Author Topic: CR750 project New Zealand  (Read 2585 times)

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Offline 750deepsouth

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Re: CR750 project New Zealand
« Reply #25 on: March 13, 2019, 10:48:11 pm »
Hi I received, and replied, to your PM
Cheers

Offline 750deepsouth

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Re: CR750 project New Zealand
« Reply #26 on: November 19, 2019, 02:22:52 pm »
I've spent some time recently working on the footrests. I had replica footrests for some time, but I didn't want to strip the bike back enough to weld the brackets to the frame. This is the easier solution. I'm also fitting a cable to the rear brake, rather than the modified solid rod. All this work also means removing the existing muffler brackets and making up new ones. This project brings the rear end of the bike more in line with the look of the original CR's (and slightly lowers the footrests). I was having trouble bending my legs to get my feet on them - a problem with ageing  ::) I'll put up some more photos when this work is completed.

PS: Added image of previous footrest/brake
PPS: photo, brake pedal fitted
« Last Edit: November 24, 2019, 04:34:44 pm by 750deepsouth »

Offline 750deepsouth

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Re: CR750 project New Zealand
« Reply #27 on: November 25, 2019, 04:43:25 pm »
Another shot of the changes

Offline 750deepsouth

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Slow progress, Bimota Honda
« Reply #28 on: December 05, 2019, 05:18:41 pm »
Making slow progress but it's slowly coming together. Making up brackets to hold the pipes. A hiccup - that brake pedal, because the way it is shaped, it won't fit. Now the pivot point is a little tighter in, perhaps 2cm, it touches the top megga. Lot's of type of pedals on Ebay though and getting one sent.
I also recently visited the Motorcycle Mecca https://www.transportworld.co.nz/motorcycle-mecca here in Invercargill. There are not a lot of Japanese bikes, but here's a Bimoto 750 SOHC four.
« Last Edit: December 05, 2019, 05:23:27 pm by 750deepsouth »

Offline Sam Green Racing

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Re: CR750 project New Zealand
« Reply #29 on: December 06, 2019, 03:47:20 pm »
Have you checked the BOTM thread Andy, your CR cake walked it.

Sam. ;)
C95 sprint bike.
CB95 hybrid race bike
CB95 race bike
CB92
RS 175. sprint/land speed bike
JMR Racing CB750A street ET drag bike

Offline 750deepsouth

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Re: CR750 project New Zealand
« Reply #30 on: December 07, 2019, 10:20:11 pm »
I'm amazed, because the standard of the other entries is very high! So many people doing great things with their machines....!!!
Hope you are weathering the weather,
Andy

Offline 750deepsouth

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Update, rear brake, brake plate
« Reply #31 on: January 23, 2020, 09:56:15 pm »
Slow progress, but getting there. To start, I've had to find another brake lever with a shape that doesn't arc down then up, like the one in the photo posted in Nov last year, which touches the top exhaust megga and doesn't allow enough room for adjustment.

I also decided to have a go at converting a 1965 CB160 rear brake plate, which has a cable mount. The two plates are pictured, the drum size is the same at 180mm.

It will need drilled out to 20mm to fit the 750 rear axle. The inner plate for both 750 and 160 fits against the wheel bearing, and the width to the outer on the 750 is 45mm. The 160 is narrower, only 28mm. So another spacer 17mm will need to fit to bring it up to 750 specs.

The inner 'shrouding' on the 750 plate is fractionally greater diameter than the 750's inner hub, at 71mm. On the 160 it's only 59mm in diameter so the entire shroud needs to be milled out to approx 72mm, and just deep enough to allow the inner brake plate, where it is slightly raised, to sit against the wheel bearing. That is, a slightly raised section where the axle fits through.

Finally, there is a double 'flange' around the outside of the 160's plate. To get it to fit snug, the inside part of this flange needs to be milled down 1-2mm for it's entire circumference.

All this should work. I'll let you know !
« Last Edit: January 25, 2020, 10:31:27 pm by 750deepsouth »

Offline Rocketman

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Re: CR750 project New Zealand
« Reply #32 on: January 25, 2020, 06:46:47 am »
Really like your CR750 replica.  A cable operated rear brake is a nice detail.  Thanks for sharing your build.

Offline Sam Green Racing

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Re: CR750 project New Zealand
« Reply #33 on: January 25, 2020, 08:22:22 am »
Andy, I wish I could help but I can't.
I've looked for pics of the one I built but this is the best I could find.
The brake peddle was a copy of an original and the rear brake was a CB160 like the one you have but the guy who did all the mods for the frame, he also did the mods for the brake and supplied the brake peddle.
Here's the best picture I have.

C95 sprint bike.
CB95 hybrid race bike
CB95 race bike
CB92
RS 175. sprint/land speed bike
JMR Racing CB750A street ET drag bike

Offline 750deepsouth

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Re: CR750 project New Zealand
« Reply #34 on: January 26, 2020, 12:54:31 am »
Thanks guys.
Sam, thanks for the pic. I'm fairly sure I'm on the right track. I think I'll also be able to fit the standard CB750 shoes into this. The CB160 shoes and brake drum are slightly narrower by about 5mm or so but there will be space to fit a slightly wider shoe.

Another small thing is the little 'cam' that actuates the shoes. Its the same size on both bikes, but the shaft on the 160 is 12.5mm, but on the 750 it's a bit over 14mm. So you can't just swap over the brake arm. The parts I bought didn't have the brake arm and I've had to purchase a NOS CB160 brake arm to fit  >:( And all the moving parts were quite well seized up. That's not a biggie of course, not uncommon to find issues with parts >50yrs old. Nothing that an hour of CRC and gentle working to and fro to get it free and apart.

I'm hoping to have it all set up in inside the next 2-3 weeks, and I'll post when completed.
« Last Edit: January 26, 2020, 02:14:55 pm by 750deepsouth »

Offline Sam Green Racing

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Re: CR750 project New Zealand
« Reply #35 on: January 26, 2020, 04:09:42 am »
 ;)
C95 sprint bike.
CB95 hybrid race bike
CB95 race bike
CB92
RS 175. sprint/land speed bike
JMR Racing CB750A street ET drag bike

Offline 750deepsouth

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Re: Update, rear brake, brake plate
« Reply #36 on: January 30, 2020, 04:39:12 pm »
The inner 'shrouding' on the 750 plate is fractionally greater diameter than the 750's inner hub, at 71mm. On the 160 it's only 59mm in diameter so the entire shroud needs to be milled out to approx 72mm, and just deep enough to allow the inner brake plate, where it is slightly raised, to sit against the wheel bearing. That is, a slightly raised section where the axle fits through.

We are now thinking of making a steel insert to fit into this hub, outer diameter 72mm, inner 20mm, then milling out enough to fit this larger insert. This makes inner part of the CB160 plate more like the 750, and keeps it stronger and deals with the extra spacing at the same time. More $$  :-[ of course, but trying to do this properly. Photos in due course.

Offline 750deepsouth

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Rear brake update
« Reply #37 on: March 01, 2020, 05:59:30 pm »
Well, the machinist spent a few weeks thinking about this modification then pulled the pin. From a liability point of view, he didn't want his firm to be responsible for anything should an accident occur down the track.

So I've done it all myself apart from drilling to take the 20mm axle. The rest is just the original work I first envisaged. No inserts, nothing, and looks strong enough to me. It sits in there with no binding anywhere at all so I have fingers crossed that it is all Ok. It should be.

Finally there is an image of FEDEX tracking for road trip the CB160 brake plate took across the USA to Portland, from whence it was shipped to New Zealand  :)

IPs I've just edited in that last photo to make is clear exactly what to cut away on the inside.


« Last Edit: March 01, 2020, 07:12:44 pm by 750deepsouth »

Offline 750deepsouth

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More pictures.....
« Reply #38 on: March 01, 2020, 09:34:19 pm »
Before and after....

Offline 750deepsouth

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Change to cable brake on rear complete
« Reply #39 on: May 21, 2020, 08:59:50 pm »
This has taken a long time, what with the events over the last few months putting us in lock-downs: level 4 (go nowhere) back to level 3 (a little activity) and now to level 2 (commercial activity back to 'normal' with social distancing and sanitisation protocols) and we are close to elimination in New Zealand  :-\

Anyway - here is the completed rear cable setup, fitted to the CB160 rear hub, it all works ok. The rear megga's got lost for a week coming back from Auckland where they were ceramic coated (I forgive couriers, who were inundated with work and people bought on-line) and footrest brackets powder coated. All up I'm pretty pleased the way these mods have come together, even though it's been slow progress and well over 6 months.
« Last Edit: May 21, 2020, 10:37:25 pm by 750deepsouth »

 

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