Kickstart Lever

Information relating to the Matchless G80 or AJS Model 18 500cc Heavyweight.
Brushwarrior
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Kickstart Lever

Post by Brushwarrior »

Wotcha All
Came up against a annoying problem in the g80 (AMC box). The kickstart lever keeps loosening off after a couple of kicks, beforehand its bolted tight.
theory 1. plain part of bolts knocks up against cutout of kickstart shaft, thread deformed on bolt when removed for investigation.
theory 2. wronmg thread BUt 3/8 UNF tap moves cleanly through when lever is off the shaft and on the bench.
Theory 3. Bolt hole too big for AMC kickstart shaft

At a loss on how to make this better, My father has kickstart on his G3L (burman box) and his bolt for the kickstart lever goes all the way through with a nut and washer on the outside and as tight as a drum,

Did see an article in Jampot magazine about redesign of the kickstart shaft and lever to BSA type fitment using cotterpin, i no longer have the magazine article or engineering facilities. :-)

Your thoughts appreciated on this.

Steve
Bury St. Edmunds
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Bury St. Edmunds
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Rob Harknett
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Re: Kickstart Lever

Post by Rob Harknett »

Worn kick starter threads, bolt threads and spline probably the problem. I just used a new nut and bolt. Relying on the nut to tighten. The kick starter threads probably worn almost to the point of overturning anyway. Of cause the kick starter and shaft splines are still worn, so need to make sure the nut & bolt is always tight. A bodge but its OK for now as long as its kept tight. AJS used a cotter pin like a push bike pedal way back in time, in fact a push bike pedal can be used as a kick stater. Being a very old arrangement, I assume splines were considered better????
Perhaps that's a kick starter I have Alan, my experiences the same as yours.
Last edited by Rob Harknett on Sun Aug 09, 2015 8:23 pm, edited 2 times in total.
OEW591
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Re: Kickstart Lever

Post by OEW591 »

Steve,

I had a similar problem with a pattern kickstart lever I bought for my Model 31. It was supposed to be a Commando lever, which has more of a bend thus allowing my knee to miss the oil tank cap.

Turned out that the 'new' lever was made of inferior material and the splines stripped on the inside. The lever would tighten up OK but as soon as I applied any pressure it slipped again. I sourced an original AMC lever and problem solved.

Alan
Triumph-Legend
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Re: Kickstart Lever

Post by Triumph-Legend »

Does the lever fit well onto the shaft prior to putting the bolt through. The splines should be in good order on both shaft and lever. The fit should be a light interference, slide on fit. given that these things are in order, it is most likely that the clamping bolt is either stretching and deforming after fitting and tightening when force is applied to the lever. Do not continue to try tightening the bolt, this will only make matters worse.
Go along to your local fastener supplier and buy a decent quality bolt and nut of the correct size. I generally replace the soft bolts supplied with new kickstart levers with a stainless socket head screw. (only because I have some in a box). Don't muck about trying to find one with cycle thread, metric will do fine.
Do not use a set screw. (threaded all along its length)

Before fitting the lever, try the bolt for size through the hole, it should be an easy drop in clearance fit. If not, drill through with a 8mm bit. This is to allow the lever end to clamp together slightly to grip onto the shaft. A tight fitting bolt will restrict this clamping force.
Fit and do up nice and tight, a bit of bearing lock on the shaft can help if the splines are less than perfect.
If the flipping thing still slips. Then you have a problem. either the splines are not the correct size or the are knackered. Usually on the lever. :headbang:
Time for a new lever. Club spares have folding levers for the AMC box in stock. I have used on and not had any problems. Not expensive. (throw the bolt away).

Usually damaged splines are more common on the Burman boxes as the lever shaft is a smaller diameter.
The BSA mod is fine if you want to fit a folding tipped lever onto a Burman box, as this type of lever is not currently available. But be sure to check the offset is enough to allow the lever to clear the silencer as it swings through.
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Merlin
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Re: Kickstart Lever

Post by Merlin »

I seem to remember a bodge that involved drilling between kick start and shaft then inserting a dowel.Other may comment further. :D
Chemists do it with test tubes
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Colin F
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Re: Kickstart Lever

Post by Colin F »

I had damaged splines on both the shaft and kickstart arm.
As I had a Triumph folding one on the shelf I decided to use that as it fits with a cotter pin.
I mounted the shaft in a lathe and carefull ground the splines and hardened coat off, I was then able to turn the shaft down to the correct diameter for a sliding fit with the lever.
I temporarally refitted the shaft and carefully aligned the lever on the shaft so that it sat in the correct position and marked this, I then ground a flat on the shaft where the cotter pin fits.
15 + years later I have had no problems with this mod, in fact the bike I am working on now has had the same mod as Triumph kick start arms are a lot cheaper than AMC ones.
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GOLDSTAR
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Re: Kickstart Lever

Post by GOLDSTAR »

similar problem with mine, took a knats off the closing faces and used the mini grinder cutting disc to put a small slot in the top of the fitting also, allows me to tighten a little more than usual, works O.K, and yes use a new bolt etc, kind regards
56G80S
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Re: Kickstart Lever

Post by 56G80S »

Resurrecting this thread rather than start a new one.

But first a lesson in memory failure. I thought I bought the cheaper of Steve Surbeys kickstart levers, understandng his comment that they may or may not last. Looking on my AMOC Spares history I see that I also bought one (at about £29). I have a feeling that the AMOC one failed and that the one that's on is Steve's. But it's never been quite right. I have the feeling that it'll let me down before long as it is floppy on the shaft. I've not removed it recently but recall that the splines on the shaft were fine.. If I slacken of the bolt, tap it with the soft mallet all is as tight as the proverbial. Carefully tighten the bolt. Couple of starts and floppiness returns.

Where are those blue pills?

I plan to follow Triumph-Legend's route and pop into Hawk Fasteners at Skippers Lan Industrial Estate, who've always been really helpful with this kind of thing, and get a better bolt. I am intrigued by the "3/8 UNF tap" comment from Bushwarrior and then the comment about "Don't muck about trying to find one with cycle thread, metric will do fine." by Tiumph-Legend.

I increasingly tend to want to keep the Matchless in rideable condition at all times if possible and don't have any thread guages. Guess I'll have to drop the bolt out and take it with me. OR I could just check the bore, run a drill through and use any bolt and nut to suit.

After reading some other threads, I'm reluctant to fork out nearly £120 and then find it doesn't fit on the shaft and have to replace that too. I'd rather try Merlin's bodge!

Maybe this winter it's out with the AMC gearbox, in with the completely refubished Burman B52 (although with CP clutch) and rebuild the AMC altogether. It's what was in on purchase and done a lot of work including pulling a sidecar while I've had it this 40 years, sometimes jumps out of first despite making and fitting a detent out of silver steel about 20 years ago.

Views welcomed.

Johnny B
Mick D
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Re: Kickstart Lever

Post by Mick D »

Hi

Is the kick start lever threaded to take the bolt which is then locked with a lock nut or is it a plain hole?

If the latter, I'd source a suitably sized high tensile replacement, lockwasher and nut, or washer and nyloc nut. Namrick should have something suitable:

https://www.namrick.co.uk/

If the bolt is threaded into the lever you will need to match the thread - if you can measure the thread diameter, (peak to peak), and count the thread peaks per 1/2" I should be able to determine the thread.

I'd shy away from Merlin's option as you report your splines to be in good condition. The lever is probably made from a softer material than the shaft, any attempt to drill for a dowel between the two will probably result in the drill wandering towards the lever as it goes deeper.

Regards Mick
56G80S
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Re: Kickstart Lever

Post by 56G80S »

That's a very helpful response.

Probably won't be able to look at this until Thursday but it's high on my list. My inclination is to do as you suggest but possibly skip the threaded side of the lever (that's what I recall) and just drilll through to suit the bolt. Or I suppose I could just get two of everything and if the in lever thread strips then try the other method.

Good point about Merlin's option.

I'll PM you with the thread info rather than take up more Forum space.

Cheers

Johnny B
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