Mainshaft taper

[coater87]

 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

[chaterlea25]

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

[coater87]

 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

[Rocket Racer]

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

[coater87]

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.

Lee

[bsa-bill]

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

[Rocket Racer]

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.

[RichardL]

The eternal dilemma Lee and possible true to say if we all took the sensible option the content on this forum would probably half.

 

[chaterlea25]

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

[coater87]

 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.

 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.

[chaterlea25]

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

[coater87]

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.

[coater87]

OK, I can post pictures now!!!

 This looks like the correct clutch, but with the basket center hole being that large I am not sure.

 Lee

[Rocket Racer]

 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

[coater87]

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.