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Need help with points #777738 07/02/19 2:55 am
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Jaybird79 Offline OP
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Ok I need some help here. I have a 65 500 with what I think is the 6CA points? Im trying to set the static timing and tried following the truimph service manual but it seem like its all over the place and think it uses the 4ca?(Not sure how much different it is). Anyways I found this site and tried following it but noticed my cam lobe does not have the same line or mark. (650 only?)

http://www.hermit.cc/tmc/technote/igtiming/

The ones that are there appear to be PO made.
[img]https://photos.app.goo.gl/7boMhCGwCH4pKSDr5[/img]

So Far I tried setting the static [email protected] .015 after the line for both. I noticed If I keep turning over the engine the gap seems to increase at half way or the top of the Lobe. Is this normal or is the timing line in the wrong place?

Thanks in advance.

Last edited by Jaybird79; 07/02/19 2:57 am.
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Re: Need help with points [Re: Jaybird79] #777745 07/02/19 5:53 am
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Are you turning the cam the right direction and timing just after the mark ( the high spot ) ?


The aau plate in your picture looks to be 6ca ( or later ) ... with remote condensers .
But the pictures angle leaves some doubt as to the cam profile and its concentricity to the aau plate .

For reference
The 4ca cam has 86 degrees of dwell ( closed degrees )
The 6ca has 160 degrees of dwell .

Perhaps some dpo moded a 4ca cam to run with a 6ca aau plate ?
.

Re: Need help with points [Re: Jaybird79] #777750 07/02/19 7:04 am
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Originally Posted by Jaybird79
Ok I need some help here. I have a 65 500 with what I think is the 6CA points? Im trying to set the static timing and tried following the truimph service manual but it seem like its all over the place and think it uses the 4ca?(Not sure how much different it is). Anyways I found this site and tried following it but noticed my cam lobe does not have the same line or mark. (650 only?)

http://www.hermit.cc/tmc/technote/igtiming/

The ones that are there appear to be PO made.
[img]https://photos.app.goo.gl/7boMhCGwCH4pKSDr5[/img]

So Far I tried setting the static [email protected] .015 after the line for both. I noticed If I keep turning over the engine the gap seems to increase at half way or the top of the Lobe. Is this normal or is the timing line in the wrong place?

Thanks in advance.

You have the 6CA system, the 4CA have the condensers on the same plate, very crowded! Sounds like your AAU is bent and doesn't run true. The "procedure" is to hit it with a hammer until it runs true.
Use a soft head hammer if you can, or at least a small one, and go about it carefully.

Re: Need help with points [Re: Jaybird79] #777752 07/02/19 7:06 am
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You need to cover that yellow wire where the copper it exposed. I haven't done points for a while, but the gap you set should be the widest the points get. If it is getting bigger at another position as you rotate then you haven't set them right. Make yourself up a little test light with some alligator clips and check when the points are just opening or closing and set the timing statically first.

Re: Need help with points [Re: Jaybird79] #777753 07/02/19 7:46 am
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Hi Jaybird79, You have 6CA points plate. I find it will work fine with the earlier cam or the later cam on 650, but I've not used it on a 500.

The 4CA plate doesn't use the sub plates for points so for 4CA you set the points gap to spec. Then rotate main backing plate to set timing for one points, then adjust points gap to set timing for the other points. The 2nd set of points gap will generally no longer be .015", but it works ok anyway. Widening points gap advances timing, closing retards.

The 6CA you have to set the main backing plate as a guess where you think it should be. Often quite offset of center on 650s. Then you set gap. Finally you set timing by moving the sub backing plates until timing is correct. Often you get it on one set, but don't have enough range of movement with the eccentric screw for the 2nd set. Think of how far you are off. Move the main backing plate more than you are off. This will get you back into adjustment range of backing plates.... Now go back & recheck/set points gap as you'll find it often changes. Now check timing on both points again. If you can't get enough range, move main backing plate again, adjust gap & so on. Until you get lots of practice it can easily take hours. With practice it's fairly easy, but still some trial & error. Be sure to back off screws enough the eccentric cam screw can move the sub backing plates without much force. Use a fine tip marking pen to make witness marks along the sub plates so you can see how far to move them.

The points gap should be set with the line on end of cam that is near the front set of points lined up with rubbing block. Not the wide notch in cam. The gap tends to increase on the bikes I've checked. So I feel that is normal to a degree. But the AAU if not centered can make this much worse.

Are you using degree wheel on AAU to set timing?

How are you holding the points cam in the full advance position when you set timing? Does your degree wheel tool bolt properly lock the points cam? You must lock the AAU in full advace (clockwise) with a flat washer like a drain plug washer with a large flat washer on top it, such it holds it in the advanced position, if your degree wheel bolt doesn't lock it properly . I take small pocket screw driver & stick it into the notch end of points cam to hold it full advance while I snug the degree wheel bolt to lock it in full advance.

Also if the AAU/cam is not perfectly seated in exhaust cam the points cam will "wobble" as it rotates making the gap huge or very narrow when the cam rotates. This can also sometimes be seen as the rubbing block of both points doesn't set flat on cam, but looks like points are canted on backing plate, when in fact the points cam/aau is not properly seated in its taper in exhaust cam. As was pointed out in photo it looks like the aau is not quite centered, but again just might be illusion in photo. But that needs to be checked. You can pop aau with the puller tool & carefully feeling it's centered as you tighten the retaining bolt. Final tighten retaining bolt. This will lock the cam on taper so it doesn't come loose when you remove bolt to install degree wheel. I've never tapped cam sideways like shop manual speaks of. I've always popped aau off taper & reinstalled straight. I've seen a few wobbly ones & they straightened out fine when I put them back on.

The static timing is pretty close within 1 degree or so. Strobe timing is better if possible. I generally set static timing first if I have to remove backing plate for any reason. Be sure to unlock the cam during strobe timing.

Once you finally get it take good photo of backing plate position. That is a key factor. Once you get it all set up& timed correctly, in the future you can replace points, set gap & go straight to strobe timing. Be sure to put a fan in front of motor to keep it cool during strobe timing. It will overheat very quickly without a fan.

Remember it's a lot of trial & error & time consuming.
Don


1973 Tiger 750
Re: Need help with points [Re: Jaybird79] #777754 07/02/19 7:55 am
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Jaybird- Don has given a really good description there.

If your crankshaft is original you won't have two slots for the timing plunger behind the cylinders- only one for tdc. This requires a different procedure for actual timing as Don describes (using disc) as opposed to the one in your link. The only thing I would add is to use the special degree disc on the cam (with compressed markings) or a normal one on the crank (other side of engine). If you have the three hole cover on the primary the latter is easy. Your bike wouldn't have had this originally.

Dave

Last edited by dave jones; 07/02/19 8:06 am.
Re: Need help with points [Re: quinten] #777788 07/02/19 4:53 pm
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Originally Posted by quinten
.
Are you turning the cam the right direction and timing just after the mark ( the high spot ) ?


The aau plate in your picture looks to be 6ca ( or later ) ... with remote condensers .
But the pictures angle leaves some doubt as to the cam profile and its concentricity to the aau plate .

For reference
The 4ca cam has 86 degrees of dwell ( closed degrees )
The 6ca has 160 degrees of dwell .

Perhaps some dpo moded a 4ca cam to run with a 6ca aau plate ?
.


I'm turning the cam clockwise and I am adjusting the the gap after the line seen in the photo. I really Hope this is not a 4ca cam. Plus this is a 500 and unsure if there are differences with that as well when it comes to 650's vs 500's.

Here is a photo of the cam straight on without the bolt.Also it is set at TDC with plunger tool.
https://photos.app.goo.gl/964GzhAtmMr9y7MJ8

Last edited by Jaybird79; 07/02/19 4:54 pm.
Re: Need help with points [Re: TR7RVMan] #777792 07/02/19 5:43 pm
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Jaybird79 Offline OP
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Originally Posted by TR7RVMan


Are you using degree wheel on AAU to set timing?

How are you holding the points cam in the full advance position when you set timing? Does your degree wheel tool bolt properly lock the points cam? You must lock the AAU in full advace (clockwise) with a flat washer like a drain plug washer with a large flat washer on top it, such it holds it in the advanced position, if your degree wheel bolt doesn't lock it properly . I take small pocket screw driver & stick it into the notch end of points cam to hold it full advance while I snug the degree wheel bolt to lock it in full advance.


Don


Hi Don,

I do have a degree wheel like this but have not got that far yet.The Cam lobe is throwing me off since it does not have a proper timing mark like the one here and the profile looks different. As for the locking the point cam I was just thinking of holding it with the screw driver from the large notch? Also want to ask how much resistance should the cam provide while advancing? I'm noticing I can advance the cam and it will stay in location without returning.(Bad springs?)



Btw to all others who have replied to this thread thank you for your responses, much appreciated.

Re: Need help with points [Re: Jaybird79] #777798 07/02/19 6:52 pm
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Just a few observations.

It does look like a short dwell cam, so likely the 4CA type that came with the bike.

Whether this has any real impact on running, I couldn't say.
From a theoretical point of view, a longer dwell allows the coils a longer time to fully charge before the contact breaks to initiate the spark.
The dwell is always the same in degrees, but as rpm rises the dwell time shortens proportionally. So a shorter dwell may result in a less powerful spark at high rpm.
Presumably there were reasons that Lucas changed to the longer dwell cam in the later 60's, and perhaps this was a factor. Other possible motivations may have been that longer dwell equals less time that the rubbing block is rubbing (so reduced wear) and maybe that improvements in alternator output allowed the ignition system to draw more power (longer dwell means longer current draw).

I cannot see a mark on your cam for gap setting, it is usually a very distinct line. All I can make out under magnification are some very vague marks, which may be nothing at all.
I would go with T150V's suggestion to set the gap when the rubbing block is upon the "base circle" high level of the cam. This would be considerably further CW rotation from where your last pic shows. The rubbing block is only part way up the ramp in that pic.

Your two point sets are clearly different, as in not installed at the same time and of different manufacture. As they're usually bought in paired sets, it is of note.

The right fixed contact is ~half way through its life.

The left ones are still close to original thickness. However, the fixed contact has that cavity, which has a suggestion of arc erosion. Also, a stain is evident on the backplate behind that contact that also suggests arcing.

I think that you'd be justified in replacing the points and condensers, and arguably the AAU/cam.

Re: Need help with points [Re: Jaybird79] #777800 07/02/19 6:57 pm
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Ok, I ended up just pulling the everything out to see what was going on.

Here is a pic of the AAC. It had a pretty large burr at the pin location on the back so I cleaned it up with a fine file. I noticed the slot is angled, is this normal?

https://photos.app.goo.gl/7RqwQLandSt9LfxDA

Here are some pics of the cam itself.

https://photos.app.goo.gl/5gW2T3BoCKATfXQS9

Re: Need help with points [Re: Jaybird79] #777801 07/02/19 7:24 pm
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That is a 4ca aau. It is not as tall as the 6ca and you can see that the points heels have been running right at the top.

I had a 4ca cam with my 4ca points but read (in a Triumph service bulletin) that it is better to use the later cam with the changed dwell as the earlier one could end up damaging the engine. I did not have any trouble but changed anyway. They are pretty cheap second hand.

Dave

Re: Need help with points [Re: Jaybird79] #777805 07/02/19 8:05 pm
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That's a good point that DaveJ raises there. I was not aware that 6CA cams were longer.

It should be obvious in the wear patterns on the rubbing blocks if they extend further than the end of the cam, let alone being evident when assembled.

If this turns out to be the case, I think new parts all round would be in order, as well as perhaps some good screwdrivers!

Re: Need help with points [Re: dave jones] #777807 07/02/19 8:58 pm
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Jaybird79 Offline OP
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Originally Posted by dave jones
That is a 4ca aau. It is not as tall as the 6ca and you can see that the points heels have been running right at the top.

I had a 4ca cam with my 4ca points but read (in a Triumph service bulletin) that it is better to use the later cam with the changed dwell as the earlier one could end up damaging the engine. I did not have any trouble but changed anyway. They are pretty cheap second hand.

Dave


Thanks for the verification, I had a hunch but I was'nt to sure.Glad I found out now don't want to have a holed piston.

Last edited by Jaybird79; 07/02/19 9:08 pm.
Re: Need help with points [Re: koan58] #777808 07/02/19 9:07 pm
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Originally Posted by koan58
That's a good point that DaveJ raises there. I was not aware that 6CA cams were longer.

It should be obvious in the wear patterns on the rubbing blocks if they extend further than the end of the cam, let alone being evident when assembled.

If this turns out to be the case, I think new parts all round would be in order, as well as perhaps some good screwdrivers!



Yea the 4ca cam is no good from what I have read and can cause some serious damage. Also you are very right about new parts as these have seen better days, I already got good drivers on hand. The PO sure did a number on these cry

Re: Need help with points [Re: Jaybird79] #778270 07/10/19 1:39 pm
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I put a 6ca timing plate on my 67 tr6c. I couldn’t find new condensers that would fit the 4ca plate. The 6ca is a lot easier to adjust. I set timing buy using the TDC notch then putting a plunger in the spark plug hole and turning crank back 7/16”. Then I set the points using a continuity meter that beeps when the point starts to open.
Runs good and starts first kick usually. I put the condensers by the coils.
This a ET ignition.

Re: Need help with points [Re: Jaybird79] #778347 07/11/19 6:24 am
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Hi All, Hmmm.... I wonder if the 6CA cams were longer because the point are on a sub base which moves them outwards (to the right) by the thickness of the sub plate?

Since the timing is set after points gap was set I can't see the dwell difference causing motor damage. I've seen dozens of guys set the gap way off & as long as the timing is set correctly the bike runs fine. Even with a gap of only .005". On paper incorrect dwell is hard on coils & it can be, but they don't seem to fail often.

The 4CA cam didn't cause damage. Even if the rubbing block was slightly off the cam end, it would work. Take a razor blade & take some plastic off end of cam. Trust me it won't wear noticeably faster.

Luckily the timing retards as the rubbing block wears & closes gap. Too much advance is the piston killer.

Points cam lube on the rubbing block is most important. I've found the rubbing block hardly wears at all using Lubricam SL-2. This stuff is good. Not many places stock it anymore. eBay has it. $10 free shipping.

It cannot be overstressed to set the timing correctly on both points after gap is set.
Don


1973 Tiger 750
Re: Need help with points [Re: Jaybird79] #778385 07/11/19 5:22 pm
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Don- You are right that the 6CA cam is taller because of the sub plates. You can see in Jaybird's pic how the heels of the points were running right at the top of the 4CA cam.

The Triumph service sheet said that bikes with the 4CA cam and a certain make of coils caused engine damage, as I remember. I will dig it out later.

Dave

Re: Need help with points [Re: Jaybird79] #778399 07/11/19 7:20 pm
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Rouge sparks with the early 4ca points cam was a huge warranty issue in the day. It's hard to imagine that any of the original ones are still around. The rouge sparks cause seizures. That sometimes causes catastrophic engine failure. (think grenade.)
However, anything is possible.
Cheers,
Bill


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Re: Need help with points [Re: HawaiianTiger] #778405 07/11/19 7:58 pm
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The 86 degrees of dwell was not the problem .
It was points bounce at higher RPMs
Or
when the points closed , at any rpm , possibly causing a secondary coil induction .

The problem showed up with the change from 6 to 12 volts .
When the Switching voltage was doubled and some brands of coils reacted unexpectedly .

The solution was to
move the points closure contact "point"
to a dwell angle
Where any errant , secondary spark would happen
at a safer angle for the piston .
This coincides with the increased 160 degrees of dwell .
( any wasted Sparks now happen where they can't do damage )

It was easier to overheat the coils ... they seem to handle it .
Than to deal with holed or seized Pistons .

Re: Need help with points [Re: Jaybird79] #778430 07/12/19 1:27 am
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Would an EI solve the problems?


1968 T120R
1972 T120RV
Any advice given is without a warranty expressed or implied.
Re: Need help with points [Re: desco] #778438 07/12/19 4:45 am
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Originally Posted by desco
Would an EI solve the problems?


Yes, with this caveat:

Electronic ignition is more voltage-sensitive than breaker point ignition, so your battery and charging system must be up to snuff at all times.

Last edited by Mark Z; 07/12/19 12:04 pm.

Mark Z

'65(lower)/'66(upper, wheels, front end, controls)/'67(seat, exhaust, fuel tank, headlamp)/'70(frame) A65 Bitsa.
Re: Need help with points [Re: Jaybird79] #778468 07/12/19 2:03 pm
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1972 Triumph. 33+ years with a Boyer. One failure due to a low battery and I still got home by revving the engine.
1968 Triumph. 15+ years with a Pazon. No problems. I would rather have to pay a little more attention to the charging system than go through the frustration, time and tears to keep those damn points adjusted.


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Re: Need help with points [Re: desco] #778524 07/13/19 3:26 am
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Originally Posted by desco
1972 Triumph. 33+ years with a Boyer. One failure due to a low battery and I still got home by revving the engine.
1968 Triumph. 15+ years with a Pazon. No problems. I would rather have to pay a little more attention to the charging system than go through the frustration, time and tears to keep those damn points adjusted.


Agreed. Going on 20 years with a Boyer EI on my A65, never looked back. Charging system should be up to snuff anyway; the EI merely forces the issue.


Mark Z

'65(lower)/'66(upper, wheels, front end, controls)/'67(seat, exhaust, fuel tank, headlamp)/'70(frame) A65 Bitsa.
Re: Need help with points [Re: Jaybird79] #778536 07/13/19 7:56 am
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Points do seem to have quite the following, however like it or not electronic ignition is the single best thing you can do to your ignition system. The idea of sticking with points in order to avoid having a working charging system has always seemed ridiculous to me.

Rod


So remember, when you're feeling very small and insecure,
How amazingly unlikely is your birth;
And pray that there's intelligent life somewhere out in space,
'Cause there's bugger all down here on Earth!
Re: Need help with points [Re: Jaybird79] #778544 07/13/19 11:37 am
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Points can be just fine. I’m finding that new sets of points nowadays are just not good enough for regular use.


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