1941 Matchless G3L - Knocking in Slow Speed

Information relating to the Matchless G3 or AJS Model 16 350cc Heavyweight
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phenry
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1941 Matchless G3L - Knocking in Slow Speed

Post by phenry »

Hello,

I replaced the engine shock absorber spring as the original ones cracked after prolonged use.
Now this is a replacement spring which i more or less of the same specifications of the original and was a direct fit. On fitting and then riding the motorcycle, I felt that at slower speeds, the engine is knocking, however at higher RPMs this doesn't happen.
Am I right in assuming that the new spring doesn't comply to standards or is the issue totally different?

PHenry
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1608
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Re: 1941 Matchless G3L - Knocking in Slow Speed

Post by 1608 »

If the knocking has only started since fitting the new spring then the new spring is probably too weak. A weak spring will let the cush-drive lobes 'top-out' or clash. Hope this makes sense. I recently re-built another make of bike and used the cush drive spring that came with it. Only after knocking when kicked over each time did I eventually find the problem and a new correct and stronger spring fixed it.
56G80S
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Re: 1941 Matchless G3L - Knocking in Slow Speed

Post by 56G80S »

"more or less of the same specifications of the original"

Perhaps that's the clue. In my experience there are springs which are round section and, IMO, not as good as the square section springs which were the "original" fitment.

Sure others will corect me if I'm wrong.

Johnny B
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Re: 1941 Matchless G3L - Knocking in Slow Speed

Post by G15 Roy »

Where did the new spring come from?
Roy
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Re: 1941 Matchless G3L - Knocking in Slow Speed

Post by 1608 »

Hi Phenry in your original post you say, "more or less the same specifications". The specs need to be the right ones.There is no guarantee that the original spring was the right one.Ie. the correct guage and number of coils.
phenry
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Re: 1941 Matchless G3L - Knocking in Slow Speed

Post by phenry »

Thank you so much for the replies. Like you mentioned for all we know the one that was on the Matchless previously might have been a non-original spring.
The spring was made locally without paying too much attention to detail.
Is there a specification to this? Attaching a pic for reference
Spring.jpg
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56G80S
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Re: 1941 Matchless G3L - Knocking in Slow Speed

Post by 56G80S »

Hi, others will know better but that looks like it is coilbound to me.

I can't see how it would perform it's function let alone make a knocking noise as there doesn't seem to be room for the spring to compress at all. I'd expect a Burman gearbox and clutch but both my AMC and B52 had scope for clutch plate adjustment, yours seems to have a blanking cover where the adjustment would occur. If someone's fitted the later AMC gearbox then there's a shock absorber in the clutch centre and the one on the end of the drive shaft isn't so important.

Sorry, I'm a bit distracted by the other things in the photo but I don't know so much about the pre SR1 magneto models. I should stick to one thing at a time as per your question raised.

Johnny B
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Re: 1941 Matchless G3L - Knocking in Slow Speed

Post by ajscomboman »

phenry wrote:Thank you so much for the replies. Like you mentioned for all we know the one that was on the Matchless previously might have been a non-original spring.
The spring was made locally without paying too much attention to detail.
Is there a specification to this? Attaching a pic for reference
Spring.jpg
That spring is nothing like correct, even if it is round profile and not square like the original. The club springs are round profile and work perfectly well, I have one on my CS and its been fine.
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