Matchless G-15CS...Get it Running!

AgentX · Jul 6, 2016

So have the mag in place, timing wheel set up, and am trying to get the points opening timed. Using a thin tissue paper (don't smoke...) is futile based on the cramped space behind the inner primary cover.

Multimeter, however, seems to show continuity between both points and ground regardless of open/closed. What am I doing wrong? Proceeding with fumbling with paper for now... Thanks!

Edit:. With the paper, I think I got it. At tdc, the points are closed but on the verge of opening with the ATU fully retarded. If I hand-advance the ATU, they are just opened. Sound right?

Edit 2: should the ATU be snapping back sharply on its own? Mine doesn't seem to want to. Guess I need to wait on some springs. Grrrr. Unless this is normal while it is not bathed in oil from the timing chest supply?

texasSlick · Jul 6, 2016

AgentX said:
So have the mag in place, timing wheel set up, and am trying to get the points opening timed. Using a thin tissue paper (don't smoke...) is futile based on the cramped space behind the inner primary cover.

Multimeter, however, seems to show continuity between both points and ground regardless of open/closed. What am I doing wrong? Proceeding with fumbling with paper for now... Thanks!

Edit:. With the paper, I think I got it. At tdc, the points are closed but on the verge of opening with the ATU fully retarded. If I hand-advance the ATU, they are just opened. Sound right?

Edit 2: should the ATU be snapping back sharply on its own? Mine doesn't seem to want to. Guess I need to wait on some springs. Grrrr. Unless this is normal while it is not bathed in oil from the timing chest supply?

Review this thread:

setting-and-timing-k2f-magneto-t22888.html?hilit=K2F#p300760

The AAU (auto advance unit) should spring back on its own, but I would say it does not "snap" back. Too tight a chain tension will cause the AAU to "stick". You should have about 3/16 inch up/down slack in the drive chain at mid run.

Slick

AgentX · Jul 6, 2016

Thanks! That is extremely thorough.

I think I'll at least refresh my ATU springs, because even with the chain detached, it won't return. Chain slack was set as described at the tightest point in the run.

Maybe there's a problem buried elsewhere in the damned thing, though...grrrr. Tried lubing the crap out of it with penetrating spray lube, just to be sure it wasn't the lack of oil causing it. Stayed problematic.

texasSlick · Jul 6, 2016

AgentX said:
Thanks! That is extremely thorough.

I think I'll at least refresh my ATU springs, because even with the chain detached, it won't return. Chain slack was set as described at the tightest point in the run.

Maybe there's a problem buried elsewhere in the damned thing, though...grrrr. Tried lubing the crap out of it with penetrating spray lube, just to be sure it wasn't the lack of oil causing it. Stayed problematic.

even with the chain detached, it won't return

Definitely not normal. It must freely return or you will be stuck in full advanced mode, and will likely get kickback when starting. The springs are very light, they will not overcome any binding or friction whatever in the AAU. I do not think a DIY can repair a bad one, but there are shops that can rebuild them, but they may be in the UK.

Slick

AgentX · Jul 6, 2016

Gah. That sucks.

Britishonly.com offers refurbs for $250 with a $100 core charge; dunno if that means it's ultimately $150, or if they charge $350 when you order.

I've only ordered gaskets and stuff from them so far...

I'll also check with the guy who rebuilt my magneto.

texasSlick · Jul 6, 2016

AgentX said:
Gah. That sucks.

Britishonly.com offers refurbs for $250 with a $100 core charge; dunno if that means it's ultimately $150, or if they charge $350 when you order.

I've only ordered gaskets and stuff from them so far...

I'll also check with the guy who rebuilt my magneto.

BritishOnly prices are high!

Here is a link: They quote 20 pounds. Even with 2 way post, you should come out better.

https://sites.google.com/site/priorymagnetos/atd-units

Google around, you may find others.

Slick

AgentX · Jul 6, 2016

Video:

http://vid6.photobucket.com/albums/y218 ... wlvcda.mp4

AgentX · Jul 6, 2016

Wow, great link--thanks! I followed its advice and kicked the bike through in 4th gear with the ATU forward. Each time, the ATU returned to the proper resting state. Maybe I don't have a problem...?

Also proven: My oil pump works! :shock:

Edit: looking through the ATD rebuild (https://sites.google.com/site/priorymag ... edirects=0) on the Priory link you provided, I see something called a "C" washer on the ATD listed, between the dished washer and the fixing bolt head. Mine doesn't have that. Could be the issue...?

texasSlick · Jul 6, 2016

AgentX said:
Wow, great link--thanks! I followed its advice and kicked the bike through in 4th gear with the ATU forward. Each time, the ATU returned to the proper resting state. Maybe I don't have a problem...?

Also proven: My oil pump works! :shock:

Yes, turning the engine over can return a sticking AAU to full retard, providing the drive chain is not too tight.

If it consistently returns to full retard with proper slack in the chain when you turn over the engine, you are probably OK.

I still cannot fathom why your AAU failed to return even with the chain detached as you posted above, except if the magneto was holding it with the contact block sitting on a cam. Perhaps that was the case. You might test it again, chain attached but with contact block OFF the cams ... it should spring back on its own. If it does, you can sleep well tonight.

I would install new springs at the very least.

Slick

AgentX · Jul 6, 2016

Once again, thanks a million.

I just returned from taking it off the bike to find your message.

It returns very well when off the bike. However, the pressure from the bolt head against the dished washer is what is fouling it up. This is, I believe, what the "C" washer mentioned above is designed to prevent. The marking in the metal dished washer from tightening down the hex fixing bolt is the major cause of sticking.

Now I'm left wondering where to get one of those without a whole new unit! Or should I just get a large, thin washer and cut a section out with a dremel wheel to improvise a solution? I can't find anything promising on McMaster or Grainger.

Ed: C-washer located! Guy who did my magneto had one in the shop. Should have it in a few days. Even he said "just get a washer from Home Depot and cut a section out" but I'm really lacking in anything more than basic hand tools, so I'd rather give him $5 for the right part than go buy a hacksaw and files and try to cut a small washer neatly. I have a *ton* of tools but they're all in a household goods shipment right now...

texasSlick · Jul 6, 2016

AgentX said:
Once again, thanks a million.

I just returned from taking it off the bike to find your message. It returns very well when off the bike. However, the pressure from the bolt head against the dished washer is what is fouling it up. This is, I believe, what the "C" washer mentioned above is designed to prevent. The marking in the metal dished washer from tightening down the hex fixing bolt is the major cause of sticking.

Now I'm left wondering where to get one of those without a whole new unit! Or should I just get a large, thin washer and cut a section out with a dremel wheel to improvise a solution? I can't find anything promising on McMaster or Grainger.

Hmmm .... The "C" washer is called a "cover clip" and is Lucas part #498131. Perhaps you can find one if you google it. You might try skipsoldbikes.com. Skip has a lot of magneto parts, perhaps AAU parts as well. As I recall, my Atlas AAU DOES NOT have that clip, but my reference materials show it should. Mine works well without the clip ... just say'n, not recommending you leave it off. As far as I can tell, there is no particular reason for the opening in the C except to extract the clip without completely removing the fixing bolt. In that case, your improvised washer should do just fine.

Slick

AgentX · Jul 6, 2016

Thanks--the guy who did my mag service has one, so I should have it in hand in two or three days. Fingers crossed.

texasSlick · Jul 6, 2016

@AgentX

You wrote:

Multimeter, however, seems to show continuity between both points and ground regardless of open/closed. What am I doing wrong? Proceeding with fumbling with paper for now... Thanks!

Edit:. With the paper, I think I got it. At tdc, the points are closed but on the verge of opening with the ATU fully retarded. If I hand-advance the ATU, they are just opened. Sound right?

Multimeter will always show continuity (points open or closed) because there is an internal stator circuit, unless you remove the center fixing screw on the contact block.

Recommendations are to set timing with AAU wedged fully advanced. Then set to full advanced specification. The Atlas specs say 32 deg. BTC, but that was written when fuels were 100 to 105 octane. Moreover, the Atlas engine had only 7.5:1 CR. With modern fuels, and especially if your engine has 9:1 CR, then the Commando spec of 28 deg is more appropriate.

Again, review the procedure to set up and time a K2F. Follow it step by step.

Slick

AgentX · Jul 6, 2016

Cool, thanks! I had it fully timed to 32 degrees before I removed the AAU (/ATU/ATD) again to check it out. I'll do it to 28 when I get it back on there. Appreciate the information. My bike doesn't have an increased compression ratio far as I know, however. Would there be an easy way to check? Feeling with a wire for a domed vs. a flat piston or something?

texasSlick · Jul 6, 2016

AgentX said:
Cool, thanks! I had it fully timed to 32 degrees before I removed the AAU (/ATU/ATD) again to check it out. I'll do it to 28 when I get it back on there. Appreciate the information. My bike doesn't have an increased compression ratio far as I know, however. Would there be an easy way to check? Feeling with a wire for a domed vs. a flat piston or something?

There are bore scopes that may be borrowed from a professional mechanic friend, or possibly from auto parts suppliers such as Auto Zone. I'll bet Auto Zone has compression testers for loan.

You might possibly feel the piston contour with a wire .... worth a try. The original 7.5 CR pistons had a dished top (concave) rather than flat. Flat tops will be about 9 CR, domed pistons are likely to be 10 or more.

FWIW .... I set my timing to 30 deg. With 10.5 CR and 93 Octane fuel, it pings only if I go WOT at low rpm. If you have 9 CR or less, 30 deg should be fine if you do not hammer it at low rpm. A friend who set his Atlas timing to 28 with 9 CR tells me he has no ping at all. You decide.

Slick

Bernhard · Jul 7, 2016

texasSlick said:
@AgentX

You wrote:

Multimeter, however, seems to show continuity between both points and ground regardless of open/closed. What am I doing wrong? Proceeding with fumbling with paper for now... Thanks!

Edit:. With the paper, I think I got it. At tdc, the points are closed but on the verge of opening with the ATU fully retarded. If I hand-advance the ATU, they are just opened. Sound right?

Multimeter will always show continuity (points open or closed) because there is an internal stator circuit, unless you remove the center fixing screw on the contact block.

+ 1 battery and bulb set up will only work with this setup also :!:

Slick

AgentX · Jul 9, 2016

Thanks! Poked around with a wire; they are not concave and may be slightly domed. Previous owner knows they are not stock as the bike had a teardown in 1968. Per his extensive notes, which start from 71, the cylinder was bored and new pistons fit, no further info. The crank was balanced by Lindskog at this point and a crank throw was also ground.

The notebook is pretty incredible. I began taking my own notes to keep it up.

Spoke to previous owner and he recalls it may have 10.5:1 CR, but he's not sure. I will time to 29 see how that works.

Edit: Also got the c-washer already

Edit II: I was following the instructions in my Haynes manual. They did not say to use the cutaway timing cover...is that an omission, or is it unnecessary? I used it when setting the chain tension, which seems to be the major function.

texasSlick · Jul 9, 2016

AgentX said:
Thanks! Poked around with a wire; they are not concave and may be slightly domed. Previous owner knows they are not stock as the bike had a teardown in 1968. Per his extensive notes, which start from 71, the cylinder was bored and new pistons fit, no further info. The crank was balanced by Lindskog at this point and a crank throw was also ground.

The notebook is pretty incredible. I began taking my own notes to keep it up.

Spoke to previous owner and he recalls it may have 10.5:1 CR, but he's not sure. I will time to 29 see how that works.

Edit: Also got the c-washer already

Edit II: I was following the instructions in my Haynes manual. They did not say to use the cutaway timing cover...is that an omission, or is it unnecessary? I used it when setting the chain tension, which seems to be the major function.

Keeping a notebook is a good practice. I did so for all my vehicles in my youth, but have fallen out. I still make notes for the Atlas.

You should be fine with 29 deg advance and 10.5 CR. I have 10.5 CR and with 30 deg. get only a ping or two if I apply too much power at low rpm. A downshift would eliminate the pings.

If you have a cut-away timing cover, by all means use it when setting chain tension.

Slick

AgentX · Jul 10, 2016

OK, I think I have the timing nailed. We'll see... Hoping to put the carbs back on today, but want to wait for the new advance springs before I button up the timing cover. Will also try a test-fit of the timing cover to ensure proper standoff. May be posting more for help on that shortly.

While I was staring at the primary after I finished timing, I decided to pull the clutch plates and give them a scrub.

I'm guessing this is an aftermarket clutch...? Barnett? 5 steel plates, 5 dual-sided friction plates, 1 single-sided outer friction plate.

Initially, I assessed all the friction plates were in good shape. However, upon inspection, I'm seeing that one side is much thinner than the reverse on two of the dual-sided friction plates.

The healthy side is about a mm, while the thin side looks to be about .3-.5mm. Should I be replacing these ? If so, I guess I'll need to identify the make.

AgentX · Jul 10, 2016

Can I yank the center/spider off without taking the whole clutch off the shaft? I don't want to lever anything too hard, but it seems I should be able to remove the allen screws to get all that off, right?

From the diagram, I can't tell what holds the clutch body to the race plate. I got the cover plate off and am staring at the spider and rubbers, but don't know if I can proceed without the puller tool, since it's really set on the shaft. Recommendations aside from the puller tool...heat? I've tried light taps with a rubber mallet but it's still on there tight.

Matchless G-15CS...Get it Running!

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