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Discussion Starter #1
I have my 67 TR6C running. Starts well. Idle is good. New Amal carb. Fresh gas. New plugs. Missing badly on acceleration.
I took off the points plate to look at the advance mechanism. The weights do not move the cam very much. There is a short peg on the cam that engages a hole underneath the back weight. This seems to keep the cam from moving more than a few degrees. Is this correct? Should the cam rotate to the limit of the slot in the weights? When retracted, notch in cam is straight down.
 

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Does this model have ET (Energy Transfer) ignition? If so then the advance is limited to 5 (?) degrees. Otherwise the advance is about 12 degrees. Crank degrees is double.
The bob weight are universal, it is the pin in the slot that limits movement.
 

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Discussion Starter #3
Yes. ET ignition. Thanks. I'm replacing points and condensers. I think the points cam followers are worn too much to get static timing set.
 

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Hi MLW9110, What does motor do when you rev it in neutral? If you slowly open throttle, will go to high rpm without misfiring?

What version carb are you using? Mono block or concentric. What size? It could be carb problem?? Check all the jets, slide, float level etc. "Ready to tune" new carb may not have the correct components you need.

When you say points cam followers, are you talking about the rubbing blocks on cam? If rubbing block is worn out, I expect you'll need new points.

Daiihci points have worked good for me. Be sure to grease the rubbing block & a thin smear on cam. I have good results with Lubricam SL-2. Regular grease is better than nothing, but I find Lubricam tends to reduce rubbing block wear better than normal grease & Lubricam stays put well in the heat of the points cavity. This also works for me on shaft of points cam & slots in weights. EBay or parts sellers for points. Some autoparts stores sells Lubricam, or eBay. $12.50 free shipping. It is worth the cost.

Yes the AAU has less advance & is specific to ET ignition so to speak.

Did the bike used to run good?

The alternator rotor has to be set in correct position in relationship to the stator to make good spark. Crank sprocket must be installed in correct position. Then pin in sprocket goes into hole in rotor.

ET ignition is sensitive to every adjustment. It all has to be just right. The thing is the rotor magnets have to be set such they line up with poles on stator & ignition timing must be just right so the coils are charged/discharged with everything in perfect sync.

Here's a link that may be helpful. Very helpful.

Back in the day we didn't give ET a though. Just set points & timing to specs. Bikes started & ran perfectly. They were only 3-5 years old though. Even the AAU wasn't worn out yet.

Don
 

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Discussion Starter #5
Hi Don. Rubbing blocks. Now I know the proper nomenclature.
In neutral, opening throttle slowly it does not miss.
Carb is a new concentric set up for my bike by vendor. I'm looking it over and will make sure it's right.
I've read the article and it has been helpful.
Spec for static timing on my bike is 29 deg BTDC.
I don't know much about the history of the bike. It ran but was missing when I got it. I rode it briefly but it had ancient Dunlop Trials on it, brake light was out and brakes were scary. Had a monobloc on it that looked pretty rough. I decided to put a new concentric on rather than try rebuilding the monobloc.
Bike now has new tires and brakes and I'm working on the other problems. It rides well and has plenty of power when it's not missing on acceleration.
Thanks,
Mike
 

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If you haven't already changed the points to 6CA from the original 4CA, it might be worth doing. It makes setting the points much easier. Then just make sure the condensors by the coils are working okay.
 

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Hi Mike,
I presume you have already fixed this bad wire.
735784


I had a BSA B50MX Fitted with ET.
Never ever will I endure ET ignition again.

Good luck, (you will need it)

Regards
Peg
 

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Discussion Starter #9
If you haven't already changed the points to 6CA from the original 4CA, it might be worth doing. It makes setting the points much easier. Then just make sure the condensors by the coils are working okay.
I'm pressing on with the 4CA. We'll see if I end up regretting it! Thanks.
 

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Hi MLW9110, I'm sure you know this. There is a direct relationship to point gap & timing.
So if your 2nd point set you set timing by changing gap. Should your gap get too far off to set timing with those points, skew the gap some on the first points that you rotated plate to set timing. Closer or wider depending on which way the 2nd set needs to be. Certainly a fiddle. It can take a lot of time to work this out.

I make cheat sheet of what changes effects where timing is. Luckily it doesn't matter how long it takes. Just the end results.

My '64 Mountain Cub has ET. I didn't ride it much but it started & ran good.
Don
 
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