Topic: CB750A Street ET bracket drag bike. A year to build it.

[Bill/BentON Racing]

 Ain't read it all, dealing with major drama. Bit if a chain is still hooked to rear wheel  T/C is spinning if wheel is. Both clutches engage via oil pressure,  no pressure it's disengaged. So if oil pressure loss occurs, clutches shouldn't effect it.  More later. Yes, Sam 5 wonderful years, love you bro,  Bill

[Sam Green Racing]

Thank's Billy, I appreciate it, love you 2 bro but due to the fact that the crash wiped out my memory, the only details I have of what happened was what you told me and that it was that a fuse blew.
A few weeks back, I found a post on Facebook where people were talking about not being able to tow an Auto with the motor not running and the only way round it was to remove the drive chain.
This got me to thinking what might have gone wrong if I was free wheeling with a dead motor after the fuse blew.
Not fully understanding how the Auto gearbox and clutches worked, I started looking to our Auto Forum where Keith joined me and I found a link to this thread.
Since then, there have been that many people with differing stories of what happened and in particular that the motor was still running that I was starting to doubt myself, did I really hear you say it was a fuse that blew and then I found this post from you in a PM message to Larry which he shared on Facebook a few days after the accident.


Sam Green's Road to Recovery
Published by Larry Romig · 27 June 2014 ·
From our Teammate Bill Benton; roughly 10:30 am EST;
Online Bill/BentON Racing
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Re: Sam Green Recovery Fund
« Reply #163 on: Today at 10:07:43 AM »
Quote
Alright, more good news. Just spoke with Sam! Much, much better! Knows where he's at and how he got there! Jon Weeks your flowers are there and looking good! Way to persevere. Sam is pining for some conversation/ or a visitor. Bring your computer if possible to show him his page etc. He'll probably want to watch video! I told him what I thought happened, fuse blew, he sat up etc. Doesn't remember right now. But did say"it ain't supposed to do that" haha. He's so much better today. Even nurse said so. You want to call PM me , I'll give you contact info. Dusterdude , she agreed on parking, but said there's a deck also. PM me if you want her number, she can probably help you find it. Anna her name, his nurse. Larry calling this afternoon, I'll check in again tonight. He did ask why am I in a hospital in Va. early on. He's on the mend big time, so cool, but still going need $$$$, $800.00 saline IV bags that cost a $1.00 add up! Bill

After watching and listening to the video, it looks like I'm sitting up just after I come back on film after Larry zoomed  in and the bike can be heard decelerating before it locked up going past the 8th mile timing trap.
Do you still think the fuse blew ?

Still love you though.  XXXXX  hahaha.

 

[Tintop]

After reading some more about towing automatics, and Sam's comment about having to remove the chain....

An interesting feature in early automatics was they had a 2nd pump that gave the ability to be push started if you could get it up to 25kph.  This rear 2nd pump is no longer used in the multi speed automatics today (they can't be push started).  Be interesting to know if Honda carried this over from cars to the 750A given it used a version of the Civic TC.  If so, then the scenario of the engine dying then restarting (or trying to, and locking the rear wheel) on it's own is possible.

[kmb69]

Ain't read it all, dealing with major drama. Bit if a chain is still hooked to rear wheel  T/C is spinning if wheel is. Both clutches engage via oil pressure,  no pressure it's disengaged. So if oil pressure loss occurs, clutches shouldn't effect it.  More later. Yes, Sam 5 wonderful years, love you bro,  Bill

I just confirmed on the transmission I have open in the shop, the torque converter is NOT FORCED to turn if the rear wheel turns. You can feel some drag in both clutches even though they are both disengaged. When I remove the clutches, you can spin the main shaft and counter shaft in opposite directions easily. A clutch has to be engaged to force a connection between the torque converter and rear wheel. I have an assembled engine out there as well and you can turn the rear sprocket without moving the torque converter no matter what position the shifter is in.

After reading some more about towing automatics, and Sam's comment about having to remove the chain....

An interesting feature in early automatics was they had a 2nd pump that gave the ability to be push started if you could get it up to 25kph.  This rear 2nd pump is no longer used in the multi speed automatics today (they can't be push started).  Be interesting to know if Honda carried this over from cars to the 750A given it used a version of the Civic TC.  If so, then the scenario of the engine dying then restarting (or trying to, and locking the rear wheel) on it's own is possible.

There are 2 pumps in the CB750A - one feeds the mains, rods, and top end - the other feeds the torque converter and transmission. You cannot push start a CB750A no matter how fast you push it. There is apparently quite a bit of misinformation out there.


Mike, please confirm my findings with the automatic you have in your shop. Hold the torque converter stationary and spin the rear sprocket or output shaft.

[underdog]

  Chrysler automatics in the 50's had the pump in back of the trans, and yes, they could be push started. In the early sixties the pump was moved to the front in all the aluminum case models and could not be push started.
  There is nothing in the 750A trans that could lock up the rear wheel,  excepting catastrophic failure and there would be a lot of chunks of evidence for that. I believe the stator fins were narrowed a bit, via Jon Weeks (great mod by the way), but even a failure there, very unlikely to lock up a converter. If it had, that still wouldn't lock up the trans because the default is with the clutches is open. I cannot see a way that it could have been locked in the first and second gear, sort of like a transbrake, either. Engine running or not, would make no difference.
 I have the same left master/rear brake set up as Sam did and I'd rather not tell you how many times I've grabbed the "clutch" to slow and even change gears a couple times. That's just whats in our muscle memory and its how we respond. My 240lbs and 190 tire have prevented the rear wheel from locking up, but Sam is a whole lot lighter and with the narrower tire, I can see how that could happen. Likely the engine died, Sam sat up a bit and grabbed the clutch and around it went. I think Scottly is right. I'm sorry Sam, I know that isn't what you wanted to hear. Hang in there friend!

[MRieck]

Ain't read it all, dealing with major drama. Bit if a chain is still hooked to rear wheel  T/C is spinning if wheel is. Both clutches engage via oil pressure,  no pressure it's disengaged. So if oil pressure loss occurs, clutches shouldn't effect it.  More later. Yes, Sam 5 wonderful years, love you bro,  Bill

I just confirmed on the transmission I have open in the shop, the torque converter is NOT FORCED to turn if the rear wheel turns. You can feel some drag in both clutches even though they are both disengaged. When I remove the clutches, you can spin the main shaft and counter shaft in opposite directions easily. A clutch has to be engaged to force a connection between the torque converter and rear wheel. I have an assembled engine out there as well and you can turn the rear sprocket without moving the torque converter no matter what position the shifter is in.

After reading some more about towing automatics, and Sam's comment about having to remove the chain....

An interesting feature in early automatics was they had a 2nd pump that gave the ability to be push started if you could get it up to 25kph.  This rear 2nd pump is no longer used in the multi speed automatics today (they can't be push started).  Be interesting to know if Honda carried this over from cars to the 750A given it used a version of the Civic TC.  If so, then the scenario of the engine dying then restarting (or trying to, and locking the rear wheel) on it's own is possible.

There are 2 pumps in the CB750A - one feeds the mains, rods, and top end - the other feeds the torque converter and transmission. You cannot push start a CB750A no matter how fast you push it. There is apparently quite a bit of misinformation out there.


Mike, please confirm my findings with the automatic you have in your shop. Hold the torque converter stationary and spin the rear sprocket or output shaft.

Output shaft will turn with the torque convertor held stationary. There is a good amount of drag but the shaft will turn.

[Bill/BentON Racing]

I didn't say you couldn't hold. I stated that it will spin or turn when the front sprocket turns....at least Sam's did. I never tried to hold it, just noticed it always spun if rear wheel did. Also, when I got to it, main fuse was blown, f brake light switch wire came off or wasn't put back on......metal end caught the fork tube,  had bike running 30 minutes later.

[kmb69]

I didn't say you couldn't hold. I stated that it will spin or turn when the front sprocket turns....at least Sam's did. I never tried to hold it, just noticed it always spun if rear wheel did. Also, when I got to it, main fuse was blown, f brake light switch wire came off or wasn't put back on......metal end caught the fork tube,  had bike running 30 minutes later.

I sure as hell don't know what happened. I was working off second hand info about the engine running. Sammie sat up for some reason.

Regarding the T/C turning, my point is it will not force the engine to turn. You can certainly feel the drag of the clutches as Mike said.

[Bill/BentON Racing]

Oh yes lots of drag but you're right,  no turning of engine.

[POPS 911]

On my 1981 CM 400cc Hondamatic when I go over [ 7200RPMS ] the built in rev-limiter on this bikes motor turns off motor and you coast until the motor come back on in the run, first time it happen to me at night race I though the motor broke = but I stayed down with the throttle open an coasted for a short time and BANG THE MOTOR came back to life and I finished the pass. Turn shift light back to 70000 rpms and also shift into D when the RED light shines in my eyes. Could the CB750A have the same built in REV-LIMITER that shuts down the motor and coast as a CM400A Hondamatic ??  Made hundreds of passes on the TURTLE and it happen twice = over reving late on the shift light.

POPS BK911 NHRA

[MRieck]

On my 1981 CM 400cc Hondamatic when I go over [ 7200RPMS ] the built in rev-limiter on this bikes motor turns off motor and you coast until the motor come back on in the run, first time it happen to me at night race I though the motor broke = but I stayed down with the throttle open an coasted for a short time and BANG THE MOTOR came back to life and I finished the pass. Turn shift light back to 70000 rpms and also shift into D when the RED light shines in my eyes. Could the CB750A have the same built in REV-LIMITER that shuts down the motor and coast as a CM400A Hondamatic ??  Made hundreds of passes on the TURTLE and it happen twice = over reving late on the shift light.

POPS BK911 NHRA

No rev limiter built into the bike Pops. Sam was running a Dyna 2000 with limit about 10,500 or so.

[madmtnmotors]

Turn shift light back to 70000 rpms

Seventy thousand rpms?    Have you been hanging out with JWilde?   

[madmtnmotors]

On my 1981 CM 400cc Hondamatic when I go over [ 7200RPMS ] the built in rev-limiter on this bikes motor turns off motor and you coast until the motor come back on in the run, first time it happen to me at night race I though the motor broke = but I stayed down with the throttle open an coasted for a short time and BANG THE MOTOR came back to life and I finished the pass. Turn shift light back to 70000 rpms and also shift into D when the RED light shines in my eyes. Could the CB750A have the same built in REV-LIMITER that shuts down the motor and coast as a CM400A Hondamatic ??  Made hundreds of passes on the TURTLE and it happen twice = over reving late on the shift light.

POPS BK911 NHRA

No rev limiter built into the bike Pops. Sam was running a Dyna 2000 with limit about 10,500 or so.

Good thing you didn't injure your typing shoulder! 

[scottly]

  Chrysler automatics in the 50's had the pump in back of the trans, and yes, they could be push started. In the early sixties the pump was moved to the front in all the aluminum case models and could not be push started.
 

Actually, Chrysler auto's had rear pumps at least as late as 1965, and possibly until '67-68? I know the '69 did not have a rear pump.
Even with no rear pump, if the engine dies at a high enough RPM, there will be enough hydraulic coupling in the torque converter to keep the crankshaft spinning, providing compression braking same as with a clutch bike, until the RPMs drop below the TC's coupling/engine drag threshold.

[POPS 911]

WIBUR : At our past last weekend Halloween Hoot 3 days weekend they ran all bikes in one class on the 1/8 mile....... so I ran in low ( L ) THE WHOLE WAY at 7400 rpms and was waiting on the built in kill, but no shut off or blown up  (OLD TURTLE WAS SCREAMING RED SHIFT LIGHT GLOWING ) ...... got to the final 3 and the rains came and we split the money three ways. PS. You going to Valdosta ?

POPS BK911

[madmtnmotors]

WIBUR : At our past last weekend Halloween Hoot 3 days weekend they ran all bikes in one class on the 1/8 mile....... so I ran in low ( L ) THE WHOLE WAY at 7400 rpms and was waiting on the built in kill, but no shut off or blown up  (OLD TURTLE WAS SCREAMING RED SHIFT LIGHT GLOWING ) ...... got to the final 3 and the rains came and we split the money three ways. PS. You going to Valdosta ?

POPS BK911

Sounds like a hoot! 

Definitely looking forward to Valdosta. Were you planning on coming down? It would be good to see you. 

[dragracer]

WIBUR : At our past last weekend Halloween Hoot 3 days weekend they ran all bikes in one class on the 1/8 mile....... so I ran in low ( L ) THE WHOLE WAY at 7400 rpms and was waiting on the built in kill, but no shut off or blown up  (OLD TURTLE WAS SCREAMING RED SHIFT LIGHT GLOWING ) ...... got to the final 3 and the rains came and we split the money three ways. PS. You going to Valdosta ?

POPS BK911

Sounds like a hoot! 

Definitely looking forward to Valdosta. Were you planning on coming down? It would be good to see you. 

Maybe he'll bring us some clown hats and shoes this time. How about it Pops? Lol

[POPS 911]

I would bring that $500 cash for the winner in ST/ET on a SOHC 750 HONDA ........ I know BUSA racers would love to run for a extra $500 in ST/ET, but I will be looking at a HONDA BLACKBIRD to buy all set up and many times winner in my neck of the woods to ride for my 75 years old birthday present. Hard for me to give up the matic but I got a rider for the TURTLE he weighs 101 lbs.

POPS BK911

[Jerry Rxman Griffin aka MuthaF'er]

Nice birthday present Pops.

[ivanhoew]

RE the auto oil pump ,and the engine stopping .

 I don't know if this is of any use , but i will pop it up anyway .

way back in 93 i was drag racing my 72 tvr ,3.5 litre twin compound turbo. as a gearbox i was using a ford c4 with manual valve body mods .to drive it ,instead of a torque converter i was using a 11 " mcload clutch . i made a driven shaft ,and the oil pump drive no the lathe .

this gave me the ability to come of the line with the clutch ,then change gear with foot flat on the floor .

i found myelf racing a big block ford pickup on slicks , ( i was on treads) and we set off together , neck and neck  up the track ... i thought hhm , i will just turn the water injection flow valve a little see if i pick up a bit , , thinking the valve was a turn and a bit open ...

i then noticed water spraying out of the header tank overflow pipe ,looked at the rev counter ,and it was on zero ...yup the water had shut off completely and the engine had instantly siezed (bending two rods)

the point being that with nothing driving the oil pump of the box ,it had gone into neutral so fast i didn't even notice .


still ran a 12.85 ( but would have been a 12.32  )


regards
robert.

[Sam Green Racing]

RE the auto oil pump ,and the engine stopping .

the point being that with nothing driving the oil pump of the box ,it had gone into neutral so fast i didn't even notice .

regards
robert.

I have just found some info that might explain things but can't post it all now as I've just been invited to go out for a meal and get drunk.

It took me ages to find this thread and this last post that I have (part) quoted ties in nicely with what I have found.
Only posting this to remind me tomorrow to save me looking for the thread again.

Regards, Sam. 

[Medyo Bastos]

Enjoy the drinking tonight Sammy!


Sent from my iPhone using Tapatalk

[Sam Green Racing]

OK guys, before I go any further, let's get one thing straight. The bike can't have been running when I came to a stop.
The fuse was blown and a bike can't start up again without sparks.

Here's what I found yesterday, IT'S HAPPENED TO SOMEONE ELSE.

Luckily for this guy, he was doing 45mph in low gear when his fuse blew and the bike started rolling to a stop with a dead motor.
Something he did find after stopping, the bike had gone into neutral.

For those that don't know, unlike a normal gearbox where neutral is between 1st and 2nd, on the Matic it's at the bottom with up one for 1st and up another one for 2nd. If I was in high gear (2nd) and I've found proof that I was, did it kick down to 1st causing the lock up as both gears are locked in place all the time and it's only the two clutches that determine which gear you are in.
With the motor not running, the oil pump would not be sending oil to the clutches and at some point through lack of pressure, the selector causes a down shift without telling the other clutch to release.

Over to you guys, Sam.

[kmb69]

Don't know if this will really answer the riddle.
Both clutches require oil pressure to be engaged.
Engine quits - both clutches disengage - neutral if you will.

[Sam Green Racing]

But does it Keith. ?