My CR750 replica

[acruz]

Nap,
Your attention to detail is amazing.  I'm also enjoying your build! Keep it up.

Arnold

[Sgt.Pinback]

Great stuff!
If we don´t comment, we are just speechless.

[Nap Bollemeijer]

The standard generator is far too heavy in terms of weight and delivers more output then necessary which in term hinders performance (magnets and coils create rotational friction).
From another perspective the front profile makes for more wind resistance so another sleeker generator makes sense so does placing it more inside the frame like the RC166 for example.
Honda chose to put a lighter and sleeker generator with less output.

I could buy an original generator in fair shape, don't know if it does work if not I have to rewind the coils but the magnets are still strong.
A few years back I bought an cover which was an unmachined reproduction form a notable CR750 guru. Funny thing is the generator didn't fit when I dry fitted everything.
I don't know if the revised 971 item has different mounting holes or the generator cover I have isn't originally for the CR750 generator.

I also acquired 2 spark plug terminals which are just basically hollow.
The cam point has an advanced spark, I have to look if I can obtain one or CNC mill one with the correct characteristics in the future.

11631-300-970 Cover Dynamo (in my possession unmachined)
30200-300-970 Cam, Point  
30505-300-970 Sub Cord, Coil            
30700-300-970 Terminal Assy. A        
*30710-300-970 Terminal Assy. B  
31100-300-970 A.C. Generator Assy. (not sure if I own this one or the 971 item)
31100-286-971 Generator Assy.      
32100-300-970 Harness, Wire            
35300-300-971 Switch Assy.
98069-60711 Spark Plug *D1OES*        
98069-62410 Spark Plug *D12E*        

(the spring in the 3D model is in its free form, so in this pic it is protruding through the disc were in real life it is compressed)
(the last pic isn't mine but shows how the cover looks mounted, notice the different mounting point of the frame tube which all production racers had)

[hondasan]

Fascinating - keep the information coming please!

Chris R.

[kenhan]

Great Learning!

 

[benjixt]

hello
you can go on this website
the guy maybe can help you
he's owner of an original CR750 from Daytona 70.

http://www.motojlmreplica.com/Francais/ventes.htm

see you
benji

[ashimotok0]

Fascinating Nap and incredible attention to detail ..please see my post in wanted section.

[Nap Bollemeijer]

Thank you all for the kind words, I do know of Daniel Mercier he has some great items indeed.

For the fuel supply there have been some changes as well, most distinctively the massive tank of course.
There were two versions of this tank in 22 or 28 liter capacity as can be seen by the part numbers below.
Both had a "bulge" below which was slightly offset to the left in order to keep clear from the oil cooler line going from the engine to the cooler.

The petrolcock / Fueltap had an enlarged diameter and twin output in order to supply sufficient fuel to the gas gurgling smoothbore carbs.
I own a replica petrol cock and an original Fuel tank band, these same parts were also used on other factory race bikes like the RC166.
The tank I've got was made for me in Germany but I have to make some adjustments to it in order to really fit the bill.
The photo's of the tank are those of a real one not mine, the fuel band and petrol cock are.
Note the smaller and wider tank in the last 2 photo's

*16950-300-970 Cock Assy., Fuel               
*16997-300-970 O RING, 125x35 (I assume the punctuation marks were forgotten it should be 12.5x3.5)               
*17500-300-970 Tank Comp., Fuel (Aluminium fuel tank with a capacity of 28 liters for the sports kit and RSC kit)
17502-300-970 Clip, Fuel Tube               
*17503-300-970 Band, Fuel Tank               
17504-300-970 Sponge, Tank               
17505-300-970 Pad, Fuel Tank               
17600-300-970 Tank Comp., Fuel (Aluminium fuel tank with a capacity of 22 liters for the RSC kit)               

[Nap Bollemeijer]

I posted about the kill switch on the previous page, well I just happened to find one in a general assortment bin of a befriended Honda dealer!
He didn't have a clue as to how he got it or what it was so even after I told him whilst jumping up and down it was still at a bargain price for me.
It needs some TLC and rewiring but that's better then having none at all...  

*35300-300-971 Switch Assy.

The picture is off the CR style switch besides the regular 35150-300-730 (HL and OFF).
There seems to be a 35150-300-620 made for France, perhaps it looks the same as the CR item but I have no way of telling.

[ashimotok0]

Pretty sure you will have this already Nap. But just in case  it's here in my Dropbox (I got it from another site)

https://www.dropbox.com/s/w128vp6hqpxgpyr/HondaCR750partslist.pdf?dl=0

[Nap Bollemeijer]

Thanks, I did have this one as well as some other versions. One just couldn't do without these lists.

[Nap Bollemeijer]

The rear wheel hub is truly a thing of beauty and an enormous one to look at.
As a teacher my funds are somewhat limited which explains why I havent bought a replica of it yet (exceeding 4000,- USD).
But when the bike is finished i could always replace the standard rear wheel when funds are sufficient.

However the smaller parts i can afford and for my collection and just the heck of it I bought some.
The rear brake cables are supplied in 2 different lengths, so you can change the side on which to shift.

41231-300-970 Retainer, Bearing               
42000-300-970 Wheel Assy., Rear               
42100-300-970 Brake Assy., Rear               
42200-300-970 Hub Assy., Rear Brake               
42311-300-970 Collar               
* 42313-300-970 Collar, Side               
42601-300-970 Hub Comp., Rear               
42606-300-970 Spoke A, Rear               
42607-300-970 Spoke B, Rear               
* 42620-300-970 Collar, Distance               
42701-300-970 Rim, Rear Wheel               
43100-300-970 Panel Assy., Rear               
43102-300-970 Washer, Brake Pin               
43120-300-970 Shoe, Rear Brake               
43141-300-970 Cam, Rear Brake               
43151-300-970 Spring, Brake               
43200-300-970 Panel Assy., Rear Brake               
43411-300-970 Arm A, Rear Brake               
43421-300-970 Arm B, Rear Brake               
43451-300-970 Rod, Rear Brake               
43452-300-970 Nut, Brake Rod Lock               
* 43460-300-970 Cable, Rear Brake               
* 43470-300-971 Cable Comp., Rear Brake               
43472-300-970 Spring, Brake Arm Return               
43473-300-970 Pin, Rear Brake      
* 90128-300-970 Bolt, Sprocket   
* 90665-300-970 Circlip, External, 115mm               
            
The complete hub isn't mine, the parts are.

[Nap Bollemeijer]

The steering damper is the next subject of the journey.
Honda used a steering damper for the Daytona bikes which was directly fixed to the frame and steering stem.
In both cases the fixing points were integral of the above mentioned parts, for the kit bikes this wasn't an option.
So for the kit bikes brackets were made available to attach the steering damper to the frame and front fork.

The steering damper itself was a special part but was closely related to the CR93 (CYB72/CYB77 and CL72/CL77).
With some minute differences off course mostly using the same components but a slightly different exterior.

For my bike a bought several CR93/CL72 dampers in different conditions and started to taking the worst apart.
Checking the internals and replacing the fluid (which is a real pain in the @ss to do) to make them better again.
I am still contemplating on welding/reworking the exterior but as these CR93/CL72 dampers are getting rare as well I don't dare screwing one up.

53700-300-970 Damper, Steering
53710-300-970 Bracket A
53720-300-970 Bracket B
53131-268-810 Rubber, Steering Damper

The complete bikes with dampers aren't mine, the mounting eye for the frame side is cylindrical for the CR750.
All the dismantled pics are mine, here you can see the mounting eye being ball shaped.

[Nap Bollemeijer]

I would also like to say a big thanks to ashimotok0 for making it possible to buy some original 970 parts from him!
Its this type of helping each other out within a very specific nice in the CB750 variants and documenting which I like so much in this hobby.

[bojje]

Hi Nap!
If you are going to visit Bikers Classic at Spa 28/6-1/7 it would be interesting to meet you there. Since I have a pure CR750 and also find your work with your CR-replica interesting it might be interesting to have a talk about  R:s. I will be at Spa from 28/6-1/7. You can call my cellphone +46709519040 and let me know if we can have a medting.
Bo from Sweden