Author Topic: The 1970 Daytona CR750s. (Read 269957 times)

voxonda · « **Reply #700 on:** March 06, 2011, 08:32:46 AM »

Just finished a great read from Graeme Crosby, nicknamed the "Croz", he raced for Yoshimura for years in the late 70's and beginning of the 80's, won all great races like Daytona 100, Daytona 200, Imola 200, Suzuka 8hour, Isle of Man etc. He stated that Yoshi was not into nicely prepped bikes, just preppin' for one thing 'winning races'. Quess it worked, also his Honda 750's were seriously faster than the works CR's, although did not stay in one piece.

MRieck · « **Reply #701 on:** March 06, 2011, 08:59:47 AM »

Quote from: voxonda on March 06, 2011, 08:32:46 AM

Just finished a great read from Graeme Crosby, nicknamed the "Croz", he raced for Yoshimura for years in the late 70's and beginning of the 80's, won all great races like Daytona 100, Daytona 200, Imola 200, Suzuka 8hour, Isle of Man etc. He stated that Yoshi was not into nicely prepped bikes, just preppin' for one thing 'winning races'. Quess it worked, also his Honda 750's were seriously faster than the works CR's, although did not stay in one piece.

You are right Rob. Those bikes were purpose built and the purpose wasn't for show.I swear it wasn't until the 90's that Yosh built USA race machines got the "visual treatment". Suzuka stuff always looked great.

Sam Green Racing · « **Reply #702 on:** March 07, 2011, 03:33:11 AM »

Quote from: veloce430 on March 05, 2011, 10:14:30 PM

Well, it's not a Daytona bike, but these are pictures I took at the AMA national at Seattle back in either '71 or '72. Gary Fisher's Yoshimura bikes. Dick Mann was on a BSA that year and the Suzuks were still 500 twins.

Stu

Welcome Stu, the welding along the bottom edge of the tank looks a bit iffy but cool pics all the same, shame it took you nearly 11 months to post.

enjoy your stay with us.

Sam.

kos · « **Reply #703 on:** March 09, 2011, 03:23:49 PM »

Yoshimura stuff when Pop's was working on them was pure awefull. Stick welding, oil leaking all over, parts falling off, even into the Suzuki Superbikes of early 80's they were not good. Fast as hell! but I remember Wes Cooley chasing after Pops in the pits at Daytona 1974 after one of the ex pipes on the Kaw Z1 fell off, Cooley went back, picked it up drove back to the pits and chased Pops all over threatening to to clobber him with it. And did you ever see Pop's in person? The only guy you thought who good catch on fire...he was so dirty! Come to think of it...he did catch on fire in a dyno fire they called it... back in Japan. Boy that guy could build some powerfull engines.

KOS

CPHjimm · « **Reply #704 on:** March 10, 2011, 03:52:09 AM »

Gents,

Another request for your expertise

Brake lines. im not quite sure if I should go with two full lenght hoses or one with a split. if a split where would you recommend it to be?? and how was it done original?

Also. I have used the org. rear hub with a brake cable. but the brake shoe springs aint strong enough to pull the brake pedal back in place... any thoughts? a torsion spting could be fitted but maybe thees another solution.

Thanks

Jimmy

martin426 · « **Reply #705 on:** March 10, 2011, 05:03:28 AM »

I have run both setups Jimmy, and IMHO simple is always better. Two lines straight from the master cylinder.

voxonda · « **Reply #706 on:** March 10, 2011, 05:39:05 AM »

In theory there should not be a noticable difference. The pressure will build up the same, but..... less couplings = less change of leakage.
Just my thoughts.

Rob

CPHjimm · « **Reply #707 on:** March 10, 2011, 11:38:51 AM »

Thanks, I think I'll go with the two hose solution

anyone have an easy idea how to get my cable activated rear brake to back to start position? Harder LS springs? Torsion spring? I cant afford the replica magnesium hub and would like my org hub to look alike-

Thanks
Jimmy

voxonda · « **Reply #708 on:** March 10, 2011, 12:24:01 PM »

I have changed my rear in cable operated this way.

Rob

Ricky_Racer · « **Reply #709 on:** March 10, 2011, 06:43:21 PM »

Hey, Rob. Is there any adjustability in your rear cable setup? I can't tell from the photo. Thanks. RR

voxonda · « **Reply #710 on:** March 10, 2011, 10:53:02 PM »

Hey Ted,

Yes, there is actually two adjust points. One at the actuator arm, and one at the welded on 'stud'(?) Hope this pic clears it.

Cheers Bud,

Rob

CPHjimm · « **Reply #711 on:** March 11, 2011, 04:37:42 AM »

ROb,

Im pretty close to the dame set-up- however, the pedal get back to its posision after being engaged. did you use other springs?

Another thing, I can see on your posted picture that you filled the starter motor hole with a filter?!? do the motor need to "breathe" through this hole, or can I plug it out??

Thanks in advance
Jimmy

voxonda · « **Reply #712 on:** March 11, 2011, 04:41:31 AM »

Jimmy,

I do use a cable with teflon liner in it. Did not use other or extra springs. Made sure pivot point run freely.
I use the starter hole as a extra breather. You can plug it out.

Rob

CPHjimm · « **Reply #713 on:** March 11, 2011, 05:46:52 AM »

Quote from: voxonda on March 11, 2011, 04:41:31 AM

Jimmy,

I do use a cable with teflon liner in it. Did not use other or extra springs. Made sure pivot point run freely.
I use the starter hole as a extra breather. You can plug it out.

Rob

Thanks Rob.
Where did you purchase this cable? any link?

thanks

voxonda · « **Reply #714 on:** March 11, 2011, 07:11:18 AM »

It was (is) a small manufacturer in the northern part of the Netherlands who made (makes) them.

Rob

lordmoonpie · « **Reply #715 on:** March 14, 2011, 01:54:55 AM »

Quote from: CPHjimm on March 11, 2011, 05:46:52 AM

Thanks Rob.
Where did you purchase this cable? any link?

thanks

Hi Jimmy - if you know the cable inner length and outer length plus can describe the nipple you want on the end of it, you can get anything made up by Venhill Engineering here in the UK. A lot of top flight teams use them as their cables are sooooo smooth. My rear brake, tacho and clutch cables are all custom items from them. They have a website too!

CPHjimm · « **Reply #716 on:** March 14, 2011, 03:02:35 PM »

Thanks Simon,

Guess the Suzuki GT brake cable didn't work after all

Hopefully the build will be done late summer...

kos · « **Reply #717 on:** April 04, 2011, 01:15:20 PM »

ONLY FACTORY WORKS BIKES HAD SPECIAL FRAMES, THAT WERE PURPOSE BUILT FROM 4130 CROME MOLY STEEL. THEY HAD STEERING HEADS THAT WERE 50MM LOWER THAN OEM PRODUCTION CB750 STREET MACHINES. NO CR 750 "KIT" FRAMES WERE EVER MADE. THEY ONLY SOLD THE FITTINGS, BRACKETS, ETC THAT CONVERTED STREET OEM FRAMES/BIKES TO CR750 SPECS.

KOS

kos · « **Reply #718 on:** May 12, 2011, 08:31:06 AM »

Here is a picture I have never viewed before. Gives more details of left side, with fairing off. Not sure if it is Dick's bike but for sure one of the 4 Daytona 200 1979 RC750's works machines.

Mark @ m3 racing

Note: also note the large rubber band holding the rear brake cable away from front of oil tank and that it looks like there are no 6mm screws holding down top cam cover? Front tyre does look to be Goodyear that they tried in practice.

MCRider · « **Reply #719 on:** May 12, 2011, 09:35:46 AM »

Dang! Who were they trying to fool with that shift linkage!

I just remembered its shift right, brake left with a cable. Man, why?

Sam Green Racing · « **Reply #720 on:** May 12, 2011, 10:45:53 AM »

In the late 60s, most of the best experienced riders had been brought up on British bikes and had got used to the controls being the oposite way round, so had the Japanese bikes converted to suit their prefference.

Sam

MCRider · « **Reply #721 on:** May 12, 2011, 10:48:15 AM »

Quote from: SamCB750A on May 12, 2011, 10:45:53 AM

In the late 60s, most of the best experienced riders had been brought up on British bikes and had got used to the controls being the oposite way round, so had the Japanese bikes converted to suit their prefference.

Sam

For about 9 months I owned my 67 Bonnie and my new CB750K1 at the same time, so i can sympathize with that experience. I really didn't know they did that to the CR750s though. A lot of work!

Sam Green Racing · « **Reply #722 on:** May 12, 2011, 11:22:15 AM »

Yes, it can be quite dangerous when the controls are not where you're used to finding them.

When I rode the auto drag bike, every time I crossed the finish line my right foot went for the rear brake peddle, It's opperated from the clutch leaver,

I also closed the throttle each time I changed gear when I didn't need to

Sam.

Sam Green Racing · « **Reply #723 on:** May 12, 2011, 01:33:30 PM »

Quote from: kos on May 12, 2011, 08:31:06 AM

Here is a picture I have never viewed before. Gives more details of left side, with fairing off. Not sure if it is Dick's bike but for sure one of the 4 Daytona 200 1979 RC750's works machines.

Mark @ m3 racing

Hi Mark, what make of front tyre is that in the picture? All the pictures that I have of the factory bikes show them to be shod with Dunlop KRs. (all 4)
Wondering if any of them tried diferent tyres, I asked Tommy Robb and mechanic Steve Murray but neither could confirm if they did or not. At 77 and pushing 80,

both said their memories are not what they were and it was 41 years ago after all.

Tommy said he would have been contracted to Dunlop at the time and wouldn't have been able to use any other tyre anyway.
He's going to phone Smithy tomorrow to see if he can remember and get back to me.
I would imagine if it is a Daytona bike, it will probably be Dick Manns as the tyre looks like a Goodyear.

Sam.

scottly · « **Reply #724 on:** May 12, 2011, 06:33:28 PM »

Quote from: kos on May 12, 2011, 08:31:06 AM

Here is a picture I have never viewed before. Gives more details of left side, with fairing off. Not sure if it is Dick's bike but for sure one of the 4 Daytona 200 1979 RC750's works machines.

Mark @ m3 racing

One would think they would have paid more attention to proper shift linkage geometry!!

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Author Topic: The 1970 Daytona CR750s. (Read 269957 times)