Primary chain question

Schurminater

Schurminater

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Location
Surrey Hills
Finally got out today on the Jota for the first time this year,and wow i remember why i love this bike so much. 8)
Having changed the clutch cush drive rubbers over winter,the gear change is now silky smooth and the take off perfect,very pleased indeed.
Now the question......I also fitted a new Duplex (mercedes) primary chain and she sounds different,with more of a modern bike "whine" i'm not sure if that is the right word..........however is this to be expected with the new type of chain?

When i fitted it I didn't seem to be able to get much feel on the adjuster bolt,but didn't expect to get much as its a new chain?
now its had a run i will obviously check the adjustment.

any help or comments very much appreciated.



Schurmy
 
Hi, you should hear the whine as you screw the adjusters in and then just back it off.
Only thing I've ever had go wrong and lost adjustment was the weld failing on the tension arm too the privet tube that the pin goes through. If that makes sense.
Regards Andy 😁
 
Do not use the whine technique to tension those duplex chains. They need to be a bit looser. 1 1/2 turns out on the adjuster. It shouldn't whine, if it does, it's too tight.

Paul
 
Thank you Guys,

i'm aware of not using the whine technique with the duplex chains,i will check the adjuster bolt for tension and report back.

If i were to remove the tension bolt completely and used a punch or other through the hole would i be able to feel movement of the tensioner paddle against the chain being that its new?
 
Not sure what you're expecting to 'feel'.  Screwing the adjuster bolt in you'll feel no real change in resistance until the slipper contacts the chain and takes up the slack. I use fingertip pressure on the screwdriver handle to avoid overtightening the screw, then back off. 

Obviously you can swing on the screwdriver and end up with the chain still being too tight after backing off.

Did you check chainwheel alignment with a straightedge after changing the clutch rubbers?
 
Rob said:
Not sure what you're expecting to 'feel'.  Screwing the adjuster bolt in you'll feel no real change in resistance until the slipper contacts the chain and takes up the slack. I use fingertip pressure on the screwdriver handle to avoid overtightening the screw, then back off. 

Obviously you can swing on the screwdriver and end up with the chain still being too tight after backing off.

Did you check chainwheel alignment with a straightedge after changing the clutch rubbers?
Click to expand...

Hi Rob,what concerns me is that i don't seem to have tensioned the chain,and i am wondering if the slipper is stuck or assembled incorrectly.......When i first set the screw adjuster after fitting the chain it didn't seem as though i was moving anything and i certainly didn't feel like i was taking up any slack.......thinking this may be because its a new tighter chain i then left alone.

However on removing the adjuster bolt just now,in less than a 1/4 turn it came straight off the slipper ie with no tension on the adjuster bolt.........so coming to that conclusion it didn't seem to be over tensioned which is why i asked about the whine?

does that make sense?
 
Didi you fit the spring correctly? It pushes the chain against the tensioner screw, not the chain.
 
yes as far as i can remember,i did check a lot of posts! :D

From what i can tell the slipper is against the casing which means the spring is doing its job as I understand it is mean to.
If i screw the tensioner bolt in finger tight till it stops..... meaning its making contact with the slipper and then use a screwdriver against tension its hard to gauge but if i stop when i feel i should by the time i turn back 1 1/2 turns its almost backed right off again back to finger tight?
 
If you everything's is in there spring, slipper and pin then the casing will go on quite firm and solid to the touch. If anything is out of line then your chasing would leak oil.
You should be able to hear the nose of the chain if you overtighten, well i always do and then back it off.
Don't want to imply anything but my mate wanted me to set the tappets on his GS 1150 because he he said they were noisy. So Monday goes to his workshop where he started the bike which was as quiet as a mouse so I did them anyway Inlet . 15mm exhaust. 30mm, turned to my mate and asked him if anybody had put a rattly tappet noise in his earring aid to which he replied what did you say 🤔
Regards Andy 😁
 
Heh - nice one Andy

Back to the 'problem'.  You should use a screwdriver to adjust the tensioner so that it has removed all the slack in the chain.  What you don't want to do is heave on the screwdriver to get it the last nth of a turn tight.  That's why I suggested finger pressure on the screwdriver handle rather than a gorilla grip.  That's not the same thing as using your fingers on the adjuster bolt!!!  Apart from getting it started in the thread, stick with the screwdriver!

You will notice the adjuster screw go noticeably tighter over the last part turn as the last bit of slack is removed by the tensioner pad. Then back off. 



 
That's a much better word picture, I was also finding this difficult and Keith used to say oil your hand so the screwdriver slips a bit. Just like Rob said firm, but not a Gorilla grip. You need to take the slop out of the chain but not make it bow tight.
 
Okay Guys,thanks for all your help and i do understand what you are saying Rob and i don't generally over tighten things its just that this feel adjustment seems a little ambiguous to me. :-X

It is all back together now so i will test it out in the morning........lets hope it is all good or i will be the one whining! :D
 
For what it's worth, I pt a dab of oil on my fingers and hold the screwdriver by it's shaft. fingers slip as soon as the slack is taken up.
 
Agree, you feel when it is about right. For a beginner, you can approach the sweet spot in an iterative way, by backing it off 1/2 turn from feeling tight and then go 1/4 turn in again to see how that feels and so on. With a new set of cush rubbers and Merc Duplex not much of chain slack to be expected anyway. I added a freshly lined chain slider to that combo on my 3C, and finally needed to resort to plenty of spare copper washers under the domed counter nut to get it fully seated, with the adjusting bolt lifting the chain slider just about 1 mm to get the slack out of the chain.

Regards,
Stefan
 
I have some concerns that the chain is whining without any apparent action from the tensioner. Did I read that correctly? If it was that tight, you?d never have got the chain on.
From the description, I?d be whipping off the side cover for another look!
 
For what it's worth, I pt a dab of oil on my fingers and hold the screwdriver by it's shaft. fingers slip as soon as the slack is taken up.

Legs - I like this method of yours. I'm gonna give it a try.

Andre
 
That tensioner blade spring has no active role in tensioning the chain, it just stops the blade flapping about. It's the screw which tensions the chain.
Too loose is better than too tight. Keep in mind that Laverda used to race bikes 24 hours without a tensioner and change the triplex mid race.

Paul
 
Paul Marx said:
That tensioner blade spring has no active role in tensioning the chain, it just stops the blade flapping about. It's the screw which tensions the chain.
Too loose is better than too tight. Keep in mind that Laverda used to race bikes 24 hours without a tensioner and change the triplex mid race.

Paul
Click to expand...

Hopefully the duplex will last more than 12 hours  :D

bazzee
 
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