Author Topic: The 1970 Daytona CR750s. (Read 267044 times)

fang · « **Reply #800 on:** February 16, 2013, 09:07:03 AM »

Thread is un-stickied. (is that a word?) Soon this will be lost forever. So sad.

Sam Green Racing · « **Reply #801 on:** February 16, 2013, 10:45:36 AM »

I doubt it Mr Fang, you seemed to have found it easily enough.

There were quite a few threads that were sticky that weren't doing anything so I decided to let a few of them run.
Thanks for noticing.

Sam.

rollo21 · « **Reply #802 on:** February 19, 2013, 07:28:13 AM »

Hi Folks
Finished one CR at last! Started the next one. Hope to finish this year...

Here's a pic of the first one:

voxonda · « **Reply #803 on:** February 19, 2013, 07:58:41 AM »

Very tidy job, rollo21

Sam Green Racing · « **Reply #804 on:** February 19, 2013, 07:59:39 AM »

Welcome 21, it took you long enough to make your first post.

How about some more detailed pictures and specs?
Did I mention how nice it is.

Sam.

lordmoonpie · « **Reply #805 on:** June 15, 2013, 07:23:06 AM »

Sam - I reference this thread a lot and I suspect many others do too but it's getting harder and longer times to find it now it's not sticky. Can we have it back as a sticky please? Surely this thread if any, deserves to be sticky in a HiPo forum? Please, pretty please? 8-)

johno · « **Reply #806 on:** June 15, 2013, 07:01:20 PM »

+1

johno

Greg H · « **Reply #807 on:** June 16, 2013, 01:20:10 AM »

Quote from: rollo21 on February 19, 2013, 07:28:13 AM

Hi Folks
Finished one CR at last! Started the next one. Hope to finish this year... Here's a pic of the first one:

That is stunning It would look good in my garage , complete with a day -time MOT

CrazyRocketMan · « **Reply #808 on:** June 16, 2013, 11:37:23 PM »

lordmoonpie · « **Reply #809 on:** June 17, 2013, 12:21:16 PM »

Thanks Sam, you're a Gent!

johno · « **Reply #810 on:** June 19, 2013, 04:14:40 AM »

echo +1
While your in a good mood Sam !
Lets start working on your fear of black rims

johno

voxonda · « **Reply #811 on:** June 19, 2013, 02:05:40 PM »

http://width=600 height=306]http://sphotos-a.ak.fbcdn.net/hphotos-ak-ash4/999898_470215563054267_1270577645_n.jpg
IMO the best RC of all, the 1973 Morio Sumiya / Steve McLaughlin version. Morio's 6th was as hard fought, if not harder, than the Mann victory. Sorry...............

Interesting is the (crankcase?) ventilation hose connected to the exhaust. Only seen it on NASCAR's. Looks like it is purpose build for lowering the crankcase pressure.

Anyone any thoughts?

Cheers, Rob

Old Scrambler · « **Reply #812 on:** June 19, 2013, 04:56:12 PM »

Cool pic...........and very cool bike/rider.............the crankcase vent to the exhaust is an effort to 'vacuum' the crankcase and relieve internal pressure. My reading on the subject hints at lost oil-mist in dry-sump motors so squirters have been added for lubricating the piston pins. Quite a few NASCAR and LSR motors have electric vacuum pumps set at low levels to maintain constant negative crankcase air.

MRieck · « **Reply #813 on:** June 19, 2013, 06:15:02 PM »

Quote from: Old Scrambler on June 19, 2013, 04:56:12 PM

Cool pic...........and very cool bike/rider.............the crankcase vent to the exhaust is an effort to 'vacuum' the crankcase and relieve internal pressure. My reading on the subject hints at lost oil-mist in dry-sump motors so squirters have been added for lubricating the piston pins. Quite a few NASCAR and LSR motors have electric vacuum pumps set at low levels to maintain constant negative crankcase air.

....and cooling the underside of the crowns like diesels, aircraft and early GSXR's etc???

Sam Green Racing · « **Reply #814 on:** June 20, 2013, 02:09:52 AM »

Quote from: voxonda on June 19, 2013, 02:05:40 PM

IMO the best RC of all, the 1973 Morio Sumiya / Steve McLaughlin version. Morio's 6th was as hard fought, if not harder, than the Mann victory. Sorry...............

Interesting is the (crankcase?) ventilation hose connected to the exhaust. Only seen it on NASCAR's. Looks like it is purpose build for lowering the crankcase pressure.

Anyone any thoughts?

Cheers, Rob

It's funny you should mention Steve McLaughlin Rob, I posted on Facebook yesterday and got a like off Steve, how cool is that.

Sam.

voxonda · « **Reply #815 on:** June 20, 2013, 03:02:34 AM »

Sammy, sammy, you keep on making me smile!

Posted it on FB and directed it to Steve and he came up with an answer to ask Mark (McGrew). Hopefully he'll chime in here.

Love you Sammy!

Cheers, Rob

Sam Green Racing · « **Reply #816 on:** June 20, 2013, 03:10:07 AM »

I figured it would make you smile.

johno · « **Reply #817 on:** June 21, 2013, 04:33:42 AM »

Re the exhaust vac for neg crankcase pressure.
In the 70's I had a go at it on a customers bike. Basically copied the morosso kit on the market at the time.

First meeting just bolted the system on and not much changed.

Second meeting I gas ported the top ring and painted the piston tops with white ( Sam

) exh paint and super fine hone cylinder finishand nothing changed.

I didnt pursue it any more cos the customer was running out of money and I didnt have the guts to run the engine with reduced ring tension to try and pick up the miniscule hp gain from less friction.
johno

Sam Green Racing · « **Reply #818 on:** June 21, 2013, 12:43:40 PM »

Should have tried black paint mate, it's ok on pistons, it just makes it look like carbon.

Sammy black rims.

CrazyRocketMan · « **Reply #819 on:** June 21, 2013, 02:17:54 PM »

Re Johno's white piston tops.

I can picture someone opening that motor up nowadays seeing white piston tops. Better richen this sucker way up! Lucky there's not holes burned in the pistons from running so lean! lol....

johno · « **Reply #820 on:** June 21, 2013, 07:40:18 PM »

If I remember rightly it was early AM on sat morn, had to race sunday , usual thrash around and white was the only colour VHT I had

The reason for the paint I told the customer it would simulate carbon and reduce heat transfer

more power. Grumpy Jenkins does it all the time.
The real reason was I had cut the valve clearance pockets too deep into the piston and I measured the thinnest point at 1mm or .040. I was stressing my guts out thinking they would hole out on the first pass and the only thing I could think of was " hope 4 coats of VHT exhaust paint will stop the heat "
As far as I'm aware the engine is still running today.

bear · « **Reply #821 on:** June 21, 2013, 09:02:42 PM »

Quote from: johno on June 21, 2013, 07:40:18 PM

The real reason was I had cut the valve clearance pockets too deep into the piston and I measured the thinnest point at 1mm or .040. I was stressing my guts out thinking they would hole out on the first pass and the only thing I could think of was " hope 4 coats of VHT exhaust paint will stop the heat "

As far as I'm aware the engine is still running today.

We popped all four on start up. (instant smoke bomb)

Cheers,
Brian

johno · « **Reply #822 on:** June 21, 2013, 09:31:46 PM »

bear

Sam says white paint is the go

dont use black
johno

Sam Green Racing · « **Reply #823 on:** June 24, 2013, 09:18:07 AM »

Daytona CR750s French style.

the language might be a problem if you can't speak french but the pics are in ENGLISH.

http://www.pit-lane.biz/t3460-oldies-honda-750-daytona

Sam.

Carco · « **Reply #824 on:** March 06, 2014, 05:23:54 AM »

For all which have interest a little page with informations about the CB750R kit.
The most is in German language but it should be not a problem.

http://www.tr4-rally.com/histo-cr750.html

Carco

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Author Topic: The 1970 Daytona CR750s. (Read 267044 times)