Author Topic: The 1970 Daytona CR750s. (Read 267088 times)

ttr400 · « **Reply #450 on:** September 14, 2009, 07:53:25 AM »

Looking for pistons for the CR replica. I can't seem to get into the Dynoman website to look at the kits that he has for sale. any one know if the site is down.
I have found replicas of the original CR750 2 ring pistons, made to order at EUR800.00 for the set with rings,pins etc. but wanted to see the dynoman kits.

His site just won't load for me?

Kevin

ttr400 · « **Reply #451 on:** September 14, 2009, 07:55:34 AM »

Posted a video of one of them little screemers.......in the movie section. check it out.

Kevin

voxonda · « **Reply #452 on:** September 14, 2009, 10:19:08 AM »

Well, that sounds a whole lot better than the tired old original 350.

kos · « **Reply #453 on:** September 14, 2009, 10:41:01 AM »

Who sells those 2 ring CR replica pistons?

Address please...

Mark @ M3

ttr400 · « **Reply #454 on:** September 15, 2009, 11:39:12 AM »

Not sure who makes them, but a friend told me about them in Europe. If I find out I'll post the info.

Anybody have a clear photo of the Cr tach and oil pressure guage.

Thanks

Kevin

voxonda · « **Reply #455 on:** September 15, 2009, 12:04:09 PM »

Hope this helps, cheers mate.

H2Eric · « **Reply #456 on:** September 16, 2009, 05:20:55 AM »

The tacho shown goes way too high for the CR750. The '970' part was made by Nippon Denso, starts at 4000 and goes up to 12000rpm. The oil pressure gauge should be a Smith's instrument with a range from 0 to 160psi. Being new to this forum, if somebody could tell me how to insert / upload pictures I'll post a photo of the correct gauges.

Eric

voxonda · « **Reply #457 on:** September 16, 2009, 05:41:28 AM »

Quote from: H2Eric on September 16, 2009, 05:20:55 AM

The tacho shown goes way too high for the CR750. The '970' part was made by Nippon Denso, starts at 4000 and goes up to 12000rpm. The oil pressure gauge should be a Smith's instrument with a range from 0 to 160psi. Being new to this forum, if somebody could tell me how to insert / upload pictures I'll post a photo of the correct gauges.

Eric

Hey Eric, welcome here! I put my pic on 'photobucket' and copy them. Use the insert image button and paste the link.
Hopethis makes it clear, would like to see the 'real' deal! Know the rev goes way too high, but it is the only pic I have of this setup.

Cheers,

Rob

H2Eric · « **Reply #458 on:** September 18, 2009, 07:58:46 AM »

Hi Rob

Thanks for the techno info, as a result enjoy the pics (hope all the links have worked)

Eric

PS
Before anybody asks, no, they're not for sale.

kos · « **Reply #459 on:** September 21, 2009, 12:01:12 PM »

Nice pics, BUT that oil gauge is not correct, real CR part. real one has chrome ring 'round outside. There is on on the CR750 kit bike... I built for Mr George Barber in Birmingham, Alabama.

KOS

M3 Racing USA

lordmoonpie · « **Reply #460 on:** September 22, 2009, 04:59:22 AM »

Mark's right - and these Smiths 160 psi oil gauges are like rocking horse droppings!

A little trick I learned in securing mine is that the same spec. gauge was used in period Aston Martins (DB4/5?) so you can source them only slightly more easily through the classic car spares/autojumble route, which is where I got mine.

My tacho goes up to 14,000 but is a genuine item. I figure the extra 2K will be good for my motor coz I'm gonna rev it up there naturally

Well - more like I'd rather have a genuine ND 14K gauge than a non-genuine 12k gauge...and once again I have to thank Mark for supplying that, nice one kos!

voxonda · « **Reply #461 on:** September 22, 2009, 05:44:29 AM »

I wonder if there were ever 'kit bikes', which were the same. Could be wrong here, but have seldom seen 2 kit bikes with the same equipment. There were different footrest, maybe the gauges also?

Rob.

ttr400 · « **Reply #462 on:** September 22, 2009, 07:15:06 AM »

Nice article here on rebuilding a CR750.

http://www.ozebook.com/cr7508.htm

He refers to the front tyre size as a KR84 3.00/3.25-18 and the rear as a KR83 3.50-18. can anyone confirm this?
Also refers to the oil pressure gauge as having a chrome bezel and was replaced for the correct black one.?
Another interesting kit part, was a 2.5mm spacer for the R/H disc to correctly space it.

Anyway have a read, lots of info there and pics etc etc.

Kevin

H2Eric · « **Reply #463 on:** September 25, 2009, 03:56:53 AM »

I can assure His Lordship that the picture of the tacho is the genuine article (Part No. 37240-300-970). It's a NOS item and I still have the original Honda box and the shipping ticket from American Honda Motor Co. Inc.
Perusing the internet I've come across a replica of a Smith's tacho (scale 1-12000) that was allegedly fitted to the Honda works bikes (can anybody confirm this), but it has a straight drive as opposed to the 90 deg angle drive of the ND version. Other than that it appears to be very similar if not identical in shape. 525 Australian dollars will buy you one. See www.roadandrace.com.au
I also remember seeing a ND tacho that peaked at 14000 rpm being advertised on e-bay for a CR750 within the last twelve months, but that was actually from a Suzuki. The Suzuki 'S' logo on it being a bit of a give away.

Thanks Mark for the constructive criticism concerning the oil pressure gauge. However, is it possible that the kit bikes had a chrome bezel and the works bikes had a black one?

Cheers
Eric

MRieck · « **Reply #464 on:** September 25, 2009, 05:07:28 AM »

Quote from: voxonda on September 22, 2009, 05:44:29 AM

I wonder if there were ever 'kit bikes', which were the same. Could be wrong here, but have seldom seen 2 kit bikes with the same equipment. There were different footrest, maybe the gauges also?

Rob.

Exactly.

kos · « **Reply #465 on:** September 26, 2009, 07:07:51 PM »

Mike is correct in that no two kit bikes were ever the same. The parts were not sold in KITS! EVER! They were sold by individual part numbers...thus, many dealers ordered what they thought necessary or would work as they would expect for racing purposes. However, having said this, 5 partial sets of parts were sent to the dealers I mentioned, in an earlier post for free, to help support the factory effort.

The other point that I would make here is....THE factory Bikes were not CR 750's they were RC750...meaning FACTORY WORKS bikes, that were not sold to anyone.

In fact the team members that Bob Hansen was in charge of, all had T-shirts that had CB750 on them! Honda of America wanted to promote CB750,s not CR 750's or even RC750's.

The CR designation was taken from the front page, of the parts bulletin that American Honda sent to all of their dealers.

I hope this helps with this continuing interest in these great racing bikes.

KOS

Mark McGrew
M3 Racing USA

H2Eric · « **Reply #466 on:** September 27, 2009, 11:05:44 AM »

Quote from: kos on September 14, 2009, 10:41:01 AM

Who sells those 2 ring CR replica pistons?

Address please...

Mark @ M3

This could be the man, Daniel Mercier
http://daytona70.com/English/Sales/pistons.htm

Regards
Eric

Sam Green Racing · « **Reply #467 on:** September 28, 2009, 06:38:45 PM »

Thanks for posting guys, some really usefull info on this page.

give yourselves a few brownnie points.

Sam.

lordmoonpie · « **Reply #468 on:** September 29, 2009, 04:05:18 AM »

Quote from: H2Eric on September 27, 2009, 11:05:44 AM

Quote from: kos on September 14, 2009, 10:41:01 AM
Who sells those 2 ring CR replica pistons?

Address please...

Mark @ M3

This could be the man, Daniel Mercier
http://daytona70.com/English/Sales/pistons.htm

Regards
Eric

Hmmm, send your money and wait two years....

I had a long discussion with Arai about the twin ring pistons originally supplied as 970 parts as I wanted a modern reproduction of the ones I owned at the time. They came back with a long long list of reasons why you wouldn't want to reproduce them like the kit parts for modern day usage. Aside from the materials improvement and modern metallurgy, they claimed the design was low technology compared to what can be done now.

I guess you have to answer the question as to whether you want an exact replica or the best working replica you can build, after all 100% authentic just means it's 100% authentic not 100% better.

lordmoonpie · « **Reply #469 on:** September 29, 2009, 04:10:26 AM »

Quote from: H2Eric on September 25, 2009, 03:56:53 AM

I can assure His Lordship that the picture of the tacho is the genuine article (Part No. 37240-300-970). It's a NOS item and I still have the original Honda box and the shipping ticket from American Honda Motor Co. Inc.

Hey Eric - so you have an original -970- box....how do you know the contents are original?

bwaller · « **Reply #470 on:** September 29, 2009, 04:19:52 AM »

Tough decision for the purist builders. Although I've never been able to get behind the thought process I understand the exact replica deal in appearance so it will be easily recognizable.

However in my mind what goes on inside an engine would be a different story, use the best materials available now.

voxonda · « **Reply #471 on:** September 29, 2009, 07:11:20 AM »

It is great to find some rare stuff from time to time, but afterall it still is not the real thing. Imho things sometimes get blown out of proportion, the beloved CR, or RC's for that matter, do not exist anymore and won't come back.
There are a lot of people world wide who have build their own version and have a lot of fun with it. Think that is the meaning behind all of this.

Rob.

kos · « **Reply #472 on:** September 29, 2009, 09:08:02 AM »

Not to use the two ring pistons.....

Exactly...those two ring, slipper type pistons were throw back designs from late 1950's early 1960 Honda GP bikes. Remember Dick Mann's bike smoking like a burning tanker ship at Daytona? I do and that was not from the cam chain problems, BUT from those two ring pistons giving up. I have two modern design pistons for AHRMA legal engines (762cc) that I can sell anyone, but who needs to be at the size anyway? There are three kits out there for 836cc and that works well for most hot street bikes and/or track day bikes. Thin rings are the key, along with 3 piece oil rings for complete oil control...unless you are going with high cylinder pressures from turbo/supercharger applications.

And, as for purchasing anything from that French guy who claimed to have the Dick Mann bike....I don't think he actually makes anything...so buyer beware!

KOS

Mark
M3 Racing USA

lordmoonpie · « **Reply #473 on:** September 29, 2009, 12:35:42 PM »

Quote from: kos on September 29, 2009, 09:08:02 AM

Not to use the two ring pistons.....

Exactly...those two ring, slipper type pistons were throw back designs from late 1950's early 1960 Honda GP bikes. Remember Dick Mann's bike smoking like a burning tanker ship at Daytona? I do and that was not from the cam chain problems, BUT from those two ring pistons giving up. I have two modern design pistons for AHRMA legal engines (762cc) that I can sell anyone, but who needs to be at the size anyway? There are three kits out there for 836cc and that works well for most hot street bikes and/or track day bikes. Thin rings are the key, along with 3 piece oil rings for complete oil control...unless you are going with high cylinder pressures from turbo/supercharger applications.

And, as for purchasing anything from that French guy who claimed to have the Dick Mann bike....I don't think he actually makes anything...so buyer beware!

KOS

Mark
M3 Racing USA

LOL! You're dead right Mark and as a result I have a nice set of your pistons in my CR replica

I did look at getting a front fender from Mr Mercier - 500 Euros, 6 months delivery and he wouldn't even paint it, nor would it fit the K0 forks and carriers, so some replica! I went my own way, took me the same six months from scratch but cost me a total of £28 and I have the satisfaction of knowing I made the darn thing.

+1 to that then. Hey Eric - have you got your frame from France yet

Ricky_Racer · « **Reply #474 on:** October 02, 2009, 07:45:17 PM »

Thanks for posting the pic of the 12K CR750 ND tach, Eric. You've just made my day!

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Author Topic: The 1970 Daytona CR750s. (Read 267088 times)