The BSA A7-A10 Forum
Technical (Descriptive Topic Titles - Stay on Topic) => Gearbox, Clutch, Primary => Topic started by: coater87 on 28.01. 2016 03:58
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I am gathering materials to do a gs550 clutch conversion. Looking at a stock clutch center, I can see no way to make it work without a lot of welding, which will distort the internal taper I believe.
I am mimicking RRs' solution and probably going to have to make a custom center.
Does anyone know, did BSA use a standard taper ( like a brown and sharp or like a Morse taper are well known and considered standard tapers) or did they use a custom taper of their own?
If it's a standard taper, I can get close on the lathe then finish with a taper reamer. If it's all BSA, that makes life much harder...
Thank you,
Lee
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HI Lee,
I am gathering materials to do a gs550 clutch conversion. Looking at a stock clutch center, I can see no way to make it work without a lot of welding, which will distort the internal taper I believe
I'm puzzled *????*
When I sent you the photos I mentioned welding up the Suzuki 550 alloy centre to add material so it can be machined to suit the BSA adaptor,
The mainshaft adaptor in the photos I sent you is a machined standard BSA 4 spring type
like this
http://www.ebay.co.uk/itm/BSA-A7-A10-RGS-4-SPRING-CLUTCH-HUB-ADAPTOR-42-3170-MADE-IN-ENGLAND-/321990695113?hash=item4af82418c9:g:g24AAOSw2s1Uwko5
HTH
John
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John,
That must be the problem. I have a six spring adaptor. It's way too short to engage the clutch center by enough for comfort.
As I don't have a four spring adaptor, can someone confirm its longer than a six spring?
Lee
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I can't claim mine is anything special but as its off currently while I work on the swing arm have taken a few photos
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I can't claim mine is anything special but as its off currently while I work on the swing arm have taken a few photos
I have done a little machining, and I can confirm that if your conversion works, its something special.
Little things are popping up. Like my basket center is slightly larger than the r22 bearing ( by I want to say .017 but that's from memory). So now do I weld shut and re-cut to size, or turn a special steel insert that will fit under the center.
And is there really going to be that much money saved if I consider time/materials/ machine wear/ frustration and mistakes?
It would be one thing if a guy had a Pearson or Colin tye in hand, and just mimicked that, but to engineer the thing from scratch based off of pictures when you have never even seen one is another thing all together.
I am going to have to take a step back from this and decide how deep the hole I am throwing money into can get. *eek*
Lee
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And is there really going to be that much money saved if I consider time/materials/ machine wear/ frustration and mistakes?
The eternal dilemma Lee and possible true to say if we all took the sensible option the content on this forum would probably half.
however the often ridiculed "because it's there" syndrome leads men (and more so bikers I think) to do things because we think we can, and when we can the rewards are something else - hard to quantify against financial considerations for sure.
there you go grass hopper
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I can't claim mine is anything special but as its off currently while I work on the swing arm have taken a few photos
I have done a little machining, and I can confirm that if your conversion works, its something special.
Lee
Lee,
I can tell you it does work. I ran it on my race sidecar (dry) originally with a dural sprocket. That did shed a fair bit of dural, so a steel sprocket was fitted. I had run single row chain on a prior race sidecar dry and came to the conclusion a belt drive was preferable so this clutch has now been passed to the super rocket project bike where it will be run wet. The sidecar is now running a belt BNR clutch dry.
The sprocket houses the bearing and bolts to the original cage
I passed the job to a sympathetic semi retired engineer, who has since retired fully so I cannot take any credit.
As its currently off, I can take some measurements if that helps.
I do love the bearing it runs on. A proper bearing. No wobble in this clutch!
While a 4 spring clutch is fine, this is certainly a far better clutch than a 4 spring.
I'm also running an oil seal behind the clutch on the sliding plate.
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The eternal dilemma Lee and possible true to say if we all took the sensible option the content on this forum would probably half.
*lol* *lol* *lol*
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Hi Lee,
Yes the 4 spring adaptor is longer than the 6
In the pics I sent you the bearing used wasa metric one, and there is an adapting sleeve in the inner
40mm to fit the bearing and 1.375 to fit the 4 spring adaptor
The 16008 bearing is 68mm od so bigger than the R22 by 4.5mm, that may solve the problem you found with the Suzi part??
John
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I had the wrong inner basket dimension before. It's not .017 too large, it .176 too large. I see no sleeve in any of these clutches for the basket, so now I am even questioning the clutch I have. *conf*
RR, any dimensions you can measure will help for sure. Especially the distance between the clutch center and basket at the back. I don't know how much clearance this needs or should have. I am worried if I allow to much, the clutch will rub on the case cover.
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Hi Lee,
Could you post some pics of the clutch parts you bought
I'm afraid things are getting mixed up between us?
The Suzi 550 inner clutch drums I got have 6 splines to fit the Suzi mainshaft, 16 x 20mm (from memory)
If this is opened up to fit the 4 spring adaptor (1.375in) the centre boss dissapears, which is why I mentioned adding material to it with weld???
I machined away some of the rear of the Suzi outer basket to get it nearer the sprocket
The inner drum will need to be as near as possible to the outer basket, without contact
The overall depth of the clutch may need to be reduced to clear the primary case ??
John
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Try and post a couple of pictures here. I machined off the lip on the basket, other than that I have only removed the gear and springs.
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OK, I can post pictures now!!! *smiley4*
This looks like the correct clutch, but with the basket center hole being that large I am not sure. *conf*
Lee
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RR, any dimensions you can measure will help for sure. Especially the distance between the clutch center and basket at the back. I don't know how much clearance this needs or should have. I am worried if I allow to much, the clutch will rub on the case cover.
The home made centre pictured (007_1) measures 5.2mm then 22mm, the 15mm for the lengths of the various steps.
We also removed the steel ring, machined off basket height then replaced the steel ring
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OK,
I think I have a solution to the bearing fit inside the basket, I will sleave it and add a collar. It's going to take some messing around and time. I will add pictures when I have a solution.
Thanks RR, I will also remove 4 mm from the basket height.
I have tried to find a supplier for a blank sprocket over here, but no success.
43 tooth blank sprocket for a 428 chain must be pretty odd. *conf*
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Hi Lee,
I got the 43 tooth sprockets from "sprockets unlimited" in the UK
www.sprocketsunlimited.com/
The bearing will mostly be housed in the sprocket,
maybe you can incorporate the adaptor ring into the bearing retaining plate?
John
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[email protected]
I got my blank sprockets from these guys in the UK. (6 years ago) they had 43 tooth 428 blanks in steel and dural.
My bearing goes into the sprocket. If you look at my basket you'll see the bearing is not in the basket, the basket bolts to the sprocket and bearing housing.
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The sleave I am making will house the bearing and attach to the basket. Then the basket will be bolted to the sprocket. So 6 fasteners total, three each.
Now I am a little concerned with chain alignment, because it will affect some decisions for sure.
On the four spring adaptor, there is a build in washer. I need a dimension from the clutch side of the washer to the transmission side of the sprocket so I can build this close to being aligned right from the start. Would anyone have this dimension or be able to get it easily?
I know on the 6 spring its close to .600, but I have no idea on the four spring... *conf*
Lee
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I think I may have found the answer to this question on a site for British bike bits. They have a picture of a four spring with adaptor installed and it looks like the adaptor butts up right to the sprocket, which makes things easier.
Does that sound correct to you guys?
Lee
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HI Lee,
it looks like the adaptor butts up right to the sprocket
Yes in the standard clutch..
When using the the wider R22 beariing the shoulder on the 4 spring adaptor needs to be machined back as in the photo,
(The 1.9mm is for a 9mm wide bearing so R22 is wider by 0.5mm so needs 0.25mm more removing)
Machining back the adaptor shoulder brings the sprockets back into line
The bearing is centered in the sprocket, ie, the bearing sticks out an equal amount each side
The retaining plates are recessed to accomodate this
John
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John,
That is one of the things I did not like about the clutch pictures I have seen- that the bearing is centered inside the sprocket but still protrudes on both sides.
This is why I am trying to sleeve the sprocket and basket, the bearing will be entirely supported. At this point I believe the outer race of the bearing will be a light press fit/ tight slip fit held with a snap ring on each side.
This should also let me line everything up, then cut the snap ring grooves which should set the final alignment. Hope that makes sense.
One other concern I have, is basket wobble. Will I need to make some type of disk that will rub on the sprocket to keep it straight when the clutch is pulled in , or not?
Lee
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Hi Lee,
THe bearing is a good tight push fit onto the adaptor, theres a hardened washer outside it when using the R22 bearing (a radial needle roller thrust washer 35mm id x 1mm thick)
The inner drum is clamped tight to this assembly by the clutch centre nut and & thick washer or a specially made nut with intgral washer
The outside of the bearing is clamped in place by the retaining plates
So the only "wobble" will be the clearance in the bearing
I wonder if adding to the thickness of the assembly to incorporate snap ring grooves will lead to clearance problems at the rear of the clutch???
John