1965 Matchless G15-CS

AgentX

Over 1,000 Posts
Just found a timing cover and attached tach drive on Ebay for $120; given the cost of a tach drive alone is $100-300 depending on source, I went with this.

The timing covers on all G15s and related models I've seen online have the tach drives oriented vertically, clearing the exhaust and routing close to the gas tank up to the tach head.

The timing cover on my bike doesn't seem to be original and has the cable oriented 45 degrees towards the downpipes; this causes the cable to run askew and hard on the pipe, and may exacerbate the tach problems. It also looks awkward and puts the cable in an exposed position, so I'll give this one a try. Hopefully between all the parts I now have, I can frankenstein it all together. Not super-looking-foward to opening up the timing side again, but c'est la vie.
 

AgentX

Over 1,000 Posts
Looks like this new timing cover will work...had to check on whether this set screw needed to be in the oil passage here or what...Norton guys confirm it's so.

1585007725819.png


Tach drive is set for the correct angle, but was modified to do so...old bosses filled and new ones drilled. No matter, looks solid.

1585007757906.png


1585007788649.png
 

AgentX

Over 1,000 Posts
So a I got a very clean solution to sealing an exploded tach drive from a respected Norton guy, using epoxy. But I also remembered I had a book on bike restoration a solution that is just a little more "me," which is pounding a nickel in place for a tight friction fit.

Original thin cover, against which the gear turns minus some end play, is underneath. They just tend to come loose, as there is little meat for a good lasting fit between the two.

Honestly, I couldn't say no to the chance to put Thomas Jefferson's face right next to "Made in England," especially as a fix to an engineering deficiency.

IMG_20200329_105532352.jpg
 

AgentX

Over 1,000 Posts
I had to go to the store and brave coronavirus (well, actually giving it to other people, it seems...we've been down with light symptoms for a week now...)...

BUT, thankfully, I was able to procure two nickels for only $15.34 plus tax!!! So lucky!
 

canyoncarver

'hacking is learning'
DTT BOTM WINNER
That's a neat trick. I'll guess you packed some grease back there first? I need to do this on the P11.
 

AgentX

Over 1,000 Posts
Yeah, I got pretty precious about finding the right kind, then just went with the thick brown hi-temp grease I had on-hand and a little Gibbs Lube sprayed in which thinned it up. Little stiff at first, but ran the unit by hand then via the cable in a drill and it is smooth and easy-turning.

I think gray moly grease is what was in there before.

Also, not to commit any violations of the US code, but...check and adjust your fit carefully on those nickels.
 

AgentX

Over 1,000 Posts
Other notes: Figured out why the previous owner changed timing covers...he transitioned the bike from its original low-pressure rocker feed off the return pipe to the high-pressure feed off the timing chest, necessitating a later-model cover. Very common mod.

New cover is being a bastard about fit, though, binding somewhere. I'm slowly working with the locating dowels to try to get it fit smoothly, so that I can do a proper standoff check. The oil pump mates with the oil galleries of the timing cover via a small conical rubber seal, and it needs to have just the right standoff via gasket and shimming to operate properly once screwed down. To check that, you're supposed to gauge the (allegedly even-all-around) gap between the cover and the cases resulting from the seal pushing the cover back away, but as it won't slide on smoothly, it's not really something I can do without a lot of guesswork.

Also going to re-time it to 28 degrees while the covers are off. It was timed to 32 or so before...I didn't realize that there were high-compression pistons in it, nor that these needed a different timing spec.
 

AgentX

Over 1,000 Posts
So over the past few days, I got the timing spot-on-nailed at 28 BTDC, re-set the timing chains' tension (was way too tight as set by the garage who re-timed it earlier on), pulled and reinstalled the oil pump to check for gaskets behind it (part of setting the timing cover's offset...) and a few other things.

Re-timing and setting the tension is best done with a "cutaway" cover, either factory or home-made...I inherited this one.
IMG_20200403_130056399_HDR.jpg

I can't even begin to explain how tedious all that is. Both the primary and the timing covers need to come off; this means the pipes and footrests need to come off...the footrests in particular are a mallet-fest pain in the ass, locating on a big square stud that runs across the bottom through the engine plates.

However, my inner primary mods were 110% worth it, and gave much better access to the magneto face without needing to take off the alternator and clutch and inner plate. Much more accurate timing it without anything else in the way. The inner plate is its own nightmare to remove and re-mount because of a finicky support bolt mid-point, added to the 1965 year after issues with earlier primaries. Subtract yet another messy oil bath and gasket nightmare from the equation for a bigger bonus.
IMG_20200402_162455061_HDR.jpg

I'm sure a guy named Nigel in 1967 could have done it all in 10 minutes, but it's pretty finicky stuff for the rest of us. I applied mind-lube liberally to improve the situation.

IMG_20200402_162553180_HDR.jpg


After the re-time, still didn't have confidence the left hand cylinder was firing as it should. Thought maybe the air filter was obstructed, but nah. Then found the plug lead off the magneto was tenuous, so I fixed that and got a spark that made me wish for a welding helmet. Then I realized the actual problem was just an imbalance in the carb air screws and it started running really strong. Sound was what the "snortin' Norton" should be, finally. New tach drive was running smooth, though cable not yet attached.

Again, a lot of things like that wouldn't be such a problem if everything on the bike wasn't so physically hard to access...fitting the plug lead back, even, is a major bit of guesswork because it's on the underside of the mag with little clearance to the gearbox in which to work, and has to be done by feel because there's literally no way to see it, even with a mirror laid in there.


Anyhow...test ride round a few blocks after that really showed a re-awoken engine through the powerband. Can't work more on it now, or ride, but hoping for a longer opportunity tomorrow. Will get the tach cable reattached and, um, put the rear brake back on. Speedo is still bouncing, and I've narrowed it down to the interface between the speedo drive and the cable. Whether the cable is too short or the drive unit shot, I can't say...but both are brand-new, so we'll see.
 
Last edited:

AgentX

Over 1,000 Posts
Mr. Jefferson in situ, working well and routing the cable in a much better manner.
IMG_20200407_170830203.jpg
 
Last edited:

teazer

Over 10,000 Posts
DTT BOTM WINNER
Has that K2F got an automatic Timing devise in the gear drive? It's been a long times since I rebuilt one of those but they give an amazing spark as long as the pickups are good and the small screws at the other end are there to short out stray sparks. I always used a Manual advance retard on my Triumph pre-unit motors. The brass balls in a ATD always wore out of round and timing could wonder lonely as a cloud.

And yes. you should be able to arc weld with one (almost) But what is that shiny thing where the wobbly steel top hat usually sits and why does that primary chain look like a belt......
 

AgentX

Over 1,000 Posts
Yeah, the ATU sits in the timing chest at the mag drive gear. Read back for the story on the belt...

(Edit: This ATU has no brass balls...bob weights with springs...)

Which top hat do you mean?


Altogether, I've found the carbs now need a full readjustment and it's been annoying me, but am gradually learning the ways of dual-amal twins. Problem is getting it running well enough at the outset so that it will run on one cylinder so I can work on each cylinder independently.

(I found part of the unneveness I was experiencing between cylinders was due to the top ring of one carb backing itself off.)
 

AgentX

Over 1,000 Posts
I think it calls for video and awesome sounds.

From yesterday...probably needs another after more tuning...

But still it's like it has 58.6% more snortin' in mah Norton now.
 

teazer

Over 10,000 Posts
DTT BOTM WINNER
Clutch pressure plate = top hat.

Brass balls in some ATU - may be they were in BTH mags and not Lucas. I had one and threw it out to revert to manual A/R?
 

AgentX

Over 1,000 Posts
Ah. Yeah, I rebuilt the clutch with a nice new pressure plate and hub and cushes and barnett plates, only to switch to the Newby unit.

And I cannot get the LH cylinder running well now (again). Argh this thing is gonna kill me.
 

teazer

Over 10,000 Posts
DTT BOTM WINNER
Newby stuff is super nice.

I never had any isues with Amal carbs. They are pretty basic, but the mounting flanges bow really easily allowing air leaks. Might be worth popping them off and get the faces flat. I use wet and dry on an inspection slab but there are other ways. Is it possible that the left flange O ring might be undersize and not sealing properly?
 

AgentX

Over 1,000 Posts
Just test-rode for a bit. LH exhaust was burbling and snapping coming off throttle, which should mean lean, right? But the plug is black and crusty while the RH is clean and tan. (That said, in mid-range and up it seemed to be fine, to me...however I don't have any experience with the bike at its optimum for comparison.)

Both are set precisely the same way...totally in sync, same throttle stop height, same pilot mix. (Edit: after more riding and adjusting, I think maybe the difference in pilot mix just due to the difference between the carbs...as I narrow down, maybe it is only a turn or a turn and a half, which seems huge but could be due to very slight differences in the old carbs and their adjuster screws I'm thinking.)



I originally thought maybe there was a significant timing variation, and there IS a .001 difference between the points gaps on either side, but it didn't seem to me it'd cause this much of an issue.

Guess I'll check for an air leak best I can, then take the carbs off and check/clean everything, and take care re-mounting them. Might be worth putting in richer pilot jets, too, as the ideal mix (so far) has been with the air screws almost fully in, at least on the RH cylinder that's working OK.

They were fully cleaned when they were sleeved, but I guess with it sitting around so much over the past few years it's possible they need some again.


That said, the difference between the cylinders has always manifested somehow. Hmmm. I will do another compression test, but last time it was about even.
 
Last edited:

AgentX

Over 1,000 Posts
Well, carbs are off and I think the flanges have a bow to them. I had tightened them down really gingerly but who knows when it happened... Also, I had them re-sleeved when I got the bike and the slides move perfectly, so the carb body is not warped. I may try sanding them flat with some wet/dry taped to my buddy's band saw table in the garage.

Also my tach drive shat itself AGAIN. I cannot understand this at all. Gears mesh, thing turns fine, good friction fit between the plug and the drive body...tach just serviced and running smooth...what the hell gives?

I will try to get the engine-driven gear out of one of the other tach drives and replace that gear once I get the bike running again. Maybe it has an imperfection that's the issue.
 
Last edited:

DTT Bike Of The Month Gallery

DTT Light or Dark

www.jadusmotorcycleparts.com
www.cognitomoto.com
https://www.townmoto.com
www.speedmotoco.com
www.lostapostle.ca/
www.sparckmoto.com
Top Bottom