Author Topic: Drive chain tensioning conundrum.  (Read 1035 times)

Offline bsaketcase650

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Drive chain tensioning conundrum.
« on: 29.04. 2009 19:23 »
Correct me if I am wrong (and I'm sure you will!) but I was always led to understand that when adjusting drive chain tension it is the lower run of the chain on which the up and down free movement is gauged. Why is it therefore, that my 60 A10 with the fully enclosed chaincase has the inspection hole adjacent to the top run of the chain? This clearly suggests that BSA expected the top run of chain to be used as the reference point. Can anyone throw any light on this as I am not altogether convinced that the top run is the best place on which to measure.

Regards to all

Simon

Offline beezalex

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Re: Drive chain tensioning conundrum.
« Reply #1 on: 29.04. 2009 19:26 »
If the bike is in neutral, it doesn't matter if you check deflection (tension is irrelevant in this case) at the top or bottom.
Alex

Too many BSA's


Offline LJ.

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Re: Drive chain tensioning conundrum.
« Reply #2 on: 29.04. 2009 21:51 »
Simon thats an interesting question in which I think Alex is right, but... IKBA!
Ride Safely Lads! LJ.
**********************
1940 BSA M20 500cc Girder/Rigid- (SOLD)
1947 BSA M21 600cc Girder/Rigid-Green
1949 BSA A7   500cc Girder/Plunger Star Twin-(SOLD)
1953 BSA B33  500cc Teles/Plunger-Maroon
1961 BSA A10  650cc Golden Flash-Blue
1961 BSA A10  650cc Golden Flash-Red

Online RichardL

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URGENT. Re: Drive chain tensioning conundrum.
« Reply #3 on: 29.09. 2018 23:04 »
I don't think I've had to use the "URGENT" plea before, but with DGR tomorrow morning, I need some help.

In checking over the bike before the ride, I checked drive chain slack. It was almost 2", so decided to adjust. Got it to 1-1/4" and tightened things up. Checked again, 1-1/4". Great.  Later, after doing some cleaning involving rotating the rear wheel, checked again, tight as hell, but loosens to correct slack at the same point in rotation for every turn of the wheel. All that, and the question is one word: Why?

Richard L.
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Offline a10gf

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Re: Drive chain tensioning conundrum.
« Reply #4 on: 29.09. 2018 23:20 »
imo,

rear sprocket slightly off center
or
uneven chain wear
or
bent gearbox sprocket shaft (very probably (hopefully) not :O)

or all 3:O)

Check the rear sprocket dia with a piece of string from the frame somewhere and turn wheel. Will probably be fine. I'd opt for a full check of the chain, clean it well in solvent, dry, place it in full length on a table and do some compress-stretch tests at different spots (10-15 links at the time) and see if something obvious shows up.

A10 GF '53 My A10 website
"Success only gets you a ticket to a much more difficult task"

Online RichardL

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Re: Drive chain tensioning conundrum.
« Reply #5 on: 30.09. 2018 01:12 »
If the gearbox shaft, maybe it's the cause of the noise in "RICHARDL is not OK"?
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Online berger

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Re: Drive chain tensioning conundrum.
« Reply #6 on: 30.09. 2018 01:47 »
if the big gearbox ball race was dropping to bits you would know when you spin the back wheel, and a bent main shaft would ware {whatching dutch?}the two bushes out in the sleeve gear very rapidly and your clutch would be all over the shop, and so would primary chain adjustment

Online muskrat

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Re: Drive chain tensioning conundrum.
« Reply #7 on: 30.09. 2018 06:05 »
G'day Richard.
Chain can wear in patches. Adjust it at it's tight spot to give 1" play and get out there to the DGR.
Cheers
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Offline Triton Thrasher

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Re: Drive chain tensioning conundrum.
« Reply #8 on: 30.09. 2018 09:28 »
Adjust it at it's tight spot

Yes, that’s how you adjust a motorbike chain.

Second paragraph, page 34.