Threaded hole on exhaust header - plug it?

[Schming]

Hi boofer, You have one of the nicest looking bikes on this site.

Stellar, stunning job on the resto.

I've listened to the vids a number of times and sounds like a sticking lifter to me.

Is the crankcase oil level correct ?


You may have to pull the cam cover to inspect the valve train and measure the clearances.

[boofer]

Here is a better video of the "ping knock" sound.....it is pretty noticeable in this one:

View My Video

I'm curious about your comment on the vacuum canister.......do you mean the little brass canister down there on the vacuum advance assy ? It sure sounds like that area is rattling when I scope it but I just cant tell for sure Given the fact that it did run awesome for 10 minutes and I was able to sync the carbs......I am ruling out any kind of carb or core engine issue for now.

My steps at this point will be;

1. Run the coil / electrical tests to eliminate that side of it
2. Test vacuum advance operation (think there is a process for that)
3. Call my brother and have him come down from the artic U.P. of Michigan and fix it for me


Here are some more pics and thanks for all the advice over the last couple years on the project !! I might get it finished by the time we land a person on Mars if I am lucky.....

Front shot (the tank and side covers are fully repainted "Magenta Red".....AKA.....BROWN !!! FYI



Shot from the top:



Front:



Rear shot:



Fusebox area:



Bottom shot:

[IanDMacDonald]

Oooh. I know the feeling with the unknown rattles . . . What are your compression numbers? Disconnect the vacuum hose from the carb, pinch it, and see if the rattle continues. Suck on the hose (lol), and see if anything happens. Besides a bad pod on my mind, possibly a loose inner pipe on one of your headers? Have you tried cleaning the vacuum pod? I hope for your sake that's not a valve train issue.

[boofer]

Howdy,

Thanks IAN, I initially thought it was a valve type issue and the first thing I did was to indeed check the valve area for oil and it is perfect. I should mention that the engine ran like a clock prior to tear down....and I stored it here in a nice comfy garage and I had good rubber plugs in the exhaust portals....etc...etc........I'm thinking that the engine is okie dokie, at least the important stuff.

The perplexing thing is that at one point it kicked in and started running perfect....after warming up but I cannot get it to do that again. That led me to think electrical or vacuum advance.

I just checked the coils and such and actually have spares of everything and even changed them out with same results.

The vacuum advance advice above was interesting because there is clearly a rattle coming from the left side cover vacuum advance assy. I cannot find/see anything in there that is loose to rattle !!! I found a thread by TopCatGr58 (thread 9326) that gave a quick way to check vacuum advance. So I gave it a try and when I suck on the vacuum advance line it does indeed pull the plunger up, but when I hold and release the vacuum as he suggested, the plunger snaps back down really fast as if it were spring loaded or something.

Is it possible that the vacuum advance has sat too long and is bad ?

I'm not sure how that would cause a rattle sound under the cover but I can see how it would cause a misfire problem........I can also see where it may have possibly started to work for a while and then conked out again.......

Thanks for all the hints......I'm guessing that if I keep digging on the net and testing, I will be able to whittle down the possibilities.

Craig

[boofer]

Update, just for grins I connected the vacuum advance hose to the #2 carb boot intake and boy did I hear and see the clacking noise that you all are probably describing in that scenario..........so I'm still dinking around with it.

I wonder if somehow my timing chain is slipping.....hard to imagine since the engine was running perfect 4 years ago........oh well......that is why they call it a HOBBY

Craig

[donebysunday]

Could you try a new vacuum line from the advance to the carb ?

[boofer]

Just a quick update and a couple videos.

I think I am dealing with maybe a couple problems but narrowed it down a bit I hope.

Just for grins I hooked up the carb sync sticks to see how the vacuum was looking and the bike pretty much fired right up and sounded pretty good (no "knock ping"). I found that interesting because all that I did was to remove the vacuum line plugs on carb 1-4 and plugged in the gauges.

The carbs were a little out of sync as seen here:

View My Video

I then synced the carbs a bit real quick and it all looked pretty good as in this video:

View My Video

I still hear a valve like tick when she gets up over 3000ish RPM and I swear that when I put my ear up to the vacuum advance at idle I hear a rattling noise coming from it......I just cannot pin it down though......the advance is properly hooked up to carb 2 (carb, not boot).

I am starting to feel better that its not a major engine issue, probably the finiky vacuum or even a valve issue from maybe sitting too long ??

Anyhow, thought you might like to see the update

[boofer]

Oh....and I decided to put some smaller vacuum caps on the carb boots for now just so they are nice an tight.....maybe the ones I had on there were bigger than I thought and were leaking a little.....although it was not obvious....

[jetmechmarty]

The OEM vacuum caps are a little pricey, but they fit perfectly and last 25 years or so.