Crack in Kickstart Shaft

Has anyone experienced a crack in the kickstart shaft right below the pawl? This very narrow part of the shaft takes a major amount of pressure when in use. Both of the shafts in my MK 111 are cracked; one p.o. tried to weld over the crack but this solution failed.
Before ordering replacement parts, I would like to know if there has been any changes made to the design or is this a problem area that will need remedial work/part replacement every so often at $150 to $200 per time?

Thanks,

Tom

ludwig said:

ctsbc said:

Has anyone experienced a crack in the kickstart shaft right below the pawl? ... . I would like to know if there has been any changes made to the design ..

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Yes , and not that I know of ..

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Absolutely. It doesn't seem to be a constant problem though.

ctsbc said:

Has anyone experienced a crack in the kickstart shaft right below the pawl?

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Have a MKII 850 with the same problem. Never seen the problem on 750's.
I was hoping they fixed it on the MKIII. I guess not

I have had this area crack as well in the past. After looking closely at several---with a magnifying glass---you can see why. The machining process left a stress riser there at the edge---should have been a nice radius not a sharp 90'.
i think the damage occurs more easily if the bushings are worn and the kick starter is forced through to the stop too many times--too agressively. Just something else to check when the box is opened---poor design maybe from the start.

Aw some compression releases should get more life out the cracked ones.

Of the five stubs I have on hand only one has a hairline crack perhaps 1 mm long on the inner face of the knuckle. I'm not sure that would be an operational problem since the load during kick-starting would be well behind, on the pawl pin


Tim Kraakevik
kraakevik@voyager.net

Thanks for the comments--looks like a design flaw that I will have to manage. Would like to know how to get the compression releases that Hobot recommends.

I would think if your going to try to weld that you should grind out a V first. I wouldn't know but they may not like the heat.

ctsbc said:

Thanks for the comments--looks like a design flaw that I will have to manage. Would like to know how to get the compression releases that Hobot recommends.

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Stand on the lever until it goes over compression, you can feel it.

Dave
69S

Does it look like this? If so no difference on the '75 Estart either.Did mine last year.

I believe cracked units like this come from improper technique. Jabbing at the kicker like a 2 stroke and the like. Kickback can also be a factor but I think one is more prone to cause such failures than the other.

If these bikes don't start in a few kicks or 6, stop and assess. Kicking and kicking and kicking ala SD is asking for.....well....a cracked kickshaft, blown splines and busted pawls. Patience and common sence will keep things like this from happening.

But, it's easier to blame bad part than bad practices.

Bite the bullet and buy the new parts and think about technique.

My 2 cents. She prefers a gentle yet firm touch.

I get so annoyed by the reflex for some to always blame technique, and certainly bad technique to Kick off on center or side stand, but jeeze louise, you got to put as much umph down on it as takes to break over TDC and with cold parts and cold oil and cold fuel that can take one's body mass to shove down, ugh. Ideally Cdo's will start just stepping down on first time ever time and I've had enough intervals long enough to expect that or stop and check key or fuel or wires, but also had plugs fail or sediment in pilot jet or water in gas and temp changes that only enough kicking in combos of fuel or not got her going when away form home and shed.

Cdo's have the worse kicker leverage ratio of about any bike ever sold but for
some Spargthrops and 22.5 to 28 cubic inches per jug of fairly high CR with little cam over lap to bleed off at TDC so an innate weakness with stress riser machining at fault way way more that caveman owners, excepting swooshdave's marathon display that in the long winded end worked out as intended. Put this part on radioactive component list, ie: some will fission no matter what, this one seems to have half life of 60 yrs though. Same goes for the kicker splines with kicker side half life about 10 yr in the ones passed down to me.

Hey, batrider. Tell us some stories about kicking that Matchless over with less than perfect technique, the rideless days related to it and the days spent limping afterwords.

Velocette owners may have the award won for the kick starter ratio problem. Very hard to start unless kick starter--piston and the planet Venus are in perfect alignment.
Have to agree there on the statement that may not be a great idea to continue jumping on the kick starter if engine refuses to start after 2nd or 3rd attempt. Best to stop and do some quick checks to see if there's a glitch someplace---like kill switch --choke---battery condition--old fuel---etc. etc. MPO

Velocette owners may have the award won for the kick starter ratio problem.

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OK then will add Velocette to Shragthrope models, but at least its only one lung to kick over the top.

Its tricky to figure out why a Cdo won't start right off, I've had most a year now to get familiar with Trixie Combat, even a video of hand starting but she's let me down and wore me down last 3 times I thought weather fair enough to ride. Got spark, got fuel got compression, nothing altered since last nice cold day starts 10 days ago. Even new plugs just in case. ugh. I can see the kick lever beginning to get loose on splines and we know what that leads to next.

Buy new shaft and have stress riser relieved and then sent for cryo tempering is what I'm doing on my special.

Mine too..

pvisseriii said:

Hey, batrider. Tell us some stories about kicking that Matchless over with less than perfect technique, the rideless days related to it and the days spent limping afterwords.

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OK well of course I do have a story... When I built my first Matchless ('66 G80CS) it came in 6 boxes so I had no idea what it would be like. It was all nicely painted and beautiful looking when I tried starting it for the first time. Before this I had only read about starting a big single. Anyway - first kick - the bike surprised me and somehow I got way off balance. We fell over on the concrete floor of the garage with a crash and the headlight ears got bent etc. I'm glad my wife wasn't around to see it. So I'd have to say it was a learned technique. I was used to the Norton but the single would put a black and blue mark on the bottom of my foot. Lesson learned - if your bike has a mag get the armature rewound and capacitor replaced! It did start on the second kick though!

I never saw a kickstart shaft break like that though and 3 of my bikes have the AMC box.

Well, Steve I never try to kick it right through TDC, I always put some weight on it until it's just over TDC, then a long smooth stroke with everything I've got including weight.

Dave
69S

after studying the parts, it looks like "bottoming out" wasn't the problem.. (never is... is it? ) as there are no witness marks whatsoever on the stopper boss or shaft shoulder. Also, by the time the kicker is at 6:00 position, the riders transferred energy is vertical, while the kicker arm is moving horizontally. Much less torque generated. Must be the kickback, or, after watching mankind interact with machinery for decades, I am inclined to think it's the savage beast who never knew the correct way to engage a starter (kick OR pull) before launching all his bulk on it, ESPECIALLY if the starting isn't going well.

Who has run one knowingly with a crack? for any length of time? any images of TIG welded repairs?

concours said:

after studying the parts, it looks like "bottoming out" wasn't the problem.. (never is... is it? ) as there are no witness marks whatsoever on the stopper boss or shaft shoulder. Also, by the time the kicker is at 6:00 position, the riders transferred energy is vertical, while the kicker arm is moving horizontally. Much less torque generated. Must be the kickback, or, after watching mankind interact with machinery for decades, I am inclined to think it's the savage beast who never knew the correct way to engage a starter (kick OR pull) before launching all his bulk on it, ESPECIALLY if the starting isn't going well.

Who has run one knowingly with a crack? for any length of time? any images of TIG welded repairs?

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It may bottom out if the kick starter lever was positioned to far forward in the attempt to get more spin on the kick over ???? Longer travel and then the bump stop would make contact--maybe--?