

Looks likes threads not helicoil. Helicoil will be steel that looks like aluminium.

Flat spot is normal machine marks.

How miles on the engine?

[Tim in Ohio]

Guys thanks for the feedback so far.  Glad to hear that flat spot is normal.  Kghost, the bike has 22,000 miles on the speedo...  BUT, noticed that the ID number on the engine does not match the frame, so who knows???

The cam bearings look smooth and shiney,  What next?

[MCRider]

Guys thanks for the feedback so far.  Glad to hear that flat spot is normal.  Kghost, the bike has 22,000 miles on the speedo...  BUT, noticed that the ID number on the engine does not match the frame, so who knows???

The cam bearings look smooth and shiney,  What next?

ID numbers seldom, if ever,  match on Hondas.

[kghost]

Guys thanks for the feedback so far.  Glad to hear that flat spot is normal.  Kghost, the bike has 22,000 miles on the speedo...  BUT, noticed that the ID number on the engine does not match the frame, so who knows???

The cam bearings look smooth and shiney,  What next?

+1 on the frame vs engine numbers

[Spikeybike]

well , not sure if the cam chain has external tension adjustment like my 550 (dont see one in the pics)  if it does loosen that ,  turn the big nut in the center of the ignition to turn the motor over until a mounting bolt is showing on the cam sprocket, remove that bolt. repeat to get to the other bolt, slide the sprocket off mounting surface, it should drop down a little, take the chain off the sprocket, remove the cam   ,viola. 

take the head off , .. if i were you, removing the head is simple, just loose the nuts (criss-cross pattern of coarse) and pull it off

but you should make you son do it, and then when he hands it to you , you get to say the classic line " huh huh , you just gave me head"

"i don't care who ya are, thats funny right there"     

[Tim in Ohio]

BWAHAHAHahaha!!!!

[kghost]

If your going to completely disassemble that engine...

Pay particular attention to the starter sprag clutch.

If it goes out you will have to disassemble it again to repair it and I would replace it with a new before I put it back together.

[mattcb350f]

Wha?     I wondered off and missed a whole bunch of fun 

You're making great progress Tim 


The Oil Manifold.......... You see the rubber 'grommet' thing in the pic by your finger:



that holds the manifold in place, away from the cam. There is a little aluminium tab between the valve spring and the  head bolt in the pic where that grommet centers on, and I belive a simmilar one on the cam cover.

So, no it won't hit the cam, unless it is assembled with the grommet in the wrong spot. Even then, with the nozzles facing the cam, it should be pushed away............. so don't worry bout' that either 

And about the play on that manifold: each side is has an o-ring which seals the manifolds in the head. They are kind of a loose fit and wiggle a bit. Each side is a different diameter to ensure that they face the right way...... so yeah its normal that they're loose.


The Camshaft looks good to me, but check the rockers to see if any of the hard faces which ride on the cam have any damage. If there are chunks out of the rocker arm faces (like mine had  ) than usually the cam has been damaged.


OH YEAH... DONT FORGET THE LITTLE BOLT IN THE MIDDLE OF THE BACK OF THE HEAD when you go to take the head off. 

 Matt.

[Tim in Ohio]

Hi Matt, welcome back!  Thanks for the feedback.  The rocker faces look good, but I do have a concern/question about the "springs" on the rockers.  See the following pics.

Most of them seem to 'stay put' (seems good) nice and tight in their designated area when I move the rocker back and forth with my hand, here is one that 'stays put':


However, there are two of the that seem to ride out a little bit, like so:




Is this an issue to be concerned about?  Or, maybe when the head cover is snugly in place, these are held in their spot and can't travel out like that?   

[mattcb350f]

  I thought my springs were faulty too.

For how well Honda engineered the rest of the bike, you'd think they would have done a tidier job with those springs

That's just the way they are I'm affraid. Both my cam covers w/springs are just like yours.

BTW, the cam bearing surfaces and rockers do look to be in great shape for 22k 

Given that the head is the last place to get oil, this means that the bottom end should be in even better shape.....lets hope

 Matt.

[Tim in Ohio]

As an aside... before I dig into today's work on the project...  I want some opinions on a good torque wrench for when it comes time to reassemble.   In looking over the torque specs, it looks like I will need to cover a range of 5 ft-lbs all the way up to over 50 ft-lbs (granted, the high end is for working on the steering assembly).   On eBay, I see that there is a 3/4 inch drive 5 - 80 ft lb craftsman out there, it appears to go for over $100 bucks.  What do you guys use? 

[Spikeybike]

i use 3/8 bar type , they stay calibrated for years and years,    the micometer style you speak of need calibration on a regular basis   (but really i use a bar type because it only cost 20 bucks(craftsman) so if it ever falls out of spec, i can just go get a new one)

[Tim in Ohio]

Spikey.  $20 is good.  What is the range on that thing?  From xx ft lbs to xx ft lbs.