The BSA A7-A10 Forum
Technical (Descriptive Topic Titles - Stay on Topic) => A7 & A10 Engine => Topic started by: berger on 11.06. 2018 14:44
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i have not been to the pub for 5 DAYS! but the question is now I have found a matched up pair of engine sprocket and cush drive piece I notice on kicking over that they are riding nearly to the top of the peaks. can any of you in the know people tell me what the spring length diameter and thickness of wire[carnt think of another word] should be fitted to a 1960 engine. I've never seen this problem before because they were slightly mismatched.
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i have not been to the pub for 5 DAYS! but the question is now I have found a matched up pair of engine sprocket and cush drive piece I notice on kicking over that they are riding nearly to the top of the peaks. can any of you in the know people tell me what the spring length diameter and thickness of wire[carnt think of another word] should be fitted to a 1960 engine. I've never seen this problem before because they were slightly mismatched.
Have you got the nut up to 65 Ft lbs ?
The cush drive lobes should be a good match.
CUSH DRIVE SPRING PART NUMBER 67-1136
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cheers roy the nut butts up to the srocket bearing and I can get it that far using my hand, to find out whats goin on I need the dimensions of the spring to start with. then I can sus out whats wrong. there are many different bearing lengths and springs lengths{ to many to think about}the only reason it didn't ride up as it is now is because the sprocket lobes and cush drive sleeve were not quite compatable and had more friction
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Another thread here - https://www.a7a10.net/forum/index.php?topic=7588.0
Found this. https://www.feked.com/bsa-cush-drive-spring-pre-unit-a-b-and-m-models-1955-62.html
Looks to be around the 1 5/8 mark.
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https://www.a7a10.net/forum/index.php?topic=9646.msg70166%3btopicseen#msg70166
Reply 5
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hi roy mine has 4 coils and measures 41 mm.. ive just found a couple in a buried box and they are thicker guage7.5 mill as apposed to mine just under 7mm ime going to attack and see what happens with heavier guage spring thanks for your help ..... be back later...
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G'day burger.
Also look at John's picture #8 http://www.a7a10.net/forum/extimagebackup/limit_of_travel_zps3brxtuth.jpg
Cheers
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Hi All,
I thought I recognised those fingers *lol* *lol*
John
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wow what a past 5 days, but now sorted , the beefier spring I found [possibly original factory] has sorted the job *clap* the engine sprocket is no longer trying to jump the lobes.... it does as it should do and cushes *woo*. cheers for the help...
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wow what a past 5 days, but now sorted , the beefier spring I found [possibly original factory] has sorted the job *clap* the engine sprocket is no longer trying to jump the lobes.... it does as it should do and cushes *woo*. cheers for the help...
Cushty!
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There was a thread about this not long ago.....my Plunger sleeve slides further but none should jump the lobes- good you got it sorted quickly.
Actually(slight hijack here) GB ol' buddy *smile* maaaate... I know you'll be busy again mixing *stiff* cocktails and doing reviews, but if you have to pull your cush apart again, is any chance you can measure your spring dimensions *please* ? Reason being, my spring busted a while ago, and was sent a replacement that is different to the original (shorter/fatter), so the preload isn't up to the game....
Later on I'll dig up the thread I did on it, so I can jump out of this hijack....(ransom anyone?? *whistle*)
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Actually(slight hijack here) GB ol' buddy *smile* maaaate... I know you'll be busy again mixing *stiff* cocktails and doing reviews, but if you have to pull your cush apart again, is any chance you can measure your spring dimensions *please* ? Reason being, my spring busted a while ago, and was sent a replacement that is different to the original (shorter/fatter), so the preload isn't up to the game....
Yup
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dutch get ya fingers outa my pie... *razz* anyway ive had a look see back at some posts and it seems to me what gaggs told me in the eighties is correct. and that is there is a fare assortment of engine sprocket bearings , regarding how far they stick out from the crank splines, and the thickness where they butt up to the collar that keeps the roller bearing tight on the crank. I think this assortment of different sizes only applies to swingarm models but can be a problem if you've got the wrong bits and your trying to keep the chain in line with the clutch.. also there are many different springs *problem* *rant* ps and sprocket and sleeve slippery slope thicknesses
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This could all get a bit messy, but I've compiled a bunch of hijacked Plunger Cush Drive thread links into a fresh post so hopefully it will be helpful;
https://www.a7a10.net/forum/index.php?topic=13067.0 (https://www.a7a10.net/forum/index.php?topic=13067.0)
It needs work, but the fundamentals are there; Plunger Cush Drive only I think (intended)
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Actually(slight hijack here) GB ol' buddy *smile* maaaate... I know you'll be busy again mixing *stiff* cocktails and doing reviews, but if you have to pull your cush apart again, is any chance you can measure your spring dimensions *please* ? Reason being, my spring busted a while ago, and was sent a replacement that is different to the original (shorter/fatter), so the preload isn't up to the game....
Yup
I've annotated pictures of my spring and put it in a new post in 'Engines'
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Thanks GeeBs, much appreciated *wink2*