timing keeps going bad

djbrett · Post by **djbrett** » Wed Jan 18, 2012 4:21 pm

Ok, here's the situation. I've put about 6000 miles on my 65 this year and have run into a little problem. for the first 4000 or so, the timing was great everything ran great... I adjusted the timing once (broke a valve cover, thanks spokes for the replacement) and had no problems for a long time.
Then, I had a problem that was, apparently a number of things (plugs, carb adjustment, timing) that was posted earlier. I got everything dialed in and it was running beautifully again, but it would slowly begin backfiring and become a little difficult to start about a week after adjusting the timing. I have since adjusted it three times (the last one last week). Each time the timing has been off.
This project has made me begin to be more attentive and, this last time, it was only the valves on the exhaust side that were out.
One things that I am certain about is that my coil is ohming out (not sure that is correct term) at about 1 which is low.
My neighbor said that he knew that with big v 8's a bad coil can lead to misfiring and eventually engine damage.
In your expert opinions, could this be a coil issue? other ideas?
thanks,
brett

ByTheLake · Post by **ByTheLake** » Wed Jan 18, 2012 5:26 pm

Hmm ... can't see how a coil could cause a variance in timing.

Is the mechanical (centrifugal) advance sticking? Are the advance springs still there and connected properly? Do the advance weights return all the way to the inner position on their own, or do they need to be nudged?

I'm interested in watching this one play out.

Grunt · Post by **Grunt** » Wed Jan 18, 2012 6:03 pm

Loose cam chain, chain tensioner, or worn sprockets?

kartgreen · Post by **kartgreen** » Thu Jan 19, 2012 4:16 am

I agree with By The Lake ,checking the advance unit operation would be #1 on my list . Also setting the cam chain tensioner to take that variable out of the equasion ,although I don't think thats the cause .
When setting the point gap ,I set them at .014" and rotate the crank several times and recheck the gap .
Another observation that applies to any vehicle , clean the battery termnals and especially the ground wire at the ground point . It's amazing how many electrical problems clear up once a vehicle has good solid electrical connections .
Good luck in searching out your problem and please keep us informed .

Sam Green · Post by **Sam Green** » Fri Jan 20, 2012 7:55 am

Providing everything is locked up tight and nothing can slip, the only thing that can cause the ignition timing to alter (we are talking ignition timing are we) is drastic wear of the points heal, the part of the points that runs on the points cam.
I have been promising myself for sometime that I would make a guide that will allow the generator cover to be installed dead centre over the crankshaft.
This cover when fitted can be quite a bit out in any dierection and will cause excessive heal wear which will result in the ignition needing to be retimed at much more regular intervals.

Sam.

Sam Green · Post by **Sam Green** » Fri Jan 20, 2012 8:01 am

If I remember when I get home, I'll measure the heal on a new set of points so that you can compare the measurement with yours.

Sam.

Sam Green · Post by **Sam Green** » Fri Jan 20, 2012 10:43 am

The measurement is about 2.25mm from the inside of the foot to the heal on a new set of points.

Sam.

ByTheLake · Post by **ByTheLake** » Sat Jan 21, 2012 5:17 am

djbrett wrote:Ok, here's the situation. I've put about 6000 miles on my 65 this year ...

How many miles were you planning on putting on your '65 this year? I fully subscribe to "Ride 'em, don't hide 'em", but wow.

Jetblackchemist · Post by **Jetblackchemist** » Sat Jan 21, 2012 11:19 pm

Definitely check the cam springs 20+ years on springs is definitely iffy. Another cause of backfires and bogging down is if the needle jet clip is in the wrong spot...as it's position effects the mixture causing it to run rich or lean.

Dropping the needle lower leans it out, raising the needle makes it run richer. If it backfires and pops in mid range lower the clip a notch which raises the needle jet.

So don't forget Raising the clip lowers the needle and lowering the clip raises the needle.

djbrett · Post by **djbrett** » Sat Feb 11, 2012 3:31 pm

Wife is having a baby so I apologize for not getting back to everyone sooner. To answer a few questions:
As many miles as I can!

I'm talking tappets not ignition timing. It stalled on me on my way to work the other day. Spark, fuel, air but was kicking over funky. Again a tappet went out of adjustment. Exhaust side on left. Just adjusted it and it is running beautifully again.
1 I could just be an idiot figuring out how tight to tighten the lock bolts on them.
2 something like a spring or tensioner or wear.
time to start taking it apart a little to educate myself. Then, more info
it does kick over like I've got the clutch held in sometimes when it is really cold (for arizona)
Don't know if that is a clue or not
Thanks
Brett

Spokes · Post by **Spokes** » Sat Feb 11, 2012 4:18 pm

I think you answered your own question. The readjustment of the exaust valve and realizing good engine performance again tells the story. Perhaps some strong loctite on the tappet adjuster threads (after the next adjustment) might keep the lock nut tight longer.

djbrett · Post by **djbrett** » Sun Feb 12, 2012 6:49 am

Also, it looks like I need a new seal kit before I take off any side covers. Apparently that will have to wait if I want to ride today.

DanUhr · Post by **DanUhr** » Sun Feb 12, 2012 8:14 am

djbrett wrote:Wife is having a baby so I apologize for not getting back to everyone sooner. To answer a few questions:
As many miles as I can!
I'm talking tappets not ignition timing. It stalled on me on my way to work the other day. Spark, fuel, air but was kicking over funky. Again a tappet went out of adjustment. Exhaust side on left. Just adjusted it and it is running beautifully again.
1 I could just be an idiot figuring out how tight to tighten the lock bolts on them.
2 something like a spring or tensioner or wear.
time to start taking it apart a little to educate myself. Then, more info
it does kick over like I've got the clutch held in sometimes when it is really cold (for arizona)
Don't know if that is a clue or not
Thanks
Brett

It is also agood idea to check the cam for galling. If it isn't smooth it can very quickly wear the lifter.

djbrett · Post by **djbrett** » Fri Mar 16, 2012 9:23 am

My exhaust side, left adjustment is running out of room. Each time I have to adjust it, I have to screw it out a little more, and there is currently not much room between the bottom of the adjustment and the bottom of the thing it screws into (rocker arm?). Having never seen the inside, I was wondering if there are two rocker arms total (going straight through?) and I could just screw the intake side on the left out to gain more play on the exhaust side. Or is there another remedy for this?
To Spokes: Would that be the red loctite or the high heat? Also, how would I clean off the threads to get it to stick? A q tip and some carb cleaner?
Thanks,
Brett

ByTheLake · Post by **ByTheLake** » Fri Mar 16, 2012 9:55 am

If you have to back out the adjuster screw this much, that suggests the valve is quickly receding. Hard to imagine what else it could be.

Perhaps there's accelerated wear of the valve seat or the valve face or both?

Were these valves ground or lapped in recent memory? If these valves used a hard plating like stelite, lapping or grinding could remove this protective surface, accelerating wear.

It doesn't sound like an issue with the adjuster working its way loose.

Regarding your comment about the "insides" ... each valve has one rocker arm, and each works independently of the other. Adjusting the valve lash on one can't directly affect another.

If it was my bike, I'd pull the head for inspection and measurements to learn more.