Creating my own motorcycle scratch
- Old England
- Posts: 120
- Joined: Thu Oct 05, 2006 1:44 pm
- Location: Bath, UK
Creating my own motorcycle scratch
A few folks have mentioned the idea of building there own vintage style racing motorcycle, possibly using the internals of some modern engine to speed the project along. I did this between 2012 - 2016 working in my home shop evenings and weekends.
I posted a couple of photos in another thread, I wondered if members would be interested in the retrospective build log so to speak?
I'll make a start and if it's not suitable or appropriate please let me know!
Shop machines are a heavy duty varispeed 40INT turret mill of 1970's vintage with DRO and Deckel FP1 clone from 1938 with DRO. Lathes are Bulgarian ZMM and a Myford ML7.
I had built sprint racing motorcyles for my wife, son and daughter over many years in the usual way by buying some old bike and modifying/tuning. At the end of the 2011 racing season my wife said why don't you build yourself a bike at last? Little did either of us know where this would lead! Books were purchased, museums visited and ideas roughed out. I settled on the late 1920's and the bikes that raced at the famous Brooklands Circuit in England, mine would not be a copy but in the spirit of bikes that raced at the track at that time.
I decided on a Kawasaki KLR800 as the donor engine as this had the longest stroke available, combined with a Velocette piston I'd have a long stroke 500cc single.
An engine was bought on eBay but my plans were thrown into disarray when it turned out to be the 750 version with shorter stroke. Unfortunately my Father passed away at this point and by the time things were back on track it was to late to return the engine. Never mind onwards and upwards!
With the crank out I was able to get to work in Turbocad and soon 3 billets of 6082T6 were ordered, these would be the crankcase halves and timing cover.
First up carving out the inside of the crankcases, that was the easy bit! Next profiling the outside of the driveside case, by this time there was a lot of swarf, and much more to come!
OK there you go the first instalment, hope this is of interest and inspires someone else to have a go.
I posted a couple of photos in another thread, I wondered if members would be interested in the retrospective build log so to speak?
I'll make a start and if it's not suitable or appropriate please let me know!
Shop machines are a heavy duty varispeed 40INT turret mill of 1970's vintage with DRO and Deckel FP1 clone from 1938 with DRO. Lathes are Bulgarian ZMM and a Myford ML7.
I had built sprint racing motorcyles for my wife, son and daughter over many years in the usual way by buying some old bike and modifying/tuning. At the end of the 2011 racing season my wife said why don't you build yourself a bike at last? Little did either of us know where this would lead! Books were purchased, museums visited and ideas roughed out. I settled on the late 1920's and the bikes that raced at the famous Brooklands Circuit in England, mine would not be a copy but in the spirit of bikes that raced at the track at that time.
I decided on a Kawasaki KLR800 as the donor engine as this had the longest stroke available, combined with a Velocette piston I'd have a long stroke 500cc single.
An engine was bought on eBay but my plans were thrown into disarray when it turned out to be the 750 version with shorter stroke. Unfortunately my Father passed away at this point and by the time things were back on track it was to late to return the engine. Never mind onwards and upwards!
With the crank out I was able to get to work in Turbocad and soon 3 billets of 6082T6 were ordered, these would be the crankcase halves and timing cover.
First up carving out the inside of the crankcases, that was the easy bit! Next profiling the outside of the driveside case, by this time there was a lot of swarf, and much more to come!
OK there you go the first instalment, hope this is of interest and inspires someone else to have a go.
- Attachments
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- crank.jpg (92.75 KiB) Viewed 3807 times
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- billets.jpg (79.01 KiB) Viewed 3807 times
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- first_step.jpg (68.41 KiB) Viewed 3807 times
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- outside.jpg (130.69 KiB) Viewed 3807 times
Re: Creating my own motorcycle scratch
Very pretty work!
Sorry to read of your father's passing.
H
Sorry to read of your father's passing.
H
Wise people talk because they have something to say. Fools talk because they have to say something.
Re: Creating my own motorcycle scratch
Yes, please continue. you do fine work.
- Old England
- Posts: 120
- Joined: Thu Oct 05, 2006 1:44 pm
- Location: Bath, UK
- Old England
- Posts: 120
- Joined: Thu Oct 05, 2006 1:44 pm
- Location: Bath, UK
Re: Creating my own motorcycle scratch
Yes, indeedy! That was a lot of hogging. You could almost make another case half out of the swarf.Old England wrote: ↑Thu Mar 30, 2023 2:34 pmFirst up carving out the inside of the crankcases, that was the easy bit! Next profiling the outside of the driveside case, by this time there was a lot of swarf, and much more to come!
Those cases look great. Keep posting. I want to see how this engine turned out.
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Music isn’t at all difficult. All you gotta do is play the right notes at the right time!
Music isn’t at all difficult. All you gotta do is play the right notes at the right time!
- Old England
- Posts: 120
- Joined: Thu Oct 05, 2006 1:44 pm
- Location: Bath, UK
Re: Creating my own motorcycle scratch
A lot of time went into profiling the outside of the timing side crankcase half, in the first photo you can see detail emerging, I love working in billet like this, finding what lies within I found with a bit of planning I could use the cylinder studs from the KLR750 which was handy as they are high tensile with rolled threads, one is visible in the photos.
Second photo shows an intermediate stage in carving the webs on the case around the timing gear housing. Photo three on my Alexander Master Toolmaker mill, with it's compound table and swivelling head it allowed me to profile the radial webs.
Second photo shows an intermediate stage in carving the webs on the case around the timing gear housing. Photo three on my Alexander Master Toolmaker mill, with it's compound table and swivelling head it allowed me to profile the radial webs.
- Attachments
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- roughing.jpg (85.48 KiB) Viewed 3758 times
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- ribs_2.jpg (130.76 KiB) Viewed 3758 times
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- ribs.jpg (84.45 KiB) Viewed 3758 times
Re: Creating my own motorcycle scratch
I like how you’ve taken the time to relieve excess material around the gasket faces. Gives it more of a factory look.
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Music isn’t at all difficult. All you gotta do is play the right notes at the right time!
Music isn’t at all difficult. All you gotta do is play the right notes at the right time!
- Old England
- Posts: 120
- Joined: Thu Oct 05, 2006 1:44 pm
- Location: Bath, UK
Re: Creating my own motorcycle scratch
When the cylinder billet arrived it looked pretty massive as the diameter had to incorporating the base flange, but at least it was mostly a straightforward turning job. By this time the crankcases were finished as regards machining and I admit to twirling the crankshaft quite a few times After boring and turning the OD of the fins the base flange was milled and then it was on to cutting the fins followed by pressing in the commercial cast iron liner. This liner was fitted and honed by an expert in Bristol who has done all my cylinder boring, honing and crankshaft work for many years.
I fitted a piston from a Yamaha SR500 and things were starting to look promising. However the next step was many tedious hours with needle files, Dremel, abrasive paper and finally bead blasting to give an impression of castings. In the final photo of this group you can see the result and the timing cover taking shape. At this stage I wasn't sure what ignition I was using so the face of the timing cover was left blank.
I fitted a piston from a Yamaha SR500 and things were starting to look promising. However the next step was many tedious hours with needle files, Dremel, abrasive paper and finally bead blasting to give an impression of castings. In the final photo of this group you can see the result and the timing cover taking shape. At this stage I wasn't sure what ignition I was using so the face of the timing cover was left blank.
- Attachments
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- cyl1.jpg (88.05 KiB) Viewed 3705 times
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- base_flange.jpg (155.89 KiB) Viewed 3705 times
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- cyl2.jpg (124.55 KiB) Viewed 3705 times
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- cyl3.jpg (81.91 KiB) Viewed 3705 times
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- timing_cover.jpg (79.56 KiB) Viewed 3705 times
Re: Creating my own motorcycle scratch
Respect!
RussN
RussN
Re: Creating my own motorcycle scratch
Indeed!
I have been engaged in similar work in the distant past. So many opportunities to make mistakes!
H
Wise people talk because they have something to say. Fools talk because they have to say something.
- Old England
- Posts: 120
- Joined: Thu Oct 05, 2006 1:44 pm
- Location: Bath, UK