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Post by donkeychomp on Jul 9, 2021 21:40:01 GMT 1
That'll add 10 bhp instantly Alex
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Post by alankelly on Oct 15, 2021 23:17:33 GMT 1
Hi all As some of you may know my rear drum on the CB400F has developed a crack that renders it either scrap or look to a possible repair. If you know me I alway like to do stuff a bit different so now looking to see what is involved in conversion to a rear disc rather than repair the drum brake using the original wheel hub like I did for the front end twin disc conversion First thing I needed to do was suss out a way of fitting a “disc carrier” that fits the standard hub to see what design was needed. Spent some time modelling up a simple dummy disc carrier unit in 3d so I could then overnight print and then dummy up the build on the bike just to see how it all fitted together and from first dry fit it looks good. This is the 3d printed disc carrier in ABS. And this is how it all fits together on the wheel and bike. The final carrier itself will be machined from a solid aluminium billet and will be designed to lock the carrier in the internal bore so that it is solidly held in place to prevent sideway movement and other features such a extra bosses to lock it in place using some of the internal hub features to prevent possible rotation under braking (and also a oil seal and an extra outrigger bearing to ensure the disc is supported correctly and the bearing is protected from outside crap getting in But for now I am happy with the overall shape and size / distance of the disc from the swing arm and there is plenty of space to add a caliper hanger etc The next stage will be to source a caliper and then design a caliper mount to suit my chosen unit to mount the caliper on the disc and use the original torque arm mount with a new torque arm arrangement Again this will be modelled and printed so I can first test fit my design Then the final stage will be how to convert my rear sets to operate a remote master cylinder Once these three parts of the design are finalised I can then commit to the final parts in aluminium and then fit Will update as thing go Catch up soon Best wishes Al Sent from my iPhone using Tapatalk
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Post by JonW on Oct 15, 2021 23:25:33 GMT 1
superb idea and execution Al, love it!
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CB400/4
Oct 16, 2021 10:34:53 GMT 1
via mobile
Post by midlifecrisisrd on Oct 16, 2021 10:34:53 GMT 1
Absolutely fantastic
Anybody else would have just bought a disc brake hub and had the wheel laced up
Thinking outside the box at its best 👍
Steve
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Post by alankelly on Oct 16, 2021 10:49:30 GMT 1
Absolutely fantastic Anybody else would have just bought a disc brake hub and had the wheel laced up Thinking outside the box at its best 👍 Steve Yes that’s me for you I though about doing that but trouble is that has its own complications such as was first I would need to find a 36 spoke hub. Then as well as rebuilding the wheel I would most likely needed to adjust chain alignment sort out correct wheels bearings and matching sprocket etc This way retains all and for me a easier solution as the wheel can remain as it is and I just add a disc😁😁 Catch up soon Best wishes Al
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CB400/4
Oct 16, 2021 11:04:54 GMT 1
via mobile
Post by midlifecrisisrd on Oct 16, 2021 11:04:54 GMT 1
Finding a 36 hole hub isn't the biggest problem, I've had 5 in the last few years and they are around £200 each 😢
Steve
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Post by alankelly on Oct 16, 2021 11:10:13 GMT 1
Finding a 36 hole hub isn't the biggest problem, I've had 5 in the last few years and they are around £200 each 😢 Steve Ouch😳 I am lucky I can make everything so that part of the project is “free “ and would be a big cost for a project like this☹️ And for the bought in parts (the whole set up including sourcing a suitable disc, caliper, master cylinder and raw material) will be around this figure or just slightly over👍
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CB400/4
Oct 16, 2021 11:14:37 GMT 1
via mobile
Post by midlifecrisisrd on Oct 16, 2021 11:14:37 GMT 1
I tend pick a disc, caliper and matching bracket
The cheap discs on eBay are helpful as a lot give the diameter and offset. You can then pick a matching caliper and mount
Steve
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Post by alankelly on Oct 16, 2021 11:18:21 GMT 1
Hi Steve Got a disc ok and going to use a CB400n disk so it’s a match for the front conversion I did last year Also have a caliper and cylinder in a box in the garage so hopefully that all the bought in parts got
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Post by midlifecrisisrd on Oct 16, 2021 13:44:21 GMT 1
Sounds like a plan 👍
Steve
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Post by donkeychomp on Oct 16, 2021 21:16:47 GMT 1
Superb idea Al!
Alex
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Post by oldbritguy on Oct 16, 2021 21:25:28 GMT 1
That is a neat idea Al. A solution to many cracked drum issues and a brake upgrade into the bargain. The anorak purists would frown but that is a fantastic idea. Have you looked at a similar thing for LC wheels? I know nk do a conversion but yours looks a better option as it is a rear wheel to start with. John
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Post by alankelly on Oct 16, 2021 21:41:51 GMT 1
Hi John Yes they say necessity is the mother of all inventions Yes spoke to Nigel at NK on how he did the disc conversion as just want to know his approach and he uses a front wheel with a bolt on sprocket carrier Cannot do this and wanted to keep the original rear wheel as only just rebuilt it last year ☹️ The idea is sound and just need to spend a bit of time getting the disc carrier right Got the disc mounting design sorted now and now going to add some “dogs” on the other side that locate in the internal cavities of the hub to lock the disc to the wheel and most likely add a “Cush” the fits between the these dogs and hub to remove any final slight movement between the two assemblies as the disc carrier will run on is own on two separate bearing like a second “wheel” but connected to the main wheel hub via this dog drive Lastly bike like I said earlier was never intended to be a original restoration so this disc upgrade should look cool and different from the crowd This is the old girl at the moment and that rear disc system will look a bit different Will update thread as I progress Best wishes Al
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Post by donkeychomp on Oct 16, 2021 22:27:55 GMT 1
I really, really like that bike.
Alex
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Post by alankelly on Oct 19, 2021 20:03:06 GMT 1
I really, really like that bike. Alex Just for you Alex My darling wife took this the other night of my toy under the streetlight without telling me after I got back from a ride out So late 1970,s 😎 Just needs a cafe in the background and a bloke in a black Lewis leathers next to it Fantastic piccy Thank you my darling wife❤️
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Post by alankelly on Oct 19, 2021 20:35:25 GMT 1
OK back to the rear drum disc conversion and like to ask all what they think to my idea Now sorted out out how to control lateral “float” using an out rigger bearing on my disc carrier that is spaced with a sleeve just like a wheel bearing assembly and I will share the final design once I have my pc repaired Now looking on how to lock the disc carrier in place to stop rotational movement relative to the main wheel hub and have come up with this idea I have made four 30mm diameter”dogs” that will located in the four internal pockets of the wheel hub and under braking they will sit against the four cast bosses for the external rear sprocket bonded rubber bushes thus preventing any rotational movement But to ensure there is no “slop” in the system (as there will be clearance in the other direction) my thoughts were to create a set up piece so the dogs are correct positioned like this Then once I am happy I was going to make up some 90 shore polyurethane casting rubber ( like you use for custom engine mounts) and then fill each hub pocket up to the top of the ribs ( just below the original brake drum lining) so the dogs are held firmly in place and you have an inbuilt cush drive And then to finish the assembly the disc carrier simply bolts onto the fixed dogs as shown with my second generation3d printed disc carrier There will be no actual flex of the polyethylene under heavy braking as the dogs are already positioned hard up again the four internal bosses in the right direction direction but this design both solves the disc carrier to wheel hub drive connection and solves the possibility of mechanical backlash Also access to the original wheel bearing is not an issue as you simply remove the disc and then the disc carrier What are people thoughts please? Best wishes Al Sent from my iPhone using Tapatalk
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CB400/4
Oct 19, 2021 21:26:54 GMT 1
Post by donkeychomp on Oct 19, 2021 21:26:54 GMT 1
Very clever idea Al. One query, where are you going to put the caliper mount? Some sort of torsion bar with it on there?
Alex
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Post by alankelly on Oct 19, 2021 21:31:49 GMT 1
Hi Alex Going to design a caliper hanger that uses the wheel spindle as a central mounting point a bit like this one Then hang the caliper at 6oclock and have a torsion bar from the mount back to the original fixed mount on the swing arm like the original drum system used The tricky bit will be modifing my rear sets to operate a small master cylinder
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CB400/4
Oct 19, 2021 22:13:09 GMT 1
Post by donkeychomp on Oct 19, 2021 22:13:09 GMT 1
That's pretty much what I had in mind. What you seem to be doing is building a 400/4 if Honda made one now. Keep up the good work Al!
Alex
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Post by alankelly on Oct 20, 2021 17:49:38 GMT 1
Ok Quick update for those following Correct disc arrive today and bolted it to the revised disc carrier ok All the off sets with the wheel in place look spot on and plenty of clearance for the caliper now I can place it over the disc itself Next job is to turn the disc down to 230mm from the 240mm it currently is so it a match in diameter for a Cagiva motor rear disc (and the pad width then will match the discs face width and then I can start the design of the caliper hanger itself) Once that is sorted will update the thread and then I will commit to finishing the rear wheel with aluminium production parts with the additional seals and bearing etc Catch up again soon Best wishes Al Sent from my iPhone using Tapatalk
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Post by oldbritguy on Oct 20, 2021 20:10:12 GMT 1
This is great Al. Proper problem solving as per most top special builds. Much like Yamark’s triple (and four when done) will look factory when complete. It will only be when some informed admirer is looking it over and says “Hey………😉 Like all adaptations involving brakes a strip down and thorough component inspection will be the order of the day once you have clocked a few miles. But I know you will cover that as par from the course. Top stuff sir, well impressed John
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Post by midlifecrisisrd on Oct 20, 2021 20:14:17 GMT 1
Nice work 😎
Steve
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Post by billbott on Oct 21, 2021 10:43:07 GMT 1
Loving this Alan, keep up the good work.
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Post by alankelly on Oct 21, 2021 13:22:15 GMT 1
Disc sorted[emoji16][emoji16] In the end reduced disc by 14mm to match pad width[emoji106] Sent from my iPhone using Tapatalk
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Post by alankelly on Oct 21, 2021 21:47:04 GMT 1
Bit more of the jigsaw solved and had a go at designing and printing o prototype caliper hanger tonight now my disc diameter is correct It not quite right as need to allow a bit more clearance for the lower section of the swing arm but not too far off either so happy so far Not at work tomorrow so can sort out the changes and print a mk2 version Happy days Best wishes Al Sent from my iPhone using Tapatalk
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CB400/4
Oct 21, 2021 22:05:29 GMT 1
Post by donkeychomp on Oct 21, 2021 22:05:29 GMT 1
Love seeing this stuff. Modern tech to keep an old bike alive. Keep at it mate!
Alex
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Post by alankelly on Oct 26, 2021 19:37:05 GMT 1
Hi all Quick update Now as I have the final design for the disc carrier have bit the bullet and now made my first aluminium part for this disc conversion project[emoji41] Also as you can see for the disc carrier assembly I have added a smaller lip seal seal housing that mounts on the main carrier which both seals the assembly and due the is inner bore being less than the outrigger bearing OD locks the outrigger bearing in its location bore to remove and possible side float [emoji106] Like mentioned the disc carrier is designed with an out rigger bearing to support the outer end. And also the rear of the disc carrier has a bore that locates on the original machined hub boss, And as you can see below there is the required bearing spacer so that you can tighten up the wheel spindle correctly without placing any side loading on any of the three ball bearing assemblies Lastly disc bolts on and a spacer fits in the lip seal to keep any dirt out Then fitted on the bike with an extra dummy 17mm spacer (to represent the caliper hanger thickness) and all looks good and with wheel spindle tight the wheel and disk revolve as planned Lastly finally after a few design changes got the caliper hanger right, that now has the required torque arm fitting, and now ordered two rose joints so I can make up the torque arm to length using the rose joints, a length of m8 studding and a nice alloy tube cut to the correct length to cover up the studding I still have the disc to wheel hub locking part to finish and this is going to be a one piece part rather than four separate posts for strength but the project is making good progress and really happy so far[emoji106] Next big job is to design and print the disc to hub locker and once this is done and both the disc locker and the hanger are in aluminium that’s pretty well the back wheel assembly complete Think that’s all for now Catch up soon Best wishes Al Sent from my iPhone using Tapatalk
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Post by donkeychomp on Oct 26, 2021 21:10:14 GMT 1
Fantastic work Al!
Alex
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Post by billbott on Oct 27, 2021 9:45:10 GMT 1
Great work Alan.
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Post by alankelly on Oct 30, 2021 17:55:21 GMT 1
Got torque arm sorted today And now fitted on Must admit pretty proud of what has been achieved so far and will leave it to you to decide, but looks factory fresh / OEM Still got to fit the disc carrier locker unit which is now designed in my head and the final design of caliper hanger has now being subbed out to a mate. So going to start work out how to modify the rearsets to take a master cylinder as that is really the next thing to be solved Catch up soon Best wishes Al Sent from my iPhone using Tapatalk
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