Topic: 1973 CB350F "Modest Original" build

[grcamna2]

Plan of attack is as follows..luckily none should involve removing that damn exhaust!

First, I will try to touch up the points with sandpaper or a fine file. I know filing points is typically a no-go but since these are considered shot I figured I would give it a try.  If they show any sign of improvement I will know this was the source of my problem and replace.  Then I will re-gap them and redo the static timing, then check the timing and full advance timing with my timing gun.  If there is any sign of improvement here I will know I'm on the right track and will replace condenser, and OEM points.

If none of that solves the problem or it looks like the mechanical advance is at fault, I'd consider switching this bike over to a Pamco electronic ignition: http://www.cb450ignition.com/Index350.htm.  What are all of your thoughts on that?  My thinking is an issue with the mechanical advance will be hard to replace.  To note, the cost of OEM points and high quality condenser are just about the same as the Pamco unit.  Seeing as I am also handing the bike back to a man who will not be checking and setting the timing every 3k miles or whatever the service interval is this could further be a good option.

Atlas,
I suspect the points have been 'arcing'/burning for quite a while w/ bad condensers(I'm kind of surprised that other members here haven't 'backed me up' on that..)and when they do that it's near impossible to file that burn't stuff out of the metal of the contact surfaces.Mechanical advance isn't difficult to fix,I have parts from a few advance restore jobs including shims,they usually just get stiff and then won't advance the timing freely.

I like the idea of electronic ign. and when you find a good system it's worth installing.I have heard some different opinions on the 350 twin Pamco and not sure I would have that as 1st choice,imo.
I just wanted to let you know that condensers fry points when they go bad.Why don't you send a PM to HondaMan and ask him about his electronic ignition box which still uses points but makes them last for many years w/o replacement.I bought the one I used on my CB350 twin from him for a Great price(on special)and it is guaranteed for life by HondaMan(Mark)and he has excellent quality control on his units.

[540nova]

Others will disagree, but I highly recommend a Charlie's Place ignition as opposed to Pamco. Speaking from experience, I have had both. Enough said on that, take it for what it's worth


Sent from my iPhone using Tapatalk

[iiAtlas]

also,  http://www.ebay.com/itm/68-73-Honda-CB350-CL350-SL-CL-CB-350-IGNITION-POINTS-TIMING-ADVANCE-UNIT-SPARK-/262741928188?fits=Model%3ACL350&hash=item3d2ca3a8fc:g:1~MAAOSwImRYPsGc&vxp=mtr


on the way to work, good luck Atlas

Thanks Larry, good cheap find.  Hopefully doesn't come to that but will keep in mind.

[seanbarney41]

I'd just to ditch the points asap... points are great on sohc4, not so much on the twins

[iiAtlas]

I'd just to ditch the points asap... points are great on sohc4, not so much on the twins

Speaking of, check this...







PS: Guess where all that blood is from...damn exhaust...

I would consider that some pretty significant pitting on both sets of points, agreed?  Most likely from that arcing we saw in the past videos.  I will try to file these down to see if I notice an improvement.  I took the mechanical advance off too.  It was pretty sticky, most likely from that cam lobe grease flying around, but not "rusty" as far as I could tell.  Tossed it in the parts cleaner nonetheless.

Before:



After:

[SOHC4 Cafe Racer Fan]

Nice little battle wounds.

[iiAtlas]

Nice little battle wounds.

Can't go near this thing without getting another! 

[grcamna2]

The heat shields on the CL model exh.'s have lots of sharp edges.

[iiAtlas]

The heat shields on the CL model exh.'s have lots of sharp edges.

You're telling me!   

Anyways, got the mechanical advance unit cleaned up and reinstalled.



She is actuating free and clear, so I am at least confident mechanically the unit is not seized.  I have yet to hook up the timing gun.  We sanded down the points with 400 grit paper (useless, I know).  We set the static timing to a tee.  The points are still arcing out of control and the bike, again, will not rev past 5k rpms.  The points will need to be replaced and I am leaning towards the Pamco unit.  I hope this will solve the problem..

Two other things worth mentioning.

1) We messed with the pilot screw.  I know you all mentioned this only affected the mixture at and just off idle but we played around with it anyone.  The base setting is 1 1/8 turns out.  When turning the the screw all the way IN the affected RPM range shifts to 6k rpm.  When turning the screw all the way OUT the affected RPM range shifts to 4k RPM.  Interesting or moot?

2) I just remembered the float valve I rebuilt both with looked different than the remaining OEM one.

OEM:





Replacement:



The way I see it setting the float height to 26mm would be compensating for this as the reference line is static, the float bowl.  But alas maybe I am wrong.  Another thread worth a read..sounds eerily similar: http://www.hondatwins.net/forums/49-fuel-supply-carburation/21437-722a-carbs-lean-26mm-float-height.html

[grcamna2]

Pamco ? 

[iiAtlas]

Pamco ? 

Yes will go Pamco 

Ride report (not from me) -- bike pulled hard and revved clean through 7k when warm with choke ON. Issue remains with choke off. Thoughts?

[RAFster122s]

A lot of your images show up as broken images, nothing there.  Any idea what is going on with that.  I thought it was the tablet I'm using but it even does it on my PC with Chrome.

David

[iiAtlas]

A lot of your images show up as broken images, nothing there.  Any idea what is going on with that.  I thought it was the tablet I'm using but it even does it on my PC with Chrome.

David

Shoot I am sorry to hear that David!  I've had that issue happen a few times with the image host I use...can anyone else confirm?  I do love my images...

[seanbarney41]

pictures show fine to me...I dont remember if these carbs have adjustable needles?

[grcamna2]

Atlas,
I always clean-up the orig. carbs. brass parts rather than replacing it w/ suspect 'carb. kits'
The thing I do replace is all the rubber o-rings,etc. w/ an oem Honda rubber seal kit;stock parts never mess up.

[RAFster122s]

Atlas,
When did you last change the condensors? Might be a weak condensor issue.
What are your floats set to?  Have you checked the fuel height with a clear tube method?
(attach tube to drain port with either a fitting that screws in with barb or a tube that can be inserted into the opening to seal and allow fuel to fill the tube. You hold the tube up beside the float bowl and it will reach the height that is inside the float bowl before the float closes the fuel feed needle.

Is the above 5 k with the bike stationary with a fan blowing on the front or under load trying to ride the bike?

David

[iiAtlas]

pictures show fine to me...I dont remember if these carbs have adjustable needles?

No such luck! My only points of adjustment are float level, throttle stop screw, and pilot screw.

Atlas,
I always clean-up the orig. carbs. brass parts rather than replacing it w/ suspect 'carb. kits'
The thing I do replace is all the rubber o-rings,etc. w/ an oem Honda rubber seal kit;stock parts never mess up.

I wish I had this option!  Sadly only one carb had the OEM brass and it was rather chewed up.  I've cleaned up all the jets and would be happy to reinstall, but that would only result in one OEM carb leaving the other one left with the iffy brass.

Atlas,
When did you last change the condensors? Might be a weak condensor issue.
What are your floats set to?  Have you checked the fuel height with a clear tube method?
(attach tube to drain port with either a fitting that screws in with barb or a tube that can be inserted into the opening to seal and allow fuel to fill the tube. You hold the tube up beside the float bowl and it will reach the height that is inside the float bowl before the float closes the fuel feed needle.

Is the above 5 k with the bike stationary with a fan blowing on the front or under load trying to ride the bike?

David

Condensers look like they were never changed.  I am leaning towards the Pamco unit but after we saw that improvement with the choke on it made me think the problem is not local to there, rather the carbs.  I will check the float height with the clear tube method later in the weekend, I haven't tried that but I do have some clear tube lying around.  It may be worth noting that despite the fuel seeping out the float bowl sides I have yet to see any fuel out the overflow tubes.

The 5k is both stationary and under load, though when stationary we can occasionally "overcome" the stumble and rev higher where as under load we cannot.

Thanks for all the input guys!

[calj737]

Have you bothered to check the plug caps for their resistance value?

[iiAtlas]

Have you bothered to check the plug caps for their resistance value?

No..how would I do that?

[calj737]

Multimeter set to ohms. Unscrew the cap from the plug wire, and probe both ends with the meter. What's the reading between the probes for both caps?

[iiAtlas]

I'm going to need a bigger parts cleaner! 

[grcamna2]

You maybe could do 1/2 at a time..

[iiAtlas]

You maybe could do 1/2 at a time..

Slow going, I'll inch it around every 30 minutes.  Could remove the tray and let is rest a bit deeper if I could come up with something to suspend it from.

[MoMo]

You maybe could do 1/2 at a time..

or you could just work on smaller bikes

[iiAtlas]

You maybe could do 1/2 at a time..

or you could just work on smaller bikes

Hah!  I thought thats what I was doing...

Anyways, some progress is better than none..right?





Around, around, the engine block goes - It is cleaning up quite well!  Will have some pictures to show you all soon.  Happy with how this is coming out though!  Next I will try to pressure wash it to get the areas I couldn't reach with the parts cleaner.  I'd try to clean them up just in the sink but I don't have one big enough!!

The only spot I think I made a mistake on was here:



I left this roller bearing and the one opposite it in place.  They are removable with just those two circlips.  Probably not wise to have them sitting in the solvent?  You tell me.

In between rotations of the crank case I decided to tackle something, anything, else.  I went over to my overwhelming pile of parts and picked these two out.



Plan of attack was 220 grit sandpaper then red scotchbrite for a majority of the work, then polish up with the higher grit gray scotchbrite.  They were already buggered so I wasn't worried about sanding the fork tubes.  If it got better: great, if not: they were in need of replacement anyway.



The bottom portion of the forks began to clean up well.





And much to my surprise so did the tops!  I will keep working it but I think this is a good direction.  I will at least be able to rebuild the bike with these forks.  Should they just keep chewing through fork seals well then I'll know it's time to replace.  That was all for last night!

As for the CL350, I ordered the Pamco ignition and will be installing that in the new year.  Will try 24mm on the floats to see if that helps with the overly rich mixture and seepage out the float bowls.

Now don't get me started on the other projects....all this just to remove the oil pan!