750 roadster re build

Cheesy · Aug 30, 2011

Just a shame the inside looks better than the outside!

Next step will be making some bushes to weld into the cradle for the centre stand (the side stand lug was bent so I cut it off) pivots, drilling some holes for the linkages and and making some caps for the ISO tubes (one was rusted on)

Cheesy · Sep 10, 2011

Havent been able to do too much lately so I sat the motor in the frame for a bit of motivation...

Jeandr · Sep 13, 2011

Nice front end, what is it from? What about the carbs?

Jean

Cheesy · Sep 13, 2011

Jeandr said:
Nice front end, what is it from? What about the carbs?

Jean

Its a Ceriani front end, it came from a Ducati race bike, the taper roller that came with it fitted straight into the commando frame, havent got a top bearing yet so thats just got a plastic bush for the mock up. There is a 5mm spacer above the outer race on the bottom bearing and you can see another 5mm spacer under the bearing, just need to grind a little bit off the stem clamp on the bottom clamp to clear the frame, its a shame the triple clamps were machine with the minimum offset for the castings, the other way and they would have been a perfect fit.

The carbs are not carbs..... Thats a TPS on the bottom. It will go together with a single mikuni and roadholders first though as I still have more bits that I need to collect

Jeandr · Sep 13, 2011

Nice looking things you have there. So you will have fuel injection :?: Will you use one from another bike and adapt it or go from scratch :?:

Looking at the forks, do they have the same offset the stock ones have :?: With less offset, you will get more trail and slower steering (I think)

Jean

Cheesy · Sep 13, 2011

Jeandr said:
Nice looking things you have there. So you will have fuel injection :?: Will you use one from another bike and adapt it or go from scratch :?:

Looking at the forks, do they have the same offset the stock ones have :?: With less offset, you will get more trail and slower steering (I think)

Jean

It will eventually, the throttle bodys are off a triumph triple of some sort, kind of fit but kind of dont.... Ive got a megasquirt ecu but I may change that to another open source design that has a few advantages such as correct track widths and no ground loops and other silly things like that.

The forks have less offset, maybe not such a bad thing on a 750 frame, thats why I did the CAD model in the first place to look at the steering geometry.... hmm could have done that in minutes with a 2d sketch and I still havent done it

Cheesy · Oct 16, 2011

Its started to warm up in this part of the world so I laminated my tail piece/seat pan. Unfortunately I had a mishap with the vacuum pump (it broke) but luckily the glass stayed pretty well put on the plug.

Bag off, peel ply still in place

Peel ply removed

Off the plug with the rough edge trimmed, this will still be thinned down a bit towards the back to match the tail light lens, it sits further forward than a real on as well.

Ive still got to make something for the underside/mudguard, I might also make a separate small seat pan to bond the foam and cover to that will clip into the main seat. If the original tail pieces were anything like the fuel tanks this will be a lot lighter.

Cheesy · Dec 18, 2011

Ive got a bit more done on my seat, it is sanded and ready for primer on the top, the underside has the foam blocks glued in place, once these are shaped to fit nicely over the frame rails and clear the mudguard/wheel they will be glassed over and the whole thing painted. I still need to put a couple of brackets on to hold it to the frame at the shock bolt mounts and I will use rubber straps to hold it at the foam blocks.

The actual seat pan is made as well, this was just molded over the base with some bits of cardboard as spacers so there is clearance for the cover

T95 · Dec 19, 2011

Cheesy said:
Ive got a bit more done on my seat, it is sanded and ready for primer on the top, the underside has the foam blocks glued in place, once these are shaped to fit nicely over the frame rails and clear the mudguard/wheel they will be glassed over and the whole thing painted. I still need to put a couple of brackets on to hold it to the frame at the shock bolt mounts and I will use rubber straps to hold it at the foam blocks.

The actual seat pan is made as well, this was just molded over the base with some bits of cardboard as spacers so there is clearance for the cover

Cheesy,
Thats some really nice fiberglass work!

Cheesy · Dec 19, 2011

T95 said:
Cheesy said:

Ive got a bit more done on my seat, it is sanded and ready for primer on the top, the underside has the foam blocks glued in place, once these are shaped to fit nicely over the frame rails and clear the mudguard/wheel they will be glassed over and the whole thing painted. I still need to put a couple of brackets on to hold it to the frame at the shock bolt mounts and I will use rubber straps to hold it at the foam blocks.

The actual seat pan is made as well, this was just molded over the base with some bits of cardboard as spacers so there is clearance for the cover

Click to expand...

Cheesy,
Thats some really nice fiberglass work!

Thanks, its actually not too hard to do, although if the vacum pump had of worked it would have been less work and lighter because of less fairing. It should still end up significantly lighter than the roadster seat though. I am using epoxy instead of polyester though, many will say its too expensive and too hard to mix accurately but with the metered pumps its easy and the cost is far out weighed by the ease of use and the lack of smell.... The one thing that did make this easy, well its kind of a missed step really, is using packaging tape (the brown plastic stuff for boxes) to cover every thing you dont want the glue to stick to instead of polishing, applying release agent and polishing again and again. It does take a little bit of effort to put the tape on without wrinkles though, and I would recommend the brown over the clear I had, you can see spots that are not covered! Im not sure if the tape will survive polyester resin though.

Cheesy · Jan 7, 2012

A little bit more done, nothing of much substance though, a front and back mudguard, the back was just laid up straight over the original steel one (after being covered in packaging tape). For the front one I just cut a couple of pieces or cardboard and taped them to the mount plate to fill up the gap. I almost expected these to not work as it was a quick lazy try, they came up pretty good after just one go at fairing.

Cheesy · Mar 13, 2012

Work and family are making this a slow process at the moment, good thing it is just a toy really!

A bit more glass work:
Tail section and fender mocked up

Underside of tail with frame/fender mounts glassed in

Fender sitting in tail section

I will bond some nuts/tapped plate into the tail section so the fender can be screwed on from underneath once I get some fasteners, I could have done it already but I dont feel quite right about using metric hardware on the Commando.

Now completely off topic but Im sure some of you will be interested in some industrial machinery....

A spring making machine:

And a close up of part of it:

A bolt head upsetting machine:

Thread rolling:

cjandme · Mar 13, 2012

I'm loving your build thread Cheesy, keep up the good work- top notch stuff, even if you think it's only so so, great craftsmanship! The fiberglass, the crack repair, the reamed out mounting holes etc... thanks for the post and pictures. not a fan of the black wrinkle finish paint job on the engine cases, had a Honda SOHC 750 with it and found it difficult to keep clean/looking good from road grime oil leaks and such. Looking forward to your future posts. Cj

swooshdave · Mar 14, 2012

Cheesy said:
I will bond some nuts/tapped plate into the tail section so the fender can be screwed on from underneath once I get some fasteners, I could have done it already but I dont feel quite right about using metric hardware on the Commando.

I used the dzus fastener from the side cover to attach my seat. Makes for instant removals.

Cheesy · Dec 28, 2012

Well I have got some of the gearbox bits sorted. The bearings were loose in the bores so I drilled tapped and counter sunk for a 5/16 unc countersunk cap screw and then ground a notch in each of the bearing races. The whole lot was then glued in with Devcon.

A new opportunity that has arisen is the end float of the kickstart shaft. Of the two boxes I have the bush sits 1.5mm further in on one shaft allowing first gear to rub on the kick shaft, I dont think this is correct so I put a 1.35mm shim washer between first gear and the kickstart shaft, this gives me about 1.3mm of clearance. I still need to shim the kickstart shaft about 1.39mm to get 5 thou end float

\

Cheesy · Jun 22, 2013

Ive had a little bit of time to get a few more things done:

Modified cradle with Iso installed

Engine and Iso mount bolts/studs and modified Z plates, I welded the spacer on for the ISO bolt and counter bored it, the outside face is counter sunk

I also knocked up a Ludwig style head steady

DogT · Jun 22, 2013

I'm glad to see someone use ludwig's design. Are you going to install the spring?

What was the object of filling in the cradle trans area?

Dave
69S

Cheesy · Jun 23, 2013

DogT said:
I'm glad to see someone use ludwig's design. Are you going to install the spring?

What was the object of filling in the cradle trans area?

Dave
69S

It was partly playing with my new welder, but I also dont think that they were designed to well in the first place, my original cradle had broken and been repaired there previously and the cutouts are pointless once you take a bit out near the ISO tube so the gearbox can be removed without undoing any of the cradle to engine bolts. I also welded in some pieces of key steel where the centre stand hits the bottom edge as well as a couple of bosses on the swing arm spindle tube which are drilled and tapped to help tighten up the spindle.

I will probably use a spring, there is a hole in the bracket for it and I will just make a little plate to bolt the frame on the other side. The design is a wee bit different in that I have two plastic washers on each side of the head steady so there is only plastic on plastic rubbing, the centre washers have a flange that locates in the head steady and the outer washers are tight on the spacer/bolt. I have done the same thing with the ISO washers as well.

Cheesy · Feb 1, 2015

Hmm been a while since I put anything here, truth be told I havent done much either....

This is about where Im at

Ive also been playing with tanks a bit, Im not sure I want to make a composite one and Ive never tried metal shaping.... but I was thinking along the lines of this, unless I come across something else

The wheels are laced, 18" WM3 and WM4s just need to true and tension the back one, everyone has seen nice shiny shouldered Exel rims before

Snorton74 · Feb 2, 2015

Cheesy said:
Hmm been a while since I put anything here, truth be told I havent done much either....

This is about where Im at

Ive also been playing with tanks a bit, Im not sure I want to make a composite one and Ive never tried metal shaping.... but I was thinking along the lines of this, unless I come across something else

The wheels are laced, 18" WM3 and WM4s just need to true and tension the back one, everyone has seen nice shiny shouldered Exel rims before

Looks good! What do we call this model... Fastbackster?

750 roadster re build

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