[LexCorbett]

Okay gentlemen I've come to you in my time of need for some advice.
Bear with me, I am relatively inexperienced, especially in this company.

Some potentially relevant information:
1971 CB450 K4 DOHC Twin
Stock Exhaust
Stock Airbox w/ Paper element cut out and replaced with UNI foam as per reco on here.
Stock battery box and subsequently stock size battery.
From what I can tell, original regulator and rectifier.
Coils have been replaced at some point, but do not know how recently.
Has a PAMCO electronic ignition system sourced from 4into1
Wiring harness as a whole leaves much to be desired but all lights/indicators/switches function, with the exception of the starter motor (more on that in a second).
Stock carbs with stock jetting.


So, as the bike currently sits, it is very near completion (or so I might optimistically think). The battery has primarily been stored for the past 7 months, as the rest of the bike was looked after; occasionally on a 2 amp charger. As I thought all else was ready, I charged the battery to full (according to the charger), and placed in the bike. I just rebuilt the starter clutch and the electric start system was working fine at that time. Now, the button does nothing. No electric motor noise, certainly no engine turning noise, etc. Thoughts?
Anyhow, the bike kicks over (and with only my '74 CB360 daily driver as reference, the kick seems less resistive, indicative of low compression; can this be caused by poor valve clearances or is it solely a cylinder and piston issue?). The bike starts on second or third kick (without choke) and runs on both cylinders, holding a decent idle. To me, again with only my 360 for reference, there was valve chatter (hence my earlier suspicion), but I don't have a proper running 450 to truly know the difference. After 30 or so seconds, the bike will slowly die, regardless of inputs. It will start again, but only run for a few moments.
My initial thoughts are perhaps loose valves and a **** battery (as after this cycle it was about 2/3 depleted (again according to the charger).
Could it be the charging system not sufficiently charging the battery to continue to run? Could it be failing coils?

Where should I start?

Thank you gentlemen, sorry for the long read. Hope my laimen nature won't impede the story. I will happily clarify anything else if it aids in advice and troubleshooting, as well as provide photos if necessary.

 

[Lefty]

Set the valve clearances, tension the cam chain and do a compression test. then I'd make sure carbs are adjusted properly to run long enough to check timing with a strobe light. Put a volt meter on it while running. If close to 12 volts it's good enough for now but a new Reg/rect unit is probably due and is the best thing you can do for you bike except maybe tires.

 

[WintrSol]

Is that a 'smart' charger, or a common automotive type? A common 2A charger will kill a battery that should only get ~1.5A max, which a 'smart' charger will compensate for.

At idle, with all lights off, the charging system barely kept the battery up when new; the old rectifier will work against you here, as it doesn't pass as much charge into the battery as it ages. A meter on the battery will tell you if it is going down.

The ground for the starter button comes through the handlebar, and there should be a ground wire around the risers, connected to the frame under the cross bridge. Does your horn work?

Make sure there is not too much or too little oil; if you don't know, it should be checked with the bike on the center stand, and the dip stick resting on the case to measure, not turned in.

 

[LexCorbett]

Thank you for the advice gentlemen.

Timing chain was tensioned and valves are set as per Common Motor Collective instructions and specs by a red seal mechanic (or so I was told and paid for..). The carbs were also tuned (by same mechanic). This got the bike from non-running to the state it is in now.
Granted, my self diagnosing the excessive tappet noise was/is based on minimal experience, as I tried to express in the original post.

What is the procedure for checking timing with said light?

It is a typical 2A charger, rather than a smart one. I can't get the bike to run longer than 30 or so seconds to determine if charging really is the issue. Would the battery still operate the lights and accessories while failing to supply the ignition system?
The bike has been wired to meet Canadian automotive law (namely all time headlight and taillight operation), so minimizing draw at idle is impossible (I will work on wiring in a headlight switch). Horn does currently work, yes. I will check oil tomorrow.

 

[Lefty]

You could dissconnect the head light but I'd put a volt meter on it first and see what you got. Get an inductive timing light that clamps around the plug wire. Remove the left generator cover(lean bike to right so oil doesn't drip) and fire it to see if the rotor marks line up with index marks. A factory service manual worth a look.

 

[WintrSol]

Be prepared for the mess; oil will spray around the rotor when the engine is running. I bought a damaged but useful stator cover on eBay and cut a hole over the timing marks. There is still some oil to clean up, but lots less.

 

[Lost_Cause]

+1 on a spare stator cover to keep the oil in.

If you have a pamco... its almost a must to getting a really good idle and high rpm performance.

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