CR750 replica build

[philward]

I'm saying nothing, 😄 Actually I will, it's excellent, unfortunately it makes mine look like what it is a cheap lookalike! 😄

Me too Mark - but I am only building my CR with a hammer, drill and bench vice! Great build though!

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[royhall]

I'm enjoying this thread as well, can wait for the next exciting episode.  You're probably the only one of us doing anything at the moment.

Ive got plenty on Mike just not Honda. I would put it on here but as its a Triumph special, probably not. And just to add another comment, what a great build well done.

[MarkCR750]

I'm saying nothing, 😄 Actually I will, it's excellent, unfortunately it makes mine look like what it is a cheap lookalike! 😄

Me too Mark - but I am only building my CR with a hammer, drill and bench vice! Great build though!

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That's 2 more tools than I used!😄

[onethumb]

Embarrassed by the quality. Good work.


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[CR21]

Cheers for the comments guys 

Just a quick update on the build. The recent session has now come to an end as I am back to work . I loosely through the rolling chassis back together to get an idea of how the bike is starting to look, some quick images below. Obviously, the forks are sitting high due to the lack of weight...





A starting point for the front dash and fairing bracket:




Pleased with how this footpeg is sitting with the 'correct' bolt:



This HONDA oil cooler may be a good starting point. I will have to re-work the inlet/outlets though to look more standard:




Back to the research and planning for the next building phase,

Cheers
CR21

[CR21]

Tiny update regarding the fuel cap

There is much talk around the CR750 fuel filler cap. Here is my interpretation of the situation around the fuelcaps:

The original three Daytona bikes were fitted with magnesium filler caps, to save weight. Many of the factory CR parts were cast from magnesium. Replica magnesium caps are available, but at a price of 400 

The kit bikes that were available from Honda, supposedly had the same chrome cap as the CB400 CB500 CB550 CB750 SL350 street bikes.

To cut a long and not very interesting story short, the plan is to use a CB750 fuel cap. Luckily the fuel caps and latch are still available from Honda  .

So I had to find a bezel, I placed an advert on the SOHC forum for a rotten/crashed tank that was not worth repairing and came up lucky! I have drawn the bezel up, so may get one machined from stainless or aluminum but I have not decided yet:






This/a replacement bezel will be bonded onto the filler neck of the aluminum tank to replace the Monza cap.

Plans for this weekend: sort out the double disk fitment 

Cheers!
CR21

[philward]

Scott, I'm on the double disc adaptation tomorrow - mines the later fork legs so will be slightly different to the early legs on yours

[CR21]

I'm on the double disc adaptation tomorrow - mines the later fork legs so will be slightly different to the early legs on yours

Nice  How are you dealing with the speedo-drive collar? I was thinking of machining one up to fit when both disks are fitted?

Cheers
CR21

[philward]

I'm going to look at it tomorrow - was speaking to Simon Tappin (just ordered exhausts!) and he made up a spacer - I intend to use some tube as a mock up then have a spacer made - it will be trial and error in conjunction with previously posted guide's

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[CR21]

I'm going to look at it tomorrow - was speaking to Simon Tappin (just ordered exhausts!) and he made up a spacer - I intend to use some tube as a mock up then have a spacer made - it will be trial and error in conjunction with previously posted guide's

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Exciting 

[philward]

Twin discs done! Nothing like the previously posted guide's (worryingly!) - done away with speedo gear and made a spacer to locate replace speedo bits. Main issues that have been previously seen as an issue, lining brake arm parallel to disc which normally requires filing of bottom pivot arm - I had to shim it to get arm parallel! (And shim upper m6 mount's about 5 mm). Both discs are parallel to discs but won't know if all works properly until all hydraulics connected (no where near that point). I'll now have some proper spacers made up from stainless

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[MarkCR750]

Well if the arms are parallel to the discs and the callipers with pads fitted fit and the wheel rotates it should be fine, before I fitted the callipers I put a 12" steel rule edge on across the calliper mounting face on the arms and down across the discs, then measured the gap between the edge of the rule to the disc altering the shims until the gap was parallel across the disc, I had to file the bottom bolt mounting lug on mine, anyway there are bound to be differences between bikes so if it's all parallel sounds like the jobs a good un!.

[philward]

Only minor issue I have is the new pad that goes on the arm side is a lot thicker and pushes the arm out of parallel so I swapped it to the other side and the new pad from the other side is a few mm thinner fitted in the RH side fine and allowed parallel. The LH now binds slightly (pushing arm slightly out of parallel) and so a mate is going to mill the thicker pad down to the same size as the thinner one. The pads are different makes so don't know why they are different thickness'. The pads surface to the red max wear line is smaller on one set.
I'm glad it's not a use everyday bike as its going to be a pain to take the wheel off!

[MarkCR750]

Yes it's annoying having to take the 2 calliper bolts out to remove the calliper every time you need to remove the front wheel, only a problem during build though, I don't think my front wheels been out again for at least 18 months, so barring a puncture it's a small price to pay for brakes that actually work! 😄

[CR21]

Just a quick update:

This will allow me to fit disks to both sides of the hub whilst retaining the speedo drive unit without the need to modify any other parts. The machined part will replace the original two part pressing which can't be used as it locates in an area that the disk.

Designed up in CAD, now to draw and then machine:






Some progress on the replica hinged clip-on parts:





More to come (hopefully) soon!

Cheers
CR21