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Discussion Starter · #1 ·
I have a 72 cb350. I rode it around the block a week ago - seemed to ride fine - I have no comparison. I decided to do some maintenance. I purchased new points from common motors. Now I previously adjusted cam chain and performed valve lash adjustment. I am having a tough time having the light come on on the LF mark. Comes on late after the LT mark. If I adjust it ever so slightly I have the light on all the time. I feel like I don’t have enough play to time this correctly.

So I decide to make sure everything looks correct. On TDC on LT I have a pic of the cam position at 6:00. I took another pic of when I’m suppose to loosen the screw for the cam chain adjustment. I verified both pistons are lowered and all valves have some play. It’s just when I loosen the screw - I don’t hear a sound like in some of the YouTube videos. I have taken the tensioner off and it seems like it’s working correctly.

I’ve tried common motors method and the method in the sticky on hondatwin where I set the left point to 0.14 at the widest opening on cam. On the compression stroke of LF I cannot get the light to come on if I rotate the base plate. I feel like I took 2 steps back by replacing the points.
 

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You need to start with the CAM PIN at 12:00 NOT 6:00.
Otherwise you are on an intake stroek NOT a COMPRESSION Stroke.

When you remove the Adavance assembly it is "REAL" Easy to put it back 180 Deg out of sync.
There should be a Punch Point Mark that matches up with the Cam Pin.

Do you have a copy of the FSM ?

While some of the vendors make real nice general purpose videos and all there is nothing like the FSM for the correct proceedures.
 

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Did you turn the points plate or open the points gap bigger? Once the left points gap is set, don't touch it again, rotate the whole points plate assy. to line up the mark. Then tweak the right hand points gap to line up that mark.
 

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Discussion Starter · #4 ·
Yendor, I’m pretty sure that my cam is not off 180 degrees - it was running fine. So if I understand correctly, on the compression stroke for LT - the cam pin is suppose to be at 12:00? I purchased this bike used and I’m just slowly going through the maintenance. Would the bike even run if the PO installed the cam incorrectly? I rotated to LT - feeling the pressure build up in the spark plug hole. I know it’s not the preferred method to verify - so I verified the left piston at the top via the spark plug hole. I’ll go re-read the FSM, I just went with the videos since the instructions seemed consistent. Thanks for your assistance.
 

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Discussion Starter · #5 ·
Mike, after I set the left points to spec - when the opening is the widest - I tried to time LF with the light by turning the base plate. Unfortunately, I wasn’t able to get the light to come on. If I left the plate in the middle and tried to time LF by adjusting the left point, it comes on late - after LT. The slightest adjustment pushing the point to the right keeps the light on all the time - points are open. I have zero play to time it light on LF.

I did notice that my baseplate is not sitting flush without the screws. I’m thinking about sanding the base plate so it’s flush. Do you think this could be causing the issues?
 

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Do NOT sand it to make it sit flush. Especially if it ran before.
There may be some light corrosion on either the plate or the Cam End Cap that may need to be removed but "IF" you have to sand remove ONLY the rust or corrosion NOT any Metal.

Pages 103- 104 of the FSM that I have is where the Points/Timing adjustment is outlined in detail.

I'm not sure how you are posting your pictures but I am unable to ZOOM them to see better detail.
 

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In the picture it doesn't appear that the points plate is nested in the recess in the head. There's actually a visible gap between the top of the points plate and he machined recess in the head. That will make a BG inference where the points open. Pull the points plate off and check for burrs or raised metal on the od . Likewise, check out the matching surface on the head for defects. Once it fits properly in the recess you should be able get things adjusted.
 

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It appears in your photos that the points cam (sleeve at the end of the cam shaft) isn't properly seated on the shaft. Remove the machine screw and washer that hold it in place. Grab it with two fingers and push it in while twisting back and forth a few degrees each way to wiggle it into place. You should feel it click into place and the outer face of the sleeve will end up about flush withe the end of the cam shaft.

Sent from my SM-G386T using Tapatalk
 

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Discussion Starter · #9 ·
The cam end is flush, it just appeared that way from the pics. Even with cam advancer removed - fitment is the same. So I removed the new points and installed the old points back. I’m almost able to time the left perfectly. It’s still slightly late but pretty close. I had to stop and take a break - started getting frustrated.

Confused because the baseplate was never a tight fit like it is now. I can get it in flush and centered if I tighten the two screws. I just can’t rotate the plate once it’s tightened done - super snug fit. I need to use a screwdriver to pop it lose.

I feel like the more I try and work on the bike, the more problems I create or is created.

I appreciate all the help everyone.
 

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Did you ever get it figured out?
If your new points were bought from common, you have to modify them by boring the mount holes on them to allow enough play. I got them and it was a pain in the ass.

Sounds like you had similar problems I'm dealing with now. My idle is up and down. Likes to stall inconsistenly. Right side exhaust is cold and backfires.

Carbs have been rebuilt, can chain, valves and timing was done, petcock changed....
 
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