BSA Bantam - Yamaha Clutch Conversion Part One - First on YouTube?

Part one of my take on the Yamaha Clutch Conversion for the BSA Bantam. I'm working on a D10 engine but the principles are the same for all models.
I'm not the first to do this conversion, but perhaps the first to publish the work on KZbin. Full credit is given to those whom I know to have done this work before, and whose footsteps I may follow in.
Let's see if we can put some Retromeccanica into the job!
Please like and Subscribe if you like what we do.
Best wishes, Dean.
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[@leslieaustin151]

Err, Mr Tweed directed me here. I’m glad he did… I had three Bantams back along, loved them - and their idiosyncrasies! - though I’m on oldish Japanese bikes now, but this is a fascinating project and I’m enthralled by it. So a new sub from me and I’ll follow along as you go. Thank you. Les

[@retromechanicalengineer]

Thanks Les, more to come although the day job is taking up my time at the moment. Welcome aboard! Dean.

[@carlwilson1772]

That was brilliant. I loved every second. Really informative and interesting. It is going to be an excellent series and is sure to become the KZbin reference on how to approach these conversions. Great idea to make and use a plug gauge. I agree with others; I was totally invested and didn't want the video to end. My only regret is that we don't live closer together so that we can collaborate and pool resources. Like we did in the old days. For the turning on the basket, I was thinking you could maybe bolt the clutch basket to the faceplate, using the rivet holes for the bolts.

[@retromechanicalengineer]

Thank you, yes it would be good to do these projects together like we used to. The faceplate was definitely on my list of options, it's only been used once since I bought the machine so a run out (pun intended!) might be just the ticket. Best wishes, Dean.

[@tonyjover]

Interesting. I had several Bantams in my youth - one of them even had the plunger frame. Another sheared the crank where the heavy flywheel was keyed (objected to being bump started). I played around with enlarging the inlet port… loads of fun. I think I’ll subscribe and follow your journey here.

[@retromechanicalengineer]

Thanks very much and welcome to the channel. I have a D7 which is almost finished and the makings of a D5/D10 project. Hope you enjoy the journey. Best wishes, Dean.

[@montana2strokeracer]

This is some fine machine work, am enjoying this and will be watching you complete the modifications.

[@retromechanicalengineer]

Thanks Dale, it's a project I've wanted to try for some time. Best wishes, Dean.

[@InTheShedUK]

Very interesting, I like the idea of reusing the original hub. Already been mentioned but yes my first thought was bolt the basket to a faceplate to remove the raised area.

[@retromechanicalengineer]

Ian, thanks for watching and commenting. It's an interesting project so far. I have a couple of options on tap for machining the back of the clutch, the Faceplate is definitely on the list. Best wishes, Dean.

[@LarryBees]

Enjoyed watching you work.Well explained and very interesting . Looking forward to next part.😃

[@retromechanicalengineer]

Thanks Larry

[@makerepairbin]

Nice to see, adapting things is an art form that has been lost. My motto is if you haven't got one make one. Well done.I would mount it in the 4 jaw again to take away the central lip and a shim plate is a good idea. Depends on thickness of the chain because you may have to lose a few plates from the basket.

[@retromechanicalengineer]

Thanks my friend, I'm hoping to keep the same number of plates but I have to get the chain in and the correct alignment of the sprockets. All good fun!

[@OzBSABantams]

Yes it's a well known mod in Bantam circles Dean, but I'm yet to see a practical demonstration of how it's done. I get asked about this by customers and now I know where I can refer them to. Great stuff again and can't wait for Ep 2 of this installment. Given there is very little meat to come off the protrusion on the inside bore, have you thought of a heat shrink of your clutch basket fit to your aluminum test piece, might have to turn another diameter slightly larger and freeze it, then correspondingly heat your clutch basket to achieve the fit. There is very little to come off, therefore no need for deep cuts. Heat your basket up to get it off. The clutch basket is a little bit "lightweight" in areas and I think some of your concerns about clamping against it were justified. Last think you need is to damage it this far through the process. Back to the shed quickly for you we want to see the end result!

[@retromechanicalengineer]

Thanks Bones, that's a really good idea re the shrink fit. It won't take much turning force so that could be a great technique. I'm hoping to get back on it soon, as you know day to day sometimes gets in the way of fun stuff! Best wishes, Dean.

[@mowoggreen7878]

Excellent as usual, pity you had to stop, I was well into it, looking forward to the next one 👍

[@retromechanicalengineer]

Thanks very much, I'm looking forward to progressing it. Lots of problems to solve. Best wishes, Dean.

[@carlwilson1772]

Totally agree.

[@BritanniaMotorcycles]

Excellent. I have been thinking of doing something like this with the four stroke singles. I make enough mistakes as it is so now I can get an idea of how to do it..

[@retromechanicalengineer]

Thanks Michael, much appreciated that you spent some time with me. You'll definitely get an idea of how to make mistakes if you watch me! Best wishes, Dean.

[@anthonytilling3442]

Awesome stuff mate! Keepin me occupied while I'm waitin for delivery of my new shocks for my trials build! Tempted to do this clutch route conversion now!:).

[@retromechanicalengineer]

You're welcome mate. Good luck with the build.

[@oldguysoldbikes]

Very interesting Dean. Love watching your procedures although I'll probably never use them. I am, however, learning some things from your video techniques and editing.

[@retromechanicalengineer]

Hey Jack, thanks for spending time with me. I'm not sure I'm a good example for video making! Best wishes, Dean.

[@MrFactotum]

eyup Dean Interesting conversion, like your new approach, should be a sound job, see you next time atb Kev

[@retromechanicalengineer]

Cheers Kev.

[@A65Rocket]

Many thanks for the nice comment about my Clutch conversion document.

[@retromechanicalengineer]

You are very welcome Andy. It was the starter for ten I needed. Thanks for commenting. Best wishes, Dean.

[@paulhewitt1488]

Extremely interesting and well presented.Thank you , looking forward to the next instalment 👍👍

[@retromechanicalengineer]

Thanks Paul, glad you enjoyed it. Best wishes, Dean.

[@cainbeeping8480]

First

[@retromechanicalengineer]

I can always rely on you Cain.

[@carlwilson1772]

@@retromechanicalengineer Where would we be without him? At least I know I'll always get one view!

[@AGEngineering]

Started watching, have to pause for work unfortunately 😢

[@retromechanicalengineer]

Just about to start that lark myself Ade. It gets in the way of the fun stuff.

[@jamescornflake1542]

Is there a kit for a 1951 D1? Please.

[@retromechanicalengineer]

@@jamescornflake1542 I did this as a one off. I have considered introducing a kit, but at the moment I don't have the time to commit to it. Send me an email and I'll let you know if I make it happen. Best wishes, Dean.

[@cedley1969]

Wouldn't it have been easier to fit an mz clutch as they were dkw based as well?

[@retromechanicalengineer]

The Yamaha clutch is well proven in competitive Bantams. Other clutches may well also fit. I've had a number of MZs and Simsons, but I don't remember them being so similar to the Bantam. Memory is subjective, especially as you age!The main problem is availability, you don't want to fit something to a competition machine that isn't easily sourced. The Yamaha clutch is abundant and cheap to buy. Best wishes, Dean. PS - When BSA used the DKW as a base, they converted all of the metric dimensions to imperial. I think you would have the same issue with the metric MZ parts, you would need to transpose the imperial spline sizes into it. You've got me thinking that I want to see an MZ clutch again though!!